2008 Chelyabinsk Antonov An-12 crash
RA-12957, the aircraft involved in the accident
|Date||26 May 2008|
|Summary||In-flight fire leading to the destruction on aileron wiring that led to aileron failure|
|Site||Chelyabinsk Balandino Airport
|Aircraft type||Antonov An-12|
|Flight origin||Chelyabinsk Airport, Chelyabinsk, Russia|
|Destination||Perm Airport, Perm, Russia|
|Wikinews has related news: Nine killed as Russian cargo plane crashes in Siberia|
On 26 May 2008, a Moskovia Airlines An-12 cargo aircraft crashed near Chelyabinsk, Russia. After departure to Perm, it turned back due to fire on board and crashed 11 km away from the airport, killing all nine crew members.
During the pre-takeoff checklist, the crew saw warnings about power supply failure in engine 1 and 2, but ignored them, as recorded by the CVR:
- Flight radio operator: "Sanya." (name of the engineer)
- Flight engineer: "Yes?"
- Flight radio operator: "Number two failed"
- Instructor pilot: "And number one too"
- Flight radio operator: "Alternator"
- A crew member: "Screw it"
- Flight radio operator: "Here we go"
The investigation team concluded that "here we go" probably referred to successful reactivation of the alternators by the radio operator.
The flight took off at 14:03 from Runway 09. At 14:03:55, the captain asked "What's the matter?". The flight engineer responded "doors open". It is unclear whether he referred to cargo doors or chassis doors, but the final report states that it was probably the chassis doors. The investigation found that the doors were closed at the time of the crash, and the false alarm was one of the first signs of problems in the power lines in the aircraft.
Another warning sounded 6 seconds later: "Too low, gear". This was unexpected because the aircraft was climbing, and this warning can only be triggered during descent.
At 14:04:09, other crew members in the cabin advised the pilots about the fire.
- Captain: "Come on, have a quick look... take a look what's going on there"
- Flight radio operator: "Let's land maybe, or... OK, requesting"
- Captain: "Wait, wait"
- First officer: "My attitude indicator failed"
- Captain: "Got it, taking control"
At this time, the aircraft was at 470 m and turning left. At 14:04:28, the captain decided to turn back to Chelyabinsk. The crew contacted ATC and requested priority landing due to smoke in the cockpit.
The weather was cloudy, ceiling at 90–100 meters, visibility 1100 meters. CVR recordings showed that pilots discussed further failures of multiple systems, as well as multiple false failure alarms. They also discussed that the source of fire was in the cargo section and considered depressurizing the cabin.
A trimmer failure warning was triggered at 14:07:15, and at 14:08, engine dislodging indicators were also triggered. The flight engineer warned the crew to operate the throttle slowly.
At 14:09:13, when the aircraft was turning left base, engine 2 became unstable. Moments later, multiple fuses went off. At 14:09:54, engines 1 and 2 stopped due to fuel starvation.
The cockpit voice recorder stopped working and the data recorded by flight recorder became unreliable.
At 14:10:21, the captain started turning to final. With only two engines operating, its speed went down to 280 km/h, the minimum permitted without flaps. Engine 3 was operating at 20% and engine 4 was throttled to 85%.
At 14:10:43, the crew contacted Tower and reported "Gromov 9675, on landi... turning to final, 400, approaching, continuing approach". This was the crew's final transmission.
Starting from 14:10:40, the aircraft heavily banked left (to 32 degrees). At 14:10:42, the aircraft continued increasing its bank angle. It began descending at 14:10:48.
At 31 meters above ground, the aircraft clipped a high-voltage power line with its left wing. The aircraft then crashed in a field, 11 km from Runway 09 at 14:10:56. The vertical speed at the time of impact was 5000 fpm.
The investigation concluded that during the last fifteen seconds of the flight, the crew was unable to effectively operate the ailerons. Medical experts ruled out incapacitation due to smoke inhalation, meaning that the pilots could not operate the ailerons because of mechanical failure caused by the fire.
A fire broke out after the crash; there were no survivors.
Because of the fire on the crash site, the investigation could not determine the exact location of the fire in the electrical system that caused the accident.
The flight recorders were severely damaged, but remained usable.
The final report states the following reason of the accident:
The aviation incident with An-12 aircraft registered RA-12957 occurred as a result of impact with ground caused by lost control over the aircraft due to the destruction of aileron control wires during an emergency approach for landing because of smoke in the cabin.
[...] Aileron control wires were destroyed most probably due to significant heating of nearby steel wires and subsequent breaking under operating load.
The heating may have been caused by in-flight fire of nearby power lines, which is evidence by smoke in the cabin, unexpected triggering of multiple warnings, equipment failures and failure of two engines.
The captain had 14928 hours of flying experience and the navigator had 11021 hours. Both of them had no prior incidents.
- Ranter, Harro. "ASN Aircraft accident Antonov 12BP RA-12957 Chelyabinsk Airport (CEK)". Retrieved 15 July 2016.
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- "Разбившийся Ан-12 перевозил деньги". Retrieved 15 July 2016.
- "Второй круг для Ан-12 оказался смертельным". Retrieved 15 July 2016.
- "Катастрофа Ан-12Б ОАО Авиакомпания Московия близ Челябинска (борт RA-12957), 26 мая 2008 года. // AirDisaster.ru - авиационные происшествия, инциденты и авиакатастрофы в СССР и России - факты, история, статистика". Retrieved 15 July 2016.
- "ОКОНЧАТЕЛЬНЫЙ ОТЧЕТ ПО РЕЗУЛЬТАТАМ РАССЛЕДОВАНИЯ АВИАЦИОННОГО ПРОИСШЕСТВИЯ" (PDF). Retrieved 2016-07-16.