What happened
On February 28, 2019, a Societe Morane-Saulnier MS-893-A, registration EC-HPS, was performing a private VFR flight from Madrid/Cuatro Vientos to Lillo aerodrome. During the initial landing attempt on runway 30, the pilot felt a vibration and heard a sharp sound as the nose wheel made contact with the pavement. Fearing a mechanical issue, the pilot immediately applied full power and performed a go-around.
During the climb, the pilot noted a slight reduction in engine power. The pilot then completed a standard circuit and returned for a second landing. To mitigate potential damage, the pilot attempted to keep the nose gear off the runway for as long as possible. However, the nose gear eventually made contact, causing the aircraft to stop almost immediately. Upon inspection, the crew discovered that the nose wheel had detached from the aircraft and the propeller blade tips were damaged from striking the ground. Both occupants were uninjured.
The investigation
The investigation focused on the structural failure of the nose gear and the maintenance history of the aircraft. Laboratory analysis of the nose wheel support axle revealed a fracture surface with distinct "beach marks" and microscopic striations, which are definitive indicators of a fatigue failure caused by reverse bending stresses.
Investigators also examined the maintenance records provided by the CAMO and the maintenance organization. While the records indicated that EASA Airworthiness Directive (AD) 2015-0302 had been implemented during a 100-hour inspection in October 2018, neither the maintenance organization nor the CAMO could produce the required documentation for the mandatory dye penetrant inspection of the axle. Given that the aircraft had only flown approximately 10 hours since that inspection, investigators concluded that the fatigue cracks were likely advanced enough to have been detected had the inspection been performed.
Findings
- The primary cause of the accident was the failure of the nose wheel support axle due to a fatigue process.
- The maintenance organization failed to properly implement the required inspections mandated by EASA AD 2015-0302.
- The CAMO failed to verify the actual implementation of the Airworthiness Directive through proper documentation.
- The pilot's decision to perform a go-around after sensing a mechanical anomaly, while not the direct cause of the failure, introduced additional risks by taking the aircraft back into the air with an unknown structural defect.