Robinson R44 ground impact following hydraulic assist disconnection

Casualties unknown • Conséquences, FR

A student pilot's training flight ended in a ground collision at Bourg en Bresse after the hydraulic assistance was inadvertently turned off during takeoff.

What happened

On June 9, 2011, a Robinson R44 helicopter, registration F-GPSI, was conducting a training flight at the Bourg en Bresse aerodrome. The student pilot, who had been training with the aero club for only one week, was performing a series of maneuvers including a hover and turns. Following an initial landing, the student attempted a second takeoff. During this departure, the student noted a lack of stability in the aircraft. The student reported that while their feet were on the pedals and their hand was on the collective, they were not actively controlling the cyclic, leaving that task to the instructor. The aircraft subsequently drifted laterally to the left and backward before the student lost consciousness of the sequence of events. The helicopter was recovered lying on its right side.

The investigation

The investigation focused on the mechanical state of the aircraft and the cockpit configuration. Examination of the wreckage revealed no mechanical failures, but investigators found that the hydraulic assist switch, located on the cyclic control, was in the OFF position. The loss of hydraulic assistance in this aircraft type significantly increases the physical effort required to operate the cyclic and collective controls, making flight much more difficult. Meteorological conditions at the time involved light, variable winds of approximately 5 knots.

Findings

  • The primary cause of the difficulty in controlling the aircraft was the inadvertent deactivation of the hydraulic assistance system.
  • The student pilot, who had experienced high levels of stress and tension during early training sessions, likely gripped the controls so tightly that they accidentally toggled the hydraulic switch to the OFF position.
  • The instructor was likely caught off guard by the sudden increase in control heaviness, preventing effective recovery.
  • The instructional methods used by the instructor were deemed inappropriate for a student at such an early stage of training, particularly during critical phases like takeoff and landing.

Probable cause

The student pilot's physical tension during takeoff led to the accidental deactivation of the hydraulic assist switch, resulting in much heavier control forces that neither the student nor the instructor could manage.

Frequently asked questions

What happened in the 2011-06-09 aircraft accident near Conséquences, FR?

A student pilot's training flight ended in a ground collision at Bourg en Bresse after the hydraulic assistance was inadvertently turned off during takeoff.

What aircraft was involved and where did it happen?

The accident on 2011-06-09 involved a aircraft, at Conséquences, FR.

What was the probable cause of the accident?

The student pilot's physical tension during takeoff led to the accidental deactivation of the hydraulic assist switch, resulting in much heavier control forces that neither the student nor the instructor could manage.

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