Accident Details
On May 13, 2019, at approximately 0926 mountain standard time, a Piper PA-28R airplane, registration N4992J, was substantially damaged when it was involved in an accident near Gila Bend, Arizona. The pilot sustained minor injuries. The flight was a personal operation conducted under Title 14 Code of Federal Regulations Part 91.
The pilot reported that while descending toward the airport for landing, he performed a before-landing checklist but could not recall whether he verified that the landing gear were extended and locked. During the landing approach, he heard an aural alarm, which he dismissed as a false stall warning. The airplane touched down on the main landing gear. As he lowered the nose, he heard an unusual sound and decided to add power. He later determined the sound was likely the propeller contacting the runway. The airplane turned about 45° to the left and departed the left side of the runway before coming to rest in the dirt.
A witness on a nearby taxiway stated that the airplane’s landing gear were not extended when the airplane began the landing flare. The witness attempted to advise the pilot of the landing gear anomaly via radio but was unsuccessful.
Aircraft Information
The airplane was equipped with retractable tricycle landing gear, hydraulically actuated by an electrically powered reversible pump. The pump was controlled by a selector switch on the instrument panel, and the landing gear could be retracted and extended in about 7 seconds. The airplane also featured a pressure-sensing device that lowered the gear regardless of the gear selector position, designed to occur at airspeeds below approximately 105 mph. A gear warning horn was triggered under specific conditions: when the throttle was in the idle position and manifold pressure was below 14 inches; if the backup gear extender had extended the gear and the selector was in the retracted position; or when the selector was in the retracted position while on the ground. A landing gear position indicator displayed three green lights for gear down and locked, and a yellow light for transit.
The most recent annual inspection was completed on November 7, 2018, at 3,994 total flight hours, and 35 hours before the accident. This maintenance entry did not specify whether a landing gear swing was accomplished; however, a previous annual inspection on November 10, 2017, verified landing gear retraction and emergency extension.
Examination
The airplane came to rest about 100 ft off the south side of runway 22 at the runway's midpoint. The runway surface showed striated gouges and two long skid marks indicating the airplane's departure path from the runway. Both the right main landing gear and nose landing gear sustained damage from the impact, and the airplane received substantial damage to the fuselage and wings.
Examination of the landing gear system revealed that the gear selector switch was in the down/extended position. The nose landing gear fell without intervention from the motor or manual manipulation into the extended position multiple times and could be locked into place with slight pressure. The right main landing gear displayed multiple fractures consistent with overload separation; it could be manipulated once manually extended beyond the gear door but could not lock due to impact damage. The left main landing gear moved freely by hand into the down and locked position.
Electrical power was applied to test the landing gear system. The aural warning horn did not annunciate, but the landing gear motor functioned normally and the gear extended and retracted successfully. Manipulation of the nose landing gear down lock switch caused the landing gear motor to start and stop accordingly.