NATKDNAL AIRCRAm ACCIDENT REPORT pz-9 .,L -- -A.. “ ‘ 1:, ‘.. ,- - .-!1.-- . i Fe 1; c. 7 ‘,,- -!; .-’ 7 -+. :,-:,: -. ‘ .’ I’ * UNITED AIRLINES, INC. M C DONNELL-DOUGLAS, DC-8-61, N8082U PORTLAND, OREGON .. DECEkER 28, 1978 NTSB-AAR-79y7e. _ _ --yp . UNITED STATES GOVERiWENT ’ w - _. _-.---__-- - . ..-- : --___ - NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 Page 15 , Sectic’:: Page 25, 1.16.1, link2 5: c:‘1.3:1gt’ “Cause” to “caust2d .‘I second f u! 1 paragrapll, 1 ir,e 9: to “flir:ht engineer.” UNITED STATES GOVERNMENT c h ,‘. n g e “first office-r” 20594 AiRCRAFT lI:r-.b-:g -- p:.p.\-’ .‘.,:r 2 I*-- ._*’.-+r.. ...I ACCIDENT REPORT Fe’ <. :.;-: - 1:r: : --*::“; -. ..‘, :. z: : . ,~ _.. *_*.;_ .’ UNITED AIRLINES, INC. M C DONNELL-DOUGLAS, DC-8-61, N8082U PORTLAND, OREGON DECEMBER 28,19!8 NTSB-AAR-79-7 . -4c - ._ ,‘/.? * . UNITED STATiSGOVERNMENT ! . -. -_. _--_-- . .- ._-_. -- _ _. .t 1 I I ,. w .YZ- _. .,,_ .- ___-- -..- -.a,.... _.---_ _. _)_ b NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 ERRahTA - ‘-\:? 1 . 1 6 . 1 , line j: Ch2:ll;e "cause" to "caustzd." I’ngc 12, Sectic Page 25, second fu! 1 paragraph, 1ir.e 9: t o “flight e n g i n e e r . ” UNITED STATES GOVERNMENT ChJZ&C “ f i r s t o f f i c e r ” TECHNICAL' REPORT DOCUMENTATION PAGE 3.Recipient’s C a t a l o g NO. 1 .R e p o r t N o . NTSB-BBR-79 - 7 4 . Title and Subtitle Aircraft Accident Report - United Airlines, Inc., McDonnell-Douglas DC-8-61, N8082U, Portland, -5.Report D a t e 7. 1979 rforming Organization Code 8.Performing Organization Report No. 8 9. Performing 1 2.Covernment Accession No. Organization Name and Address lO.Work U n i t N o . National Transportation Safety Board of Accident Investigation Washington, D.C. 20594 Bureau Period Covered 12.Sponsoring Agency Name and Address NAT IONAL TRAKSPORTAT I ON SAFETY BOARD W a s h i n g t o n , 0. C . 20504 IS.Supplenentary f;oles 16.Abstract About 1815 Pacific standard time on December 28, 1978, United Airlines, Inc., Flight 173 crashed into a wooded, populated area of suburban Portland, Oregon, during an approach to the Portland International Airport. The aircraft had delayed southeast of the airport a1 a low altitude for about 1 hour while the flightcrew coped with a landing gear malfunction and prepared the passengers for the possibility of a landing gear failure upon landing. The plane crashed about 6 nmi southeast of the airport. The aircraft was destroyed; there was no fire. Of the 181 passengers and 8 crPwmembers aboard, 8 passengers, the flight engineer, and a flight attendant were killed and 21 passengers and 2 crewmembers were injured seriously. The National Transportation Safety Board determined that the probable cause of the accident was the failure of the captain to monitor properly the aircraft’s fuel state and to properly respond to the low fuel state and the crewmember’s advisories regarding fuel state. This resulted in fuel exhaustion to all engines. His inattention resulted from preoccupation with a landing gear malfunction and preparations for a possible landing emergency. :I Contributing to the accident was the failure of the other two flight &wmembers ?ither to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain. 118.Oistribution Statement 7. Key Words ?uel exhaustion, fuel state, preoccupation, landing This document is available through the National Technical Information Service, Springfield, VA 22151 rear malfunction, yaw, retract cylinder assembly, fuel Iages, to talker. dentifier: McDonnell-Douglas DC-a-61 Accident I Y.Security Classification (of this report) UNCLASSIFIED 1 20.Security Classification 2l.No. of Pages 122.Price (of this page) ( 62 1 UNCLASSIFIED ‘KSB Form 1765.2 (Rev. 9/74) \ j \\ . *_ -., . -- TABLE OF CONTENTS !1 ii 1. 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.16.1 1.16.2 1.16.3 1.16.4 1.16.5 1.17 1.17.1 1.17.2 1.17.3 1.17.4 1.17.5 1.17.6 1.18 2. 3. 3.1 3.2 4. 5. Synopsis . . . . . . . . . . . . . . . . . . . . . . . . . . Fat tual Information . . . . . . . . . . . . . . . . . . . . . History of the Flight . . . . . . . . . . . . . . . . . . . . Injuries to Persons . . . . . . . . . . . . . . . . . . . . . Damage to Aircraft . . . . . . . . . . . . . . . . . . . . . Other Damage . . . . . . . . . . . . . . . . . . . . . . . Personnel Information . . . . . . . . . . . . . . . . . . . . Aircraft Information . . . . . . . . . . . . . . . . . . . . hleteorological Information. . . . . . . . . . . . . . . . . . Aids to Savigation . . . . . . . . . . . . . . . . . . . . . Communications . . . . . . . . . . . . . . . . . . . . . . Aerodrome Information . . . . . . . . . . . . . . . . . . . Flight Recorders . . . . . . . . . . . . . . . . . : . . . . . \Vreckage and Impact Information. . . . . . . . . . . . . . . hiedical and Pathological Information . . . . . . . . . . . . . . Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . Survival :1spects . . . . . . . . . . . . . . . . . . . . . . Tests and Research . . . . . . . . . . . . . . . . . . . . . Retract Cylinder Assembly. . . . . . . . . . ........ Fuel Control Test . . . . . . . . . . . . . . ........ Aircraft Systems Examinations . . . . . . . . ........ Fuel Quantity System Error . . . . . . . . . ........ Fuel Burn Time History . . . . . . . . . . . ........ Other Information. . . . . . . . . . . . . . ........ Kesponsibility of the Crew . . . . . . . . . . ........ United :1irlines Flight Operations Bulletin 22-76, Fuel Policy-Domestic . . . . . . . . . . . ........ Excerpts from DC-8 Flight Jlanual . . . . . . ........ Excerpts from Xaintenance/Overhaul Handbook. ........ hlain Landing Gear Retract Cylinder Assembly . ........ Dispatch Responsibility and Authority . . . . . ........ New Investigation Techniques. . . . . . . . . ........ Analysis . . . . . . . . . . . . . . . . . . ........ Cone Ius ions . . . . . . . . . . . . . . . . ........ Findings . . . . . . . . . . . . . . . . . . ........ Probable quse . . . . . . . . . . . . . . . ........ Safety Reborn.mendations . . . . . . . . . . . . ........ Appendixes. . . . . . . . . . . . . . . . . . . . . . . . . . Appendix .. - Investigation and Hearmg . . . . . . . . . . . . Appendix B - Personnel Information. . . . . . . . . . . . . . Appendix C - Aircraft Information . . .................... Appendix D - Cockpit Voice Recorder Transcript ii 1 2 2 8 8 8 8 8 10 10 10 10 11 11 12 13 13 14 14 15 15 16 17 18 18 18 18 20 20 21 21 22 27 27 28 29 30 30 31 33 34 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT Adopted: June 7, 1979 UNITED AIR LINES, INC. MCDONNELL-DOUGLAS DC-8-61, N8082U PORTLAND, OREGON DECEMBER 28, 1978 : SYNOPSIS About 1815 Pacific standard time on December 28, 1978, United Airlines, Inc., Flight 173 crashed into e wooded, populated area of suburban Portland, Oregon, during an approach to the Portland International Airport. The aircraft had delayed southeast of the airport at a low altitude for about 1 hour while the flightcrew coped with a landing gear malfunction and prepared the passengers for a possible emergency landing. The plane crashed about 6 nmi southeast of the airport. The aircraft was destroyed; there was no fire. Of the 181 passengers end 8 crewmembers aboard, 8 passengers, the flight engineer, end a flight attendant were killed and 21 passengers and 2 crewmembers were injured seriously. * The National Transportation Safety Board determined that the probable cause of the accident was the failure of the captain to monitor properly the aircraft’s fuel state and to properly respond to the low fuel state and the crewmember’s advisories regarding fuel state. This resulted in fuel exhaustion to all engines.’ tiis inattention resulted from preo&upation with a landing gear malfunction end preparations for a possible landing emergency. Contributing to the accident w a s t h e f a i l u r e o f t h e o t h e r t w o f l i g h t crewmembers either to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain. .. II’: / ; 1. FACTUAL INFORMATION History of the Flight 1.1 IiI’ !. On December 28, 1978, United Airlines, Inc., Flight 173, a McDonnell-Douglas DC-8-61 (N8082U), was a scheduled flight from John F. Kennedy International Airport, New York, to Portland International Airport, Portland, Oregon, with an en route stop at Denver, Colorado. Flight 173 departed from Denver about 1447-l/ with 189 persons on board, including 6 infants, and 8 crewmembers. The flight was cleared to Portland on an instrument flight rules (IFR) flight plan. The planned time en route was 2 hrs 26 min. The planned arrival time at Portland was 1713. 21 the x According to the automatic flight plan and monitoring systemtotal amount of fuel required for the flight to Portland was’31,900 lbs. There was 46,700 lbs of fuel on board the aircraft when it departed the ga te at Denver. This fuel included the Federal Aviation Regulation requirement for fuel to destination plus 45 min and the company contingency fuel of about 20 min. During a postaccident interview, the captain stated that he was very close to his predicted fuel for the entire flight to Portland ‘I... or there would have been some discussion of it.” The captain also explained that his flight from Denver to Portland wes normal.I’ ’ At 1705:47, Flight 173 celled Portland .\pproech end advised that its altitude was lO!OOO ft 3/ end its airspeed was being reduced. Portland responded and told the fGght to maintain its heeding for e visual approach to runway 28’. Flight 173 ecknowledged the approach instructions and stated, “. . . we have the field in sight.” At 1707:55, Portland Approach instructed the flight to descend and maintain 8,000 ft. Flight 173 acknowledged the instructions end advised that it wes “leaving ten.” At 1709:40, Flight 173 received and acknowlec@ed a clearance to continue its descent to 6,000 ft. During e postaccident interview, the captain stated that, when Flight 173 was descending through about 8,000 ft, the first officer, who was flying the aircraft, requested the wing flaps be extended to 15’, then asked that the landing gear be lowered. The captain stated that he complied with both requests. However, he further-stated that, as the landing gear extended, ‘I. . . it was noticeably unusual and (I) feel it seemed to go down more rapidly. As (it is) my recollection, it was a thump, thump in sound end feel. I don’t recall getting the red and transient gear door light. The thump was much out of the ordinary for this airplane. It was noticeably different and we got the nose gear green l&W times herein are Pacific standard, based on the 24-hour clock. j/ A computer printout which predicted the amount of fuel that would be used between several identifiable en route points. The flightcrew was able to check the actual fuel used against the predicted fuel use at each of these points. 3/ All altitudes are mean sea level unless otherwise indicated. . . . . _ . . . . . r‘ .’_ _. . ._ . -. . -. - ____., .-. .-.-.-. _ .I .._- - _ .-_ -. --. .- _- -. .._ . ._ ___ “ --?-~~~;~~~ -3light but no other lights.” The captain also said the first officer remarked Flight attendant and that the aircraft “yawed to the right. . . .