What happened
On August 20, 2012, an HB-350B helicopter, registration PT-HZE, was conducting an annual reevaluation and autorotation training flight near Carlos Prates Aerodrome in Belo Horizonte, Brazil. The flight, operated by EFAI Escola de Pilotagem Ltda., involved an instructor pilot and a pilot under training.
During the final leg of the training procedure, the aircraft was unable to reach the intended touchdown point. The helicopter collided with a slope located just meters short of the runway 09 threshold. The impact resulted in two serious injuries to the crew and caused substantial damage to the aircraft's structure.
The investigation
CENIPA's investigation established that the aircraft was in a valid airworthiness state and within weight and balance limits. Technical analysis of the wreckage and flight instruments, including the Vertical Speed Indicator and tachometer, showed no mechanical malfunctions; the engine was producing normal power at the moment of impact.
Investigators focused on the operational sequence, noting that the instructor had decided to discontinue the flight due to increasing winds (reaching 17 knots). During the final autorotation attempt, the instructor observed an excessive sink rate and a glide path below the ideal angle. Although the instructor issued verbal instructions for a go-around, the trainee continued the descent profile. The instructor eventually took control of the aircraft, but the intervention was not timely enough to prevent the collision.
Findings
- Excessive self-confidence: The instructor's high level of experience and familiarity with the maneuver may have led to a sense of invulnerability, causing him to allow the trainee to continue the maneuver despite the deteriorating situation.
- Inadequate cockpit coordination: There was a lack of assertiveness in the communication between the crew, specifically regarding the precise timing for the go-around, which led to a delay in the instructor taking control.
- Environmental factors: The presence of a slope near the runway threshold created descending air currents and potential vortices, which were not adequately accounted for in the flight planning.
- Poor flight planning: The crew failed to sufficiently analyze prevailing wind conditions and the risk of windshear or downdrafts in the approach sector.
Safety action
Following the investigation, safety recommendations were issued to the flight school to implement more conservative training criteria, ensure the analysis of wind conditions is a critical part of training programs, and provide Crew Resource Management (CRM) training to improve communication and task definition.