Piper PA 24-250 N7985P accident near Newton, Kansas

Probable cause

The failure of the right main landing gear down-lock micro switch, which resulted in a landing gear collapse during landing, and the pilot/owner's unfamiliarity with the emergency landing gear extension procedure. Contributing to the accident was the flight instructor's lack of experience in this make and model airplane and unfamiliarity with the emergency landing gear extension procedure.

NTSB analysis

During a local instructional flight, the flight instructor reported that while on final approach at their destination airport, the landing gear did not illuminate down and locked. He reported that he tried to cycle the gear with the electric landing gear handle, but the down and locked green light would not illuminate. When the power was reduced to idle, the flight instructor reported that the audible gear unsafe horn sounded as well. The flight instructor performed a go-around, and the pilot receiving instruction reported that he began the manual gear extension checklist according to the "SureCheck" checklist.

During the manual gear extension procedure, both pilots reported that a "spring tension" prevented the emergency gear handle from extending to the full forward position. Subsequently, the flight instructor reported that he reset the motor release arm and attempted to extend the landing gear again with the electric gear handle, but the landing gear electric motor circuit breaker popped and the motor release arm jammed.

After receiving confirmation from ground personnel that the landing gear was only partially extended, the flight instructor performed an emergency landing. During touchdown, the landing gear collapsed and the airplane skidded to a stop on the runway. The fuselage was substantially damaged in the accident.

During a postaccident examination, a Federal Aviation Administration aviation safety inspector found that the right main landing gear down-lock micro switch was operating intermittently within the electrical actuating system. According to the inspector, an intermittent micro switch on this landing gear can result in gear unsafe warnings and continuous electrical motor operation. Additionally, the SureCheck checklist used did not include instructions provided in the Pilot's Operating Handbook stating, "Do not re-engage landing gear operating motor in flight." The SureCheck checklist does contain a warning stating "this product is not a substitute for any operation manual which coincides with each specific aircraft."

The flight instructor reported that he had two hours of flight time in this make and model airplane, and the pilot receiving instruction reported that he had no previous experience in this make and model airplane.

Text from the NTSB. Open the NTSB docket for GAA15CA178 for the full record.