What happened
On the morning of 26 March 2000, a Piper Cub J3C65, registration EI-CUB, was preparing for a private flight from Galway Airport to Birr. The aircraft was carrying a pilot and one passenger. During the takeoff roll on Runway 26, a powerful gust of wind lifted the aircraft's right wing. Despite the pilot's attempts to maintain control, the wind forced the plane approximately 90 degrees away from the runway centerline. The aircraft traveled about 80 meters across the grass perimeter before striking a stone boundary wall. The impact demolished part of the wall and caused the aircraft to flip onto its back in a nearby ploughed field. While the pilot escaped without injury, the passenger sustained minor injuries and required hospital treatment.
The investigation
The investigation focused on the meteorological conditions and the aircraft's configuration at the time of the accident. At the time of departure, Galway Airport was experiencing significant wind activity, with a reported surface wind of 320 degrees at 13 knots and gusts reaching 27 knots. The investigation also examined the aircraft's tailplane trim system. The aircraft utilized a screw jack mechanism operated by a manual crank to adjust the tailplane pitch. Investigators found that the tailplane was set to a fully tail-down trim position. While there was initial uncertainty regarding whether the trim handle had been moved during the rescue of the passenger, physical examination revealed that the impact damage had rendered the crank inoperable and caused the trim cable to detach from the screw jack pulley.
Findings
- The primary cause of the loss of control was extreme wind gusts that exceeded the aircraft's demonstrated capabilities.
- The aircraft's maximum demonstrated crosswind component is only 10 knots, whereas the recorded gusts were significantly higher at 27 knots.
- The aircraft was configured in a full tail-down trim position, which can create a powerful trimming effect.
- The use of a 4-point harness likely prevented more serious injuries to the occupants during the inversion.