What happened
On October 9, 2011, an AS350-B2 helicopter, registration PR-RCH, was performing a transport flight from Porto Gavião to Carauari Aerodrome (SWCA) in the state of Amazonas. The flight, operated by Helisul TáxiAéreo Ltda, carried a pilot and three passengers.
Upon completing the approach to runway 04, the pilot taxied the aircraft toward the parking area. During this maneuver, the main rotor of the PR-RCH collided with the tail rotor of another helicopter, registration PR-MET, which was parked on the grass area adjacent to the apron. The impact caused the pilot to lose control, resulting in the aircraft tumbling to the right. The force of the collision caused fragments of the main rotor blades to detach, which subsequently struck two other parked helicopters, PR-MEQ and PR-MER. The aircraft sustained substantial damage to its structure, engine, and rotors. The pilot and passengers were evacuated without injury.
The investigation
CENIPA's investigation focused on the operational environment at Carauari Aerodrome and the decision-making processes involved in the maneuver. Investigators examined the lack of horizontal signage on the apron, which had led ground personnel to park aircraft in an improvised manner on the grass area to accommodate the high volume of traffic. The investigation also reviewed the pilot's recent work history, noting a high frequency of landings and long flight hours during the final day of a 14-day duty cycle. The investigation was supported by an accredited representative from the French BEA.
Findings
- Lack of infrastructure: The aerodrome apron lacked horizontal signage to mark designated parking stands, forcing operators to use the grass area for overnight parking.
- Improper parking: Ground support personnel had moved a parked helicopter to a position approximately one meter behind its normal location, reducing available clearance.
- Pilot judgment: The pilot failed to correctly assess the risks of maneuvering in an improvised parking area and lacked precise visual references to estimate the distance between the rotors of the two aircraft.
- Operational fatigue: The pilot was performing the final flight of a long duty period, characterized by a high workload of approximately 80 landings per day, which contributed to diminished perception and judgment.
- Organizational culture: Both the aerodrome administration and the operating companies utilized the aerodrome beyond its capacity, allowing for unsafe, improvised parking practices.