What happened
On 3 October 2006, an Eastern Airways British Aerospace Jetstream 3202, registration G-BUVC, was performing a scheduled flight from Aberdeen to Wick. During the approach to Wick Airport, the flight crew configured the aircraft for landing with the flaps set and the landing gear selector in the 'DOWN' position.
Upon touchdown, the aircraft initially appeared to land at a normal height; however, the pilot flying noticed the aircraft continued to sink. The pilot immediately initiated a go-around. During this maneuver, the underside of the fuselage and the tips of the right propeller made contact with the runway surface. Following the go-around, the crew recycled the landing gear, and the air traffic controller confirmed the gear was down. The aircraft then diverted to Aberdeen Airport, where it landed safely. There were no fatalities or injuries during the event.
The investigation
The AAIB investigation determined that while the crew was properly licensed and qualified, the company's standard operating procedures did not require the pilot flying to monitor or cross-check the landing gear position. Consequently, the crew was unaware the gear had failed to extend.
Crucially, the investigation found that the three green landing gear indicator lights—which operate on a circuit independent of the extension system—were illuminated, providing a false indication of the gear's status. Furthermore, the failure was not accompanied by any audible warnings. The investigation also noted that the radio altimeter had been incorrectly configured in the TAWS, though this did not contribute to the accident.
Findings
- The primary cause of the failure was mechanical wear and electrical arcing across the poles of the gear selection switch. This created a layer of cupric oxide that acted as an insulator, preventing the electrical current from reaching the landing gear extension and warning systems.
- The remaining poles of the selector switch functioned correctly, which allowed the green indicator lights to illuminate and prevented the activation of the warning horn and TAWS audible alerts.
- The crew did not identify that the gear was not locked in the down position prior to landing.
Safety action
- The airline amended its briefing procedures to require the flight crew to verify the gear position by visually checking the green indicator lights with the cabin crew.
- Safety recommendations were issued to the US Federal Aviation Administration regarding the technical data for the Sandel ST3400 TAWS and the radio altimeter configuration.
- Recommendations were made to BAE Systems to amend flight manual procedures to include a dual-pilot confirmation of the gear handle position and to review the safety analysis of the gear selector lever.