Status: | Accident investigation report completed and information captured |
Date: | Monday 3 August 2020 |
Time: | 10:00 |
Type: | Antonov An-74TK-100 |
Operator: | UTair-Cargo |
On behalf of: | United Nations - UN |
Registration: | RA-74044 |
MSN: | 36547097936 |
First flight: | 1994 |
Total airframe hrs: | 13302 |
Cycles: | 6496 |
Engines: | 2 Lotarev D-36-3A |
Crew: | Fatalities: 0 / Occupants: 7 |
Passengers: | Fatalities: 0 / Occupants: 4 |
Total: | Fatalities: 0 / Occupants: 11 |
Aircraft damage: | Destroyed |
Aircraft fate: | Written off (damaged beyond repair) |
Location: | Gao Airport (GAQ) ( Mali)
|
Phase: | Landing (LDG) |
Nature: | Cargo |
Departure airport: | Bamako Airport (BKO/GABS), Mali |
Destination airport: | Gao Airport (GAQ/GAGO), Mali |
Flightnumber: | UNO052P |
Narrative:An Antonov An-74TK-100 transport plane, operating for the United Nations, suffered an accident on landing at Gao Airport, Mali.
The aircraft operated flight UNO 052P from Bamako to Gao, Mali. There were 7 crew members on board the aircraft and 4 passengers (representatives of the UN mission).
While en route, about 1 hr. 10 min after takeoff, the right engine generator failed. The captain initiated a descent and attempted to start the APU. At that moment the left engine generator failed as well. Two attempts to start the APU failed.
After about 20 minutes of flight, the batteries were completely discharged, which led to a complete loss of power supply on board the aircraft.
The crew continued the flight to Gao in VFR under the clouds. Landing approach at Gao was performed visually. Due to the on board powerloss, the flaps remained retracted.
The aircraft touched down at a distance of about 500 m from threshold of runway 25. Due to the power failure, the thrust reverser could not be used.
The aircraft could not be stopped on the runway and overran, coming to rest 389 meters past the end of the runway. Two crew members were injured, other crew members and passengers were not injured.
Probable Cause:
Conclusion:
The aviation incident occurred during rollout after landing, resulting in the longitudinal excursion of the aircraft beyond the runway and collision with a sewage collector during ground movement. The landing was performed on a fully unpowered aircraft with wing flaps retracted, without the possibility of using spoilers and engine reversers for braking. Immediately after landing, the wheel brake system failed due to its usage by the crew at speeds significantly exceeding the established FCOM maximum values for the An-74TK-100 aircraft. The landing under these conditions exceeded the expected operating conditions, as there is no data in the FCOM for its calculation and execution.
The most probable contributing factors were:
- The absence of information in the FCOM regarding landing calculation and crew actions during unpowered flight (landing with retracted flaps without the possibility of using spoilers and engine reversers) due to the aircraft developer's assessment of such a situation as practically improbable.
- Poor execution of pre-flight refueling of generator oil systems and a lack of proper control over their execution, leading to exceeding the permissible maximum oil level, its overheating in flight, melting of thermal sensors, and sequential automatic disconnection of two GP21 generators.
- Failure of the crew to adhere to standard operational procedures for the APU in-flight (failure to activate the APU compartment heater), as well as the preparation and start-up methods outlined in the FCOM, leading to the inability to start the APU and complete loss of power in the aircraft after the battery voltage dropped below the permissible value.
Accident investigation:
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Investigating agency: | MAK Russia |
Status: | Investigation completed |
Duration: | 3 years | Accident number: | final report | Download report: | Final report
|
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Classification:
Electrical system problem
Forced landing on runway
Sources:
»
maliweb.net»
Photos
accident date:
03-08-2020type: Antonov An-72TK-100
registration: RA-74044
accident date:
03-08-2020type: Antonov An-72TK-100
registration: RA-74044
Video, social media
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does
not display the exact flight path.
Distance from Bamako Airport to Gao Airport as the crow flies is 945 km (590 miles).
Accident location: Approximate; accuracy within a few kilometers.
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.