Braniff Airways Flight 542

Braniff Airways Flight 542 was a scheduled flight between Houston International Airport and Idlewild Airport in New York City. On September 29, 1959, while en route to a scheduled stop at Dallas Love Field, the Lockheed L-188 Electra operating the flight broke apart in mid-air without warning, about 4 mi southeast of Buffalo, Texas. Eyewitnesses who saw the crash said they saw an explosion in the air, and then the aircraft plummeted to the ground. The left wing separated from the plane close to where it attaches to the fuselage and landed more than a mile (two kilometers) from the main crash site. The explosion and resulting crash left no survivors.

The aircraft was almost brand new, and had been in commercial service for only nine days after it was delivered from the factory. Crash investigators combed through the wreckage in search of the cause of the breakup, but after six months, they had still not determined what had caused the wing separation. As they were preparing to close the investigation without determining a probable cause, Northwest Airlines Flight 710 crashed near Cannelton, Indiana. That aircraft was a seven-month-old Lockheed Electra, and witnesses also described seeing it explode in flight before crashing to the ground. Investigators found that the entire right wing and portions of the left wing had broken off that aircraft while it was in flight.

The similarities between the two crashes led to the Federal Aviation Agency placing flight restrictions on the Electra until the cause of the two similar crashes could be identified. It ordered Lockheed Corporation to reevaluate the aircraft's structural integrity and prove its airworthiness. The subsequent investigation, involving over 250 engineers and technicians, found that when an Electra with damage to the mounting structures of one of the engines flew at high speeds or in turbulent conditions, a destructive phenomenon called "whirl mode wing flutter" could occur. The phenomenon caused the wing to flutter severely, causing the metal to fatigue and eventually snap. After discovering the cause of the wing failures, Lockheed launched a program to design structural changes to prevent whirl mode wing flutter and to retrofit all Electras already in service. The changes successfully resolved the issue, and modifications to the final aircraft were completed on July 5, 1961.

Background

In 1959, Braniff Airways served 48 cities in 17 states across the United States. The previous year, it had carried more than two million passengers, and at the beginning of 1959 it operated a fleet of 66 piston-engine aircraft. That year, the company planned to put eight new L-188 Electra turboprop aircraft into service. Braniff had ordered nine of the new aircraft in 1955 as part of a $57 million fleet expansion program. It received the first two aircraft on May 7, 1959, and placed them into service in mid-June. The first routes to use the Electra were flights from Texas to Chicago and from Texas to New York City.

Turbine-powered aircraft were a recent development in the aviation industry and were welcomed by the flying public. Turboprop flights attracted more passengers than comparable piston-powered flights because they were faster and smoother. Airlines operating the Electra promoted it as a faster and more powerful aircraft that would reduce flight times by an average of 20 percent compared with piston-engine aircraft. The Electra cruised approximately 100 mph faster than any other propeller-driven aircraft of its time. American Airlines, which began operating the Electra between New York and Chicago in January 1959, reported that 80 percent of the seats on its Electra flights were sold, 20 percent more than on its piston-engine flights. Eastern Airlines reported that sales on Electra flights were 10 to 15 percent higher than on comparable piston-aircraft flights.

Braniff operated Flight 542 as a regularly scheduled service from Houston International Airport to Idlewild Airport in New York City, with scheduled stops at Dallas Love Field and Washington National Airport. On September 29, 1959, the aircraft assigned to the flight was one of the airline's newest Electras. When it departed Houston, it carried 28 passengers and a crew of six, leaving the aircraft less than half full. Additional passengers were scheduled to board in Dallas for the next leg of the flight. Earlier that day, the aircraft had experienced problems with an engine-driven electrical generator. Repairs performed in Houston delayed Flight 542's departure by 22 minutes. The aircraft left the gate at 10:37 p.m., and took off at 10:44. The overnight flight was scheduled to arrive in New York City at 6:20 the following morning.

Accident

At 11:05 p.m., the aircraft was flying at an altitude of 15000 ft east of Waco, Texas. Visibility was good, with scattered clouds below the aircraft at about 12000 ft. The pilots contacted the San Antonio Air Route Traffic Control Center (ARTCC) to report their speed and altitude and to advise that they had crossed a planned waypoint over Leona, Texas. Controllers told them to contact the Fort Worth ARTCC for further clearance. Two minutes later, the pilots contacted Braniff Airways on a private frequency to report several mechanical issues that would require attention upon arrival in Dallas. The aircraft had problems with its propeller de-icing system and one engine had a malfunctioning fuel sump pump. Neither issue was considered a critical emergency, but Braniff's maintenance policies would have prevented the plane from leaving Dallas until the fuel pump issue was resolved.

When Flight 542 failed to check in with Fort Worth Center as instructed, the controllers attempted to contact the crew. After receiving no response, they continued trying to reach the flight for more than 30 minutes. Believing that the aircraft might have been experiencing radio problems, controllers kept air traffic clear of airports in Houston and Dallas in case the crew attempted to land without being able to communicate.

At 11:09 p.m., the aircraft broke apart in flight, producing flashes and fire seen by witnesses on the ground. Witnesses described seeing a blinding flash in the sky, followed by a loud clap of thunder and flaming objects falling for several seconds before the flames disappeared. One witness described hearing a series of explosions, sounding like "boom, boom, boom," while others believed the noise was a sonic boom caused by supersonic aircraft from nearby James Connally Air Force Base. An Air Force pilot said he initially thought the sound was that of an atomic bomb exploding. People as far as 100 mi away reported seeing the explosion.

Over the next five minutes, debris and bodies fell from the sky. The wreckage was scattered across an area approximately 2+1/2 mi long and 1 mi wide. The nose and the tail section came to rest within 100 yd of each other and only 150 yd from a farmhouse, whose occupants described the noise as "like a bulldozer falling out of the sky". Because the farmhouse did not have a telephone, one of the residents drove to the nearby town of Buffalo to notify authorities. There, he encountered a Texas Highway Patrol officer who had already been awakened by the noise. The officer called the regional office of the Texas Department of Public Safety in Waco to report that an aircraft had crashed before proceeding to the farm. By 1:00 a.m., eight men and five ambulances had arrived at the scene, and additional personnel arrived during the following hour.

The crash was the fifth fatal accident in Braniff's 31-year history and the first in which there were no survivors. The airline had one of the strongest safety records in the industry, and had received annual safe-operation awards from the National Safety Council. The accident was the second fatal crash involving the Lockheed Electra, which had entered commercial service less than a year earlier.

Accident report

The CAB released the final accident report on May 5, 1961. It said that the aircraft had suffered an in-flight breakup into a number of major sections, including the propeller and gearbox from the left outboard engine; the left wing containing the remaining parts of the outboard engine and the entire inboard engine; the right outboard engine; the end of the left stabilizer; the outer portions of the right wing; and the remaining fuselage and empennage with the right inboard engine and the inner portion of the right wing. The left wing struck the ground first and the fuel in the wing fuel tank triggered an intense ground fire. The point where the wing break occurred was located between the inboard engine and the fuselage. The report made note of the fact that a great deal of effort had been made to verify the working condition of the engines at the time of the crash, and that the investigators could not find any sign of failure of malfunction in the engines prior to the start of the separation from the wing. It said that it was evident that the aircraft broke up quickly and with little warning due to the fact that only one of the seats was found with the safety belt fastened, suggesting that there had been no time to order passengers to fasten them. The report concluded that the investigation was not able to determine a positive indication of the cause of the breakup, but through a process of elimination of other factors, the evidence supported the conclusion that whirl mode wing flutter had caused the crash.