What happened
A charter flight operated by Alas Nacionales was traveling from Puerto Plata to Frankfurt, with scheduled stops in Gander and Berlin. The flight was transporting 176 German passengers and 13 crew members from Turkey. During the takeoff phase, the captain observed a discrepancy between the two airspeed indicators, noting that the co-pilot's instrument appeared accurate while his own was providing incorrect data.
As the aircraft reached an altitude of approximately 4,700 feet, the captain's airspeed indicator showed 350 knots, despite the actual airspeed being only 220 knots. This erroneous data caused the autopilot and autothrottle systems to react by reducing engine power and increasing the aircraft's pitch. During this period, the crew received several advisory warnings, including 'Rudder ratio' and 'Mach airspeed' alerts.
Confusion increased when the co-pilot reported his airspeed indicator was dropping toward 200 knots while simultaneously triggering an excessive speed warning and a stick shaker. Believing both instruments were unreliable, the crew disconnected the autopilot. However, because the autopilot had already reduced speed to near-stall levels based on the faulty data, the crew applied full thrust to recover. Shortly after 23:47:17, a GPWS aural warning sounded, and the Boeing 747 impacted the ocean eight seconds later. The accident resulted in 189 fatalities.
Findings
The primary factor in the accident was the erroneous data from the captain's airspeed indicator, which caused the automated flight systems to incorrectly adjust the aircraft's pitch and power, ultimately leading to a near-stall condition.