Taipei City (臺北市)

The accident was the result of many contributing factors which culminated in a stall-induced loss of control. During the initial climb after takeoff, an intermittent discontinuity in engine number 2’s auto feather unit (AFU) may have caused the automatic take off power control system (ATPCS) sequence which resulted in the uncommanded autofeather of engine number 2 propellers. Following the uncommanded autofeather of engine number 2 propellers, the flight crew did not perform the documented abnormal and emergency procedures to identify the failure and implement the required corrective actions. This led the pilot flying (PF) to retard power of the operative engine number 1 and shut down it ultimately. The loss of thrust during the initial climb and inappropriate flight control inputs by the PF generated a series of stall warnings, including activation of the stick shaker and pusher. After the engine number 1 was shut down, the loss of power from both engines was not detected and corrected by the crew in time to restart engine number 1. The crew did not respond to the stall warnings in a timely and effective manner. The aircraft stalled and continued descent during the attempted engine restart. The remaining altitude and time to impact were not enough to successfully restart the engine and recover the aircraft.
The following findings related to probable causes were noted:
An intermittent signal discontinuity between the auto feather unit (AFU) number 2 and the torque sensor may have caused the automatic take off power control system (ATPCS):
- Not being armed steadily during takeoff roll,
- Being activated during initial climb which resulted in a complete ATPCS sequence including the engine number 2 autofeathering.
The available evidence indicated the intermittent discontinuity between torque sensor and auto feather unit (AFU) number 2 was probably caused by the compromised soldering joints inside the AFU number 2.
The flight crew did not reject the take off when the automatic take off power control system ARM pushbutton did not light during the initial stages of the take off roll.
TransAsia did not have a clear documented company policy with associated instructions, procedures, and notices to crew for ATR72-600 operations communicating the requirement to reject the take off if the automatic take off power control system did not arm.
Following the uncommanded autofeather of engine number 2, the flight crew failed to perform the documented failure identification procedure before executing any actions. That resulted in pilot flying’s confusion regarding the identification and nature of the actual propulsion system malfunction and he reduced power on the operative engine number 1.
The flight crew’s non-compliance with TransAsia Airways ATR72-600 standard operating procedures - Abnormal and Emergency Procedures for an engine flame out at take off resulted in the pilot flying reducing power on and then shutting down the wrong engine.
The loss of engine power during the initial climb and inappropriate flight control inputs by the pilot flying generated a series of stall warnings, including activation of the stick pusher. The crew did not respond to the stall warnings in a timely and effective manner.
The loss of power from both engines was not detected and corrected by the crew in time to restart an engine. The aircraft stalled during the attempted restart at an altitude from which the aircraft could not recover from loss of control.
Flight crew coordination, communication, and threat and error management (TEM) were less than effective, and compromised the safety of the flight. Both operating crew members failed to obtain relevant data from each other regarding the status of both engines at different points in the occurrence sequence. The pilot flying did not appropriately respond to or integrate input from the pilot monitoring.
The engine manufacturer attempted to control intermittent continuity failures of the auto feather unit (AFU) by introducing a recommended inspection service bulletin at 12,000 flight hours to address aging issues. The two AFU failures at 1,624 flight hours and 1,206 flight hours show that causes of intermittent continuity failures of the AFU were not only related to aging but also to other previously undiscovered issues and that the inspection service bulletin implemented by the engine manufacturer to address this issue before the occurrence was not sufficiently effective. The engine manufacturer has issued a modification addressing the specific finding of this investigation. This new modification is currently implemented in all new production engines, and another service bulletin is available for retrofit.
Pilot flying’s decision to disconnect the autopilot shortly after the first master warning increased the pilot flying’s subsequent workload and reduced his capacity to assess and cope with the emergency situation.
The omission of the required pre-take off briefing meant that the crew were not as mentally prepared as they could have been for the propulsion system malfunction they encountered after takeoff.