‘I passenger statements also indicate that there was a loud noise and a severe jolt when the landing gear was lowered. d At 1712:20, Portland Approach requested, “United one seven three ‘heavy, contact the tower (Portland), one one eight point seven.” The flight responded, “negative, well stay with you. Well stay at’ five. Well maintain about a hundred and seventy knots. We got a gear problem. Well let you know.” This was the first indication to anyone on the ground that Flight 173 had a problem. At 1712:28, Portland Approach replied, “United one seventy-three heavy roger, maintain five thousand. Turn left heading two zero zero.” The flight acknowleged the instructions. ._ At 1714:43, Portland Approach advised, “United one seventy three heavy, turn left heading, one zero zero and I’ll just orbit you out there“ti1 you get your problem.” Flight 173 acknowledged the instructions. For the next 23 min, while Portland Approach was vectoring the aircraft in a holding pattern south and east of the airport, the flightcrew discussed and accomplished all of the emergency and precautionary actions available to them to assure the l,yF3tJt$&l landing gear leas locked in the full down position. The -3cer checked the visual indicators on top of both wings, which’ ex?end ‘above the wing surface when the landing ge,ar is down-and-locked. The captain stated that during this same time period, the first flight attendant came forward and he discussed the situation with her. He told her that after they ran a few more checks, he would let her know ivhat he intended to do. 3 About 1738, Flight 173 contacted the United Airlines Systems Line Maintenance Control Center in San Francisco, California, through Aeronautical Radio, Inc. 4/ According to recordings, at 1740:47 the captain explained to company dispatch and maintenance personnel the landing gear problem and what the flightcrew had done to assure that the.landing gear was fully extended. He reported about 7,000 lbs of fuel on board and stated his intention to hold for another 15 or 20 minutes. He stated that he was going to have the flight attendants prepare the passengers for emergency evacuation. At 1744:03, United San Francisco asked, “okay, United one seventy three . . . You estimate that you’ll make a landing about five minutes past the hour. Is that okay?” The captain responded, “Ya, that’s good ball park. I’m not gonna hurry the girls. We got about a hundred sixty five people on board and we . . .want to . . .take our time and get everybody ready and then we’ll go. It’s clear as a bell and no problem.” s/ Aeronautical Radio, Inc., an air-to-ground radio service which provides a communication system for commercial aircraft. The aircraft continued to circle under the direction of Portland Approach in a triangular pattern southeast of the airport at 5,000 ft. The pattern kept that aircraft within about 20 nmi of the airport. (See Figure 1.1 #a From about 1744:30 until about 1745:23, the cockpit voice recorder (CVR) contained conversation between the captain and the first flight attendant concerning passenger preparation, crash landing procedures, and evacuation procedures. During his initial interview, the captain indicated that he neither designated a time limit to the flight attendant, nor asked her how long it would take to prepare the cabin. He stated that he assumed 10 or 15 minutes would be reasonable and that some preparations could be made on the final approach to the airport. -c At 1746:52, the first officer asked the flight engineer,“‘How much fuel we got . . . ?” The flight engineer responded, “Five thousand.” The first officer acknowledged the response. At 1748:38, Portland Approach advised Flight 173 that there was The first officer edvised Portland another aircraft in its vicinity. Approach that he had the aircraft in sight. % At 1748:54, the first officer asked the captain, “. . .what’s the fuel show now . . . ?I’ The captain replied, “Five.” The first officer repeated, “Five.” .-It 1749, after a partially unintelligible comment by the flight engineer concerning fuel pump lights, the captain stated, “That’s about right, the feed pumps are starting to blink.” According lo data received from the manufacturer, the total usable fuel remaining ivhen the inboard feed pump lights illuminate is 5,000 Ibs. .?t this time, according to flight data recorder (FDR) and air traffic control data, the nircraft was about 13 nmi south of the airport on a west south;qesterly heading. From just after 1749 until 17-19:15, the flightcrew engaged in further conversation about the status of the landing gear. This conversation was interrupted by a heading change from Portland Approach and was followed by a traffic advisory from Portland Approach. b About 1750:20, the captain asked the flight engineer to “Give us a current card on yeight. Figure about another fiftee.n minutes.” The first officer responded, “Fifteen minutes?” To which the captain replied, “Yeah, give us three or four thousand pounds on top of zero fuel weight.” The flight engineer then said, “Not enough. Fifteen minutes is gonnareally run us low on fuel here.” At 1750:47, the flight engineer gave the following information for the landing data card: “...Okay. Take three thousands pounds, two hundred and four.” At this time the aircraft was about 18 nmi south of the airport in a turn to the,northeast. 9 At 1751:35, the captain instructed the flight engineer to contact the company representative at Portland and apprise him of the situation and tell him that Flight 173 would land with about 4,000 lbs of fuel. From ‘ . * ---_ _ . --~. ._ _ . . -- _ . - _ _ .__ -_.. .- _-_- _-._+-- ‘ - mePOHHANUINH . - I I . A . . ??-rnn cnou~omAcr< LOG GROUND IITHACK SIIL 'l "Iao'2f22 "5 - - . .. my? :31? .. . LAsr FDRPATAI POINT 3?t?t'34' ?900 ?I74050 Io174?. r3 L. . . ,Z?v10748515 2135.1: . A 1740-"Igor- Cihr. I ?181?Thm - - 4! . - LII 3175148 . I . ?f . ?$353052MFf?ivM 1009?180811?1303150? 1" -. aIwi)"Tr . . 52SCALE: I 2 0,000 "ht . ?4:513?" 5 If." 165mm20KllonIcIL-r11k?: ?1 I 41-If]? - I 17?. II I a! .L .. L..A. ?Ail. -. -. -o ?n?fh? 44? llIL? 1 Flight. SHUHWI ‘ V’ \\ -_ ’ ’ -- _. . , 1752:17 until about 1753:30, the flight engineer talked to Portland and discussed the aircraft’s fuel state, the number of persons on board the aircraft, and the emergency landing preparations at the airport. At 1753:30, because of an inquiry from the company representative at Portland, the flight engineer told the captain, “He wants to know if we’ll be landing about five after.” The captain replied, 1’Yes.ff The flight engineer relayed the captain’s reply to the company representative. At this time the aircraft was about 17 nmi south of the airport heading northeast. -r At 1755:04, the flight engineer reported the “...approach descent check is complete.” At 1756:53, the first officer asked, “How much fuel you got now?” The flight engineer responded that 3,000 lbs remained, 1,000 lbs in each tank. At 1757:21, the captain sent the flight engineer to the cabin to “...kinda see how things are going. . . .” From 1757:30 until 1800:50, the captain and the first officer engaged in a conversation which included discussions of-giving..the..__flight attendants ample time to prepare for the -c’---the event of an evacuation after in emergency, cockpit procedures landing, whether the brakes would have antiskid protection after landing, and the procedures the captain would be using during the approach and landing. At 1801:12bPortland Approach requested that the flight turn left to a heading of 195 . The first oifice; acknowledged and complied ;vith the request. At 1801:34, the flight engineer returned to the cockpit and reported that the cabin would be ready in “another Iv.*o or three minutes.” The aircraft was about 5 nmi southeast of the airport turning to a south\Acesterly heading. Until about 1802:10, the captain and the flight engineer discussed the passengers and their attitudes toward the emergency. .-, At 1802:22, the flight engineer advised, “We got about three on the ‘1 fuel and that’s it.” The aircraft was then about 5 nmi south of the airport on a southwest heading. The captain responded, “Okay. On touchdown, if the gear folds or something really jumps the track, get those boost pumps off so that. . .you might even get the valves open.” At 1802344, Portland Approach asked Flight 173 for a status report. The first officer replied, “Yeah, we have indication our gear is abnormal. It’ll be our intention, in about five minutes, to land on two eight left. We would like the equipment standing by. Our indications are the gear is down and locked. We’ve got our people prepared for an evacuation in the event that should become necessary.” At 1803:14 Portland Approach asked that Flight 173 advise them when the approach would begin. The captain responded, I’. . . They’ve about finished in the cabin. I’d guess about another three, four, five -7 minutes.” At this time the aircraft was about 8 nmi south of the airport on a southwesterly heading. )rr At 1803:23, Portland Approach asked Flight 173 for the number of persons on board and the amount of fuel remaining.- The captain replied, “. . . about four thousand, well, make it three thousand, pounds of fuel,” and “you can add to that one-seventy-two plus six lapsinfants.” From 1803:38 until 1806:10, the flightcrew engaged in a conversation which concerned (1) checking the landing gear warning horn as further evidence that the landing gear was fully down and locked and (2) whether automatic spoilers and antiskid would operate normally with .. the landing gear circuit breakers out, gr) At 1806:19, the first flight attendant entered the cockpit. The captain asked, “How you doing?” She responded, “Nell, I think we’re ready.” At this time the aircraft was about 17 nmi south of the airport on a southwesterly heading. The conversation between the first flight attendant and the captain continued until about 1806:40 when the captain said, “Okay. \$e’re going to go in noIf*. \\‘e should be landing in about five minutes.” Almost simultaneous with this comment, the first officer said, “I think you just lost number four . . . ,” followed immediately by advice to the flight engineer, “. . . better get some crossfeeds open there or something.” ,& At 1806:46, the first officer told the captain, “We’re going to lose an engine. . . .‘I The captain replied, “\t’hy?” At 1806:49, the first officer again stated, “We’re losing an engine.” Again the captain asked, ” 1% hy 3. ” The first officer responded, “Fuel.” p Between 1806:52 and 1807:06, the CVR revealed conflicting and confusing conversation between flight crewmembers as to the aircraft’s fuel state. At 1807106, the first officer said, “it’s flamed out.” At 1807:12, the captain called Portland Approach and requested, II . . . would like clearance for an approach into two eight left, nowl” The aircraft was about 19 nmi south southwest of the airport and-turning left. This was the first request for an approach clearance from Flight Port land Approach 173 since the landing gear problem began. immediately gave the flight vectors for a visual approach to runway 28L. The flight turned toward the vector heading of 010’. 4 F r o m 1807:27 until conversation took place: 1809:16, the following intracockpit 1807:27 - Flight Engineer: “We’re going to lose number three in a minute, too.” 1807:31 - Flight Engineer: “It’s showing zero.” Captain: “You got a thousand pounds. You got to.” N -. ’ 0 _._. . , Flight Engineer: “Five thousand in there . . .but we lost it.” Captain: “Alrigh t.” 1807:38 - Flight Engineer: “Are you getting it back?” 1807~40 - First Officer: “No number four. You got that crossfeed open?” 1807:41 - Flight Engineer: “No, I haven’t got it open. Which one?” 1807:42 - Captain: “Open ‘em both--get some fuel in there. Got some fuel pressure?” Flight Engineer: “Yes, sir.” 1807:48 - Captain: “Rotation. Now she’s coming.” 1807:52 - Captain: “Okay, watch one and two. We’re showing down to zero or a thousand.” Flight Engineer: “Yeah” Captain: “On number one?” Flight Engineer: “Righx” 1808:08 - First Officer: “Still not getting it.” 1808:ll - Captain: “\i’ell, open aII four crossfeeds.” Flight Engineer: “All four?” Captain: “Yeah.” 1808:14 - First Officer: “.Alright, no1.i it’s coming.” 1808:19 - First Officer: “It’s going to be --on approach though.” Unknown Voice: “Yeah.” 1808:42 - Captain: “You gotta keep ‘em running. . . .” Flight Engineer: “Yes, sir.” 1808:45 - First Officer: “Get this. . .on the ground.” Flight Engineer: “Y’cah. It’s sho\\*ing not L’ery much more fueL” 1809:16 - Flight Engineer: “i\‘e’re do;vn to one on the totalizer. [dumber two is erzpty.” rit 1809:21, the captain advised Portland Approach, “United, seven three is going to turn to\\‘ard the airport and come on in.” ..I f t e r confirming Flight 173’s intentions, PortIand :Jpproach cleared the flight for the visual approach to runii’ay 281,. At 1810:17, the captain requested that the flight engineer “reset that circuit breaker momentarily. See if we get gear lights.” The flight engineer complied with the request. 1810:47, the captain requested the flight’s distance from the airport. Portland approach responded, “I’d calI it eighteen flying miles.” At 1812:42, the captain made another request for distance. Portland Approach responded, “Twelve flying miles.” The flight was then cleared to contact Portland tower. At At 1813:21, the flight engineer stated, “We’ve lost two engines, guys.” At 1813:25, he stated, “We just lost two engines - one and two,” At 1813:38, the captain said, “They’re all going. We can’t make Troutdale.” 5/ The first officer said, “We can’t make anything.” 5/ A small airport on the final approach path to runway 28L. -g- +A - . ’_ -. . . At 1813:46, the captain told the first officer, “Okay. Declare a mayday.” At 1813:50, the first officer called Portland International Airport tower and declared, “Portland tower, United one seventy three heavy, Mayday. We’re--the engines are flaming out. ,We’re going down. We’re not going to be able to make the airport.” This was the last radio transmission from Flight 173. About 1815, the aircraft crashed into a wooded set tion of a populated area of suburban Portland about 6 nmi east southeast of the airport. There was no fire. The wreckage path was about 1,554 ft long and about 130 ft wide. The accident occurred during the hours of darkness at latitude 45’31’21”N and longitude 122’29’59”W. The elevation of the accident site was 285 ft. 1.2 Injuries to Persons Injuries Fatal Serious lMinor/None 1.3 Crew 2 2 4 . Passengers 8 21 152 I ; Others 0 0 0 Damage to Aircraft The aircraft was destroyed. 