What happened
On April 13, 2017, at 16:10 LMT, a Tecnam P2008-JC operated by LOT Flight Academy was performing a flight training mission for a PPL(A) student license. During the landing phase on runway 21 at EPPT, the aircraft experienced intense lateral vibrations in the nose gear. Following an audible crack, the nose gear failed, causing the aircraft to drop and the engine cowling to strike the runway. This impact caused the propeller to contact the pavement, resulting in the destruction of the propeller blades. The aircraft came to a stop approximately five meters from the point of failure. The crew, consisting of an instructor, exited the aircraft without injury.
The investigation
The PKBWL investigation examined the aircraft, which had a total of 828 hours and 17 minutes of flight time. Investigators analyzed tracks on the asphalt runway, which showed a normal two-point touchdown followed by sinusoidal patterns indicating the onset of severe lateral oscillations (shimmy) leading up to the gear failure. Detailed metallurgical examinations of the broken nose gear strut were conducted at the Institute of Aviation in Warsaw. The investigation also reviewed maintenance records, noting that a visual inspection of the nose gear, required every 25 flight hours per Service Bulletin SB 215-CS-Ed.1 Rev.0, had been performed approximately nine days prior to the accident.
Findings
- The failure of the nose gear strut was caused by an overload resulting from intense lateral vibrations (shimmy).
- The structural design of the nose gear assembly contributed to the accident by creating a concentration of loads at the junction where the diagonal braces meet the strut.
- A micro-crack originating from corrosion in a weld connecting one of the braces to the strut initiated the failure.
- The aircraft's high-intensity use in flight training contributed to the rapid progression of the fatigue.
- The manufacturer had previously introduced a redesigned nose gear to address these structural issues, and older units were being progressively replaced.