What happened
On October 7, 2007, an SA-316B Alouette III, registration OB-1852-P, operated by Helinka SAC, was performing a scheduled flight from Cusco to the Las Bambas mining camp in the Apurímac region of Peru. The aircraft was transporting five passengers, all employees of Xstrata Copper, to a remote helipad located on a soccer field at an elevation of 12,200 feet.
During the final approach, the pilot encountered a strong tailwind gust that increased the aircraft's descent rate and airspeed. To manage the situation, the pilot executed a running landing. During the deceleration phase, the aircraft's path was interrupted by a soccer goal. The yellow tip of the main rotor struck the crossbar of the goal, causing a centrifugal imbalance. This imbalance led to the remaining rotor blades flapping and striking the right vertical stabilizer and the tail rotor drive shaft cover, resulting in damage to the tail rotor blades.
The investigation
The CIAA investigation examined the aircraft's maintenance records, fuel quality, and the environmental conditions at the time of the incident. Investigators found that the engine, transmission, and rotor components were in airworthy condition and that the fuel used was of satisfactory quality. The investigation also reviewed the operator's flight manuals and training programs, noting that the company's route guide did not include specific approach procedures for this particular remote helipad.
Findings
- The primary cause of the incident was the loss of control during the final approach due to a strong tailwind gust, which necessitated the running landing into obstacles.
- Inadequate flight planning regarding the estimated time of arrival failed to account for variable wind conditions at the remote site.
- The operator's route guide lacked established approach and departure procedures for the Las Bambas helipad.
- Obstacles, specifically the soccer goals, were present within the landing area.
- The helipad at the Las Bambas camp had not been formally certified by the DGAC.
- Communication between the aircraft and the ground personnel was hindered by mountain effects on the VHF radio.