What happened
On June 14, 2021, a Flight Design CTLS-LSA, registration D-EPAB, was performing a private VFR flight from Robledillo Aerodrome to Herrera de Pisuerga Aerodrome. Upon arrival, the pilot noted that while it was not raining, a recent storm had left the grass runway 23 wet and waterlogged in several areas.
During the final approach, the pilot configured the aircraft with 15º of flaps. The aircraft touched down at approximately 60 knots, which was 5 knots faster than the speed recommended in the Pilot's Operating Handbook (POH) for that specific configuration. As the pilot applied the brakes, the aircraft began to skid due to the wet surface. Unable to stop the aircraft before the end of the runway, the aircraft overshot the threshold of runway 05, descended an embankment, and entered a field where it overturned. The pilot sustained one minor injury after striking his head against the cockpit's structural beam during the overturn.
The investigation
The CIAIAC examined the aircraft's GPS data, which revealed that the pilot had increased the descent angle to clear a nearby power line, contributing to the higher-than-recommended touchdown speed. The investigation also reviewed the aircraft's POH, specifically the checklists for short and soft field landings, which suggest using 30º of flaps to achieve lower approach speeds and increased aerodynamic drag. Additionally, the investigation analyzed the cockpit ergonomics, noting that the pilot's head position was close to the overhead structural beam.
Findings
- The runway surface was contaminated with water.
- The aircraft touched down at a speed exceeding the POH recommendations for the selected flap setting.
- The pilot did not utilize a configuration (30º flaps) that would have facilitated a slower approach and provided more drag to assist braking on the slippery surface.
- The primary cause of the accident was the landing on a contaminated runway.