Flight and Accident Sequence
On June 9, 2018, a Piper PA-38-112 aircraft, registration LV-OMN, departed from Casilda aerodrome in Santa Fe, Argentina, for a training flight. During the landing phase, after touching down on runway 33 at approximately 15:45 UTC, the aircraft was about to begin a 180-degree turn to return to the runway threshold. At that moment, the nose wheel detached from the aircraft, and one of the propeller blades struck the ground. The instructor and student pilot evacuated the aircraft unaided and sustained no injuries. The accident occurred in daylight and under good weather conditions.
Investigation Findings
Examination of the aircraft revealed that the nose wheel had separated during the landing roll. According to ground marks, the wheel came off about 550 meters from the runway threshold, while the aircraft was at very low speed. All components of the wheel assembly were recovered except the self-locking adjusting nut. Marks on the nose landing gear fork indicated that the wheel had been rubbing against the right side of the fork before detaching. The recovered components, including the through-bolt, showed no abnormal deformation, thread damage, or dragging.
Technical Analysis
The aircraft was operated by the flying school Flying Time and had been assigned to it since August 2010. It was maintained by the school's own workshop, which had eight Piper PA-38-112 aircraft on its operation specifications. The aircraft's documentation showed that the correct retaining nut for the nose wheel was a self-locking, heat-treated steel alloy nut (cadmium plated), which could be reused depending on its condition. The main and nose wheel assemblies required inspection every 100 hours.
The investigation concluded that the most probable cause of the nose wheel loss was the disappearance of the adjusting nut. Given that the mounting components were in good condition, the nut was likely lost because its locking ability had degraded due to wear from repeated use and reuse. After the accident, the operator replaced the nuts on all aircraft of the same type.
Conclusions
The nose wheel detached during the aircraft's taxi/landing roll. The adjusting nut for the nose wheel was not recovered. The wheel separated due to the loss of the adjusting nut, which likely resulted from a loss of the nut's locking action.