What happened
On October 26, 2007, an MI-8T helicopter, registration OB-1818-P, operated by AVIARET S.A.C., was performing a cargo delivery mission at the H-5 remote helipad near Curaray, Loreto. The aircraft was in a vertical descent for landing when a sudden wind gust caused the helicopter to drift diagonally backward and to the right. This movement caused the five tips of the main rotor blades to strike the foliage of a nearby tree. The crew heard a hissing sound and immediately performed a vertical landing. After shutting down the engines, the crew inspected the aircraft and found damage to the main rotor blades.
The investigation
The CIAA investigation examined the aircraft's maintenance records, engine and rotor condition, and the operational environment. The investigation confirmed that the engines, transmission, and fuel quality were all in satisfactory condition. The aircraft was operating under Visual Flight Rules (VFR) in clear weather, though the remote helipad lacked a windsock or ground markings. The investigation also reviewed the company's route guides and safety prevention (PREVAC) procedures regarding the use of remote landing sites.
Findings
- The primary cause of the incident was a loss of control during final approach caused by a strong wind gust, resulting from inadequate flight planning and execution by the pilot, who failed to account for the minimum required clearance area for the H-5 helipad.
- The pilot failed to adequately plan for the landing time and the potential for wind variations at the remote site.
- The company's route guide did not include specific approach and departure procedures for the H-5 helipad.
- The remote helipad lacked essential safety equipment, such as a windsock or surface markings.
- The company's safety prevention system failed to properly evaluate and approve the H-5 helipad for operations, as the site contained obstacles that violated the company's General Operations Manual (MGO).