What happened
A cargo flight operating from Ulyanovsk to Leninakan was transporting 37.2 tons of tools and construction materials along with 10 crew members and 5 passengers. During the descent phase, air traffic control provided a local pressure setting of 637 mm Hg. However, the crew incorrectly configured the altimeters to 736 mm Hg.
This error resulted in an altitude discrepancy of approximately 1,100 meters. The Il-76 continued its approach at a descent rate of 10 meters per second. While flying through nighttime conditions with limited visibility, the aircraft descended to an altitude of 270 meters, triggering the Ground Proximity Warning System (GPWS) alarm. Although the flight engineer identified the error and alerted the captain 19 seconds after the initial warning, no corrective maneuvers were performed. The aircraft subsequently struck a mountain at 440 km/h, causing the plane to break apart. There were 15 fatalities and no survivors.
Findings
Investigations into the accident identified several contributing factors:
- An incorrect altimeter setting of 736 mm Hg instead of the actual 637 mm Hg caused the aircraft to descend below the minimum descent altitude.
- The crew did not utilize radio altimeters, which would have provided critical data regarding their low altitude.
- The pilot failed to respond to the flight engineer's warning or initiate an emergency climb.
- Ineffective crew resource management was noted during the approach.
- The crew lacked sufficient training for responding to GPWS alerts.
- The flight involved an instructor captain and a student pilot, both of whom were flying the Il-76 into Leninakan for the first time.