1.4 Other Damase Two unoccupied homes were destroyed. Telephone lines were cut and high-tension electrical powerlines were damaged. 1.5 1.6 Personnel In for ma tion The crewmembers were properly certificated and qualified for the flight. (See Appendix B.) .. K Aircraft Information The aircraft was certificated and maintained in accordance with Federal Aviation Administration (FAA) requirements. The gross weight and center of gravity were within prescribed limits for the approach and landing. There was no usable fuel in the aircraft when it crashed. The figures below illustrate the aircraft’s approximate takeoff gross weight, approximate landing weight, and the approximate pounds of fuel remaining upon arrival in the vicinity of the Portland International Airport; these figures are based on normal operations. Zero fuel weight from weight manifest Total fuel on board from fuel service form Aircraft weight before departure from gate at Denver Fuel consumption on taxi Takeoff gross weight Fuel consumption en route to Portland, based on flight plan Landing weight at Portland Zero fuel weight from weight manifest Fuel remaining at Portland lbs 200 27 +46,7 00 248,627 - 1,000 247,6 27 -31,900 215,727 -2oi,927 13,800 /9 fl Throughout the landing delay, slight 173 remained at 5,000 ft with landing gear down and flaps set at 15 . Under these conditions, the Safety Board estimated that the flight would have been burning fuel at the rate of about 13,209 lb.spe,r_-hour--220 lbs per min. At the beginning of the landing delay,?here were about 13,332 lbs-df fuel on board. X new type of fuel quantity indicating system was retrofitted to this aircraft on Slav 12, 1978. The retrofit was authorized by Change Order Authorization ko. 2-1849. \iith the new system installed, there are eight individual tank quantity gages. Each of these gages has three digits which are seven-segment incandescent lamps. On these individual tank gages, the digital reading is multiplied by 100 to obtain the total amount of fuel in the tank. The totalizer gage receives input from each individual tank gage and displays the total fuel available on three digital readouts. However, this digital reading must be multiplied by 1,000 to obtain the value of the total amount of fuel on board. The smallest increment of change that can be indicated on the individual tank gages is 100 lbs. The smallest increment of change on the totalizer is 1,000 lbs. Before the implementation of the change order, each individual tank gage displayed five digits which were read directly to obtain the amount of fuel in each tank. The change order also replaced the flight engineer’s totalizer gage, which had displayed six digits read directly for total fuel on board. -_ According to United Airlines, the primary purposes of installing the fuel quantity indicating system were (1) to reduce erroneous system indications because of stray pickup of 400 Hz signals in the fuel quantity indicating system wiring, and (2) to reduce indication errors from current leaks across the elements of the capacitive probes and compensators. After the accident, United Airlines determined that the aircraft was burning fuel in accordance with the automatic flight plan and monitoring system. In October 1978, fuel burnoff examination indicated that the aircraft was not consuming fuel as fast as predicted; it was 1.04 percent -=a .’ __. ,. -110 less than predicted. In addition, another method for determining burnout was begun by United engineers. Each trip’s total burnout was divided by total time. For December 1978 these aggregate values verified that this aircraft’s fuel consumption was within 1 percent of the plan. The aircraft was also engine which displayed, in being used by the engine. forward engine instrument tzeges. 1.7 equipped with a fuel flow indicator for each ; hundreds of pounds, the hourly rate of fuel{ These indicators were located on the pilot’s/ panel along with other engine monitoring: Meteorological Information Surface weather observations taken before and after the accident at Portland International Airport by National Weather Service personnel were: 1655 - 4,500 ft scattered; visibiljty - 30 mi; temperature - 30’F; dewpoint - 13’F; wind - 340 at 8 kns; altimeter setting - 30.16 inHg. 17z5 - Clear; visitoility - 15 mi; temperature - 29’F; dewpoint-13 F; wind - 010 at 11 kns; altimeter setting - 30.17 inHg. 1829 Local - Clear; visibility - 15 mi; temperature - 28’F; dewpoint--12’F; wind - 35O’at 11 kns; altimeter setting - 30.19 inHg; AIRCRAFT MISHAP. 1.8 Aids to Navipation During his deposit ion, the captain stated that he had set the Portland VORTAC, which is located 9.2 nmi north-northeast of Portland International Airport, in both of his VOR receivers. He stated also that he was receiving distance measuring equipment information. 1.9 Communications No communications difficulties were reported. 1.10 .. Aerodrome Infor mat ion Runway 28L at Portland International Airport is hard surfaced and is 11, 014 ft long and 150 ft wide. The published touchdown zone elevation and field elevation are 19 ft and 26 ft, respectively. The runway is equipped with high intensity runway edge lights, centerline lights, and visual approach slope’indicator lights. The airport has two other runways. Runway lOL/28R, which is parallel to runway 28L, is 8,004 ft long and 150 ft wide. It is the primary instrument runway. Runway 02/20 is 7,000 ft long and 150 ft wide. It is used mainly as a crosswind runway. The airport is located near the south shore of the Columbia River /fm-Y&&f o Portland. The terrain southeast of the airport is characterized by low.rolling hills, which rise from the river valley. ’ I 1.11 ___ . ( Flight Recorders N8082U was equipped with a Fairchild model 5424 flight data The recorder showed no outward recorder (FDR), serial No. 6043. evidence of damage. The foil recording mediu.m was not damaged; all parameter and binary traces were present and active with no evidence of recorder malfunction or recording abnormalities. Electrical power to the recorder was terminated about 44 set before the aircraft crashed. A readout was made of the final 15 min 44.7 set of the recorded traces. This readout covers the 15 min of flight before all parameter traces altitude, airspeed, magnetic heading, and vertical acceleration - ceased to be recorded and continues for an additional 44.7 set where all binary traces became atypical. N8082U was also equipped with a Sundstrand model V557 CVR, serial No. 1427. The recorder was removed from the aircraft and the entire tape was transcribed. The quality of the recording. was good. (See Appendix D.) 1.12 Wreckage and Impact In for ma tion The aircraft first struck two trees about 100 ft above the ground. These trees were about 1,554 ft from the point where the wreckage came to rest. About 541 ft farther along the flightpath on a heading of about 345’, the aircraft struck two trees about 85 ft above the ground. rIbout 400 ft farther, the right wing struck a tree about 45 it above the ground. About 225 ft beyond that point, the left outer wing struck a tree about 8 ft above the ground. The aircraft then struck and destroyed an unoccupied house which was located about 1,230 ft from the first tree. Pieces of the aircraft’s left wing structure were located just beyond the house. The two main landing gear and the nose section of the aircraft first struck a 5-ft embankment next to a city street about 1,275 ft from the first tree. TheRircraft continued across the street and came to rest on a heading of 330 between some trees and on top of another unoccupied house. The tail of the aircraft came to rest about 1,350 ft from the first tree. Just after crossing the street, the verticle stabilizer struck a series of high tension cables, which ran parallel to the street. The fuselage, from about the fifth row of passenger seats forward, sustained severe, extensive impact damage in a generally rearward The cockpit upper structure, which included the cockpit direction. forward windows, had separated and was found to the right of the fuselage just forward of the inboard end of the right wing. The cockpit floor structure, which included portions of the crew seats, sections of the instrument panel, and the nose tunnel structure with the nose gear assembly partially attached, had separated and rotated to the right and aft; This structure was in a partially inverted position. All portions of the fuselage structure were accounted for and all of the structural damage was caused by impact with the ground and the numerous large trees in the immediate area. r + .- . , _-- ; -130 The lower left side of the fuselage, between the fourth and sixth rows of passenger seats and below window level, had been torn away. The remainder of the underside of the fuselage sustained heavy damage from contact with several large trees and tree stumps. The passenger cabin interior, from row 6 to the aft bulkhead, was relatively intact. At several points along the fuselage, windows were smashed and the fuselage had been dented by large trees and separated portions of the main landing gear. The empennage showed moderate impact damage. The vertical stabilizer leading edge had been damaged by high tension cables at three points just forward of the upper three rudder-tostabilizer hinge points. The left wing had separated from the fuselage about 3 ft outboard from the fuselage attachment point. The No. 2 engine had separated from its pylon and was located adjacent to the wing trailing edge. The No. 1 engine remained attached to a section of left wing structure. A 7-ft-long section of the left wingtip had been sheared off and was found near the first house. The right wing separated about 5 ft from the fuselage. x Z-it opening was evident between the fuselage and wing leading edge structure. The wing leading edge, from a point about 5 ft outboard from the leading edge inboard end, was cut and torn aft to the front spar assembly. A large section of right wing leading edge structure had separated during the impact sequence and was also found near the first house. A section of right wing with the So. 3 engine and pylon attached was located just forward of the right horizontal stabil izer. The outboard wing set tion, which included the No. 4 engine, was to the right of the fuselage. All four engines were inspected and found to be! capable of operation. None showed signs of rotation at impact. Both main landing gear were fully extended but were torn from their mounting strut tures. They were located near main wreckage. Inspection of the right main landing gear retraction mechanism showed corrosion in the threads of an attachment eyebolt. The eyebolt was pulled out of the actuator cylinder piston. The nose landing gear was fully extended and remained attached to the nose tunnel structure. 1.13 Jj’ Medical and Pathological Information A review of the flightcrew’s medical records revealed no evidence of medical problems that might have affected their performance. AThe 10 persons who were killed in the crash died from impact trauma. Toxicological analyses showed no acidic, neutral, or basic drugs or ethanol in the blood taken from the flight engineer and first flight at tendant. 