What happened
On 19 January 2015, a DHC-8-402 Dash 8, registration G-JEDM, arrived at Inverness Airport from Manchester. Following landing on Runway 23, Air Traffic Control instructed the crew to continue along the runway to exit A1 and then taxi toward the South Apron.
As the aircraft began the right-hand turn onto the taxiway, the pilot lost control of the aircraft. The plane entered an uncontrolled slide toward the left, eventually coming to a halt on the grass. The aircraft ended up positioned parallel to the taxiway centerline, with all three landing gears partially embedded in the soft ground. There were no injuries to the 47 passengers or 4 passengers on board, and no damage was sustained to the aircraft. Following the incident, the crew shut down the engines and passengers disembarked after the airport fire service inspected the landing gear.
The investigation
Investigators examined the conditions of the airfield and the aircraft's performance. An airport operations assistant witnessed the landing and noted that the aircraft appeared to be traveling at an unusually high speed as it reached the end of the runway. He also reported hearing tires squeal during the turn.
The pilot noted that the paved surface felt very wet due to de-icing fluid and mentioned the presence of icy patches and slippery painted markings. However, airport records showed that de-icing had been completed earlier that morning, and subsequent tests of the fluid indicated a freezing point of -24ºC. Inspections of the pavement revealed no evidence of ice, and visible tire marks suggested that sufficient friction had been present during the turn.
Data retrieved from the Flight Data Recorder confirmed that the aircraft was traveling at a groundspeed of 29 knots during the turn. The recorder also showed that very little braking had been used during the landing roll. No mechanical faults were identified within the aircraft's braking system.
Findings
- The aircraft was traveling at a higher than normal taxi speed during the turn.
- The aircraft's groundspeed of 29 knots was a significant factor in the loss of directional control.
- While the pilot perceived slippery conditions due to de-icing fluid, evidence indicated adequate friction was available on the pavement.