What happened
On 2 January 2015, a Saab 340B, registration G-LGNL, was attempting a takeoff from Runway 18 at Stornoway Airport under significant crosswind conditions. The aircraft was operating a commercial passenger flight with 26 passengers and 3 crew members on board. At the time of the incident, a gale warning was in effect, with winds reaching 27 knots and gusts up/to 43 knots.
As the aircraft accelerated through approximately 65 KIAS, it experienced a sudden and violent swing to the left. Although the pilot applied right rudder to correct the deviation, the aircraft continued to skid, eventually departing the paved surface. The aircraft traveled approximately 250 meters on the grass before the nose landing gear collapsed. The aircraft came to a halt with extensive damage to the nose gear, propellers, and the underside of the fuselage. There were no injuries among the 29 people on board.
The investigation
The investigation examined flight data recorder (FDR) and cockpit voice recorder (CVR) information, as well as the aircraft's nosewheel steering (NWS) system and the environmental conditions. The FDR revealed that the engine torques increased symmetrically and that the aircraft's heading changed sharply at 65 knots. The investigation also reviewed the crew's takeoff technique and the transition of control from the nosewheel steering wheel to the control yoke.
Findings
- The aircraft's departure from the runway occurred at an airspeed of approximately 80 knots.
- The sudden leftward swing coincided with the handover of control from the nosewheel steering to the control yoke.
- The pilot's use of the rudder was neutral from 40 knots until the deviation occurred, suggesting that directional control was likely being maintained via the NWS alone.
- The power levers remained at full power throughout the excursion and were not moved to ground idle before the aircraft left the pavement.
- The nose landing gear collapsed due to the impact of the aircraft's forward movement on the unpaved surface.