TWA Flight 841 (1979)

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For the 1974 incident on the same flight number, see TWA Flight 841 (1974).
1979 TWA Flight 841
N840TW, the aircraft involved in the incident.
Accident summary
Date April 4, 1979
Summary Unknown
Site Detroit, Michigan
Passengers 82
Crew 7
Injuries (non-fatal) 8
Fatalities 0
Survivors 89 (all)
Aircraft type Boeing 727-31
Operator TWA
Registration N840TW

On April 4, 1979, a Boeing 727-31 (tail number N840TW) operating as TWA Flight 841 took off from John F. Kennedy International Airport, New York City, en route to Minneapolis-Saint Paul International Airport in Minneapolis, Minnesota. At around 9:48 p. m. local time, over Saginaw, Michigan, while the plane was cruising at 39,000 feet (11,887 m) and Mach 0.816, it began a sharp roll to the right. The roll continued despite the corrective measures taken by the autopilot and the human pilot. The aircraft went into a spiral dive, losing about 34,000 feet (10,363 m) in 63 seconds. During the course of the dive, the plane rolled through 360 degrees twice, and crossed the Mach limit for the 727 airframe. Control was regained at about 5,000 feet (1,524 m) after the first officer, with the captain in agreement, extended the landing gear in an attempt to slow the aircraft,[1][2] and following the loss of the #7 slat from right wing. The plane suffered substantial structural damage, but made an emergency landing at Detroit Metropolitan Airport, Michigan, (airport code DTW) at 10:31 p. m. local time without further trouble. No fatalities occurred among the 82 passengers and seven crew members. Eight passengers reported minor injuries relating to high G forces.[3]


The National Transportation Safety Board investigated the accident and established after eliminating all individual and combined sources of mechanical failure, that the extension of the slats was due to the flight crew manipulating the flap/slat controls[4] in an inappropriate manner. The rumor was that 727 pilots were setting the trailing edge flaps (which were normally only deployed at low speeds along with leading edge slats) to two degrees during high altitude cruise, while at the same time pulling the circuit breaker for the slats so that they would not activate. This configuration was rumored to result in increased lift with no increase in drag, thus allowing more speed, higher elevation, or decreased fuel consumption.[5]

The crew, Capt. Harvey "Hoot" Gibson, first officer Jess Kennedy, and flight engineer Garry Banks, denied that their actions had been the cause.

At no time prior to the incident did I take any action within the cockpit either intentionally or inadvertently, that would have caused the extension of the leading edge slats or trailing edge flaps. Nor did I observe any other crew member take any action within the cockpit, either intentional or inadvertent, which would have caused the extension.

—Capt. Gibson, April 12, 1979


The crew suggested instead that an actuator on the #7 slat had failed, causing its inadvertent deployment. The NTSB rejected this as improbable and attributed the extension of the flaps to the deliberate actions of the crew. The crew claimed that such failures had happened on other 727s[8] prior and subsequent to this incident. The NTSB report notes seven such cases.[3]

Despite the sworn testimony of the crew that they had not engaged the flaps, the NTSB argued that they probably were attempting to use 2 degrees of flaps at cruising speed.

While cruising at Mach 0.816 and 39,000 feet pressure altitude and with the autopilot controlling the aircraft, an attempt was made to extend 2º of trailing edge flaps independently of the leading edge slats, probably in an effort to improve aircraft performance.[9]

When retraction of the flaps was ordered, the Number 7 leading edge slat failed to retract, causing the uncommanded roll to the right.

The Safety Board determines that the probable cause of this accident was the isolation of the No. 7 leading edge slat in the fully or partially extended position after an extension of the Nos. 2, 3, 6, and 7 leading edge slats and the subsequent retraction of the Nos. 2, 3, and 6 slats, and the captain's untimely flight control inputs to counter the roll resulting from the slat asymmetry. Contributing to the cause was a preexisting misalignment of the No. 7 slat which, when combined with the cruise condition airloads, precluded retraction of that slat. After eliminating all probable individual or combined mechanical failures, or malfunctions which could lead to slat extension, the Safety Board determined that the extension of the slats was the result of the flightcrew's manipulation of the flap/slat controls. Contributing to the captain's untimely use of the flight controls was distraction due probably to his efforts to rectify the source of the control problem.[10]

Captain Gibson appealed the NTSB's findings, first to the NTSB itself, and then to the U.S. Ninth Circuit Court of Appeals. Both petitions were rejected: the former for lack of new evidence, and the latter for lack of jurisdiction due to the NTSB's "unreviewable discretion".