1.14 Fire There was no fire. 1.15 Survival Aspects The accident was partially survivable. The 10 occupants killed in the crash were located between the flight engineer’s station in the cockpit and row 5 in the passenger cabin. All of the passengers who were killed had been located on the right side of the cabin. That section of the aircraft was destroyed during the accident sequence. The most seriously injured passengers were seated in the right forward portion of the cabin near an area of the fuselage which appeared to have been penetrated by a large tree. These persons were s2ated near those passengers who were injured fatally. Some seriously injured passengers were seated in the rear cabin near the trailing- edge of the wings. The fuselage in this area had been penetrated and the floor and seats had been disrupted. Some passengers sustained serious injuries during the evacuation. Two passengers sustained fractut-es and others sustained lacerations and abrasions when they either fell from exits or as they climbed through debris outside the aircraft in order to reach the ground. As a result of the accident, 22 persons were admitted to hospitals with serious injuries ranging from multiple fractures of extremities and fractures of cervical vertebrae, to observations for possible injuries. J& The plane crashed in the jurisdiction of Multnomah County Rural Fire Protection District No. 10. Three fire departments sent personnel and equipment to the scene: The Port of Portland (Airport) Fire Depart men t; Jlultnomah RFPD No. 10, and the City of Portland Fire Bureau. A total of 39 fire units and 108 on-duty fire personnel responded to the scene. Numerous off-duty fire personnel from all fire departments also responded to the scene. Because there was no fire, the basic fire service functions were search and rescue, extrication, triage, emergency medical care, precautionary foaming of some aircraft parts and surrounding area, laying standby firefighting water supply lines, transporting or assisting ambulatory.victims to a nearby church, setting.up area lighting, providing some interagency radio communications, and setting up the onscene command post. Although there were many occupied houses and apartment complexes in the immediate vicinity of the accident, there were no ground casualties and no postcrash fire. Injured persons were transported to nearby hospitals by helicopter and ambulance. The aircraft was equipped with 10 floor level exits, each provided with automatically inflatable emergency escape slides. h addition to slides at the boarding doors (1L and 5L) and at the two galley service doors (2R and 5R), slides were located at the six “‘jet escape” floor level exits (lR, 2L, 3L, 3R, 4L, 4R). The ‘Ijet escape” doors were hinged at the bottom and were designed to swing down and outward when opened. Movement of the door actuated the automatic inflation of the escape slide. The slide from exit 1L was found wrapped around a tree at the left wing. The slides from exits 3L and 3R were found packed and uninflated. These exits were reportedly blocked by debris outside the aircraft. The slide at exit 1R reportedly inflated inside the cabin and extended across the aisle and lodged against seat 8C. The door was prevented from opening fully because of cockpit and forward cabin debris outside the aircraft. The slide at exit 2R also reportedly inflated inside the cabin and blocked the cabin aisle. The exit door was displaced inward when the plane hit a tree. l The slide at exit 4R reportedly inflated inside the cabin when the door was opened by a passenger. The slide inflated upward and partially blocked the exit opening. Because of debris outside the fuselage, the exit door was prevented from opening fully. The passenger who opened the door reported that about 10 persons used this exit before the slide was The remaining escape slides pushed out the exit and onto debris. reportedly deployed outside the aircraft and inflated but were punctured or torn by debris during the evacuation. The escape slides were removed from the accident site and were examined on January 3, and on January 9, 1979. No discrepancies were found in the installation, maintenance, manufacture, or design of the escape slides. The evacuation was completed in about 2 min. Except for seats at rows 20 through 22 which were torn loose from the floor attachments, there was only minor disruption of the cabin furnishings aft of row 6. The emergency lights provided adequate illumination during the evacuation. 1.16 Tests and Research 1.16.1 Retract Cylinder Assembly -. The Safety Board examined the piston rod and the mating end from the right main landing gear retract cylinder assembly at its metallurgical labora tory in Washington, D.C. The examination showed that the primary cause of the se aration of the rod end from the piston rod was severe corrosion causJby moisture on to the mating threads of both components. As a result of the corrosion, the joint was weakened to such an extent that only a comparatively low tensile load was required to pull the rod end out of the piston rod. The pattern of mechanical damage indicated that all of the rod threads had been engaged and that the rod end had been pulled straight out of the piston rod without any significant rotation. ‘LO’ \ 1.16.2 -- ’ . -.__ ’ , . Fuel Control Test Functional testing of the fuel controllers from each of the four engines was conducted at the company’s maintenance base. No discrepancies or out-of’tolerance conditions were found. 1.16.3 Aircraft Systems Examinations * During the week of January 8, 1979, the following examinations were conducted at the company’s maintenance facility: (1) Fuel Flow Indiiators The shop examinations confirmed that the four indicators were indicating zero fuel flow. The front face, case, and electrical connections were all damaged and none could be opera ted or testeb before being repaired. After minor repairs to the electrical connections only the flow meter for the No. 2 engine became operable, and it met the linearity specifications. (2) Fuel Quantity Gages During the wreckage salvage, the eight fuel quantity gages were recovered. All units were damaged and repairs were attempted on each. Three gages could be repaired sufficiently to allow functional testing. The No. 4 main tank gage was given a lamp check, segment and self-test check and all were within specification. In addition, a linearity check was made at full, at 1,000 lbs, at 500 lbs, and at ernpt;;. The results were within specifications. The No. 4 alternate tank gage and the No. 2 main tank gage were tested in the same manner, and the results were within specifications. The other tank gages were not operable because of damage and, therefore, could not be tested. check, (3) Totalizer Gage The glass face was broken, the electrical connector bent, and the case punt tured. The damage was too extensive to enable repair for testing. (4) No. 1 Nlain Fuel Tank Capacitance Probes The five capacitance probes from the No. 1 main fuel tank were examined according to company specification. All units were within specification except probe No. MR 28062, serial No. 525856-31X. This unit did not meet resistance tolerance specification when wet. --Y. . . s ./.. ,.-1__-.. ----r-----.--.7-,- r__ - k ’ ’ _.-_ * , -17(5) Tank Reference Capacitors One of these units is located in each main tank. All four units were recovered and, when tested, met specifications. (6 Right Main Landing Gear Down-Lock Switch ) This switch is activated when the gear reaches a down-andlocked position. A similar switch was installed on the left main landing gear. A comparison of the damage to the two switch cases showed that the switch from the right landing gear had been damaged apparently by an internal part that pushed the case outward and had distorted it. Electrical tests of the switch and attached wiring indicated an intermittent short’ circuit when the switch was shaken. X-rays of the switch showed that’s large spring had become free of its mounts within the switch case. Normally this spring returns the down-lock switch to the gear-not:-down posit ion when the landing gear is retracted. The switch case was cut open and several coils of the spring \vere found spread apart When the spring and switch case damages were matched, one end of the spring fit into the distorted portion of the case. The other end of the spring touched wiring terminal No. 8 of the nicroyV\.itch and marks indicative of electrical arcing were found on the spring where it contacted terminal No. 8. Y (7) Left Main Landing Gear Down-Lock Switch The spring of the left main landing gear down lock switch was free of its mounts. The coils of this spring were not bent and no marks similar to electrical arcing were found. (8) Landing Gear Warning and Interlock Circuit Breaker When examined in the field, this circuit breaker appeared to be mechanically extended or electrically open. There was some mechanical damage. Later, shop tests verified that the circuit breaker was open. It could be operated mechanically and it opened and closed the electrical circuit properly. (9) Distance Measuring Equipment -. Two distance measuring equipment units, Collins Model 860E2, serial No. 3954 (No. 1) and serial No. 617 (No. 2), were opened in the company maintenance shops and the distance modules were removed. When connected to a test panel, the mileage readouts were 16.05 nmi for the No. 1 unit and 16.0 nmi for the No. 2 unit. Both units were selected to channel 113X, which corresponds to a VOR frequency of 116.66 MHz. 1.16.4 Fuel Quantity System Error Upon request, United Airlines provided the Safety Board with an error analysis of the fuel quantity indicating system for the accident aircraft. Analyses were prepared for three different assumptions The -A.” \\ .- ’ ’ _.-. , * first analysis asumed that all errors were at their limits and in the same direction. The second analysis assumed that all errors were at their limits but were distributed randomly with respect to sign (rootsum-square analysis). The third analysis was a probable error analysis. All errors in this analysis were those asociated with empty or near empty tanks. These analyses indicated the following: Analysis Method , Worst-Case Error 1.16.5 Sum of Indicators High Error Low Error lbs. lbs. Totalizer High Error Low Error lbs. 3,961 High lbs. 2,283 High 1,482 Low Root-Square-Sum Error 828 High 28 Low 1,312 High, I 957 Low Probable Error 685 High 185 High 1,239 High 885 Low Fuel Burn Time History At the request of the Safety Board, Douglas Aircraft Company and United Airlines studied fuel burn performance for the accident flight. Ln both studies, the fuel on board at the gate in Denver was 46,700 lbs. The fuel remaining at cruise at 35,000 ft was almost identical in both studies. United’s calculations of fuel burn rate for the descent from 35,000 ft to the 5,000-ft holding altitude were 13 percent lower than Douglas’. IIowever, United’s fuel burn rate while in the holding pattern was 1-I percent higher than Douglas’. This disparity was a result of different interpretations of meteorological and FDR data which resulted in differing math values. Both studies had similar fuel remaining values when both flight recorders ceased operation; Douglas had calculated 178 lbs and United had calculated 73 lbs. Both studies compared favorably to the fuel burn time history computed by the Safety Board using information from the automatic flight plan and monitoring system and CVR data. A correlation of CVR information with both fuel burn studies shows the observed and calculated fuel remaining values to be in Agreement. The CVR transcript indicated an observed fuel remaining value of 5,000 lbs about 1749. The Douglas figure for that time was 5,250 lbs and United’s was about 6,000 Ibs. if the totalizer accumulated probable error of 885 lbs was applied, the calculated and observed fuel remaining values would be in agreement. In addition, the two studies indicated that the accident aircraft’s fuel consumption was normal during the accident flight. Although both studies had similar fuel remaining values when the aircraft lost its engine power, the Safety Board believes that the Douglas’ study more closely approximates the fuel burn during the 5,000-ft hold period. Therefore, fuel remaining computations for this period are predicated on the manufacturer’s figures of a calculated fuel burn of 13,209 lbs per hour (220 lbs per min). According to the manufacturer’s study, the aircraft, entered into the hold with about 13,334 lbs of fueL 3,606 Low + -- I ’ _. -. , . -19. 1.17 $\1.17.1 Other Information Responsibility of the Crew E x c e r p t f r o m United Airlines Flight Operations Manual, paragraph 6.2, June 30, 1978: “16. Except as otherwise specifically directed by the captain, all crew members noting a departure from prescribed procedures and safe practices should immediately advise the captain so that he is aware of and understands the particular situation and may take appropriate action.” 1.17.2 United Airlines Flight Operations Bulletin 22-76, Fuel Policy Domestic FAR 45 Minute and Overwater/International 30 Minute Reserve Fuel. “FAR 121.639 (C) does not specify in detail how the aforementioned requirements are to be calculated. United Airlines has established the following criteria for computing required fuel. \Veight - The operating weight empty of the airplane plus maximum a. structural payload or maximum space payload, whichever is smaller, plus the weight of the 45 minutes of reserve fuel. b. Speed - Long range cruise speed. C. Altitude - 25,000 Feet. The ability to loiter at 5,000-feet at clean holding speed for 45 I d. m inu tes.” "From the aforementioned criteria is derived the following DC-8-61 fuel requirements. 1. 2. 