1959 — Sep 29, Braniff Air 542 left wing structural failure, crash, near Buffalo, TX — 34
— 34 AirDisaster.Com. Accident Database. Accident Synopsis 09291959.
— 34 CAB. AAR. Braniff Airways, Inc., Lockheed Electra…Buffalo, Texas, Sep 29, 1959.
— 34 Kimura. World Commercial Aircraft Accidents 3rd Ed., 1946-1993, V.1. 4-11-1994, p.3.6.
Narrative Information
Civil Aeronautics Board: “A Braniff Airways Lockheed Electra, Model L-188A, N 9705c, broke up in flight and was further destroyed by ground impact and fire 3.19 miles east-southeast of Buffalo, Texas, on September 29, 1959, about 2309 c. s. t. -All occupants, 27 passengers, six crew members and one company employee, were killed.
“Flight No. 542 of September 29, scheduled between Houston, Texas, and New York International Airport, with stops at Dallas Texas, and Washington, D. C., departed the Houston Airport at 2237…. The estimated time en route to Dallas was 41 minutes….
“Flight 542 contacted company radio with a message for maintenance, advising that the generators were then OK but that there had been insufficient time for maintenance to insulate the terminal strip on No. 3 propeller at Houston and it would like to have it done in Dallas. At this time the flight also said it would give the communication center a Dallas estimate of 25. This was then followed by one other item for maintenance, which was that No. 3 sump pump was inoperative. This was the final transmission from the flight and was logged as completed at 2307….
“Structural failure of the aircraft occurred at approximately 2309…A review of all records and crew reports indicated a routine operation from Houston, except that upon departure a terminal strip on No. 3 propeller was not properly bonded and the No. 3 fuel tank sump pump became inoperative shortly after takeoff.
“The probable cause of this accident was structural failure of the left wing resulting from forces generated by undampened propeller whirl mode.
Investigation
“Witnesses reported hearing various noises of different intensities and of different pitches. Many of the sounds were likened to known noises such as the “clapping of two boards together,” the sound of thunder,” “the roar of a jet plane breaking the sound barrier, “whooshing screaming noise,” “creaking noise of a bulldozer,” and “awful explosion.”
Aircraft History
“N 9705C was a new aircraft. Its final assembly was started in April 1959, and the first of its three production test flights was on September 4, 1959, 25 days prior to the accident.
“Braniff Airways accepted delivery of the aircraft at the factory, Burbank, California, on September 18, 1959. Acceptance had been preceded by a total of three production test flights and one acceptance flight.
“The four propellers and three engines in Nos. 2, 3 and 4 positions had been installed new (zero time). The No 1 engine had accumulated 26 hours and 25 minutes of operation at the time of installation….
Analysis
“The investigation of this accident has produced such a voluminous quantity of data that this report will be confined to the discussion and analysis of only those data considered to be apropos to the consideration of probable cause. Several incidents and accidents involving Electras have occurred during the course of this investigation, all of which have also been investigated. None of these is considered to have any association with this accident except the accident to a sister aircraft at Cannelton, Indiana, on March 17, 1960….Following the accident at Cannelton, Indiana, Lockheed undertook a reevaluation program in which the entire Electra concept and design was audited. An enormous quantity of data was produced, the majority of which was negative. It is sufficient for the purpose of this report to state that, insofar as causal factor is concerned, only one area of the program is significant. This is the phenomenon known as “whirl mode,” an oscillation which under certain conditions can produce flutter….
“…all of the witnesses who were indoors first heard a noise which was followed by a ball of fire….
“That the aircraft broke up violently is self-evident. That the breakup process was both quick and with little or no warning is also clear for two reasons. First, only one of the 37 aircraft’s passenger seats recognizable as such was found with the safety belt fastened, and this probably means there was no time to order their fastening. Second, the final radio message preceded the breakup by an interval of something less than two minutes and that message gave no hint of trouble….
“A definite sequence of failures and breakages appears discernible and will be mentioned because it may be considered as somewhat basic for this analysis. Separation of the left wing and the No. 1 gear box propeller and QEC structure occurred at about the same time, it is impossible to say which went first. The horizontal stabilizer then broke up under the impact of parts coming from the wing; wing planking from the right wing tip came free; the No. 4 powerplant tore loose; and the right wing outboard of No. 4 separated. All of these events happened in a short period of time. Somewhat later, at much lower altitudes, the fuselage broke in two separate portions at a point about halfway back near fuselage station No. 570….
Conclusion
“There was in this investigation no positive indication of the cause. For this reason, an attempt has been made in this report to eliminate certain possibilities by application of the available evidence to each of them. Once these possibilities have been disposed of, the only remaining causal factor for which there is some known basis is the condition of whirl mode. The probability that this accident was so caused is supported by the following.
• So far as is known, the aircraft was in straight and level flight and at a normal cruise speed with no serious mechanical problems.
• A sound identified as a supersonic or high speed propeller occurred 30 seconds prior to fuel ignition (wing failure).
• There was structural damage evidence compatible with oscillatory motion of the No. 1 QEC and the left wing….
• The probable cause of a similar accident of another Electra was due to whirl mode….
“The Board determines that the probable cause of this accident was structural failure of the left wing resulting from forces generated by undampened propeller whirl mode.” (CAB. AAR. Braniff Airways, Inc., Lockheed Electra…Buffalo, Texas, Sep 29, 1959.)
Sources
AirDisaster.Com. Accident Database. Accident Synopsis 09291959. Accessed at: http://www.airdisaster.com/cgi-bin/view_details.cgi?date=09291959®=N9705C&airline=Braniff+Airlines
Civil Aeronautics Board. Aircraft Accident Report. Braniff Airways, Inc., Lockheed Electra, N 9705C, Buffalo, Texas, September 29, 1959. Washington, DC: CAB, May 5, 1961, 28 pp. At: http://dotlibrary1.specialcollection.net/scripts/ws.dll?file&fn=8&name=*P%3A%5CDOT%5Cairplane%20accidents%5Cwebsearch%5C092959.pdf
Kimura, Chris Y. World Commercial Aircraft Accidents 3rd Edition, 1946-1993, Volume 1: Jet and Turboprop Aircrafts. Livermore, CA: Lawrence Livermore National Laboratory, Risk Assessment and Nuclear Engineering Group. 4-11-1994.