The aircraft was repaired and returned to service in May 1979.

Cockpit Voice Recorder[edit]

The aircraft was equipped with a Fairchild Industries Model A-100 cockpit voice recorder (CVR). However, 21 minutes of the 30-minute tape were blank. Tests of the CVR in the aircraft revealed no discrepancies in the CVR's electrical and recording systems. The CVR tape can be erased by means of the bulk-erase feature on the CVR control panel located in the cockpit. This feature can be activated only after the aircraft is on the ground with its parking brake engaged. In a deposition taken by the Safety Board, the captain stated that he usually activates the bulk-erase feature on the CVR at the conclusion of each flight to preclude inappropriate use of recorded conversations. However, in this instance, he could not recall having done so.[11]

The NTSB made the following statement in the accident report: "We believe the captain's erasure of the CVR is a factor we cannot ignore and cannot sanction. Although we recognize that habits can cause actions not desired or intended by the actor, we have difficulty accepting the fact that the captain's putative habit of routinely erasing the CVR after each flight was not restrainable after a flight in which disaster was only narrowly averted. Our skepticism persists even though the CVR would not have contained any contemporaneous information about the events that immediately preceded the loss of control because we believe it probable that the 25 minutes or more of recording which preceded the landing at Detroit could have provided clues about causal factors and might have served to refresh the flightcrew's memories about the whole matter."[12]

Critique of NTSB investigation[edit]

The NTSB's investigation, from April 1979 to June 1981, was then the longest and most expensive case in the history of the Safety Board. Because the Board's final AAR81-8 mostly ignored the physical evidence, press reviews documented investigative-misconduct.[13] Documentaries included "The Plane That Fell From the Sky", first published by the Saint Paul _Pioneer Press_[14][won the Livingston Award], then presented as an hour-long TV documentary on _CBS Reports_,[15] aired at 10pm Wednesday July 14, 1983. This critical press coverage, of the NTSB's investigative methods, prompted the case review by D. Yorke [former Director of Supersonic Aircraft Development at Grumman]:[16] Yorke refuted the "Boeing Scenario" endorsed by the Safety Board in AAR81-8, showing that the physical evidence was ignored by the NTSB, and showing the #7 Slat remained in the more secure retracted position during the initial upset and dive; then the #7 Slat was pulled from the retracted position after loss of "A" System Hydraulic Pressure. Thus, based upon the Trail of Debris, and "wreckage examination", the Flight Data Recorder (FDR) contents, and crew observations, Yorke proved that the "Boeing Scenario" had misled the NTSB's staff to the erroneous assumption that the #7 Slat had extended at 39,000 feet. Yorke's paper demonstrated that the physical evidence was clear, the initial upset could not have been caused by an extended #7 Slat. Yorke's powerful insight, correlating the direct evidence, was later presented to the NTSB in a formal Petition For Reconsideration,[17] receipt acknowledged by the NTSB on October 9, 1990.[18] The petition included an affidavit by TWA Captain P. T. Williams stating that two years before Flight 841 he had taken the very same airframe (N840TW) on a test flight. Upon disconnecting the autopilot at high altitude the airplane became very difficult to control laterally.[19] NTSB refused to correct the errors in AAR81-8, and refused to reply to the 1990 Petition.

In 1995, faced with an impending court decision, the NTSB sent a letter to H.G. Gibson [dated May 4, 1995] response to a 1991 Petition for Reconsideration by the Pilot: This NTSB "response" was never reviewed by the investigative community, never disclosed to ALPA. Much later, as the "web" developed, the Investigation Research Roundtable published that NTSB denial of a minor petition from the pilot: That May'95 NTSB "denial" of reconsideration included falsification of the "facts" previously documented by on-scene investigators in April 1979. Since the investigation community hadn't reviewed that letter sent to only the mishap-pilot, press never presented any "news" discussing that 1995 cover-up, and investigative-fraud. The erroneous, unwarranted assumption—that an Extended #7 Slat caused the INITIAL upset—fouled each phase of the NTSB investigation from 1979 to June'81. The Board's May 4, 1995 denial-of-Reconsideration was a forced response to an impending court decision, a "cover-up": The NTSB's staff had strayed from investigative-err (AAR81-8), into investigative-misconduct and fraud, by falsifying the "facts" previously documented Unwarranted assumptions & investigative misconduct.

