10 Unsolved Airplane Mysteries

Mechanical Failure or Suicide?
This graph of the EgyptAir Boeing 767 flight drawn up by the U.S. National Transportation Safety Board shows some key moments before the plane crash. © Ron Sachs/CNP/Sygma/Corbis

This one sparked an international controversy. On Oct. 30, 1999, EgyptAir Flight 990 took off from Kennedy Airport in New York bound for Cairo with 217 people aboard. A senior pilot named Ahmad al-Habashi was in command of the Boeing 767 jetliner, and a veteran co-pilot, Gameel al-Batouti, was assisting him.

The plane climbed to 33,000 feet (10 kilometers) and flew normally for 30 minutes, before plummeting into the Atlantic Ocean 60 miles (97 kilometers) south of Nantucket, Mass., killing everyone aboard [source: Langewiesche].

So what caused the accident? Egyptian officials believed that mechanical failure was to blame, stating that suicide is against Islam. But the U.S. National Transportation Safety Board (NTSB) concluded that the co-pilot had deliberately caused the crash, citing that the autopilot was off, the plane was in a wings-level dive and the co-pilot muttered calmly to himself, "I rely on God" many times. The final report said that the crash was due to the co-pilot's "manipulation of the airplane controls," a claim Egypt still disputes [source: Wald].

However, one EgyptAir pilot told the FBI that Batouti had just been demoted because of accusations of sexual misconduct, and might have crashed the plane to commit suicide or to take revenge against his supervisor, who was a passenger on the flight [source: Wald].