What happened
On May 19, 2010, a Schweizer Hughes 269C helicopter, registration G-SBHH, was conducting a solo instructional flight departing from Jerez Airport. While flying north of Medina Sidonia at an altitude of 1,300 ft, the student pilot attempted to climb to 2,500 ft. To initiate the climb, the pilot moved the cyclic lever aft and increased collective pitch.
As the aircraft failed to respond to the control inputs, the pilot became concerned due to local wind conditions and decided to perform a precautionary autorotative landing. During the landing sequence, the helicopter struck the terrain heavily and overturned. The aircraft sustained significant damage to its structure and rotor system, but the pilot escaped the wreckage without injury.
The investigation
The CIAIAC investigation focused on the pilot's flight technique and the environmental conditions during the maneuver. The investigation established that while the pilot attempted to follow the correct sequence for a climb—adjusting attitude first—they failed to make the necessary throttle adjustments to maintain constant rotor RPM. By increasing collective pitch without compensating with the throttle, the pilot contributed to a progressive decay in rotor revolutions.
Furthermore, the investigation examined the wind conditions. While the pilot was initially unaware of the wind direction, it was determined after the impact that the maneuver was being performed with a tailwind. The investigation also noted that the pilot's previous experience as a fixed-wing pilot likely influenced the decision to initiate an autorotation, as they may have associated the lack of climb performance with an engine failure rather than a loss of rotor energy.
Findings
- The primary cause of the incident was the progressive loss of rotor RPM caused by the pilot's failure to adjust the throttle after increasing collective pitch during the climb.
- The pilot's control of the aircraft was further compromised by performing the autorotative landing with a strong tailwind, which increased the descent rate and made controlling the touchdown velocity difficult.
- The meteorological conditions, which included winds of up to 20 kt, may have exceeded the recommended limits for a solo flight by a student pilot with only 69 hours of helicopter experience.