What happened
On September 13, 2015, at 17:45, a Piper PA-28-140, registration EC-CLU, operated by Airpull, was performing a local visual instructional flight at Requena Aerodrome in Valencia. The flight, involving an instructor and a student pilot, was returning to the field from the east. The crew initiated a direct approach to runway 30, bypassing the standard traffic pattern procedures.
During the final approach, very close to the runway surface, the aircraft became uncontrolled. The aircraft struck the runway and bounced. In an attempt to recover the flight, the pilot applied power, but the aircraft veered to the left of the runway. The aircraft traveled 110 meters through a vineyard perpendicular to the runway, eventually coming to a stop 500 meters from the runway threshold. The impact caused the left wing tip to detach and the left wing to separate from the fuselage at the attachment point. Both occupants sustained two minor injuries due to impact with the instrument panel.
The investigation
The CIAIAC examined the aircraft, the meteorological conditions, and the flight procedures. The investigation confirmed that the aircraft was airworthy and that no mechanical failures occurred. The investigation focused on the flight dynamics during the approach and the crew's response to the wind conditions. The investigators analyzed the wind data, which indicated moderate to strong winds from 270 degrees with gusts up to 24 knots, and the impact of the terrain on wind patterns.
Findings
- The primary cause of the accident was the improper control of the aircraft during the final approach and landing on runway 30 under moderate to strong gusty wind conditions, which led to a bounce and a subsequent leftward excursion.
- The crew was unaware of the effects of the wind gradient (the change in wind speed/direction near the surface) and therefore failed to adjust power and airspeed to compensate for the loss of lift.
- The crew performed an unapproved direct approach from the east instead of maintaining 4,000 ft and joining the standard traffic pattern.
- The instructor's vigilance was relaxed during the final approach due to the routine nature of the preceding flight and the student's previous experience.
- Significant crosswind components and moderate turbulence caused by the local topography contributed to the loss of control.
- The crew lacked precise information regarding the specific wind conditions at the runway threshold.
Safety action
- The CIAIAC issued a safety recommendation to the flight school, Airpull Aviation, S.L., to incorporate theoretical training regarding the effects of low-altitude wind gradients and active methods to counteract them into their pilot and instructor training programs.