On 24 September 2009 a BAe Jetstream 41 being operated by SA Airlink on a positioning flight from Durban to Pietermaritzburg with only three crew members on board experienced an engine fire during take off and after reaching a height of about 500 feet agl then entered a semi controlled descent to a high impact forced landing in a residential area about 1400 metres beyond the runway end. The three occupants were all seriously injured and the aircraft commander subsequently died as a result of his injuries. A fourth person on the ground was also injured.
An Investigation was carried out by the Accident and Incident Investigation Division (AIID) of the South African CAA. Both the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR) were recovered from the wreckage and successfully read out at the UK AAIB. Both contained a full record of the accident flight.
It was established that the First Officer had been PF and that the positioning cabin crew member had occupied the flight deck jump-seat.
It was found that during the take-off roll of the accident aeroplane, the pilots of another aircraft on the ground at Durban had seen “smoke pouring from (its) right engine” but had been reluctant to suggest a rejected take off because “they felt that they might be blamed had (this) gone wrong”. Instead, they had asked the TWR controller whether the aircraft was aware of the smoke and by the time the controller responded, the accident aircraft was already becoming airborne.
Recorded data showed that the right hand engine failed fully during rotation but that this was subsequently followed by a power reduction on the left hand engine to 80% torque as the aircraft climbed through about 480 feet. This action appeared to have been “the result of a misidentification and (attempted) shutdown of the engine”. When this torque setting was then increased back to 104%, it was found that “both lateral and directional control was lost because aileron and rudder deflections (made) were too small”. Shortly after that the aircraft began to descend and subsequently struck the ground. The total time from start of the take-off roll until ground impact was just under two minutes.
It was verified by means of a teardown examination that the left hand engine had remained serviceable throughout the flight. An examination of the right hand engine showed that it had experienced a pre-impact separation of the second-stage turbine seal plate which had created an imbalance of the power section-rotation which led to a fatigue fracture of the turbine bearing oil-supply tube and subsequent damage to the turbine bearing. This bearing damage had caused the power section centreline positioning to be lost so that “turbine efficiency proportional to the ability of the engine to produce positive torque to the propeller” was lost. The initiation of this failure sequence was attributed to the separation of the second-stage turbine seal plate rim which it was considered had most likely occurred following power setting for take off.
It was found that the engine failure sequence established appeared to be the thirteenth known similar failure for the engine type and application including one on another SA Airlink aircraft after which the crew had been able to successfully reject the take off. The Investigation was concerned to find that the seal plate life at which this failure had been occurring appeared to be decreasing.
Although the accident aircraft pilots had received Crew Resource Management training, it was concluded that “in this accident the CRM process failed the crew, because interpersonal communication, leadership, and decision-making in the cockpit was not evident”. The Investigation could find “no clear reason for the misidentification” of the failed engine other than “a complete deviation from the operator’s SOPs and failure to apply the CRM”. A review of the relevant pilot training and assessment procedures at SA Airlink did not identify any deviation from their specification or any “known training issues”. It was noted that the aircraft commander had been promoted to the rank of Captain just two weeks prior to the accident and that the First Officer had been issued with an ATPL 16 days prior to the accident.
The Investigation determined the Probable Cause of the Accident as:
- “Engine failure after takeoff followed by inappropriate crew response, resulting in the loss of both lateral and directional control, the misidentification of the failed engine, and subsequent shutdown of the remaining serviceable engine”.
In addition, Contributing Factors were identified as:
- Separation of the second-stage turbine seal plate rim
- Failure of the Captain and First Officer to implement any crew resource management procedures as prescribed in the Operator’s Training Manual
- The crew’s failure to follow the correct after take-off engine failure procedures as prescribed in the AFM.
Three Safety Recommendations were made as a result of the Investigation:
- That the SACAA conducts a comprehensive audit of compliance with all aspects of its Air Operator Certificate requirements, including its training procedures and assessments of the operator involved. This recommendation was actioned by SACAA and a satisfactory action plan, which was implemented, was submitted by the operator to SACAA.
- That the SACAA conducts a comprehensive audit of the compliance with all
aspects of engine inoperative training at flight schools and that more emphasis is placed on simulator training.
- That the Federal Aviation Administration (Federal Aviation Administration (FAA)) should require Honeywell Aerospace to expedite efforts to produce an engineering solution to the problem of second-stage turbine rotating air seal failures on Honeywell TPE331-14G/H engines.
The Final Report of the Investigation CA 12-12a was published on 23 February 2006.