What happened
On 22 October 2021, a Eurocopter AS-350-B3, registration EC-JEA, was conducting a training flight in the Pla de Beret area of Lérida, Spain. The crew, consisting of an instructor pilot and a pilot under instruction, were performing operational verification flights to practice the differences between the AS-350-B3 2B1 and 2B models. The specific exercise involved simulating a governor failure by switching the governor from automatic to manual mode.
During the final phase of the maneuver, while approaching a landing area at approximately 10 feet, the engine RPM dropped to the bottom of the green arc, triggering a low RPM warning. Attempting to abort the landing, the crew switched the governor back to automatic mode. However, as the pilot under instruction pulled on the collective, the RPM dropped further, causing the helicopter to lose lift and strike the ground with its right skid. The uneven terrain caused the aircraft to bounce and strike the ground a second time, resulting in significant damage to the airframe.
The investigation
The CIAIAC investigation examined the aircraft's maintenance records, the flight crew's performance, and the environmental conditions at the site. Investigators found that the aircraft was fully compliant with all maintenance programs and service bulletins. The investigation also noted that the fleet tracking system was non-operational during the flight, which prevented a more detailed analysis of the flight parameters. The investigation focused on the execution of the manual mode transition and the suitability of the chosen training area.
Findings
- The inadequate execution of the governor failure simulation procedure caused the loss of control.
- The pilot under instruction failed to properly execute the reversion to automatic mode, likely due to a loss of situational awareness and overconfidence.
- The instructor pilot provided inadequate supervision, which prevented the recovery of the aircraft during the emergency.
- The training area selected for the maneuver was unsuitable due to uneven terrain that contributed to the severity of the impacts.
- The pilot's twist grip was not in the required flight position for the automatic governor reset procedure.
- There were no injuries to the crew members.
Safety action
- The operator suspended training between the involved crew members until reassessment by another instructor.
- The operator was recommended to review its governor failure simulation procedures to ensure maneuvers can be safely aborted.
- The operator was advised to implement stricter reporting for fleet tracking system malfunctions.
- A recommendation was made to Airbus Helicopters to evaluate upgrading the dual control twist grip used for training to improve visual interpretation of its position.