Incident Overview
A four-engine aircraft operating a military/cargo flight from Aden to Tashkent, with an intermediate stop in Karachi, crashed while on the leg from Karachi to Tashkent. The aircraft was cruising at an altitude of 5,500 meters when weather conditions deteriorated, and it entered an area of hailstorm accompanied by severe turbulence.
Engine Failure
During the hailstorm, all four engines lost power. The crew was forced to shut down engines number 1 and 3, while engines number 2 and 4 were reduced to idle power.
Emergency Descent and Disintegration
The crew initiated an emergency descent. During this descent, the aircraft partially disintegrated in the air and subsequently crashed. Investigation determined that excessive g-loads caused several parts to detach during the emergency descent.
Probable Cause
It was determined that all four engines lost power in-flight after hail accumulated in the oil tanks.