What happened
On January 22, 2017, at approximately 19:50 UTC, a Robinson R44 helicopter, registration PP-MAM, departed from an uncertified landing site in Capitólio, Minas Gerais, for a scenic flight. The aircraft was carrying one pilot and three passengers. Shortly after takeoff, while performing a left turn, the pilot received a low RPM warning. The pilot attempted to return to the departure site, but the presence of bystanders on the ground prevented a landing.
As the aircraft continued its flight and entered another left turn, the low RPM warning sounded again. The helicopter subsequently lost lift and entered a descent, striking the surface of the Furnas Lake, approximately eight meters below the original takeoff elevation. The impact resulted in substantial damage to the aircraft. While two passengers and the pilot were uninjured, one passenger sustained minor injuries.
The investigation
CENIPA's investigation established that the aircraft was operating in a manner inconsistent with its registration. Although registered for Private Air Services (TPP), the aircraft was performing remunerated scenic flights, which requires a different regulatory category (TPX). Furthermore, the takeoff area was neither a registered nor a certified landing site, and the operation lacked the necessary prior authorization for such locations.
Investigators analyzed cockpit footage, which revealed that the engine's manifold pressure had exceeded the continuous power limits. Specifically, the pressure reached levels near 25 to 26 in.Hg, surpassing the established limit of 23.1 in.Hg. The investigation also noted that the pilot did not implement the emergency procedures outlined in the Pilot's Operating Handbook (POH) for a low RPM condition, which requires advancing the throttle, lowering the collective, and applying aft cyclic.
Findings
- The aircraft was likely operating above its maximum weight limit, leading to the exhaustion of available engine power.
- The pilot failed to execute the required emergency procedures to restore rotor RPM following the low RPM warning.
- The pilot lacked the specific qualifications and experience required for this type of flight operation.
- The operation was being conducted as a remunerated service using an aircraft registered for private use only.
- The use of an uncertified takeoff area and the lack of proper operational authorization contributed to the unsafe environment.