Description

On 23 December 2009, a Boeing 737-800 being operated by Irish airline Ryanair on a scheduled passenger flight from Dublin to Prestwick left the end of the destination runway in normal daylight visibility and the landing gear sunk into the adjacent wet grass after an attempt to brake on the icy surface prior to turning onto the designated exit taxiway was unsuccessful. The uninjured occupants left the aircraft via the forward airstairs onto the grass and then moved across to the paved surface of the taxiway and runway.

Investigation

An Investigation was carried out by the UK AAIB. It was established that, with the aircraft commander as PF, the approach to and landing on the 2987 metre long wet runway were found to have been normal. Braking Action had been pre-notified as ‘medium-good’ throughout. Taxiways and Aprons were pre-notified as ‘extremely icy’. With the aircraft unable to vacate at the usual intermediate point and the aircraft substantially decelerated, it was allowed to ‘roll’ to the end. When manual braking was applied at a recorded groundspeed of 42 knots, it was ineffective and, with the end of the runway approaching, the aircraft commander attempted to turn the aircraft 90° to the left onto the exit taxiway so as to avoid a runway excursion. The nose of the aircraft slewed 45° to the left but the wheels continued to track along the runway and the aircraft was found to have slid off the paved surface onto the grass at a recorded groundspeed of 24 knots some 30 seconds after manual braking had been initially attempted. It came to a stop after a further 20 metres travel.