ASN Wikibase Occurrence # 245736
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| Date: | Thursday 2 March 2017 |
| Time: | 18:35 |
| Type: |  Mil Mi-8MTV-1 |
| Owner/operator: | Alrosa |
| Registration: | RA-25129 |
| MSN: | 95745 |
| Year of manufacture: | 1991 |
| Fatalities: | Fatalities: 0 / Occupants: 24 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Verkhneye Molodo, Yakutia -
 Russia
|
| Phase: | Approach |
| Nature: | Passenger - Non-Scheduled/charter/Air Taxi |
| Departure airport: | Zhigansk Airfield |
| Verkhneye Molodo | |
| Investigating agency: | MAK |
| Confidence Rating: |  Accident investigation report completed and information captured |
The Mil Mi-8 force landed in wooded area. The 3 crew members, 2 aircraft technicians and 19 passengers on board were not injured.
The helicopter performed flight YM-9935 at the request of the Almazy Anabara diamond mining company along the route: Verkhneye Molodo - Saloli River - Burovaya No. 3 - Burovaya No. 4 - Prilensk - Zhigansk airfield - Verkhneye Molodo for the delivery of rotational shifts to the specified sites.
The accident occurred as a result of a forced landing of a helicopter with two inoperative engines on a forest, which led to significant damage to the aircraft.
Most likely, the following factors contributed to the accident:
- the ingress of a foreign object into the main engine of the right engine during the landing approach, which caused the crew to turn off the engine at an altitude of 180 m (before the crew turned off the right engine, its operation parameters did not exceed the maximum permissible). It was not possible to establish the nature of the object that got to the entrance of the right engine;
- failure of the HP-3VM unit of the left engine in the form of a hanging mechanism for turning the corners of the guide vane due to jamming of the spool in the bushing of the pressure receiver, which, when the engine exits to the CR after turning off the right engine, led to a surge effect with a subsequent loss of power. The reason for the jamming of the spool of the pressure receiver of the HP-3VM unit was operation on fuel with an increased content of pollutant particles. It was not possible to establish the source of the pollution;
- lack of control on the part of the crews over the engine operating modes in previous and emergency flights;
- lack of control over the operability of aviation equipment according to the SOC (the operating program for express analysis of information from the SDK-8 of Mi-8MTV helicopters does not allow detecting fluctuations in the rotational speed of the rotors of turbochargers of engines and the temperature of gases more than acceptable)
The actions of the PIC at the final stage of the flight did not correspond to the provisions of the flight manual of the Mi-8MTV helicopter when landing with two engines inoperative: if the engines failed, the PIC allowed the NV speed to drop to 75% before landing, which caused the aircraft to land with an increased vertical descent rate.
Accident investigation:
 |
|
Sources:
MAK
Images:
Photo: MAK
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 15-Dec-2020 20:47 | harro | Added |
| 15-Dec-2020 20:48 | harro | Updated [Cn, Category] |
Corrections or additions? ... Edit this accident description
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