Investigators of the deadly crash of TWA Flight 800 believe the design of the Boeing 747 aircraft and its fuel tanks were at least partly to blame for the tragedy, ABCNEWS has learned.
They also cite government certification of the safety of the plane and the tanks, sources familiar with the investigation of the crash told ABCNEWS’ Lisa Stark Tuesday.
Investigators, on the first day of a two-day NTSB hearing on the crash, Tuesday said an electrical short circuit outside the center fuel tank of Flight 800 likely sent excess voltage through wires into the tank, igniting flammable vapors and causing the jet to explode.
The jet fell, in flaming pieces, into the Atlantic Ocean near New York shortly after taking off from John F. Kennedy airport more than four years ago. All 230 passengers and crew were killed.
The spark most likely occurred in a high-voltage wire outside the tank, investigators believe. They also think the wire short-circuited and the spark then jumped to a low-voltage wire that runs into the fuel tank.
In addition, the investigators believe the design of the jet is in part to blame. They believe placement of air conditioning units under the fuel tank generated heat that led to vapors in the fuel tank being explosive when touched off by the spark, the sources said. The investigators plan to present their findings today.
Boeing Stands By Design Boeing officials Tuesday stood by the aircraft design.
“The design with the air conditioning packs under the center wing tank is a very common design for Boeing and other manufacturers. It is fully certified by the FAA,” Russ Young, a Boeing spokesman, told ABCNEWS. “We’ll wait to hear what the NTSB has to say tomorrow.”
Both Boeing and the Federal Aviation Administration, which certifies plane and part safety and design, have long held to the philosophy that to prevent explosions, jets had to eliminate ignition sources, but not necessarily tank flammability.
Another Boeing official told ABCNEWS that reduction of ignition sources and flammability went hand-in-hand.
“We think that both ignition source reduction and flammability reduction are really complementary and not mutually exclusive,” said Ron Hinderberger, director of airplane safety for Boeing. “We think that both of them are needed in order to ensure that we can have the most safe system that we can possibly have.”
Other Scenarios RejectedAfter years of speculation and $35 million spent, investigators said the most extensive and expensive probe in aviation history has ruled out two other scenarios in the downing of the Boeing 747-100: structural failure and the impact of a bomb or missile.
Physical evidence “leads to the inescapable conclusion that the cause of the in-flight breakup of TWA Flight 800 was a fuel-air explosion inside the center wing tank,” Bernard S. Loeb, director of aviation safety for the National Transportation Safety Board, said.
The NTSB on Tuesday began the two-day session to discuss the final report on the TWA crash, its causes and possible new safety measures. During the four-year probe, investigators recovered 95 percent of the aircraft, reconstructed a 93-foot segment of the fuselage, and amassed 15,000 pages of documentation.