What happened
On June 1, 2008, a Bell 212 helicopter, registration CC-CIY, operated by Servicios Aéreos de Los Andes S.A.C., was performing an external load operation at the Sub Base Alfa 1 remote helipad in the Curaray Province of Loreto, Peru. The mission involved transporting supplies and fuel via sling load to other remote locations.
While attempting to take off, the crew performed several repositioning maneuvers in an attempt to find a suitable departure path. During the final attempt, while flying near the riverbank, the pilot noted a drop in the main rotor RPM. As the pilot attempted a turn to face the river, the RPM decreased further, and the aircraft began to descend toward the river. The crew managed to partially control the descent and moved toward land, but the aircraft lost control effectiveness and tilted to the left. During this instability, the external load struck the ground. As the co-pilot reduced collective to recover rotor RPM, the helicopter drifted laterally and struck the ground, causing the tail boom to collide with a 1.8-meter-tall sign marking a nearby fuel depot.
The investigation
The CIAA investigation examined the aircraft's maintenance records, the crew's training, and the operational environment. The investigation confirmed that the engines, rotors, and fuel were in airworthy condition and that the aircraft was within weight and balance limits. However, the investigators noted that the aircraft was not equipped with a Flight Data Recorder (FDR), despite being required by Peruvian regulations (RAP) for aircraft of this maximum takeoff weight. This absence of data limited the investigators' ability to perform a more detailed analysis of the flight parameters during the critical moments of the incident.
Findings
- The primary cause of the incident was the instability of the aircraft caused by the movement of the external load during the takeoff phase.
- The takeoff area did not meet the requirements specified in the operator's External Load Manual, which requires a clear area of 200 meters by 50 meters.
- The crew failed to follow established external load operation procedures during flight planning and execution.
- There was evidence of deficient Crew Resource Management (CRM), specifically a delayed reaction by the co-pilot in reducing collective to recover rotor RPM.
- The company's route guide lacked specific arrival and departure procedures for the remote helipads in the Curaray region.
- The crew did not adequately account for the departure axis, wind direction, or surrounding obstacles during flight planning.