What happened
On September 26, 2023, a Piper PA-38-112, registration LV-ONS, was conducting a local training flight at Rosario International Airport in Santa Fe, Argentina. After approximately 30 minutes of flight time, the aircraft attempted to land. As the nose wheel made contact with the runway, the nose landing gear housing suffered a structural collapse. The impact caused the nose gear to detach from the airframe, leading to significant damage to the engine, the propeller, and the engine cowlings. There were no fatalities or injuries to the flight instructor or the student pilot involved in the operation.
The investigation
The investigation conducted by the JST focused on the structural failure of the nose gear assembly. Investigators examined the collapsed component and inspected the nose gear housings of five other aircraft of the same model. In four of those five aircraft, investigators found evidence suggesting the use of unapproved parts. These components showed irregularities such as non-forged finishes, tool marks from non-standard forming processes, and inconsistent manufacturing methods, including parts made of aluminum or steel that did not match the required specifications.
Furthermore, the investigation revealed that the scarcity of certified replacement parts in the region has created a situation where operators may feel compelled to use non-certified alternatives to keep aircraft operational. The investigation also noted that while the aircraft's maintenance schedule followed manufacturer and regulatory instructions, the inspection intervals were based solely on flight hours rather than the number of landings, which is a critical factor for training aircraft.
Findings
- The primary cause of the accident was the structural collapse of the nose gear housing during touchdown.
- The failure was driven by a fatigue process originating in the lower lubrication ring of the cylinder.
- The component installed on LV-ONS showed strong indications of being an unapproved part not certified for aeronautical use.
- The aircraft was being used for basic flight training, which involves a high frequency of landings per flight hour, increasing the risk of fatigue-related failures.
- Existing systems designed to prevent the installation of unapproved parts were ineffective in this instance due to the lack of available certified spares.