Finally, the Ninth Circuit Court of Appeals shielded the USA's "independent" Safety Board, by deciding that any NTSB investigative-misconduct was NOT "reviewable":

"The NTSB regulations do not abdicate the NTSB's complete discretion to conduct its investigations as it sees fit. The denial of Gibson's petition falls within that unreviewable discretion" [Court's decision dated July 7, 1997].

The NTSB never retracted their AAR81-8. The NTSB never responded to the more thorough Petition For Reconsideration, receipt date Oct'9, 1990. [During earlier cases, the "investigating authority" had been willing to acknowledge their mistakes: See the CAB's corrections to the rumors surrounding TWA260 accident.] After repeated reminders over more than two decades, the NTSB still refuses to respond to that Petition of Oct'1990. The USA's "independent" Safety Board has "unreviewable discretion": there is no Inspector General, nor any Court of Inquiry, to review and correct investigative-misconduct of the USA's NTSB.

After decades of delay, awaiting any NTSB response to the October 1990 ALPA Petition against AAR81-8, the Chairman was again formally questioned about the status of progress (January 2009). In response, NTSB's Tom Hauter replied (letter dated May 6, 2009):

"Thank you for bringing this oversight to our attention.... we will need to contact the parties ... to determined if they ... still possess a copy of the ALPA Petition ... they will be allowed 90 days to provide comments ..."[20]

Since that "alpa" Petition (describing Yorke's analysis) was delivered to all parties in Oct'1990, with receipt-acknowledged, that 90-day comment period ended in early 1991. The NTSB staff violated their own rules [§ 845.41(b) and _Major Investigations Manual_ section 4.15]. It is doubtful that the appointed Board Members are aware of their staff's violations of NTSB's investigative procedures.

Regarding the NTSB's concern for "scientific retraction" of their published mistakes, C.O. Miller offered this critique:

"The deteriorating scope, depth and accuracy of the NTSB ... investigations is approaching the level of a national embarrassment.... because of the excessive workload, the inadequacy of investigations, or the questionable nature of some board members' qualifications, some views of parties associated with a particular case are not communicated or understood by the Board's members. Petitions for Reconsideration ... for changes in the report to present a fuller presentation or discussion of the facts, appear to be treated summarily without the objectivity which normally characterize the Board's actions. It is rare for the Board to present in its report the contrary views of competent parties unless one of the members elects to write a minority opinion supporting such a view. Such dissents are infrequent."[21]

TIMELINE -- post-mishap activities, & NTSB's investigation into mysterious upset of B727 N840TW. During the first two weeks of this NTSB investigation, several investigative mis-steps, and policy-reversals, affected the later course of this investigation.

Abbreviations: RHS = Right Hand Side; LHS = Left Hand Side; MLG = Main Landing Gear; NLG = Nose Landing Gear; A&P = license to work as Airframe and Power Plant mechanic; IIC = Investigator-in-Charge (NTSB).

Wednesday evening 4Apr79 at 2148 EST, mysterious inflight upset, B727 N840TW, at night, CRZ FL390, north of Saginaw, about 63 seconds of uncontrolled yawing-rolling dive, pull-out bottomed near 5000 feet. Diverted toward DTW: loss of System "A" Hydraulic System, both MLG displayed red Gear Unsafe indication even after attempted Manual Gear Release; Alternate Flap Extension resulted in uncontrolled rolling moment—so pilots retracted TE Flaps; first approach for control-ability check and tower fly-by to verify Gear position, then a second approach at 170 KIAS "no-flap" (no TE-Flap) landing on DTW 3L [Rwy number in 1979], at 2231EST. Parked on taxiway; Ground mechanic unable to get "pin" (safety device to prevent collapse of landing gear when, for example, hydraulic pressure is changed within landing gear system) into RHS MLG. TWA mechanic (who had accompanied Emergency Equipment) reported on Interphone to pilots about fluid leaking in RHS MLG Wheel Well; Captain elected to not "evacuate" instead directed passengers to deplane via Aft Stairs.

