|Aircraft registration number||RA-22426|
|Place of aircraft departure|
|Airport of departure|
|Intended Airport of arrival|
|Accident site||Либерия, р-н аэродрома Spriggs Payne|
|Aircraft operator||ОАО "Авиакомпания "ЮТэйр"|
|Aircraft owner||Chitala Investment Limited|
|The date of the completion of the investigation (report)||29.02.2016|
|Number of fatalities||0|
|Degree of aircraft destruction||aircraft substantially damaged|
report_ra-22426.pdf (2.12 MB)
Non-fatal accident with Mi-8AMT RA-22426 helicopter operated by "UTair" Airlines occurred in the area of Spring-Pein a/p on April 22, 1014. According to the prelininary information 4 crew members and 9 passengers on board didn't suffer.
In accordance with Annex 13 to the Convention on international civil aviation and russian aviation legislation the Interstate Aviation Committee appointed the accredited representative and adviser in order to participate in the Investigation team activity.
The Investigation team if the Interstate Aviation Committee has completed the investigation of the accident with Мi-8АМТ RA-22426 helicopter owned by "UTair" Airlines" PJSC occurred in the area of Spriggs Payne Airport (Liberia) on 22 April 2014.
Non-fatal accident with Mi-8АМТ RA‑22426 helicopter was caused by the crew erroneous actions during the abnormal cause heliborne - one of the engines failure. Noncompliance with Rotorcraft Flight Manual in part regarding the engines operation parameters and dead engine identification procedure resulted in inadvertent operating engine shutdown. The Availability of the second engine emergency mode allowed the crew to perform single-engined uneventful landing.
PIC's actions during both engines power absence allowed to prevent more severe consequences during the emergency landing in congested area.
Engine failure was caused by the fracture of outer guide vanes and rotating blade of sixth compressor stage. Fractures propagation time is more than 1 operation.
Fracture of outer guide vanes is caused by insufficient corrosion resistance of their material in actual operation conditions. Operating vane fracture has high-cycle fatigue and is conneсted with the effect of design engine operation modes resonant vibrations during long period of time caused by changes in geometry due to the damage during operation. It wasn't possible to restore mechanism and consequence of the fracture in more detail due to the lack of mating parts of fractured vanes.
The appropriate safety recommendations based on the investigation results were presented.