Aviation Accident Summaries

Aviation Accident Summary WPR19LA144

Gila Bend, AZ, USA

Aircraft #1

N4992J

Piper PA28R

Analysis

The pilot reported that, while descending toward his destination airport, he completed a before-landing checklist, but could not recall if he verified that the landing gear down and locked lights were illuminated. The pilot stated that he heard an aural alarm in the final 2 minutes of flight, which he attributed to a stall warning. During landing, the propeller contacted the runway and the airplane veered left and departed the left side of the runway, resulting in in substantial damage to the fuselage and wings. The landing gear selector was found in the down position and the left main landing gear was down and locked at the accident site. The airplane was equipped with a backup gear extender that would extend the landing gear, regardless of selector position, if the engine power was at idle at airspeeds below about 105 mph. The aural gear warning horn was designed to activate under any one of the following conditions: 1) when the landing gear was retracted and power was below about 14 inches manifold pressure, 2) if the backup gear extender has extended the landing gear and the gear selector is in the retracted position, and 3) if the gear selector is in the retracted position while the airplane is on the ground. Postaccident testing could not determine whether the aural warning system was functional at the time of the accident; however, examination and testing of the landing gear extension and retraction revealed no anomalies. Based on the available information, it is likely that the landing gear did not extend in the allotted time prior to touchdown either due to the pilot's delayed deployment or because the conditions for the automatic gear extender to engage were not met. In either case, the accident is consistent with the pilot’s failure to configure the landing gear in a timely manner before landing.

Factual Information

On May 13, 2019, about 0926 mountain standard time, a Piper PA-28R airplane, N4992J, was substantially damaged when it was involved in an accident near Gila Bend, Arizona. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, while descending toward the airport for landing, he performed a before landing checklist, but he 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 he was unsuccessful. 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. The airplane's 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, in a maintenance entry dated November 10, 2017, for the airplane's previous annual inspection, the landing gear retraction and emergency extension were verified. According to the pilot's operating handbook, 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 was also equipped with a pressure-sensing device that lowered the gear regardless of the gear selector position. A gear extension was designed to occur, regardless of selector position, at airspeeds below approximately 105 mph. Further, the airplane was equipped with a gear warning horn that was triggered under any one of the following conditions: 1) when the throttle was in the idle position and manifold pressure was below 14 inches, 2) if the backup gear extender has extended the landing gear and the landing gear selector is in the retracted position, and 3) when the gear selector switch is in the retracted position while on the ground. A landing gear position indicator on the instrument panel displayed three green lights to indicate that the gear was down and locked. A yellow light was used to show the landing gear in a transit position. 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 applied to the over-center hook. The right main landing gear displayed multiple fractures from the impact that were consistent with overload separation; however, the landing gear could be manipulated once it was manually extended beyond the gear door by hand. The right main landing gear 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 the airplane to test the functionality of 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.

Probable Cause and Findings

The pilot's failure to configure the landing gear in a timely manner before landing, which resulted in a propeller strike.

 

Source: NTSB Aviation Accident Database

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