Early AM (after midnight) Thursday, 5Apr79, about 3 hours after landing at DTW, two FAA employees (Air Carrier Inspectors, licensed A&Ps) knocked on the captain's door, DTW's Hilton Hotel, room 342, to interview the mishap-Captain. From R.L. Mongomery's FAA Form 3112: "The Captain appeared visually and emotionally upset. Inspector Gordon asked if Gibson was alright ..." This report form, relating an informal midnight conversation, between the mishap-pilot and two mechanics employed by the FAA, led to a misunderstanding (a mistaken inference by one listener) that would return to haunt the pilots months later.

Thursday mid-day, 5Apr79 -- "Reporters were permitted to inspect the plane..."[22] FAA, airline, and NTSB spokesmen hailed the Pilots as heroes. FAA Administrator Langhorne Bond inspected crippled plane at Detroit; called it a miracle; NY Times reported "it is agreed that the pilot ... saved the passengers ... from certain death ..."[1] Crew were debriefed by NTSB; "movement of the malfunctioning ... slat ... was the apparent cause ... buffeting and vibration ... right wing and nose dropped ..."[23]

The NTSB initially regarded this mishap as an "incident", and initially assigned their Chicago Field Office to lead their investigation. The initial investigation was thus limited (no NTSB Go Team was available on scene). Initially, the Investigator-in-Charge [IIC] was Fred Rathke (CHI Field Office), and the NTSB's case number was initially CHI-79-A-A040 (an investigation assigned to a field office). Thus, no Board Member was assigned to this case, no Board Member was on-scene at DTW in the days following the mishap. Later, NTSB assigned L.D. "Dean" Kampschror as IIC [the docket does not indicate just when the IIC duties were reassigned to Kampschror], with the investigation reassigned to the NTSB's main office in Washington D.C. Later still, this investigation file number was changed to DCA79AA016.

Friday, 6Apr79 -- Crew were again debriefed by NTSB; "... the cockpit voice recorder ... had nothing on it when it was examined ..."[23] No system functional testing of the Cockpit Voice Recorder (CVR) interfaces was ever accomplished. (N840TW's sensing inputs, for the CVR's bulk-erase field activation, were never examined, nor did NTSB do any bench-test of the CVR).

Tuesday, 10Apr79 -- NTSB first-draft, preliminary FDR-data superimposed the ATC-transcript (from controller's tapes).

Thursday, 12Apr79 -- Inglewood, California, City Hall. The NTSB conducted public "deposition" of three pilots, set as a media event with the press coverage: with the pilots facing TV lights & cameras, with twenty-six microphones. Pilots answered questions from NTSB, Boeing, TWA, and FAA representatives. This setting for this NTSB "depositional proceeding" violated NTSB's Order 6230.18, dated 27Sep78, which required the deposition site "shall be chosen carefully to create an informal environment and not take on either appearance or formality of a hearing." In his opening remarks, Kampschror (NTSB) stated that this was not a "public hearing" [as defined in §845.10, and it did not qualify as such per §845.11]: thus there were none of the usual procedural safeguards customary of a formal Public Hearing. In contrast to the early "interview"-style questioning from NTSB staff and Boeing (all engineers), the longest interrogation was by the FAA representative (an attorney), mostly in a hostile manor of an enforcement proceeding. This mismanaged NTSB "depositional proceeding" added to the earlier breakdown of the NTSB's "safety investigation", by mixing-in assertions of crew misconduct—rather than accomplishing the usual engineering fault-analysis of the pre-existing latent-failures in N840TW's subsystems; latent failures only uncovered after the mishap.

26Apr79 -- FDR Group Factual Report completed.

7May79 -- Systems Group Factual Report completed.

10May79 -- Structures Group Factual Report completed.

May 5, and May 7, 1979—Two sessions of simulator trials, done in Seattle using Boeing's engineering simulator, with Boeing test pilots. Then a third session on May 7, with three members of the investigation's Performance Group (Capt. York, Capt Sonnemann, Tobiason). During these simulator runs in Seattle, the Performance Group had mistakenly accepted Boeing's simulation-modeling, as "using simulator software for the B-727-100 [sic]".[24] Also, the Performance Group accepted Boeing's assertions that "The effects of autopilot or yaw damper hardovers were not directly simulated, although the magnitudes of the resulting upsets were approximated ... In either case, the pilot can easily override the effects of the failure ... Upon hardover recognition, the pilot can disconnect the faulty unit at which time the airplane ... is readily recoverable." [That same Boeing-assertion had been rejected by the CAB during their investigation into the fatal upset of AA Flight One / 1Mar62.] The Boeing simulation, presented to the NTSB's Performance Group, offered only that single failure condition: a simulation study with the #7 Slat Extended; done by modeling the sudden contribution of the "incremental rolling moment coefficient caused by the extension of the slat No. 7."[25]

