What happened
On February 18, 2014, an R22 helicopter, registration PT-YFV, was conducting a local flight instruction mission near Rio de Janeiro. The flight, operated by Nacional Escola de Pilotagem, included a simulated landing at a restricted elevated area known as Pedra da Tartaruga. Following a takeoff from this location, the aircraft experienced an abrupt loss of control. The helicopter entered a vertical descent, spinning around its vertical axis, before impacting the sea. The impact destroyed the aircraft. The student pilot was killed, and the instructor remained missing at the time of the final report.
The investigation
CENIPA investigators examined the wreckage, which was recovered from a depth of 20 to 30 meters. The analysis revealed significant damage to the main rotor blades, including one blade with an upward deflection and another with a perpendicular break. The drop stops of the main rotor head were found broken. Mechanical inspections of the engine and main transmission showed no evidence of material or mechanical failure that could have caused the accident.
Investigators focused on the phenomenon of mast bumping, a known risk for semi-rigid rotor systems like the R22 when subjected to low-G or negative-G conditions. The investigation considered that strong winds and turbulence near the coastline may have induced a low-G condition. It was hypothesized that an improper control input—specifically a left cyclic command following a right roll—likely triggered the mast bumping, leading to the catastrophic structural failure of the rotor components and the subsequent loss of anti-torque effectiveness.