What happened
On October 31, 1999, EgyptAir Flight 990, operating as a scheduled service from Los Angeles International Airport to Cairo International Airport via New York City, encountered a catastrophic failure during its cruise phase. The aircraft, identified by registration SU-GDIP, was a Boeing 767-300ER. While traversing international waters approximately 60 miles south of Nantucket Island, Massachusetts, the plane descended rapidly and impacted the Atlantic Ocean. There were no survivors among the 217 passengers and crew on board, marking it as the deadliest aviation disaster in EgyptAir's history.
Investigation
Because the crash site lay within international waters, jurisdiction fell under International Civil Aviation Organization protocols, involving both the Egyptian Ministry of Civil Aviation's Civil Aviation Agency (ECAA) and the U.S. National Transportation Safety Board (NTSB). Recognizing that the ECAA lacked the extensive resources available to its American counterpart, the Egyptian government formally requested that the NTSB lead the inquiry. The investigation focused heavily on cockpit voice recordings and flight data to determine why the aircraft departed controlled flight.
Findings
The primary focus of the inquiry was the discrepancy between the two pilots regarding the aircraft's control inputs. The NTSB concluded that the first officer had intentionally moved the thrust levers to the idle position, causing the loss of lift and subsequent crash. Conversely, the Egyptian investigators attributed the accident to a mechanical malfunction of the autopilot system, which they believed caused an unintended nose-down pitch that the crew could not correct. This fundamental disagreement on the intentional act by the first officer versus equipment failure remains the central point of contention in the official reports.