22May79 -- discussion between Boeing and NTSB defining tasks requested of the manufacturer. Letter dated 25May79: 3-page letter from NTSB (Tobiason/ Performance Gp) to Boeing, states these proposed tasks were previously discussed on April 18, and May 7–9. NTSB asked Boeing to correlate their Boeing simulation trials with mishap- FDR data, and asked for answers to dozens of questions, and NTSB then explicitly asked Boeing for their suggestion of the "probable conditions during maneuver that would cause simultaneous/ sequential separation of Slat, Flap Canoe, #10 Spoiler ... correlation with trajectories to ground locations where parts were found." Set target date of early June for a Boeing report to answer NTSB requests.

29May79 -- Operations Group Factual Report completed.

6Jun79—Technical meeting at Boeing. Ntsb's Investigator-In-Charge (IIC) asked Boeing to commit to several tasks, IIC Kampschror asked Boeing to propose a scenario to explain the mysterious upset of B727 N840TW:

"So at that particular meeting I was asked by Mr. Kamschror ... to prepare a report ... also asked to propose what we thought was a likely description of what had happened.... we delivered the report in September...."

[Witness was then asked to describe the Meeting of June 6]

"... this was an informational meeting requested by the NTSB ... We had carried out some simulation studies at Boeing facilities, we had the data at hand. My structures people had reviewed the broken parts ... my job was to ... synthesize all of the findings together and draw some conclusions.... So the part I was personally involved in are these two or three pages on the front.... Those are the conclusions...."

[Then asked,"Is this ... the conclusions at pages 3 and 4 in the Boeing Report?"]

"That is correct ... initial pages 1 and 2 cover the summary of the physical damage ..." Testimony transcript cites Defendant's Exhibit 2A-1, the Boeing Report rough draft, cover letter signed by R.A. Davis, dated August 21, 1979, titled "Analysis of TWA ... Dive Incident." Conclusions on page 3 & 4, list seven items defining the "Boeing Scenario".[26]

22Jun79 -- Human Factors Specialist's Report (included some interviews with F/As and passengers), but only few passenger interviews were retained (his notes were lost).

25Jul79 -- Performance Group Factual Report completed [several addendums added later]. Simulation Trials, conducted at the manufacturer's facilities, simulated conditions with a #7 Slat in the Extended position, while at 39,000 feet (this assumption was accepted as the cause of the rolling motion).

September 1979 -- The NTSB's IIC Dean Kampschror was interviewed by a reporter from _Aviation Consumer_. The IIC's comments were later published in the October 15, 1979 issue of that periodical:

"According to the NTSB's chief investigator on the accident, L. D. Kampschror, there is no evidence of any mechanical malfunction. 'I'm satisfied that there was nothing wrong with the airplane,' he told the _Aviation Consumer_. 'And Boeing tells us it's impossible for the slats to pop out because of aerodynamic loads.'
"Other factors point the finger of suspicion at the crew. After the 727 had landed safely, Capt. Gibson inexplicably erased the cockpit voice recorder, which would have revealed the crew's conversations after the incident.
"Second, according to Kampschror, there has long been an 'unofficial procedure' among some 727 pilots for flying at extremely high altitudes. At 40,000 feet or so, the air is so thin that the 727 staggers along at a rather high angle of attack. Hoping to improve high-altitude cruising performance and handling, adventuresome 727 crews have been known to deploy the first notch of flaps (2 degrees), which increases the effective wing area and might theoretically allow the airplane to cruise more efficiently. However, four of the eight leading-edge slats automatically deploy when the first notch of flaps is selected. Since it's obvious that leading-edge slats are a no-no at Mach 0.80, part of the unofficial procedure is to pop the circuit breaker for the slats so that they'll stay put during the flap extension. This gives the desired trailing-edge-flaps-only configuration.
"But it's not hard to imagine what would happen if the flight engineer popped the wrong circuit breaker.
"The crew has made sworn statements to the NTSB that they did nothing of the sort, but their arguments apparently have not been too persuasive.
"'I assume they're hiding something, but I can't prove it.' NTSB Investigator Kampschror told the Aviation Consumer. 'We're wrestling with that problem very hard right now.' Another NTSB spokesman voiced similar doubts, 'I think those guys were fooling around up there, and I don't think we really know what they were doing yet.'"

