Accident Sequence
Flight 800, a scheduled international flight from Rome, Italy to Athens, Greece, departed the parking area at 1300 hours GMT with the copilot at the controls. The take-off run on runway 25 began at 1307 hours. When the aircraft had accelerated above 80 kt, the pilot-in-command observed that the No. 4 engine pressure ratio gauge indicated 1 (zero thrust). Immediately thereafter, the amber light for thrust reversal of the No. 2 engine illuminated. As the speed was still below V1 for the prevailing weight and runway conditions, the pilot decided to abort the take-off and took over the controls to execute the abort maneuver. The tower was informed of this decision when the aircraft had reached a point approximately 800 to 900 m past the threshold.
The aircraft began to decelerate, but at a rate significantly slower than expected. Concurrently, it veered sharply to the right, causing the right landing gear to graze the runway edge. Reverse thrust on the two right engines was reduced in an attempt to guide the aircraft back toward the centerline. The aircraft continued beyond the declared runway limit and struck a pavement roller with its No. 4 engine. This roller was being used for maintenance work on taxiway 16/34 in an authorized area. After traveling an additional 260 m, the aircraft came to a stop with a fire on board. Following a series of explosions, the aircraft was engulfed in flames and completely destroyed. The accident occurred at 1309 hours GMT.
Aftermath
The impact and subsequent fire resulted in the deaths of five crew members and 44 passengers. An additional 24 occupants were injured, some seriously.
Probable Cause
The official investigation determined the probable cause to be: damage to the reverse thrust system of the No. 2 engine, not detectable by cockpit instruments, consisting of a disconnection of a duct that led to a lack of pressure in the pneumatic clamshell door actuating mechanism. This malfunction allowed the No. 2 engine to develop considerable forward thrust even though all four levers were in the reverse position. Additionally, the rupture of the fuel feed tube to the No. 4 engine caused by impact with the pavement roller led to ignition of spilled fuel. Failure of the surge tank drainage due to a blocked valve forced fuel out through the vent scoop, permitting fire to reach the wing. The presence of fuel-air vapor in the tanks in explosive proportions caused the explosions when ignited.