What happened
On March 8, 2011, a Piper PA46-500TP Meridian, registration N747AW, was performing a VFR flight from Dijon-Longvic to Lausanne-La Blécherette. The flight involved two pilots and one passenger. Upon landing on runway 18, the aircraft touched down normally on the main gear followed by the nose wheel. However, shortly after touchdown, the aircraft suddenly veered sharply to the left, causing it to leave the runway. During the excursion, the nose gear collapsed, and the aircraft slid into a grassy area approximately 427 meters from the runway start. There were no injuries to the three occupants, though the aircraft sustained bad damage.
The investigation
Investigators examined the aircraft's maintenance history and mechanical condition. They discovered that the aircraft had been subjected to significant stresses during previous operations, including a hard landing in Saanen approximately one month prior. Technical analysis of the nose gear revealed cracks on the steering horn stops and deformations in the steering system's mounting screws. Furthermore, the investigation found that the nose tire was unbalanced, showed asymmetric wear, and was under-inflated. The investigation also reviewed the flight manual and manufacturer communications regarding nose gear maintenance and operational procedures.
Findings
- The aircraft's mass and center of gravity were outside the limits specified in the manufacturer's handbook.
- The nose gear steering system had accumulated excessive play due to previous mechanical stresses.
- The dynamic instability of the nose landing gear was the primary cause of the loss of control.
- The pilot did not perform the specific rake angle check recommended by the manufacturer's Customer Information Letter following a previous steering deviation in Dijon-Longvic.
- The manufacturer's flight manual lacked specific operational instructions regarding nose gear steering difficulties or the potential for dynamic instability.
Safety action
- The investigation noted that the manufacturer's Customer Information Letter (no. 3/27/08) advised daily or pre-flight tire pressure checks to prevent instability, but this was not effectively implemented or utilized by the crew following the previous incident.