31Oct79 -- NTSB & parties, Progress Meeting, Washington D.C.

PUBLIC HEARING was omitted by the NTSB, never offered: § 845.10 ... The Board may order a public hearing as part of an accident investigation whenever such hearing is deemed necessary in the public interest ... § 845.11 .... a Member to serve as the chairman ... The board of inquiry shall examine witnesses and secure, in the form of a public record, all known facts pertaining to the accident ... and surrounding circumstances and conditions ..."

17Jan80 -- NTSB Board Meeting, intended as the "Sunshine Meeting" for the NTSB's staff-investigators to present the staff's "facts", findings, & recommended conclusions (Probable Cause); and then for Board Members to vote & adopt the official "Probable Cause" for the (inflight upset) B727 N840TW accident. NY Times reviewed this Meeting of the Board:

"The five-member board, after morning and afternoon meetings here, put off a final vote on the 'probable cause' ... to give investigators time to conduct additional interviews with the cockpit crewmen, the four flight attendants ... After an emergency landing in Detroit, it was quickly discovered where the trouble had been. The No. 7 wing slat was missing. It had obviously pulled the plane into its initial roll and had been torn away ... Safety board investigators questioned Mr. Gibson's recollection that the plane had consistently rolled to the right ..."[4]

After this Board Meeting, the captain was dogged by the claim mentioned during this "Sunshine Meeting". The Captain wondered: Who is it that claims that our Flight Engineer had departed the cockpit (and returned) just before the sudden rolling motion? The mishap-Captain was presented with the answer a week later—an FAA employee had reported that it was the captain himself who had made that claim.

17Jan80 -- NTSB issued Safety Recommendation A-80-8 (the formal letter dated 21Jan80): "... Safety Board believes that an extended No. 7 slat precipitated control problems that culminated in a loss of control...."

During the week of 20January 1980, ALPA received their first copy of an FAA report form filed shortly after the 4Apr79 mishap.

29Jan80, Depositions of crew, under a restriction voted by the Board Members (with McAdams dissenting), the questions posed to the crew would be limited to the rumored absence of the flight engineer from the cockpit. [Board Members felt that the crew's answers would disclose whether or not the Flight Engineer had departed Cockpit, whether or not he had walked meal trays to the Galley (located mid-ship), just prior to the crz upset: Since this assertion was a part of one popular version of the "fooling around" conspiracy-scenario, the pilots' and Flight Attendants' answers could substantiate, or eliminate, that scenario as a working hypothesis .] One disturbing aside during these depositions, which did not appear in the official transcript, was a confrontation, an emotional outburst of the IIC.

6Feb1980, Letter: ALPA's President wrote NTSB's Chairman:

"Due to unfounded allegations concerning the crew attributed to Mr. Kampschror in the media (Aviation Consumer for example, attached), his conduct at the probable cause hearing on January 17, 1980, and his extraordinary and unreasonable emotional outburst at the Kansas City deposition, it appears to us that Mr. Kampschror is no longer a neutral and impartial investigator in regard to this accident.... For this reason, we request that Mr. Kampschror be immediately replaced as Investigator-in-Charge."

21Mar1980 -- letter from NTSB Chairman J. King denying request to remove Kampschror as IIC.

23May80 -- Heading Gyro testing, on a Tilt/Turn-table at Kansas City. The Tilt/Turn-table simulated roll-angles 360-degrees, and pitch angles (previously derived from Boeing Simulator trials]. Heading Gyro output was recorded on FDR foil, for comparison with mishap Data Recorder. Test disclosed numerous instances of HDG-trace "moving backward in time", similar to time-shifts on the mishaps FDR-foil. Performance Group Rpt, Addendum 2 dated 11Aug80.

1Oct80 -- Meeting in Seattle for test-plan.

2Oct80, Flight test aboard Boeing-owned B727 E209, from BFI in Seattle.

Oct'9th, 1980 -- Letter from Capt. McIntyre (ALPA party coordinator) to NTSB Chairman James King, relating confrontation with IIC Kampschror at the Boeing Meeting. [The IIC later excluded this letter from the NTSB's docket.]

Dec'19th, 1980 -- Boeing sends to NTSB data from the Oct flight test, sent to Performance Group Chmn Von Husen [a change in the Chairman for NTSB's Performance Group].

