Braniff Flight 542
Braniff Airways Flight 542, a Lockheed L-188 Electra
Lockheed L-188 Electra
The Lockheed Model 188 Electra is an American turboprop airliner built by Lockheed. First flying in 1957, it was the first large turboprop airliner produced in the United States. Initial sales were good, but after two fatal crashes which prompted an expensive modification program to fix a design...

, registration N9705C, was a scheduled domestic flight from Houston, Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, bound for New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 with scheduled stops in Dallas and Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

. On September 29, 1959, twenty-three minutes into the forty-one minute flight from Houston to Dallas Love Field, the aircraft disintegrated in mid-air approximately 3.8 miles (6.1 km) southeast of Buffalo
Buffalo, Texas
This article is about the city in Leon County, Texas. A similarly named place exists in Henderson County, Texas, the settlement of John H. Reagan.Buffalo is a city in Leon County, Texas, United States...

, Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 killing everyone on board.

Identifying the cause of the disaster proved difficult, as the accident had occurred before the age of cockpit voice recorder
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...

s. The Civil Aeronautics Board (CAB) investigated the accident and, after interviewing numerous eye-witnesses and examining the debris field, were able to conclude that the initial failure of the aircraft had begun in the left wing. However, even though it was determined that the wing was destroyed by "cycles of reverse bending" or "flutter", the investigation failed to determine how the flutter was caused, and the investigation stalled.

In the six months following the accident further progress towards identifying the cause of the flutter was unsuccessful and the case remained unsolved. The breakthrough into unlocking the cause of the accident came after the crash of Northwest Airlines Flight 710 on March 17, 1960. The two aircraft, both Electras, disintegrated in mid-air after losing their wings in similar fashion, both resulting in the deaths of all their passengers. The investigation into the Northwest crash discovered a new phenomenon of harmonic coupling within the wings of aircraft which in the end was ultimately identified by the CAB as being the cause of both break-ups. The final accident report for Flight 542 was issued on April 28, 1961.

Aircraft and crew history

Flight 542 was a Lockheed L-188 Electra equipped with four Allison
Allison Engine Company
The Allison Engine Company was a U.S. aircraft engine manufacturer. In 1929, shortly after the death of James Allison, the company was purchased by the Fisher brothers. Fisher sold the company to General Motors, who owned it for most of its history...

 501-D13 engines. The plane was eleven days old, having come off Lockheed's
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 manufacturing line on September 18, 1959, and had only 132 hours of flight time. All six crew members - two pilots
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...

, a flight engineer
Flight engineer
Flight engineers work in three types of aircraft: fixed-wing , rotary wing , and space flight .As airplanes became even larger requiring more engines and complex systems to operate, the workload on the two pilots became excessive during certain critical parts of the flight regime, notably takeoffs...

 and three flight attendant
Flight attendant
Flight attendants or cabin crew are members of an aircrew employed by airlines primarily to ensure the safety and comfort of passengers aboard commercial flights, on select business jet aircraft, and on some military aircraft.-History:The role of a flight attendant derives from that of similar...

s - had little experience with the Electra, having only recently completed their transition training.


Flight 542 was originally scheduled to depart Houston for Dallas at 22:15 Central Standard Time (CST) but only managed to depart the ramp at 22:37, 22 minutes late. The delay was due to a minor mechanical discrepancy with the No. 3 generator. The plane was given clearance for takeoff at 22:40 and the crew reported airborne by 22:44.

Following takeoff Houston Departure Control handed responsibility of the aircraft over to San Antonio. The crew of Flight 542 reported to San Antonio as being over the Gulf Coast intersection at 9000 feet (2,743.2 m) at 22:52. The flight reached its assigned altitude of 15000 feet (4,572 m) at 22:58. The crew reported to San Antonio that it had passed the Leona omni at 23:05 and contacted company radio requesting maintenance on the No. 3 generator which they believed had been insufficiently insulated in Houston. Final transmission with the aircraft occurred at 23:07.