Findings related to probable causes:
- At the time of the accident, heavy rain and strong winds from typhoon "Xangsane" prevailed. At 2312:02 Taipei local time, the flight crewmembers of SQ006 received Runway Visual Range (RVR) 450 meters on Runway 05L from Automatic Terminal Information Service (ATIS) "Uniform". At 2315:22 Taipei local time, they received wind direction 020 degrees with a magnitude of 28 knots, gusting to 50 knots, together with the takeoff clearance issued by the local controller.
- On August 31, 2000, CAA of ROC issued a Notice to Airmen (NOTAM) A0606 indicating that a portion of the Runway 05R between Taxiway N4 and N5 was closed due to work in progress from September 13 to November 22, 2000. The flight crew of SQ006 was aware of the fact that a portion of Runway 05R was closed, and that Runway 05R was only available for taxi.
- The aircraft did not completely pass the Runway 05R threshold marking area and continue to taxi towards Runway 05L for the scheduled takeoff. Instead, it entered Runway 05R and CM-1 commenced the takeoff roll. CM-2 and CM-3 did not question CM-1's decision to take off.
- The flight crew did not review the taxi route in a manner sufficient to ensure they all understood that the route to Runway 05L included the need for the aircraft to pass Runway 05R, before taxiing onto Runway 05L.
- The flight crew had CKS Airport charts available when taxing from the parking bay to the departure runway; however, when the aircraft was turning from Taxiway NP to Taxiway NI and continued turning onto Runway 05R, none of the flight crewmembers verified the taxi route. As shown on the Jeppesen "20-9" CKS Airport chart, the taxi route to Runway 05L required that the aircraft make a 90-degree right turn from Taxiway NP and then taxi straight ahead on Taxiway NI, rather than making a continuous 180-degree turn onto Runway 05R. Further, none of the flight crewmembers confirmed orally which runway they had entered.
- CM-1's expectation that he was approaching the departure runway coupled with the saliency of the lights leading onto Runway 05R resulted in CM?1 allocating most of his attention to these centerline lights. He followed the green taxiway centerline lights and taxied onto Runway 05R.
- The moderate time pressure to take off before the inbound typhoon closed in around CKS Airport, and the condition of taking off in a strong crosswind, low visibility, and slippery runway subtly influenced the flight crew's decision?making ability and the ability to maintain situational awareness.
- On the night of the accident, the information available to the flight crew regarding the orientation of the aircraft on the airport was:
- CKS Airport navigation chart
- Aircraft heading references
- Runway and Taxiway signage and marking
- Taxiway NI centerline lights leading to Runway 05L
- Color of the centerline lights (green) on Runway 05R
- Runway 05R edge lights most likely not on
- Width difference between Runway 05L and Runway 05R
- Lighting configuration differences between Runway 05L and Runway 05R
- Para-Visual Display (PVD) showing aircraft not properly aligned with the Runway 05L localizer
- Primary Flight Display (PFD) information
The flight crew lost situational awareness and commenced takeoff from the wrong runway.
The Singapore Ministry of Transport (MOT) did not agree with the findings and released their own report. They conclude that the systems, procedures and facilities at the CKS Airport were seriously inadequate and that the accident could have been avoided if internationally-accepted precautionary measures had been in place at the Airport.

The following factors were identified:
- Wrong approach configuration as the aircraft was too high on the glide,
- Poor crew coordination,
- The crew failed to comply with published procedures,
- Poor crew training,
- The crew failed to correct the pitch up attitude during the go-around procedure,
- Lack of visibility due to night, rain and fog.

The crew failed to adhere to the published approach procedures and continued the descent below MDA until the aircraft struck the ground. Brand new, the aircraft was delivered to TransAsia Airways last December 20 and was equipped with a category II GPWS. It is believed that the GPWS alarm did not sound in the cockpit and was not recorded on the CVR.

Loss of control and short final after the aircraft has been caught by low level windshear.

It was determined that the crew was heading 210° at the time of the accident instead of the requested 252°. The reason of this track deviation (error of navigation) could not be determined.