Scheduled Revenue Flight

Findings as to Causes and Contributing Factors:
1. A planetary gear disintegrated in the propeller reduction gearbox of the No. 2 engine and caused the engine drive shaft to disconnect from the propeller, resulting in a loss of propulsion from this engine.
2. The planetary gear oil strainer screen wires fractured by fatigue as a consequence of the installation at the last overhaul. This created an unsafe condition and it is most probable that the release of wire fragments and debris from this strainer screen subsequently initiated or contributed to distress of the planetary gear bearing sleeve and resulted in the disintegration of the planetary gear.
3. Although airspeed was above Vmc at the time of the power loss, the aircraft became progressively uncontrollable due to power on the remaining engine not being reduced to relieve the asymmetric thrust condition until impact was imminent.
Findings as to Risk:
1. The propeller reduction gearboxes were inspected in accordance with the West Coast Air maintenance control manual. These inspections exceeded requirements of the de Havilland Equalized Maintenance Maximum Availability program. Since the last inspection, 46 hours of flight time before the accident, did not reveal any anomaly, a risk remains of adverse developments with
resulting consequences occurring during the unmonitored period between inspections.
2. Regulations require the installation of engine oil chip detectors, but not the associated annunciator system on the DHC-6. Without an annunciator system, monitoring of engine oil contamination is limited to the frequency and thoroughness of maintenance inspections. An annunciator system would have provided a method of continuous monitoring and may have warned the crew of the impending problem.
3. Although regulations do not require the aircraft to be equipped with an auto-feather system, its presence may have assisted the flight crew in handling the sudden loss of power by reducing the drag created by a windmilling propeller.
4. Since most air taxi and commuter operators use their own aircraft rather than a simulator for pilot proficiency training, higher-risk emergency scenarios can only be practiced at altitude and discussed in the classroom. As a result, pilots do not gain the benefit of a realistic experience during training.
Other Findings:
1. The fact that the aircraft remained upright and floating in daylight conditions contributed to the successful evacuation of the cabin without injury and enabled about half of the passengers to locate and don their life vests.
2. The aircraft was at low altitude and low airspeed at the time of power loss. The selection of full flaps may have contributed to a single-engine, high-drag situation, making a successful landing difficult.

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.

Controlled flight into terrain after the crew descended too low in poor visibility. At the time of the accident, the aircraft deviated from the approach path from 4 to 6 km.

Long landing and contact, after a high approach with excessive speed as a result of a non-precision approach, on a waterlogged runway and in adverse weather conditions (discharge of CB's in the area), with the aircraft departing from the opposite runway threshold (13).

Controlled flight into terrain after the crew continued under VFR mode in IMC conditions. The following findings were identified:
- The pilot's unsafe flying and failure to maintain adequate separation (vertical and horizontal) with mountainous terrain and not remain in VMC. Moreover, lack of timely corrective action by the crew allowed the aircraft to fly in a controlled manner and unnoticed into the ground.
- Loss of situational awareness and attention from the crew.
- Inadequate monitoring and enforcement by the pilot not flying.
- Lack of application or adherence to standard operating procedures established by SANSA.
- Using flight procedures not written or approved.
- Lack of culture regarding operational safety.

The factors contributing to the above accident were identified as a combination of the individual and systemic issues. Any one of these factors, by itself, was insufficient to cause a breakdown of the safety system. Such factors may often remain undetected within a system for a considerable period of time. When these latent conditions combine with local events and environmental circumstances, such as individual factors contributed by “frontline” operators (e.g.: pilots or air traffic controllers) or environmental factors (e.g.: extreme weather conditions), a system failure, such as an accident, may occur.
The investigation showed that no single factor was responsible for the accident to GF072. The accident was the result of a fatal combination of many contributory factors, both at the individual and systemic levels. All of these factors must be addressed to prevent such an accident happening again.
(1) The individual factors particularly during the approach and final phases of the flight were:
(a) The captain did not adhere to a number of SOPs; such as: significantly higher than standard aircraft speeds during the descent and the first approach; not stabilising the approach on the correct approach path; performing an orbit, a non-standard manoeuvre, close to the runway at low altitude; not performing the correct go-around procedure; etc.
(b) In spite of a number of deviations from the standard flight parameters and profile, the first officer (PNF) did not call them out, or draw the attention of the captain to them, as required by SOP’s.
(c) A perceptual study indicated that during the go-around after the orbit, it appears that the flight crew experienced spatial disorientation, which could have caused the captain to perceive (falsely) that the aircraft was ‘pitching up’. He responded by making a ‘nose-down’ input, and as a result, the aircraft descended and flew into the shallow sea.
(d) Neither the captain nor the first officer perceived, or effectively responded to, the threat of increasing proximity to the ground, in spite of repeated hard GPWS warnings.
(2) The systemic factors, identified at the time of the above accident, which could have led to the above individual factors, were:
(a) Organisational factors (Gulf Air):
(i) A lack of training in CRM contributing to the flight crew not performing as an effective team in operating the aircraft.
(ii) Inadequacy in the airline's A320 training programmes, such as: adherence to SOPs, CFIT, and GPWS responses.
(iii) The airline’s flight data analysis system was not functioning satisfactorily, and the flight safety department had a number of deficiencies.
(iv) Cases of non-compliance, and inadequate or slow responses in taking corrective actions to rectify them, on the part of the airline in some critical regulatory areas, were identified during three years preceding the accident.
(b) Safety oversight factors:
A review of about three years preceding the accident indicated that despite intensive efforts, the DGCAM as a regulatory authority could not make the operator comply with some critical regulatory
requirements.

A phase-to-phase arc in the left heat exchanger cooling fan relay, which ignited the surrounding wire insulation and other combustible materials within the electrical power center panel. Contributing to the left heat exchanger fan relay malfunction was the unauthorized repair that was not to the manufacturer's standards and the circuit breakers' failure to recognize an arc-fault.