3. Fuel required for 45 minutes cruising at long range cruise at 25,000 feet is 8,300 pounds. Fuel required for 45 minutes holding clean a t 5,000 feet is 7,800 pounds. FAR 45 minute reserve: 8,400 pounds.” .. Excerpts From United Airlines DC-8 Flight Manual “Landing Gear Lever Down and Gear Unsafe Light On If the visual down-lock indicators indicate the gear is down then a landing can be made at the captain’s discretion.” (Dated January 1, 1974, pg. I-44.) “Landing Gear Apparently But Not Conclusively Down If possible, have tower visually check. If there is reasonable indication that the gear is down then the landing can be made asuming gear is down. Do not taxi the airplane until gear locks have been installed.” (Dated January 2, 1974, pg I-44-59.) -?jyj- .’ _-- , ’ -- “Preparation For Evacuation 1. Notify ground station of emergency. 2. Advise the First Flight Attendant as to: a. b. c. d. e. 3. nature of emergency and expected landing conditions, time available for preparation, signal for taking protective position, signal to be used if evacuation is not necessary, other special instructions. Determine from the First Flight Attendant: :. :: the passenger load, number of infants, invalids, and other passengers who would be given -special consideration. 4. Direct all nonessential cockpit members to move to the cabin and assist Flight Attendants as requested. 5. Review the EVACL’XTION Emergency procedure. 6. slake an announcement to the passengers as appropriate. 7. Accomplish the CABIN INSPECTIOS CHECKLIST below when advised by the First Flight Attendant that cabin preparations are completed. a. Depressurize the airplane when below 10,000 feet. 9. Insure that the emergency exit lights switch is in the armed posit ion. 10. Avoid landing, if possible, until emergency equipment and crews are standing by. 11. Advise the First Flight Attendant when approximately . . five minutes from landing. 12. Advise the passengers and Flight Attendants when to assume the protective posit ion. 13. I f e v a c u a t i o n i s n e c e s s a r y , accomplish Emergency Procedure.” (Dated September 27, 1975, page I-19.) the EVACUATION “Cabin Inspect ion Checklist 1. All Flight Attendants briefed on station, duties, and signals. 2. Passengers reseated as required and seats to be used by crew vacated. E N -- I . --. ,a -213. Helper passengers briefed on station, duties, and exit operation. 4. Passengers briefed on: a. b. c. d. 1.17.4 Protective position and signal to assume position. Seat belts tight and low. How to unfasten seat belts. Assigned exits and when and how to leave the airplane. 5. Passengers’ glasses, dentures, high heels, and other possible hazardous items removed and stowed. Loose objects stowed in secure stowage areas. 6. Internal doors and curtains secured open. 7. Meal service furnishings in appropriate secure area. a. Seat backs upright and tables stowed. 9. Pillows and blankets distributed for impact protection.” (Dated September 27, 1975, page I-20) ExcerDts From United Airlines Maintenance/Overhaul blanual “Fuel Quantity Indicator System - Tolerance All tanks at empty, + 150 pounds. b. Tank at full #l & $4 Main + 400 pounds # 1 6r #4 Alt f 225 pounds #2 &. #3 Main + 400 pounds #2 & #3 Alt + 250 pounds” (Dated January 19, 1976, page 201.) a. 1.17.5 hlain Landing Gear Retract Cylinder Assembly ._ Although the purpose of the main landing gear retract cylinder assembly is to raise the landing gear during the retract cycle, the hydraulic action of the cylinder acts as a buffer during the extend cycle to moderate the rate of extension and prohibit the landing gear from free falling to the down-and-locked position. McDonnell-Douglas Corporation issued an AR-Operator Letter, AOL 8-141, in July 1967, Main Landing Gear Retract Cylinder Assemblies, DC8 Aircraft. The letter advised all DC-8 operators that several cylinder end fittings had been found with fractures in the thread roots. To alleviate this condition, the eyebolt threads were changed from machined to rolled-type threads. The letter also recommended sealing the threads with a corrosion resistant compound. & . -2 2 1’ i I 1’ _-. ,. On March 27, 1968, McDonnell-Douglas issued Service Bulletin No. :! , 32-131, DC-8 SC 1681, Landing Gear Extension and Retraction -Replace Main Landing Gear Retract Rod Assemblies. This bulletin provided information on the replacement of the retract cylinder rod end assemblies with machined threads with rod end assemblies with rolled-type threads. In 1973, United Airlines instituted a gamma ray inspection program for the main landing gear retract actuating cylinder and rod ends on the DC-8 aircraft. The purpose of inspection was to detect thread corrosion in the cylinder. The cylinder threads on the main landing gear retract actuators of the accident aircraft were last inspected using the gamma ray inspection on April 2, 1977. In order to provide additional threads and a longer eyebolt on actuator cylinders found with corrosion damage, the retract cylinder was to have been modified as provided for in the United Airlines Maintenance .Ilanual dated January 2, 197-I. The right main landing gear retract actuator on the accident aircraft had not been modified. 1.17.6 Dispatcher Responsibilitv and Authoritv Under the provisions of United Airlines Flight Operations llanual, the flight dispatcher responsibility after the aircraft is airborne is limited to computation of fuel estimate under only two conditons-when contact is not established within 20 min and during a hijacking. 1.18 Sew Investigation Techniques Sone . Ic..Y__.. _ _ ._ _ - ..- .-. __._. _.. -.__ . . 2. ANALYSIS The flightcrew was properly certificated and each crewmember had received the training and the off-duty time prescribed by applicable regulations. There was no evidence of medical problems that might have affected their performance. 4 The aircraft was certificated and maintained according to applicable regulat ions. The gross weight and c.g. were within prescribed limits. Except for the failure of the piston rod on the right main landing gear retrac_t cylinder assembly and the failure of the landing gear position indicating system, the aircraft’s airframe, systems, structures, and powerplants were not factors in this accident. A The investigation revealed that fuel was burned at a normal rate between Denver and Portland, The aircraft arrived in the Portland area with the preplanned 13,800 lbs of fuel and began its delay at 5,000 ft with about 13,334 lbs. The first problem which faced the captain of Flight 173 was the unsafe landing gear indication during the initial approach to Portland international Airport. This unsafe indication followed a loud thump, an abnormal vibration, and an abnormal aircraft yaw as the landing gear was loksered. The Safety Board’s * investbation r e v e a l e d t h a t t h e l~ing._gear_pr_ob!e-~_-is.as ca_used by s e v e r e corrosion in the matmg threadswhere theright main--.landing gear -.-retract cylinder _---9sse t mbly~as-connec&zd o the rod end. The c-Grosion -low the two parts to pull apart and the right main landing gear to fall free when the flightcrew lowered the landing gear. This rapid fall disabled the microswitch for the right main landing gear which completes an electrical clrcult to the gear-Qosition indicators in the cockpit. The XIterence between lhmfinem.-for the right maln landing gear to free fall and the time it took for the the left main landing gear to extend normally, probably created a difference in aerodynamic drag for a short time. This difference in drag produced a transient yaw as the landing gear dropped. Although the landing gear malfunction precipitated a series of events which culminated in the accident, the established company procedures for dealing with landing gear system failure(s) on the DC-8-61 are adequate to permit the safest possible operation and landing of the aircraft. Training procedures, including ground school, flight training, and proficiency and recurrent training, direct the fligh’tcrew to the Irregular Procedures section of the DC-8 Flight--Manual, which The Irregular must be in the possession of crewmembers while in flight. Procedures section instructed the crew to determine the position of both the main and nose landing gear visual indicators. “If the visual indicators indicate the gear is down, then a landing can be made at the captain’s discretion.” The flight engineer’s check of the visual indicators for both main landing gear showed that they were down and locked. A visual check of the nose landing gear could not be made because the light which would have illuminated that down-and-locked visual indicator was not operating. However, unlike the main landing gear cockpit indicators, the cockpit indicator for the nose gear gave the proper “green geardown” indication. Admittedly, the abnormal gear extension was cause for concern and a flightcrew should asses the situation before communic’ating with the dispatch or maintenance personnel, However, aside from the crew’s discussing the problem and adhering to the DC-8 Flight Manual, the only remaining step was to contact company dispatch and line maintenance. From the time the captain informed Portland Approach of the gear problem until contact with company dispatch and line maintenance, about 28 min had elapsed. The irregular gear check procedures contained in their manual were brief, the weather was good, the area was void of heavy traffic, and there were no additional problems experienced by the flight that would have delayed-the captain’s communicating with the company. The company maintenance staff verified that everything possible had been done to assure the integrity of the landing gear. Therefore, upon termination of corn municationstithcompany dispatch and maintenance personnel, whi$h was about 30 min before-the crash, the captain could have mad&%%6~~g~~ttemp~. TJe SafeZ&&a&bf&zs ----. that Hlght 173 C~!il!!-.---.. ave landed-saf.ely..+thin 30 to 40 min after th&&ing.gear rIXI~~!on. --.--Upon completing communications with company line maintenance and dispatch, the captain called the first flight attendant to the cockpit to instruct her During the ensuing to prepare the cabin for a possible abnormal landing. dmUseraptain did not assign the first flight attend&t a specified t.lm’e within Irhichta_prepareth~a~i~-~eequirbby-the-fiightm~~~TTTn~e .----. -__ _ attendant-_was_. - p&ably-left- with the *Such timP cQfst raint. the first fli&-__-___ impression that time efficiency was-not net.essarily as important asthe assurance ----_-_. .- _._- ----of thorough pre$%&on. _ _ The Safety Board believes that any time a flight deviates from a flight plan, the flightcrew should evaluate the potential effect of such deviation on the aircraft fuel status. This flightcrew knew that the evaluation of the landing gear problem and preparation for an emergency landing would require extended holding before landing. The flightcrew should have been aware that there were 46,700 lbs of fuel aboard the aircraft when it left Denver at 1433 and that there was about 45,650 lbs at takeoff at 1447. Regardless of whether they were aware of the actual fuel quantities, they certainly should have been aware that the initial fuel load was predicated on fuel consumption for the planned 2 hr 26 min en route flight, plus a reserve which includes sufficient -fuel for 45 min at normal cruise and a contingency margin of about 20 min.additional flight. ‘QTherefore, the crew should have known and should have been concerned that fuel could become critical after holding. Proper crew management includes i constant awareness of fuel remaining as it relates to time. In fat t, the Safety Board believes that proper planning would provide for enough fuel on landing for a ,) go-around should it become necessary. Such planning should also consider possible ’ fuel-quantity indication inaccuracies. This would necessitate establishing a dead< line time for initiating the approach and constant monitoring of time, as well as Such procedures 4: the aircraft’s position relative to the active runway. I + a’ _-- ,* -- al should be routine for all flightcrews. However, based on available evidence, this flightcrew did not adhere to such procedures. On the contrary, the ssx9q-k period of ku9ding. The other two flight crewmembers, although they made several hg time to fuel exhaustion would have been voiced. However, there was none until after the aircraft was already in a position from which recovery was not possib$ In analyzing the flightcrew’s actions, the Safety Board considered that the crew could have been misled by inaccuracies within the fuel-quantity meatiiing system. However, those intracockpit comments and radio transmissions in which fuel quantity was’mentioned indicate that the fuel-quantity indicating system wa.s accurate. A A Had the flightcrew reld&my 91. thc>$--&el qk_an_tit&s-.to fuel flow, -they should have