Investigation Summary
The flight was operated under IFR from Sentani but required a visual approach into Wamena, which lacked published instrument procedures. During the first approach, the aircraft overshot the final approach track, triggering 'Terrain' and 'Pull Up' warnings. The captain initiated a go-around but elected to stay in a very low-altitude right-hand circuit. Flight data showed the aircraft maintained a height of only 150 to 350 feet during the downwind leg, significantly below standard circuit altitudes. As the crew turned to base and final, they were visually identifying landmarks like the river and Pikei Hill. However, the captain's steep banking and low altitude led to a series of EGPWS alerts. The First Officer expressed increasing concern, eventually shouting for the captain to open the throttles and turn left. In the final seconds, as the bank angle exceeded 40 degrees, the aircraft entered a 10-degree nose-down pitch. The crew attempted to recover by increasing power and pulling the nose up, reaching a 12-degree nose-up pitch and retracting the gear just before impacting the mountainside at 146 knots.
Final Conclusions
The National Transportation Safety Committee (NTSC) concluded that the primary cause was Controlled Flight Into Terrain (CFIT) resulting from the crew's lack of situational awareness regarding their proximity to terrain. Contributing factors included the captain's disregard for repeated EGPWS aural warnings and non-conformance with the operator's published operating procedures for visual approaches. The investigation also found that neither pilot had received the required EGPWS training specified in the company's training manual, leaving them unprepared to respond correctly to the alerts. The final report (KNKT 09.12.04.01) was released approximately 8 months after the accident.
Photographic Evidence (1)
Video Analysis
How One Bad Decision Crashed This Plane | 2009 Aviastar Mandirini Crash — A detailed breakdown of the Aviastar BAe 146 crash, focusing on the crew's decision to fly a low-altitude circuit and their disregard for multiple EGPWS warnings.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Sigit Triwahyono
First Officer
Lukman Yusuf
Systems & Failure Modes
EGPWS
The Enhanced Ground Proximity Warning System provided multiple valid alerts including 'Terrain', 'Pull Up', and 'Don't Sink', which were ignored by the flight crew.
Visual Approach Procedures
The crew failed to follow the Company Operations Manual (COM) instructions for visual approaches, specifically regarding safety criteria at low levels.
Interesting Facts
- 01The aircraft was a BAe 146-300 modified from a passenger to a cargo/passenger combi configuration in 2008.
- 02The weight chart used for the flight was for a 110-passenger configuration, which was incorrect for the actual 42-passenger/cargo layout.
- 03Wamena Airport is situated in a valley at 5,085 feet elevation, surrounded by mountains reaching 12,000 feet.
- 04The aircraft impacted the hill at an indicated airspeed of 146 knots with a 12-degree nose-up pitch.
- 05The investigation found that the EGPWS 'Look-Ahead' function was likely inhibited after the initial go-around, but standard GPWS modes functioned correctly.
Safety Actions & Advisories
Training Standardization
Source ↗The operator was required to address inconsistencies in training manuals and ensure all pilots received mandatory EGPWS training.
Approach Documentation
Aviastar Mandiri took action to improve documentation for missed approach procedures specifically for Wamena Airport.