AEROFLOT - NORD FLIGHT 821 AT PERM.
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| Aeroflot Nord 821, Embedded fromAirline World on 30 September 2010 | Aeroflot Nord 821, Embedded fromAirline World on 30 September 2010 | |
SYNOPSIS:
On the 13th of September 2008, a B737 – 505 operated by Aeroflot Nord flying from Moscow Sheremetyevo to Perm crashed on approach to runway 21.
HISTORY OF THE FLIGHT:
On 13th September, 2008, Aeroflot Nord flight 821, a B737 – 505 with a registration of VP -BKO, operated by a two man crew, flew from Moscow Sheremetyevo to Perm.
The flight departed uneventfully, on time out of Moscow. As the crew started their descent, they were given instructions to fly to the outer marker of runway 21. The crew, after passing over the runway, were given instruction by the controller to turn right for a base turn. As the aircraft approached the landing course at 600 m (its autopilot and auto thrust disengaged), it started climbing to 1300m, rolled to the left by 360 degrees and crashed to the ground.
Spatial disorientation, lack of knowledge of the aircraft systems and loss of situational awareness were cited as the probable causes of the accident.
ILLUSTRATION OF THE THRUST LEVERS POSITION:
| Aeroflot Nord 821. (image embedded from FlightGobal on 30 September 2010) |
RECONSTRUCTION OF THE PERM CRASH:
| (Video embedded from YouTube on 30 september 2010) |
CONTRIBUTING FACTORS:
PHYSIOCLOGICAL:
FATIGUE:
Fatigue : the captain’s schedule for the three days preceding the accident did not comply with the national’s regulation and was conducive to fatigue. He conducted two night flights, had not rested at night and flew six flights prior to the accident. This may have exacerbated the spatial disorientation of the captain.
ALCOHOL:
Alcohol: an examination of the captain (post mortem) revealed that he had levels of ethyl alcohol that exceeded regulatory limits. This may have exacerbated the spatial disorientation of the captain.
LATENT ERRORS:
DRAWBACKS IN THE TRAINING SYSTEM:
- The previous aircraft that the crew flew (AN-2/ Tu-134) had an “Eastern- type” attitude indicator where the horizon remains fixed horizontally while the aircraft symbol tilts to show bank angle, whereas the 737 “Western- type” indicator tilts while the aircraft symbol remains fixed horizontally. The crew may not have received adequate training in the difference.
- Neither pilots had any previous experience with glass cockpit or with two pilot crew operations. The bulk of the flying hours of the crew were on the An-2 and Tu -134. Both these aircraft required two pilots and a navigator.
- The training facility that the captain received his training from was not approved by the Russian authorities. An adequate assessment of the captains file wasn’t possible due to missing documents from the captain’s file.
- Reports from the analysis of the recorded statements (from the CVR) by the co-pilot may have indicated that his English proficiency was not suitable for operating the 737. All the documentation of the 737 was in English.
- The pairing of two low experience pilots on type (737) by the airline. The Captain had only 477 hours on the 737 and the co-pilot had only 236 hours.
MAINTENANCE:
The aircraft had a thrust lever stagger condition that exceeded the limits specified on the aircraft maintenance manual where the thrust levers were required to flown in different positions to match the engine settings. To produce an equal power setting, the thrust levers would have to be staggered by 15 degrees, the left being ahead of the right thrust levers.
ACTIVE ERRORS:
LACK OF COMMUNICATION:
There was a lack of clear communication between the crew and the controller:
- The controller issued arrival instruction that contradicted and confused the crew, it differed from the standard arrival and approach fixes entered into the FMS by the co-pilot.
- The controller failed to inform the crew of the gross navigation error of the aircraft crossing the runway instead of the outer marker.
- The controller gave an instruction to the crew to turn base without any specific heading instruction.
MAINTENANCE:
- The airline’s maintenance personnel failed to correct the thrust lever stagger as required by the AMM, which was identified one month before the accident.
- Even though the thrust levers were designated as inoperative, the maintenance personnel failed to pull and collar the thrust levers circuit breakers as per the requirement of the minimum equipment list.
LACK OF CROSS CHECKING:
- The co-pilot made two errors in entering the parking stand coordinated into the FMS during the initialisation of the inertial reference system (IRS). This was not caught by the captain. This led to an error of more than 8.3 km as the aircraft neared Perm. As the crew neared Perm, they relied on the inaccurate IRS data without backing it up with navaids. This led to the aircraft crossing the runway rather than at the outer marker.
- Based on the CVR, there was a lack of mandatory cross check, few required callouts and no checklist was done during the approach.
- As the thrust levers increased at level 2100m , the thrust lever stagger caused the disengagement of the auto throttle. This resulted in asymmetrical thrust causing confusion in the flight deck as the aircraft started rolling left. There wasn't any cross checking by both pilots of the status of the auto throttle and automation.
LOSS OF SITUATIONAL AWARENESS AND SPATIAL DISORIENTATION:
- The autopilot reached its limit in counteracting the left moment, causing the aircraft to roll to the left. This led the co-pilot to inadvertently select the stabilizer trim switch, instead of the control wheel steering switch, causing the autopilot to disconnect.
- The late transfer of control of the co-pilot and the loss of situational awareness of the captain led to the captain applying left aileron. The aircraft's bank angle increase to 76 degrees and descended to the ground.
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REFERENCES
Aeroflot Nord 821. Retrieved 30 September, 2010 from http://www.aaib.gov.uk/cms_resources.cfm?file=/VP-BKO_Report_en.pdf
Want to know more?
Final Report 737 -505 VP-KBO, AAIB: http://www.aaib.gov.uk/cms_resources.cfm?file=/VP-BKO_Report_en.pdf
Aero Safety World: http://flightsafety.org/aerosafety-world-magazine/past-issues/july-2010
