Accident Details
A calibration flight operating at Khabarovsk-Novy Airport crashed into the wooded slope of Mt Khrebtovaya, located in the Bolchoï Khekhtsir Mountain Range, approximately 40 km southwest of the airport. The aircraft was engaged in a mission to calibrate the ILS system of runway 05R and carried six crew members.
After departing in the afternoon, the aircraft completed several circuits over the aerodrome and surrounding area. Air traffic control instructed the crew to climb to an altitude of 600 metres and turn to follow the reverse approach course. However, the minimum published altitude for that sector, up to a distance of 46 km, was fixed at 1,200 metres. The crew continued at an altitude of 600 metres on a heading of 220° for several minutes. While initiating a slight climb and flying at an altitude of 742 metres in poor visibility due to marginal weather conditions, the aircraft struck trees and crashed on the mountain slope. The aircraft was totally destroyed by impact forces, and all six occupants were killed.
Probable Cause
According to the official investigation, the cause of the accident was that the airplane was flying over the radio beacons of runway 05R of Khabarovsk-Novy Airport in instrument meteorological conditions (IMC) at an altitude of 600 metres QFE, which was significantly lower than the established minimum safe altitude of 1,200 metres QFE in that sector. This led to a controlled flight into terrain (CFIT).
Contributing factors identified include:
- Lack of current regulatory documents governing flight inspections of ground-based equipment, including for airfields with challenging topographical features.
- Unreasonable establishment of a continuous exclusion zone from 0 m to 6000 m within a radius of 99900 m from KTA for the minimum safe altitude warning (MSAW) function, preventing a warning to the controller.
- Absence of proper ATC procedures for overflights and training.
- Decision to combine two sections of trainee navigator training without necessary risk analysis or mitigation.
- Insufficient preliminary crew preparation, including failure to account for terrain and proximity to the state border, and presence of a trainee navigator not cleared for independent flights.
- Insufficient crew-ATC cooperation during preparation and execution.
- Interference by the instructor navigator in flight procedure without risk assessment.
- Failure of the trainee navigator to comply with operating procedures regarding altitude maintenance and use of equipment.
- Lack of control by the trainee and instructor controllers due to low workload.
- The operator's flight operations manual lacked standard operating procedures for the EGPWS Mark VIII system; no warnings were issued during the flight, possibly because the system was not activated.
Due to the complete destruction of the EGPWS system in the crash, the cause of its failure could not be determined.