What happened
On May 15, 2008, a Piper PA44-180, registration EI-SKR, was conducting a training flight at Waterford Airport. After completing a navigation exercise, the instructor directed the student pilot to perform a touch-and-go landing on Runway 03. The approach was executed correctly with the appropriate flap and gear configuration, and the aircraft landed normally.
During the subsequent ground roll, as the aircraft prepared for takeoff, the student pilot mistakenly reached for the landing gear lever instead of the flap lever. The student retracted the undercarriage while the aircraft was still in motion. This caused the aircraft to collapse onto the runway, where it slid approximately 230 meters before coming to a halt near Taxiway Alpha. The crew successfully evacuated the aircraft without nil injuries, and no fire occurred.
The investigation
The investigation focused on why the landing gear was able to retract while the aircraft was still in contact with the runway. The aircraft was equipped with a landing gear safety (squat) switch, designed to prevent gear retraction when the aircraft is on the ground. Maintenance records indicated that both 150-hour and 50-hour inspections performed in early 2008 had confirmed the warning system was fully functional.
Investigators determined that because the aircraft was rolling at speed, it had generated enough lift to become "light" on its wheels. This reduction in weight deactivated the squat switch, effectively bypassing the safety mechanism that would normally prevent the gear from being raised while the aircraft is on the ground. Post-accident inspections of the safety system revealed no mechanical or electrical faults.
Findings
- The aircraft sustained substantial damage, including irreparable damage to both propellers and flaps, as well as engine shock loading and damage to various antennae and the aircraft underside.
- The primary cause of the accident was the student pilot's inadvertent retraction of the landing gear during the takeoff roll.
- The safety switch failed to prevent the retraction because the aircraft's speed during the ground roll created sufficient lift to relieve pressure on the squat switch, rendering the safety mechanism inactive.