been aware_that fuel exhaustion- wouldxcur at oa~~t.l815f Other p-” evidence that the captain had failed to assess the effect of continued holding on fuel state was provided by his stated intentions to land about 1805 with 4,000 Ibs of fuel on board. Just minutes earlier, at 1748:56, he was made aware that only 5,000 lhs remained. During the 16 min between the observation of 5,000 lbs and 1805, the aircraft would consume at least 3,000 Ibs of fuel. Further evidence of .the flightcrew’s lack of concern or aivareness was provided when observations of 4,000 lbs remaining about 17 min before the crash, the left the cockpit at the captain’s request to check on the cabin evacuation preparations. Upon his return, about 4 min later, he gave the captain an estimate of another 2 or 3 min for the completion of the cabin preparation. At this time;‘.the aircraft was in the general vicinity of the airport. In the initial interview with the captain, he stated that he felt the cabin preparatmd be ea m rrom IO-0 mm and fiat the “taiIXiaafif’~could‘be accomplish;;d roach to the airport. Certain1 eCK prdc nd r ecom mended byminv- li a 7e.e .t h Portlw1 of n med and had alerted probleing. - *have been no valid reamn not ts,-. C Under these.qircumstances, there appearstheto airport discontinue their heading in order to make theii: e previb%l$ ‘ksti&k&d &tiding ‘.tim&$. However, about ‘15101:12, the first officqr accepted a’nd the”‘&$tiin“did n&t q don a vet t$ heading which would take them > away-.from-thecairpdtit -kind de@‘*their landing time.eppreciably. Moreover, after the’;turn’;-w~Sti~~,~le’t~d “non4 df the. flightcrew suggested turning toward the \ airport.fihus, it was at this time that the crew’s continuing preoccupation with the 1 landing g&r -@+oblem ad i&&g ‘preparations: t&a&$ ‘crucial and an accident :. became’ ~eyitabl&~S y i - _ ’ . -. _ . . The Safety Board also considerzthe possibility that the captain was aware of the fuel quantity on board, but failed to relate the fuel state to time and distance from the airport and intentionally extended. the flight to reduce the fuel load in order to reduce the potential of fire should the landing gear fail upon landing. The Safety Board could find no evidence, however, to support such a theory and believes that ,had he so intended, the captain would have advised the first officer and the flight engineer. Therefore, the Safety Board can only conclude that the flightcrew failed to relate the fuel remaining and the rate of fuel flow to the time and distance from the airport, because their attention was directed almost entirely toward diagnosing the landing gear problem. Although on two occasions the captain confirmed with the company that he intended to land about 1805 and that he would be landing with about 4,000 lbs of fuel, this estimated time of arrival and landing fuel load were not adhered to, nor was the expected approach time given to Portland Approach. This failure to adhere to the estimated time of arrival and landing fuel loads strengthens the Board’s belief that the landing gear problem had a seemingly disorganizing effect on the flightcrew’s per for mance. Evidence indicates that their scan of the instruments probably narrowed as their thinking fixed on the gear. After the So. A engine had flamed out and with the fuel totalizer indicating 1,000 lbs, the captain was still involved in resetting circuit breakers to recheck landing gear light indications. It \vas not until after it became apparent to the crew that tolli engine flame out is’as imminent that the captain was concerned and, in fact, mny have been confused as to the amount of fuel which actually remained. About G min before all engines stopped, the captain stated that there was 1,000 lbs of fuel in the So. 1 main tank, and the flight engineer agreed with him. .4t this same time, the captain began to describe the gage indication as changing from 1,000 ibs to zero 15s. Since the No. 1 main tank gage does not change its indication from 1,000 105 to zero ibs directly, but decreases in increments of 100 lbs, the captain must have read the gage indication incorrectly. Actually, the action he described was ttrrt of a gage changing from 100 Ibs to zero lbs. The company had recently changed the fuel quantity gpzcs 01 t!lls n~rcmft from a direct reading digital-type to a three-figure indicator tturt hrtd to be multiplied by a factor of 100 to get the actual individual tank vnlucs. In nddit ion, the new totalizer gage, of the same three-figure presentation as the indivldunl tank gages, had to be multiplied by a factor of 1,000 to get the actual totol fuel. During the stressed situation, the captain and the flight engineer may have mixed up these multipliers and used 1,000 when reading the individual.tank glgees instead of 100. However, there is no evidence from previous comments that such a mistake was made: By the .time such confusion was indicated;- the nccident was inevitable. The Safety Board believes that this accident exemplifies a recurring problem --a breakdown in cockpit management and teamwork during a situation involving malfunctions of aircraft systems in flight. To combat this problem, responsibilities must be divided among members of the flightcrew while a malfunction is being resolved. In this case, apparently no one was specifically delegated the responsibility of monitoring fuel state. --.----_- -. Although the captain is in command and responsible for the performance of his crew, the actions or inactions of the other two flight crewmembers must be analyzed. Admittedly, the stature of a captain and his management style may exert subtle pressure on his crew to conform to his way of thinking. It may hinder .-$! interaction and adequate monitoring and force another crewmember to yield his right-e..to- -_.. express __c _.-. - an ..-..opinion. __ The first officer’s main responsibiIity is to monitor the captain. In particular, he provides feedback for the captain. If the captain infers from the first officer’s actions or inactions that his judgment is correct, the captain could receive reinforcement for an error or poor judgment. Although the first officer did, infact, make several subtle comments questioning or discussing the aircraft’s fuel state, it was not until after the No. 4 engine flamed out that he expressed a direct view, “Get this . . . on the ground.” Before that time, the comments were not given in a positive or direct tone. If the first officer recognized the criticality of the situation, he failed to convey these thoughts to the captain in a timely manner. The flight engineer’s responsibility, aside from management of the aircraft systems, is to monitor the captain’s and first officer’s actions as they pertain to the performance of the aircraft, that is, takeoff, landing, holding speeds, and range of the aircraft considering time and fuel flow. Although he informed the captain at 1750:30 that an additional “fifteen minutes is really gonna run us low on fuel here,” there is no indication that he took affirmative action to insure that the captain was fully aware of the time to fuel exhaustion. Neither is there an indication that, upon returning to the cockpit at 1801:39, he relayed any concern about the aircraft’s fuel state to the captain. Although he commented that 3,000 lbs of fuel remained, he failed to indicate time remaining or his views regarding the need to expedite the landing. The first officer’s and the flight engineer’s inputs on the flight deck are important because they provide redundancy. The Safety Board believes that, in training of all airline cockpit and cabin crewmembers, assertiveness training should be a part of the standard curricula, including the need for individual initiative _ _.- ._.and effecti-v-e. expression of concern. - - ------ --_.___ In order to determine.’ whether the captain had received all available assistance during the emergency, the Safety Board evaluated the actions of the company dispatcher and his role relative to the accident sequence. According to the tape of the conversation between the captain, the company dispatcher, and company line maintenance personnel, the captain had advised the dispatcher that he had 7,000 lbs of fuel aboard and that he intended to land in 15 or 20 min. The dispatcher then checked with the captain to ascertain a specific time for the landing and the captain agreed that 1805 was Ita good ballpark.” The dispatcher, according to his interview after the accident, then relayed this landing time and the aircraft’s status to the company personnel in Portland. He also stated that his assessment of the situation was that of the fuel remaining upon landing would be low but the landing could be made successfully at 1805. The Safety Board believes that, with the information given to him by the captain, the dispatcher acted properly and in accordance with company procedures. P 3. CONCLUSIONS 3 .l Findings 1. The flightcrew was properly certificated and qualified for the flight. 2. The aircraft was certificated, maintained, and dispatched in accordance with Federal Aviation Regulations and approved company procedures. 3. Except for the failure of the piston rod on the right main landing gear retract cylinder assembly, with the resulting damage to the landing gear position indicating system switch, there was no evidence of a failure or malfunction of the aircraft’s structure, powerplants, flight controls, or systems. : 4. The aircraft departed Denver with the required fuel aboard of 2 hrs 26 min for the en route flight and with the required E:.4R and company contingency fuel aboard of about 1 hr. 5. The aircraft began holding about 1712 at 5,000 ft N ith its gear doivn; this was about 2 hrs 24 min after it departed Denver. 6. The landing delay covered a period of about 1 hr 2 min. 7. All of the aircraft’s engines flamed out because of fuel exhaustion about 1815-l hr 3 min after it entered into hold and 3 hrs 27 min after it departed Denver. a. Fuel exhaustion was predictable. The crew failed to equate the fuel remaining with time and distance from the airport. 9. No pertinent malfunctions were found during examinations of the fuelquantity measuring system. 10. A new digital fuel-quantity indicating system was installed on this aircraft on hlay 12, 1978. This was in accordance with a DC-8 UAL flee tw ide retrofit program. 11. Evidence indicates that the fuel quantity indicating-system accurately indicated fuel quantity to the crew. 12. The fuel gages are readily visible to the captain and the second officer. 13. The captain failed to make decisive timely decisions; 14. The captain failed to relate time, distance from the airport, and,the aircraft’s fuel.,_.. state. directed cbmple tely to.ward the . .._..- as _ hisattentiqn-was + --29- . ’ --- , - 3.2 Probable Cause The National Transportation Safety Board determined that the probable cause of the accident was the failure of the captain to monitor properly the aircraft’s fuel state and to properly respond to the low fuel state and the crew-member’s advisories regarding fuel state. This resulted in fuel exhaustion to all engine‘s. His inattention resulted from preoccupation with a landing gear malfunction and preparations for a possible landing emergency. Contributing to the accident was the failure of the other two flight crewmembers either to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain. *30- - 4 ’ * _.__ , , 4. Safety Recommendations As a result of this accident, the Safety Board has issued the following recommendations to the Federal Aviation Administration: “Issue an .Operations Alert Bulletin to have FAA inspectors assure t h a t c r e w training stresses differences in fuel-quantity measuring instruments and that crews flying with the new system are made aware of the possibility of misinterpretation of gage readings. (Class II--Priority Action) (A-79-32)” “Emphasize to engineering personnel who approve aircraft engineering changes or issuance of Supplemental Type Certificates the need to consider cockpit configuration and ” instrumentation factors which can contribute to pilot confusion, such as the use of similar-appearing instruments with different scale factors. (A-79-33)” (Class II--Priority Action) “Xudit S u p p l e m e n t a l T y p e C e r t i f i c a t e SX3357 \\‘E-D f o r completeness, e-pecially in the area of system calibration after installation. (Class II--Priority .4ction) (X-79-33)” “Issue an operations bulletin to all air carrier operations in-spec tors directing them to u~c their assigned operators to ensure that their flightcrews are indoctrinated in principles with particuhr o f f l i g h t d e c k resoume management, emphasis on the m e r i t s o f p a r t i c i p a t i v e m a n a g e m e n t f o r captains and assertivene.ss t r a i n i n g f o r o t h e r c o c k p i t crewmembers. (Class II, Priority diction) (X-79-17)” I ;j BY THE NXTlONXL TR.