What happened
On 13 September 2016, a Piper J5A Cub Cruiser, registration EI-AXT, was performing a private flight from a landing strip in Co. Galway to an agricultural field near Shantonagh, Co. Monaghan. While descending on a north-westerly downwind leg, the pilot surveyed the intended landing area. To manage the descent, the pilot utilized a sideslip maneuver.
As the aircraft approached the ground, the pilot misjudged the flare, resulting in a heavy touchdown on the sloping terrain. To prevent a stall following the impact, the pilot applied engine power, which caused the aircraft to bounce and travel approximately 45 meters before touching down again. A series of subsequent bounces occurred as the aircraft passed through a gap in a hedgerow. During the landing roll, the pilot lost directional control, leading to a ground loop. This maneuver caused the right wing tip to strike the ground and the aircraft to tip forward, resulting in the propeller making contact with the surface. The aircraft came to rest in a nose-down position. The pilot, the sole occupant, was uninjured.
The investigation
The AAIU examined the landing site, which featured a grass surface sloping uphill along the landing path and downhill to the sides. The investigation noted that the field was bounded by hedgerows and trees, with farm buildings located nearby.
Investigators reviewed the pilot's preparation, noting that while the site had been viewed via satellite imagery and a previous road-side inspection, the specific gradient of the terrain was not fully understood. The investigation also looked into the aircraft's condition, finding substantial damage, including a broken tubular steel frame in the cockpit area, a dented wing tip, and a propeller that was out of track due to ground contact.
Findings
- The landing site was deemed unsuitable for aircraft operations due to the combination of the sloping terrain, the presence of trees, and the narrow gap in the hedgerow.
- The pilot's decision-making was influenced by plan continuation bias, as the pilot failed to abort the landing despite noticing the significant gradient of the field during the downwind leg.
- The upward slope of approximately 3 degrees likely contributed to the hard landing by effectively increasing the aircraft's sink rate.
- A slight tailwind, which the pilot had not initially accounted for, may have increased the aircraft's ground speed and contributed to the loss of control.
Safety action
- The investigation noted that the pilot performed a take-off from the damaged aircraft at the accident site to return to Co. Galway. The AAIU concluded that performing a take-off without a formal structural inspection, especially from an unsuitable site with limited escape options, was not a prudent course of action.