At 23:09 as the aircraft was on course to the Trinidad Intersection the left wing and No. 1 engine ripped away from the aircraft. Pieces of wing then struck and dislodged the horizontal stabilizer. The right wing's planking then broke away, No. 4 power plant tore away which was subsequently followed by the loss of the right wing outboard of the No. 4 engine and splitting of the fuselage.

The fuselage continued to be torn apart as it fell from the sky. People who were not killed during the initial break-up of the aircraft were either ejected from the fuselage or trapped within it as it fell. Victims of the crash suffered massive trauma and regardless of their location within the aircraft all were killed upon impact with the ground. Debris from the aircraft was spread out over 13900 feet (4,236.7 m) with many of the larger sections of aircraft landing in a potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...

 field southeast of Buffalo, Texas.


Civil Aeronautics Board investigators arrived on the scene the morning following the accident. The left wing was found a mile away from the potato field in which most of the other pieces of aircraft lay, and the pieces of the right wing were scattered in a widespread debris field across the countryside.

Investigation determined that the break-up of the plane had begun in the left wing and progressed in a catastrophic sequence which ultimately destroyed the aircraft. However, the reason for the disintegration of the left wing proved to be elusive. Tests found that "flutter" had destroyed the wing, however the Electra's wings were supposedly flutter-free. Further tests attempting to re-create the accident by weakening the wing and exposing it to loads greater than any which would conceivably have occurred in the actual flight failed to cause a break-up similar to the one that occurred in Flight 542. Help from teams at Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

, Convair
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...

, National Aeronautics and Space Administration (NASA) and the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 (FAA) also failed to determine how Lockheed's "flutter-free" wing had simply ripped away during flight, and the investigation stalled, further progress not being achieved for nearly six months.

Renewal of interest in finding the cause for the Braniff Flight 542 crash occurred after Northwest Airlines Flight 710, another Electra model aircraft of the same kind as Flight 542, disintegrated in-flight and crashed near Tell City
Tell City, Indiana
Tell City is a city in Troy Township, Perry County, Indiana, along the Ohio River, Indiana's southern border. The population was 7,272 at the 2010 census. The city is the county seat of Perry County.-History:...

, Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

 on March 17, 1960. Following the second crash, CAB Chief Safety investigator, Phillip Goldstein, was reported as saying: "The structure was subjected to forces greater than it was designed for. We have definite evidence of a wing failure. Why this wing failure, I don't know."

Initial investigations into the second crash proved fruitless but after laborious testing investigators were able to find flaws in the aircraft which included an overly stiff wing, and outboard nacelle
The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...

s responding differently than intended in the design briefs. Further experimentation discovered that flutter in a nacelle can be passed on to even a "flutter-free" wing. Final work in the mystery also found that as the magnitude of the flutter grows, the frequency at which it vibrates decreases. In the case of the two Electra crashes the frequency of the flutter had lowered from five cycles a second to three, the same as the wing creating harmonic coupling. This harmonic coupling would have continued to cause ever larger wing vibrations until some part of the structure failed. Contributing to the two aircraft's demise was the stiffness of the wings and severe clear air turbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...

. Final analysis of the CAB, in its official Accident Report:

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.

1. So far as is known, the aircraft was in straight and level flight and at a normal cruise speed with no serious mechanical problems.

2. A sound identified as a supersonic or high speed propeller occurred 30 seconds prior to fuel ignition (wing failure).

3. There was structural damage evidence compatible with oscillatory motion of the No. 1 QEC and the left wing.

4. First stage compressor blades of No. 1 engine rubbed the air inlet housing supports.

5. The probable cause of a similar accident of another Electra was due to whirl mode.

If prior damage is a requirement for the necessary reduction in stiffness, it must be assumed that the evidence of such damage was either obliterated in the crash or never existed in a discernible form.

Probable Cause

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. Braniff 542 Accident Report

The final reports into the two accidents were released four days apart, on April 24 and April 28, 1961 respectively, with the Braniff crash report being the later of the two. Both reports were similar and blamed the same forces for destroying both aircraft.

See also

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.