Piper PA-28R-180 N4631J accident near Fort Lauderdale, Florida

Probable cause

The undetected fatigue cracks in the engine and nose landing gear (NLG) strut mount assembly, which prevented the proper alignment of the NLG after it was extended and the pilots from being able to maintain directional control after touchdown.

NTSB analysis

The flight instructor and pilot-rated passenger were conducting an instructional flight. The flight instructor reported that, after conducting some airwork, he attempted to extend the landing gear as part of the prelanding checklist, but he did not receive a down-and-locked indication for the nose landing gear (NLG). He performed the emergency gear extension procedure twice, and, during the second attempt, the NLG moved to the down-and-locked position, but a left yaw was present, and the left rudder pedal had moved fully forward, which required an abnormal amount of right rudder input. The flight instructor performed a low pass over the runway, and company personnel informed him that the NLG appeared to be deflected left. He returned to the airport and performed a soft-field landing and secured the engine after touchdown. When the NLG contacted the runway, the airplane veered left off the runway and then came to rest upright.

Postaccident examination of the engine and NLG strut mount assembly revealed fatigue fractures on both sides of the mount near the NLG pivot, which prevented the proper alignment of the NLG after it was extended and the pilots from being able to maintain directional control of the airplane after landing. The complete maintenance records were not available; therefore, the time on the engine and NLG mount assembly could not be determined. Although the available maintenance records did reveal that the engine and NLG strut mount assembly had been inspected as part of the annual inspection performed about 15 hours before the accident flight, the location of the fatigue cracks and color of the mount assembly likely would have made detecting the preexisting cracks difficult.

Text from the NTSB. Open the NTSB docket for ERA15LA289 for the full record.