Description

On 7 May 2011, a Xian MA60 being operated by Merpati Nusantara AL on a scheduled passenger flight from Sorong to Kaimana failed to complete an attempted day visual approach to runway 01 at destination when control was lost shortly after an attempted transition to a go around due to lack of sufficient visual reference. The aircraft was destroyed on impact with the sea surface 800 metres south west of the runway threshold at a high rate of descent and all 25 occupants were killed.

Investigation

An Investigation was carried out by the Indonesian NTSC. The Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) were recovered and the data from them was successfully downloaded. It was established that the First Officer, an inexperienced pilot with limited time (234 hours) on the MA60, his first multi engine type, had been designated as PF for the flight and that while the aircraft commander, who was a long term employee of the airline, had extensive experience on other aircraft types operated by the airline all of which were Fokker types, he had only 199 hours on the MA60.

It was noted that Kaimana has no Instrument approach and the applicable Visual Flight Rules (VFR) minima were visibility 5000 metres and a cloud base of 1500 ft aal or greater. As the aircraft had neared its destination, the weather had deteriorated and the aircraft commander had decided that the best chance of achieving sustained visual contact with the airport was to position to the south of it. Reported visibility at the airport then reduced to 2000 metres and after initially giving instructions to the PF in respect of track, descent and power setting, the aircraft commander had eventually taken control with the AP disconnected and the aircraft established on an approximate final approach track for runway 01 at a radio height over the sea of 344 feet.

After failing to gain sight of the runway, descent was continued below the mandatory 500 ft agl mandatory go around height. An EGPWS alert of ‘Minimum, Minimum’ which occurred when the aircraft was at around 460 feet radio altitude was ignored and a go around was not called until 250 feet agl. This go around was never properly established; although a modest climb was begun and just over 200 feet gained over 14 seconds, airspeed fell as flap retraction, power increase and retraction of the landing gear were delayed and because the Engine Regime Selector (ERS) remained in CRUISE mode instead being selected to TOGA mode, the power lever movement only led to torque reaching 70% and 82% on the left and right engines respectively. Flap retraction was also premature; on the MA60 flaps should be at 15º for a go around until speed exceeds 135 knots but were retracted to 5º and subsequently to 0 when below that speed. At the same time, a bank to the left progressively increased and as the flaps reached zero, control was lost and a rapid descent at up to 3000 fpm followed. An annotated reconstruction of the track of the aircraft during the approach is provided in the diagram below.

It was considered that there were indications that the aircraft commander may have reverted to a procedure for the previous Fokker 100 aircraft type he had flown when he asked for “Flap 25” on base leg since this setting does not exist on the MA60. The incorrect call for flaps to 5 during the attempted go around was also an action typical of the Fokker 100. It was noted that he had nearly 7000 hours on the Fokker 100 which does have a Flap 25 setting. It was considered that “stress and workload can increase the likelihood of regressing to earlier well-learned habit patterns”. In this context, the conversion training of the two pilots had been different. The First Officer had been trained by an aircraft manufacturer instructor using the manufacturer’s syllabus, while the commander had been trained more recently by a Merpati instructor using modified syllabus. It was suggested that “inadequacy/ineffectivity in the training program may lead to actions that deviated from the standard procedure and regression to the previous type.”

The investigation also noted that the MA60 FCOM and AMM used non-standard Aviation English.

Six Safety Recommendations were made as a result of the Investigation:

• that Merpati Nusantara Airlines should review the training management system to meet the standard requirements.

• that Merpati Nusantara Airlines should improve the aircraft acceptance including documentation and manuals, related to CASR requirements.

• that the Directorate General Civil Aviation should emphasis the aircraft inspection including documentation and manuals, prior to issuance of an initial airworthiness certificate related to the CASR 121 requirements including the DFDR parameters.

• that the Directorate General Civil Aviation should review the adequacy of training syllabus in order to meet the qualification requirements.

• that the Directorate General Civil Aviation should review the crew pairing policy.

• that the Directorate General Civil Aviation should review implementation of the Safety Management System (SMS) (by) all operators.

Safety Action in response to the accident was noted to have been taken by the DGCA and the Operator. The aircraft manufacturer advised that the aircraft operation and maintenance manuals are currently being revised into standard aviation English.

The Final Report of the Investigation KNKT.11.05.10.04 was published on 12 July 2012.

Further Reading

• Loss of Control
• Inadvertent VFR Flight Into IMC
• Transition to Visual Flight at Night (OGHFA SE)
• Go-around - Transition to Instrument Flying
• Situational Awareness
• Authority Gradients