\NSPORTATlON SAFETY BOARD JAMES B. KING- /S/ Chair man /s/ ELWOOD T. DRIVER Vice Chair man . ,:. _’ I /s/ FRANCIS H. McADAMS Member /s/ PHILIP A. HOGUE Member June 7, 1979 I_ --_-__ ~_. _ - - ---.. .-.-_. I .-_. --- --. --.-.---- ____. -- - _. N -- -- --.- - - -_.. .-- ’ l - __ . 4‘..._ , -315. APPENDIXES APPENDIX A Investigation and Hearing 1. Investigation The Safety Board was notified of the accident about 2130 e.s.t. on December 28, 1978. The investigation team went immediately to the scene. LVorking groups were established for operations, air traffic control, witnesses, human factors, powerplants, structures, systems, maintenance records, weather, cockpit voice recorder, flight data recorder, and performance. Participants in the on-scene investigation included representatives of the Federal Aviation Administration, United Airline, Inc., Douglas Aircraft Company, Air Line Pilots Association, Professional Air Traffic Controllers Association, Association of Flight Attendants, International Association of Machinists, ~lultnomah County Sheriff’s Office, and Port of Portland. 2. Public Hearing There was no public hearing held in conjunction with this accident investiga- tion. 3. Deposit ions The cap ta in was deposed at the Federal Aviation Administration’s Rocky Jlountain Regional Headquarters in Denver, Colorado, on March 6, 1979. Parties to the deposition included representatives of the Federal Aviation Administration, United Airline, Inc., Douglas Aircraft Company, and the Air Line Pilots Association. --%32-- - I 8 I ___ . . APPENDIX B Personnel Information Captain Malburn A. McBroom Captain Malburn A. McBroom, 52, was employed by United Airline, Inc., on May 1, 1951. He was upgraded to captain on July 1, 1959. Captain McBroom had 27,638 total flight hours, 5,517 of which were as a captain in the DC-S. In the previous 90 days, 7 days, and 24 hours, he had 210, 18:04, and 3:38 flight hours, respectively. He had 14:40 hours of free time before reporting for this flight. Captain McBroom holds Airline Transport Pilot Certificate No. 1006880, issued September 28, 1971. He is type rated in the Douglas DC-8 and, the Boeing 727. His first-class medical examination was passed September 22, 1978, with the limitation that the holder shall possess glasses for near vision while flying. Captain >lcBroom p a s s e d s a t i s f a c t o r i l y h i s l a s t p r o f i c i e n c y c h e c k September 1, 1978, and his last en route check October 5. 1978. First Office R&rick D. Beebe First Officer Rodrick D. Beebe, 45, was employed by United Airline, Inc., on June 19, 1965. He ;vas upgraded to a DC-8 first officer on June 21, 1978. First Officer Beebe had 5,209 total flight hours, 247 of ivhich ivere as a first officer in the DC-8. In the previous 90 days, i days, and 2-1 hours, he had 182, 18:01, and 3:38 flight hours, respec timely. He had l-1:10 hours of iree time before reporting for this flight. First Officer Beebe holds Commercial Pilot Certificate No. l-131046, issued September 15, 1975. tie is rated in airplane multiengine land aircraft with instrument privileges. He also holds a rotorcraft rating. His first-class medical examination ivas pa.std October 3, 1978, with no limitations. First Officer Beebe had his last emergency training June 24, 1978. He passed satisfactorily his proficiency check June 21, 1978, as well as his initial DC-8 en route proficiency check August 1, 1978. Second Officer Forrest E. Mendenhall Second Officer Forrest E. hlendenhall, 41, was employed by United Air Lines, Inc., on December 18, 1967. He was upgraded to a DC-8 second officer on January 31, 1975. Second Officer Mendenhall had 3,895 total flight hours as a second officer, 2,263 of which were in the DC-8. In the previous 90 days, 7 days, and 24 hours, he had 179, 18:04, and 3:38 flight hours, respectively. He had 14:40 hours of free time before reporting for this flight. Second Officer Mendenhall held Flight Engineer Certificate No. 1819179, issued February 14, 1968, with a turbojet rating. He also held Commercial Pilot, Certificate No. 1632855, issued April 22, 1965. He was rated in multi- and single- .,-- - -.__ -._-_-~----~--.. - ---.--------. - _... -. -.: --..-.-.-.-_ -.__ ---_-- ----_--_- ------ engine land and sea with instrument privileges. examination was passed, with no limitations. His first-class medical Second Officer Mendenhall had his last emergency training August 16, 1978. He passed satisfactorily his proficiency check February 24, 1978, as well as his en route proficiency check December 14, 1978. Flight Attendants Joan Wheeler Nancy King Sandy Bass Martha Fralick Diane woods 7/15/64 812167 10/U/67 U/67 l/26/72 10/4/42 4/16/47 g/21/46 ll/19/45 5/14/49 Date oi Init ial Training 8/19/64 g/6/67 11/15/67 12/6/67 2/24/72 Date llost Recent Recurrent Emerg Tng 4/20/78 6/16/78 u/19/78 ll/Ll/78 3/T/78 Date of Hire Date of Birth I ,, -34- *. -__ * * APPENDIX C Aircraft Information Aircraft N8082U, a McDonnell Douglas DC-8-61, serial No. 45972, was owned and operated by United Airline, Inc. It was manufactured May 22, 1968, and delivered to United Airlines cn that date. At the time of the accident the aircraft’s operating hours and maintenance inspections were as follows: Total Hours Aircraft Inspection Inspection Inspection In-Tee tion 33,114:33 Ck Kk Bk AK Maximum I, L i m i t s -25.000 3,boo 1,675 400 100 ESGISES - Pratt A \\‘hitnev JT3D-3B I T-so Date Installed j ‘! ‘t) Hours Since Overhaul 21,245:43 Hours to Next overhaul/ inqec tion 3,754:17 1,78 1:49 456:49 366:03 16:03 So. 1 Engine IlOUl-S Flight Cvcles Hours since Installed 8-8-78 29.305: 28 11,266 1,228:-A3 10-24-73 X.685:28 11,897 59T:43 1-19-78 31,080:28 11,821 2,933:33 11-26-77 31,640: 28 14,540 3,367:43 S/N 669234 $0. S/N So. S/N So. S/N ‘ -.--Y--..- _ 2 Engine 669312 3 Engine 613929 -1 Engine 64-1806 _ __.__ __ . ___ .-,-. __. ----- ------ -. --,--_-_.- .__.~.__ - - -.-rr.-~ ._-.. .- ----T-Lc-. __. . . .Tr- - -. -.‘ ---. -.-..- c -*.,-- r i .;’ --__- .---..-.. . - .-a - ....,L.--*.C _ -I- IL:“ 4..-&...z’ -.-~ - - ._.. -.- :.y . . ‘ -. L’ ..~ -------, --cl& 4 0 -- APPENDIX D 1 3 TRANSCRIPT OF A SUNDSTKAND V557 COCKPIT VOICE RECORLJER SERIAL NO. 1427 REMOVED FROM THE UNITED AIRLINES DC-8 WHICH WAS INVOLVED IN AN ACCIDENT AT PORTLAND, OREGON ON DECEMBER 28,1978 4 THE TIME IS IN PACIFIC STANDARD TISIE 2 LEGEND 5 CA,!4 Cockpit area microphone voice or sound source RDO Radio transmission from -1 Voice iderltifi ed as Captain 8 -2 Voice identified as First Officer 9 -3 Voice identified as Flight Engineer -4 Voice identified as off duty Captain -5 Voice identified as Flight Att mdant 71 -? Voice unidentifi e-d 12 UNK * Unknown Unintelligible word li Nonpertinent word 14 x Nonpertinent text 15 5% Drak in continuity ( > Questionable text Editorial insertion 17 (( 1) --- Pause 18 PA Portland Approach Control Cb United Company 6 7 10 13 16 19 VHF VHF Radio 20 xxx Nonpertinent aircraft or facility call 21 PD Portland Departures TWR Portland Tower 22 23 24 25 \ ‘a -__ ‘, -- -36INTRA-COCKPIT TNE & SOUKCE CONTENT APPENDIX D AIR-GROUND COMMUNICATIONS TIME dr SOURCE CONTENT t How you doing (Dory)? Ke’re ready for your announcement (Do) you have the signal for not evacuate also the signal for protective position. XXX Thar’s rhe only rh:ngs I need from ycu right nou’ Okav ah, u bar u ould you do? Have you g21 any suggesr:3ns abou: u -hm !o brace? ‘Xanr to do II on :hc PA? I - - - I’ll b e honncst uith hcu, I’ve ncvm had one of thee 3eiore --- .lIy firs1 you know --- l All rlghr, u,hat \;e’ll do IS u,e’ll have oh shout 3 couple of miflUiC5 before touchdown signal for brace posItIon FrOs11e 17$5:flb RDO-2 CA.\\-5 Okay, he’ll come on rhc PA CAh4-I and then ah --- CA.\l-5 And if you don’t want Us to evacuate what’s are you gonna say 1745:09 CAM-I CAM-5 We’ll either use the PA or we’ll stand in the door and hollar Okay, one or the other, ah we’re reseating passengers right now and all the cabin lights are full up Left I’*‘0 tu’cnty one seventy three heavy I . .y: ..‘ .*. .-!! ,-,e. . . I..._, .,_ . ._. . .--, __ ._ ,<-‘ -“ - - .._.. . - _. - -’ --- - ;-”-- -37 APPENDIX D AIR-GROUND COMMUNICATIONS INTRA-COCKPIT TIME k SOURCE CAhl-I Okay CAM-5 W ill go take it from there CAM-I All r i g h t 1745:23 CAXl-5 1745:43 CAA1-3 CAL\- 3 1746:21 CAM- 3 TIME dc SOURCE CONTENT We’re ready for your announcement any time I can see the red indicators from here, ya know but I can’t tell l l if there’s anything lincd up. Cause I only gor this thing to shine down there l l l all the way down XXX Last guy to leave has gotta turn the battery external power switch Off CA.Li-? You’re right C?Al-? l CAhl-? l 1746:52 CAhl-2 CAM-3 CAM-2 - How much fuel we got Frostie? Five thousand -_ Okay 1748:00 CAiM-4 Gonna get us a spare flashlight CAM-5 Sir? CAM-4 ‘Conna get us a spare flashlight 1748:17 CAM-4 Less than three weeks, three weeks to retirement you better get me outta here CONTENT INTRA-COCKPIT TIME & CONTENT SOURCE 1748:ll Thing to remember is don’t worry CAM-I CAM-? What? CALI- Thing to remember is don’t worry 1748:21 CA.l\-4 Yeah CA.\l-O If I might make a suggest eon --- APPENDIX D A I R - G R O U N D COMh4UNICATIONS TIhlE & SOURCE CONTENT You should put your coats on - - Both for your protcctlon and so you’ll be noticecl so they’ll know who you are 1745:33 C.?.\l-I C,A\!-L Oh that’s oka) But If it gets, 11 11 gets hot II sure is nice to not have bare ‘r::?s I74S:OO PA C.A\!-I 174s:43 CA.\\-I -- CA.lI-4 Unltcd one scvcnlj rhree heavy, traffic clcim o’clock f~\e rn~lu ror:? Sound i’FX Cod c l-.‘r,kno,~ n Yesh But if anything goes u’rong bou lust charge back there and get !‘our ass off, Okay 171;5:45 RDO-2 Yaah PA CAXI-4 I told, I told the gal, put mc where she wants me, I think she wants me at a wing exit CAX4-I Okay fine, thank CAM-2 (We better turn around and head west) you Yeah, \ce’ve got sorn&oc~y out there me ‘Kay . N -39INTKA-COCKPIT TIME & CONTENT SOURCE 1748:54 CAM-2 Ah, what’s the fuel show now, buddy? 1748:56 CAI\I-I Five CAM-2 Five CA.iI-3 (The lights in the fuel punlp ---1 1749:oo CA.\\-1 ___ -_. .--0 -- ( _._. . . .- , APPENDIX D A I R - G R O U N D COh~MUNICATIONS TIhtE & CONTENT SOURCE That’s about right, the feed pumps are starting to blink xxx C/1X1-? That lights too big to shine down there c .A.!\ - ? Yeoh CAhl-? Slaybe CA.\l-? You can always get a l l l XXX 1749:45 CAXI-? CAM-? PA United one seventy three heavy turn left heading one six zero RDO-2 Okay, left one six zero You got one seven three heavy ilain gear back there Yeah both of them appear to be down and locked * * 1749:50 RDO-2 That guy’s out there about nine thirty, now is that right? -4oINTRA-COCKPIT TIME & SOURCE CONTENT APPENDIX D A I R - G R O U N D COI’.~L!UNICATIONS TIME & SOURCE CONTENT 1749:53 PA Say again 1749:55 RDO-2 CA&!-? l I see him 1749:57 PA Ah, traf f it’s out There about nlnc thirty now.? Ah no, he’s about SIX o’clock now ihe one that I called earllc-r, now you got another 3sout nine ;Fl;rty, d:30<: five rnilcs c~rcl:r,g 175rJ:17 RLX-2 I7 SO:16 CA.\i-I Okay CAhl-I Hay, Frost le C/Ul- 3 CA.\l-I 1750:30 CA,\I-3 Give us 3 current card on weight figure sbou: another fifteen minutes Fifteen minutes? CAhl-I Yeah, give us three or four thousand pounds on. top of zero fuel weight CAM-3 Not 1750:34 CAM-3 CAM-? xxx enough Fifteen minutes is gonna --- really run us low on fuel here Right 1750:35 PA United one seventy three -45. INTRA-COCKPIT TIME & - SOURCE CONTENT CAM-I Okay CAAI-I Do you want to run through the approach descent, yourself? CA:\l-I So you (don’t forget something) CASl- 3 Yes, sir APPENDIX D AIR-GROUND TI5IE Er SOURCE 1754:19 PA 1754:23 RDO-2 1754~27 CAX1-2 1754:31 CAhl-I CAhl-I 1755:04 CAM-3 He’s going to have the company call out the equipment? U’e’ll (call) dispatch In San Francisco and maintenace doaxn there will handle it that way so u’e don’t get it all over local radio The ramp here is going to back it up by getting the crash equipment. How many people and all that? When we get done back there then 1’11 tell them what we’re going to do, so we don’t end up with about a million rubber neckers out there. Okay, approach descent check is complete xxx COMMUNICATIONS CONTENT United one seventy three heavy traffic at twelve o’clock a half a mile Yeah we got it down belou APPENDIX D -46INTRA-COCKPIT TWE & CONTENT SOURCE 1755:13 Okay, check the new ATIS is CAM-I delta CA.!!-1 AIR-GROUND TI.VE t?i SOURCE 175S:Sl CASI-3 Wind is three forty at eight 17)5:55 CA.\\-1 Okay 1756:S3 CAhI-2 Portland International Information delta Portland u,cather four thousand f ive hundred scattered visibility three zero t ernperatur e three zero, de.