March 1981 -- ALPA submission in response to NTSB's request for analysis:

"In this case, hypothesis not supported by fact have been presented as hard evidence ... The Investigator-in-Charge, in effect, becomes the sole arbiter of the evidence and analysis presented by the staff to the Board. Often the scope of the evidence is outside the staff's technical expertise and competence. This results in the interested party with the greatest resources and manpower actually conducting the investigation ..."[27]

Tuesday, 9 June 1981, NTSB Board Meeting [the Board's second "Sunshine Meeting"], two of the five Board Members voted to adopt their staff's Probable Cause statement for AAR 81-8:

"The board's staff concluded that the crew had extended the slats and that one ... would not retract. This caused the right wing to drop and the ... spiral ..."[28][29]
"The pilots involved ... accused the ... Board of skewing facts to fit its theory of what happened. The board ... concluded actions by the crew, not mechanical problems, triggered the ... harrowing 6-mile plunge of the ... Boeing 727 ...
"... The Boeing Co. ... was pleased by the board's conclusions. A spokesman, W.J. McGinty, said, 'We took a very, very deep look into it. What we found out was there was no way that it could have happened the way the pilots said it could.'" Pilots' account
"'I can't believe this is happening,' Gibson said after the board voted, 2 to 1, to accept a staff conclusion that extension of a wing slat by the crew caused the ... roll to the right."
"He said the board has made no attempt to question the pilots since its staff first broached the possibility of pilot error during a January, 1980 hearing. J. Scott Kennedy, co-pilot, said, 'They only wanted to use our testimony when it fit their purposes. It's unfair and incorrect and leaves the public with a misinterpretation of what actually happened.'"
"'The board's conclusions were all based on hearsay and circumstantial evidence, and selective use of testimony ... while ignoring other testimony doesn't do a damn thing for air safety,' a T.W.A. spokesman said."[30]

The Probable Cause was adopted at this Board Meeting (the second "Sunshine Meeting"). Two Board Members did not participate during this Meeting, and so did not endorse that P.C.

Afterward, the NTSB's Investigator-in-Charge, L.D. "Dean" Kampschror, approached the "party coordinator" for the pilots' association [his main rival during this longest-ever investigation], and Kampschror offered this consoling comment:

"You put up a tough fight, but we couldn't let you fault the world's most used airplane at this time."[31]

Francis H. McAdams, Member, filed the following concurring and dissenting statement:

"Although I voted to approve the Board's report which concluded that the extension of the leading edge slat was due to flightcrew action, I do so reluctantly.
"The report as written, based on the available evidence, i.e., the analysis of the flight data recorder, the simulator tests, the flight tests, and the tilt table test, appears to support the Board's conclusion. However, I am troubled by the fact that the Board has categorically rejected the crew's sworn testimony without the crew having had the opportunity to be confronted with all of the evidence upon which the Board was basing its findings....
"Furthermore, I do not agree that a probable cause of this accident, as stated by the Board, was 'the captain's untimely flight control inputs to counter the roll resulting from the slat asymmetry.' In my opinion, the captain acted expeditiously and reasonably in attempting to correct for the severe right roll condition induced by the extended slat."[32]

See also[edit]


Stewart, Stanley (2002) [1989]. Emergency: Crisis on the Flight Deck (2nd edition ed.). Airlife Publishing. pp. 150–176. ISBN 1-84037-393-8. 

