63 years ago, on September 29, 1959, Braniff Flight 542, traveling from Houston to Dallas, broke up in midair 41 minutes after taking off. The aircraft involved in the incident was only 11 days old, an Allison 501-D13 engine-powered Lockheed L-188A Electra. Let’s figure out what happened.

Braniff International Airways Flight 542 operated on a regular basis between Houston and New York, with stops in Dallas and Washington, D.C. The plane was supposed to leave Houston for Dallas at 22:15 Central Standard Time (CST), but it left 22 minutes late due to a mechanical problem with the number three generator. The plane, N9705C, was being flown by two pilots and a flight engineer who had only recently completed their transition training and had little experience flying the Electra.

READ | The small light bulb that brought this big jet to ashes

Once the plane was in the air, Houston control handed it over to San Antonio, where the pilots reported flying over the Gulf Coast at an altitude of 9,000 feet. At 22:52, the plane was at 15,000 feet and reported six minutes later that it had just passed the Leona Omnidirectional Navigation Radio (omni). Then, over the Braniff company radio, they announced that the number three generator would require maintenance because it had not been adequately insulated in Houston. The left-wing and number one (left outboard) engine separated from the plane at 23:09, en route to the Trinidad Intersection. The horizontal stabilizer was then dislodged by pieces of the broken wing. The right wing of the aircraft then separated, causing structural damage to the fuselage and the plane’s breakup.

Those passengers and crew who were not killed during the plane’s initial breakup were either ejected or trapped within it as it fell out of the sky. The wreckage landed in a potato field near Buffalo, Texas, killing all 34 passengers and crew members.

The next day, civil aviation investigators arrived at the crash site and discovered the left wing in a potato field a mile away from the wreckage. The sequence of events had clearly begun with the left wing, but they couldn’t figure out how it had happened. Engineers from NASA, Boeing, Convair, and the FAA were all unable to determine what caused the wing to break off.

READ | Australia’s close call: Emirates flight 407

The investigation stalled for six months until another Electra, this time belonging to North West Orient Airlines, disintegrated in flight near Tell City, Indiana. CAB Chief Safety Investigator Phillip Goldstein was reported to have stated following the second crash:

“The structure was subjected to forces greater than it was designed for. We have definite evidence of a wing failure. Why this wing failure occurred, I don’t know.”

Once more, investigators struggled to find a solution and ultimately came to the conclusion that the wings of the aircraft were too stiff. Increased vibrations resulted from wing vibrations and harmonic coupling, which eventually led to the failure of a portion of the structure.

All of the investigation teams came to the same conclusion: the failure of the left-wing due to an undampened propeller was the accident’s most likely cause.

Sources:

• Simple Flying
• Cover photo by: Jon Proctor