& point one three urnds three !our zero degrees at s 3li:mete: tb,:ce c!g.tt zero one SIX You want to be sure the flight Sgs and all that // are stowed l l l fastened, why don’t you put all you: books in your bag over there, ROC. .x x x How much fuel you got now? CAU-3 Four, four --- thousand --- in each --- pounds CAM- 2 Okay 1757:21 CAM-I CONTENT What I need is the wind, really VHF CA.\t- I COMMUNICATIONS l Y o u m i g h t - - - you might just take a walk back through the cabin and kinda see how things are going Okay? 1757:02 PA 1757:06 RDO-2 ., One seventy three heavy turn left two eight five Two eight five one seventy three heavy -. v _ ____ . _-- -. _----.. . Qy ’ __-- - ( . -. _ _ . -- APPENDIX D -470 INTIIA-COCKPIT TIME & SOUHCE 1757:30 CAhj-I CA.jI-3 1758:lS CAXI-2 1755:28 CA.\!-2 1755:3s CA\\-t CA.\\-1 1758:45 CAh\-2 CONTENT T I M E 6: SOURCE GONTENT I don’t want to, 1 don’t want to hurry, em but I’d like to do it in another oh, ten minutes (or so) Yeah, 1’11 see if its, --- get us ready If u*e do indeed --- have IO evacuafe assuming that none of us are incapacitated. You’re going 10 take care of the shutdou.n, right. Parking brakes, spoilers a”d flaps, fuel shut off levels, fire handles, battery switch and all thqt l l You just haul ass back rhere and do whatever needs doing 1 think that Jones is a pretty level headed gal, and Pardon? CA.\\-] I think that “A” Stew is a pretty level headed gal, and sounds like she knows what she’s doing and CAL\-I l l been around for a while, I’ m sure Duke will help out 1800:15 CAL\-2 AIR-GROUND COMMUNICATIONS We’re not gonna have any antiskid protection, either xxx 1800:24 CAM-I Well, I think the antiskid is working, it’s just the lights that ain’t working . _ 1 \\ -’ * 4 8 INTRA-COCKPIT TIME & SOURCE 1800:33 CAM-2 CONTENT Yeah CAM-2 Oh, it did CAM-J Yeah CA,\\-2 Oh 1800:50 CAhI-2 CA,\:- I _. -. , . APPENDIX D A I R - G R O U N D COMh9UNICATIONS TI.VE 6( SOURCE CONTENT That light go off when you push the circuit breaker in? CAM-I ISOO:42 CA.!!-I ’ XXX I won’t use much breaking we’ll just let it roll out easy l l You plan to land as slow as you can with the power on? Ah, I think about ref or there abouts try and hold the nose wheel off, I’m, I’m tempted to turn off the automatic spoilers to keep it from pitching down, but lets try and catch it ISr,I:l2 P:I United one seventy three heavy turn left heading one niner five 1501:15 R D O - 2 Left one niner five one seven three heavy .. 1801:34 CAM-3 CAM-I 1801:39 CAM-3 (You’ve got) another two or three minutes O k a y - - - How are the people Well, they’re pretty a h - - - some of em n e r v o u s , a h - - - but part they’re taking they --- calm and cool are obviously for the most it in stride --- -49INTRA-COCKPIT TIME & SOURCE CAlI- 3 1802:OS CA,\l-I i CA.\l- 3 lSO2:22 Crl.\l- 3 lSO2:2S CA.\!-I CONTENT TIME bc SOURCE I ah stopped and reassured a couple of them, they seemed a little bit more --- more anxious than some of the others Okay, well about two minutes before landing that will be about four miles out, just pick up the mike --- the PA and say assume the brace position Okay G’e got about three on the fuel (and ’ that’s it) Okay, on the touch down if the gear folds or something really jumps the track, get those boost pump off so that --- you might even get the valves open. lSC2:44 PA 1802:49 RDO-2 1803:14 PA I CONTENT United one seventy three heavy did you figure anything out yet about how much longer? Yeah, we, ah, have indication our gear is abnormal it’ll be our intention in about five minutes to land on two eight left, we would like the equipment standing by, our indication are the gear is down and locked, we’ve got our people prepared for an evacuation in the event that should become necessary Seventy three heavy, okay advise when you’d like to begin your approach \\ -- -SO- INTRA-COCKPIT TIME & CONTENT SOURCE l ’ _ -_. , APPENDIX D AIR-GROUND COMMUNICATIONS TIVE dr SOURCE 1803:17 RDO-I CONTENT Very well, they’ve about finished in the cabin -- I’d guess about another three, four, five minutes - I 1303:23 PA 1503:29 CA\\- 3 United one seven three heavy, if you could, ah, give me souls on board and amount of fuel One seventy two plus, ah 1803:30 CA.%\- 3 Plus six laps RDO-I One seven two an about four thousand well, make 11 three thousand pounds of fuel PA Thank you 1803:33 RDO-I CA,%\-2 I think he wants souls on board, he wants crew members and everything CA,\!-3 Ah, that right, he does, doesn’t he? 1803:58 CAIM-3 Ah, five, three, eight, nine CAhI-3 Eight, i’sn’t it? CAM-I Well, okay Okay, and you can add to that one seventy lwo plus six laps, infants 1804:04 CAM-2 One eighty five CAM-I There’s one check that we missed CAM-? What xxx INTRA-COCKPIT TIhlE h TIME & SOURCE CONTENT CAhl-I Checking the gear warning horn CAM-? l CAM-? right CAM-I right CAM-? right 1804:44 CAJI-I How do we do that? right CAhl-2 What we gotta do is get us past flaps thirty five l CALI- Thirty five what happens when you close the throttles (any idea)? CAM-2 You can do that too, it’ll be one or three 1804:59 CA!vI-I 1805:08 CAM-2 Yeah But we con? tell with that breaker out I guess CAM-3 Yeah CAM-I Push the breaker momentarily CAM-I Ready? CAM-3 Yeah 1805:26 CAM-3 Okay, pull the breaker? CAM-I Yeah 1805:35 CAM-3 1805~39 CAM-l APPENDIX D & R - G R O U N D COhlhlUNICATIONS Okay, now we won’t have the spoiler pump automatic spoilers Yes we will SOURCE CONTENT . -52INTRA-COCKPIT TIME & SOURCE CONTENT CAM-3 The antiskid? CAhl-I Well, wait a minute, I think the systems totally normal. Indications are what they are because the circuit breakers popped CA,\l- 3 Yeah CA11-2 Right CA\l- 3 ilight 1sos:Yl CA.\l-I 1506:04 Ch,hl- 2 1506:lO CA,hl- I . -- -. . . . APPENDIX D AIR-GROUND COMMUNICATIONS TIME h SOURCE I CONTENT Should have antiskid automatic spoilers and all that, ue may not get ground shift because of mechanical ground shift problems U’ell, ah (let’s have me) standby the boilers, spoilers anyway If we don’t get em, u hy I can - - I think if we get the antiskid fall light is off we’ll get the automatic spo~lcrs ISC6:13 PA United one seven three heavy turn left heading zci.0 five zero CA,\; ((Sound of cabin door)) 1806:lV CAM-I How you doing? CA,M- 5 Well, I think we’re ready 1806:21 RDO-2 1806:23 PA CAM-I Okay Left to zero five zero, United one seventy three heavy Roger -53INTRA-COCKPIT , T I M E & SOURCE CONTENT CAM-5 We’ve reseated, they’ve assigned helpers and showed people how to open exits and ah, CAlI- Okay CA,!f-5 ‘tie have they’ve told me they’ve got able bodied men by the windows CA’x\-5 The captain’s in the very first row of coach after the galley CA.Il-? Any invalids (* l pull out wInlows *I 1806:34 CALI-S He’s going to take that that middle galley door its not that far from the window CA.\\-? Yeah CA.Il-? l CA.V-? l CA.ll-I l l Okay we’re going to go in now, we should be landing in about five minutes CAL!-(3/2) I think you just lost nurnber four buddy, you --CAM-5 . Okay, I’ll make the five minute announce, announcement, I’ll go I’m sitting down now CAM-2 Better get some cross feeds open there or something CAM-3 Okay CAM-5 A l l righty 1806:46 ! : CAM-2 We’re goin to lose an engine buddy CAM-l Why? APPENDIX D A I R - G R O U N D COhlhlUNICATIONS TIVE dt SOURCE CONTENT INTKA-COCKPIT TIME & SOURCE CONTENT APPENDIX D AIR-GROUND COMMUNICATIONS TIME 8 SOURCE CONTENT 1806:49 CAM-2 We’re losing an engine CALi- l CA.\l-I Why 1506:52 CA.I\-2 Fuel CA.\\-2 Open the crossfeeds, man CA\!-1 Open the crossfeecs there or something ((sirnuitaneous *+vith above)) l l ((Voice fading out)) 1806:S5 CA.\\-3 Showing iumes CA.\\-2 (Think, maybe we) CA.\!-1 Showing a thousand or better 1 X07:00 CA.t1-2 I don’t think its in there CA.\{-3 Showing three thousand isn’t it CAh!-I Okay, it, its a 1X07:06 CAM-2 Its flamed out 1807:12 RDO-I I Uniied one seven three would like clearance for an approach into two eight left, now I 1807:17 PA United one seventy three heavy, ok, roll out heading zero one zero --- be a vector to the visual run- way two eight left and ah, you can report when you have the airport in sight suitable for a visual approach. I \\ 35INTRA-COCKPIT TIME & SOURCE 1807:27 CAhl-3 CAL\-I CONTENT U’e’re going to lose number three in a minute too Well 1807:31 CAlI- 3 CAll- I You gor a thousand pounds, you got (0 CA.\\-3 Five rhousand in there, buddy, but we lost rf CA\!-1 ,411 rrght 1507:3s CA\1-3 Are you getting II back ISO7:?3 CA\\-2 lSO7:41 CA.jl-3 1807:42 CAL\-I ’ INO, I haven’t got it open, which one Open em both, II get some fuel in there CAM-I Got some fuel pressure? CAM-3 Yes, sir 1807:48 CAM-I Rotation now she’s coming 1807:52 CAM-l Okay, watch one and two CAM-I We’re showing down to zero or a thousand CAM-3 Yeah i : So, nurnbcr four, you got that crossfeec open? . *_ _., . -- APPENDIX D AIR-GROUND COMMUNICATIONS TIME & SOURCE CONTENT 1807:25 RDO-I Very well -560 INTRA-COCKPIT APPENDIX D AIR-GROUND COMMUNICATIONS I TIME dr SOURCE CONTENT CAM-I On number one CAM-3 Right 1808: 18 CA,M-2 Still not getting it 1808:ll CA,\!-1 TIME h SOURCE xxx Well, open all four crossfeeds CA,\4-3 All four? C.A:\l-I Yeah 150X:14 CAdit- All right now, IIS coming CONTENT 1SO8:19 CA.\1-2 CA:\\-? It’s going to be D on approach though Yeah 190X:42 CA,\\-1 You CAL1-3 Yes, sir 1508:45 CAV-2 gotta keep em running, Frostie xxx Get this # on the ground CA.ti-3 Yeah CAhl-3 It’s showing not very much more fuel 1808:50 RDO-I 1808:58 PA United one seven three has got the field in sight now and we’d like an ASR to ten left er t w o e i g h t l e f t Okay, United one seventy three heavy, maintain five thousand 1809:03 RDO-I hlaintain five \\ INTRA-COCKPIT T161E 6: SOURCE 1809:16 CAXI-3 1309:17 CA.\\-3 CONTENT -- -57- . ‘ _ -., . APPENDIX D AIR-GROUND COMMUNICATIONS TIME & SOURCE CONTENT We’re down to one on the totalizer Number two is empty 1899: 21 RlIO-I lSO9:27 PA United ah, one seven three is goint to turn toward the airport and come on in Okay now you want to do on a visual is that what you want? II CA\\-2 Yeah lSrJ9:32 RDO-I ISO9:33 PA 1909:39 RI-IO-2 1809:42 PA 1809:45 RDO-2 CAM-I i . 1809:51 CA,&!-2 Yeah ((Sound of spool down)) You want the ILS on there Buddy Yeah Okay United one seventy three heavy ah turn left heading three six zero and verify you do have the airport in sight W,e do have the airport in sight, one six three heavy elt one seven three heavy One seven three heavy is cleared visual approach runway two eight left Cleared visual two eight 1 e f t . -, I -- . APPENDIX D AIR-GROUND COh4MUNICATIONS INTRA-COCKPIT I TIME dc SOURCE CAhl-I CAhl-2 CONTENT TIhIE dr SOURCE CONTENT xxx Well It’s not going to do you any good now CAL!-1 1810:17 CAX\-I No, we’ll get that Il warning thing if we do Ah, reset that circuit breaker momentarily, see if we get gear lights 1X10:24 CA.V-I Yeah, the nose gears down CA.%\-3 Off CAL{-I Yeah 1X10:33 CA.\l-I About the time you give brace position Ihat CAL!- 3 You say now CAM-I No, no but when you do push that circuit breaker in 1810:43 CAM-3 Yes, sir I X10:47 RDO-I Ho-w far you show us from the field? 1810:51 PA Ah, I’d call it eighteen flying miles 1810:54 RDO-I 1810:59 CAM-3 Boy, that fuel sure went to hell all of a sudden, I told you we had four All right ’ TIME & SOURCE 1811:lS CAV-I ___ . , APPENDIX D -59INTRA-COCKPIT ’ A I R - G R O U N D COMhlUNICATIONS TIME & SOURCE CONTENT There’s ah, kind of an interstate high --- way type thing along that bank on the river in case we’re short CONTENT xxx . 1812:03 CA.il-? Okay I812:Ob CA’.!-1 I812:22 CA.\!-2 ihat’s Troutdale over there six of one half d dozen of the other ZDOU~ Let’s take the shortest route to the arrporr 1812:42 RDO-I \Vhat’s our distance now? lSI2:45 PA Twelve flying miles 1812:CS CA.\\-? Well, l l 1812:SO RDO-I I 1812:52 CAhl-I About three minutes CAM-I Four CAhl-? (Yeah) 1813:21 CAM-3 We’ve lost two engines guys CAM-2 Sir? 1813:25 CAM-3 We just lost two and two Okay -_ xxx engines, one -6OINTRA-COCKPIT TIME Jr SOURCE 1813:28 CAM- 2 CONTENT APPENDIX D A I R - G R O U N D COMhlUNICATIONS TIME dr SOURCE You got all the pumps on and everything 1813:29 PA CA.\4-3 CONTENT United one ieyenty three heavy contact Porrland tower one one eight point seven, you’re about eight or niner flying miles from the airport Yep 1513:35 RDO-2 Okay, elghtcen seven PA Have a good one 1813:38 CA,\\-1 They’re all going , 1813:41 CAX{-I We can’t make Troutdalc 1813:43 CA.\!-2 We can’t make anything 1813:46 CA.\\-1 Okay, declare a maydab lS13:50 RDO-2 18 1 WS((impact with transmission lines as derived from tower tape.)) Portland tower United one seventy three heavy hlayday we’re the engines are flaming out, we’re going down, we’re not going to be able 10 make the airport 1813:58 TWR United 1813:59 TWR ((end of tape)) one