What happened
On the morning of 12 September 2005, a Cessna 172N, registration EI-BCK, was conducting an aerial work mission involving a wildlife survey. After departing from Weston Aerodrome, the pilot proceeded to Clonbullogue Airfield in County Offaly to collect passengers. During the approach to Runway 27, the pilot encountered a wet grass surface due to heavy morning dew. The aircraft touched down too far down the runway at a high speed. Due to the lack of braking effectiveness on the slippery surface and a slight tailwind, the aircraft failed to stop within the runway limits. The aircraft continued across the airfield, breached the perimeter wire fence, and came to rest in a boundary ditch. There were no injuries to the pilot, and the aircraft sustained only minor damage to the engine cowl.
The investigation
The investigation established that the airfield, which is a private licensed facility, had no active fire or rescue services available at the time because the owners had not been notified of the early arrival. The pilot noted that while the windsock appeared to indicate calm conditions, a small SouthEast tailwind was likely present during the landing. The investigation focused on the interplay between the aircraft's approach speed, the landing position, and the environmental conditions of the grass runway. It was also noted that the pilot manually shut down the engine by leaning the mixture to the idle cut-off position to assist in stopping the aircraft.
Findings
- The primary cause of the excursion was a combination of an excessive approach speed and a deep landing touchdown.
- The wet grass surface significantly reduced available friction for deceleration.
- A slight tailwind contributed to the increased landing distance.
- The pilot's decision to cut the engine likely mitigated more extensive damage to the propeller or airframe.