  1. ^ a b Peterson, Iver. "Plane Passengers Prayed But Expected to Be Killed." _New York Times_ (Apr 7, 1979), 6.
  2. ^ The Post-Standard (Syracuse, New York), June 10, 1981, page 11
  3. ^ a b NTSB Accident Report AAR81-08, 1.17.2.
  4. ^ a b Witkin, Richard. "Safety Board Hints Crew Errors May Have Led to Jet Dive Over Michigan." _New York Times_ (Jan 18, 1980), A10.
  5. ^ Aircraft Accident Report - Trans World Airlines, Inc., Boeing 727-31, N840TW, Near Saginaw, Michigan April 4, 1979. Washington, D. C.: National Transportation Safety Board. 1981-06-09. p. 52. NTSB-AAR-81-8. 
  6. ^ Witkin, Richard. "Crew Will Testify Today On Near-Fatal Jet Plunge." _New York Times_ (Apr 12, 1979), B10.
  7. ^ Lindsey, Robert. "Pilot Says Extending Landing Gear Was Near Last Resort to Stop Dive." _New York Times_ (Apr 13, 1979), A16.
  8. ^ Boeing Operations Manual Bulletin, OMB 75-7, March 10, 1976; Subject: "Leading Edge Slat Actuator Lock Rings"; outlined specific conditions which had previously resulted in a Leading Edge Slat being pulled from the Retracted position (Mach > .8M, with failure of "A" System Hydraulic pressure to the slat actuator, with SpeedBrakes/Spoilers Extended).
  9. ^ ibid., section 2.5, p. 32.
  10. ^ ibid., Abstract.
  11. ^ ibid., section 1.11
  12. ^ ibid., section 2.5, final paragraph, p. 33.
  13. ^ Glines, C.V. "Flight 841: The Nightmare Continues." _Air Line Pilot_ (Pt.1 Oct'81, 9-11), (Pt.2 Nov'81, 6-10, 31, 33).
  14. ^ Bissinger, "Buzz" H.G. The Plane That Fell From the Sky. _Saint Paul Pioneer Press_ (May 24, 1981), Special section. Illustrations by Van Ness, T. [Feature article won 1981 Livingston Award for National Reporting.]
  15. ^ The Plane That Fell From the Sky, _CBS Reports_: CBS News, broadcast over network TV (Wednesday July 14, 1983), 10pm EST.
  16. ^ Yorke, Duane. "Discussion and Analysis of Incident Involving TWA Flight 841 on April 4, 1979." Monograph. Massapequa, NY, November 16, 1984.
  17. ^ Air Line Pilots Association, Accident Investigation Dept . "Petition For Reconsideration of Probable Cause: Proposed changes to NTSB's AAR81-8." Monograph, as per NTSB 845.41(a). October 9, 1990 (receipt acknowledged by NTSB and all parties). [Cited as "ALPA Petition, 1990", one of numerous petitions against NTSB's AAR81-8.]
  18. ^ Steenblik, J.W. "A New Look at TWA Flight 841: With ... new analysis, ALPA petitions NTSB to revise ... report on the B-727 [sic] spiral dive in 1979." _Air Line Pilot_ . 60:1 (January 1991), 24-27.
  19. ^ "Pilots say 727-100 had control problems before 1979 dive". Aviation Week & Space Technology (McGraw-Hill, Inc.) 133 (16): 34. 1990-10-15. 
  20. ^ Hauter, Tom. Director, Office of Aviation Safety, NTSB. Letter, May 6, 2009.
  21. ^ Excerpts from "Aviation Accident investigation: Functional and Legal Perspectives," an article by Mr. C.O. Miller, past Director of the Bureau of Aviation Safety of the NTSB; Journal of Air Law and Commerce (Dallas, Tx.: SMU School of Law), Winter 1981, Vol 46.
  22. ^ AP. "87 on Airliner in Michigan Survive A Nose Dive Near Speed of Sound." _New York Times_ . (Apr 6, 1979), A14.
  23. ^ a b Witkin, Richard. "Plane's Dive Is Laid to Malfunctioning Wing Flap." _New York Times_ (Apr 7, 1979), 6.
  24. ^ Perf' Grp Rpt, pg 4, mid-page
  25. ^ Boeing Rpt, dated 24Sep79, Section C.2.4 - Flight Controls "Simulator Results", pgs C-5 & 6.
  26. ^ Testimony of Robert A. Davis, Technical Manager Triple-Seven Division, Boeing [after retirement of Paul Higgins on 6Jun79], Wicker v. TWA and Boeing. Minnesota District Court, County of Hennepin, Fourth Judicial District, DC File 760015:On 5-26-83 Witness: Robert A. Davis.
  27. ^ cover letter to the ALPA submission, analysis and conclusions, dated March 27, 1981.
  28. ^ NY Times, Jun 10'81, pg A18.
  29. ^ AP. "Safety Board Faults T.W.A. Crew In Jet's 5-Mile Dive Near Detroit." _New York Times_ (June 10, 1981), A1.
  30. ^ UPI. "Report on jetliner plunge assailed." _The Seattle Times_ (Wednesday June 10, 1981), A10
  31. ^ From the affidavit of James A. McIntyre, dated Jan 3rd, 1991; listed as Exhibit "M", in support of Petition of Captain H.G. Gibson (Landon G. Dowdey, Counsel to Petitioner).
  32. ^ AAR81-8, pg 36.

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