What aircraft was involved and where did it happen?

The accident on null involved a aircraft, registration EI-CBK, at IE.

What was the probable cause of the accident?

The runway excursion was caused by a sudden, strong wind gust from the left during the landing roll, occurring while the aircraft was transitioning between high-speed and low-speed directional control regimes.

ATR 42-300 Runway Excursion at Donegal Airport

A scheduled passenger flight experienced a runway excursion at Donegal Airport due to a sudden wind gust during the landing roll.

What happened

On 7 September 2016, an ATR 42-300, registration EI-CBK, was performing a scheduled commercial flight from Dublin to Donegal Airport. During the landing on runway 21, the aircraft touched down normally on the centerline. However, a few seconds after touchdown, while the crew was applying reverse thrust and braking, a strong gust of wind from the left caused the aircraft to veer sharply.

The aircraft departed the paved surface and traveled approximately 62 meters onto the grass adjacent to the runway. The pilot managed to regain directional control and steered the aircraft back onto the tarmac. The aircraft then taxied to the parking stand, where the 17 passengers and 3 crew members disembarked without injury. The aircraft sustained no damage during the event.

The investigation

The AAIU examined flight data recorder (FDR) and cockpit voice recorder (CVR) information, alongside meteorological data and aircraft maintenance records. The investigation confirmed that the flight crew had briefed the approach specifically to account for the high crosswind components. Analysis of the FDR indicated that the approach was stable and that the touchdown occurred within the proper zone.

Investigators also reviewed the airfield's meteorological equipment, finding it was functioning correctly and providing accurate wind data. The investigation looked into the mechanical state of the aircraft, including the undercarriage and steering systems, and found no mechanical defects contributing to the loss of control. The investigation also noted that the narrow 30-meter width of the runway at Donegal Airport played a role in the excursion.

Findings

The aircraft was operating within the manufacturer's and operator's published wind limitations.
The flight crew was properly qualified and had conducted a thorough landing briefing.
The excursion was triggered by a strong gusting crosswind occurring approximately four seconds after touchdown.
The aircraft was in a transition phase between high-speed and low-speed roll-out, a period where rudder authority is reduced and the aircraft is susceptible to lateral forces.
The narrow runway width contributed to the difficulty in maintaining the centerline during the gust.