What happened
On September 2, 2003, an R22 helicopter, registration PT-YPJ, was conducting a flight training mission at Jacarepaguá Airport (SBJR) in Rio de Janeiro. The flight, operated by NEP Nacional Escola de Pilotagem, was part of a student's pre-solo training phase, specifically focusing on hovering maneuvers with lateral movement.
During the execution of a rightward lateral hover, the student allowed the right skid to make contact with the ground. This contact caused the aircraft to enter a roll. Although the instructor attempted to intervene and stabilize the helicopter, the movement resulted in a dynamic rollover, causing the main rotor to strike the ground. The aircraft sustained severe damage, but both the instructor and the student escaped without injury.
The investigation
CENIPA's investigation focused on the flight maneuvers and the crew's response to the skid strike. The investigation established that the R22 flight manual recommends maintaining a minimum safety altitude of 5 feet AGL during hovering exercises to prevent ground contact. The manual also specifies that a skid strike during lateral movement can shift the aircraft's center of gravity, causing it to pivot over the contact point.
Investigators found that the instructor's corrective actions were contrary to the manufacturer's recommended procedure. Instead of applying the collective downward to attempt to settle the helicopter back onto the skids, the instructor applied cyclic input in the opposite direction of the tilt and increased the collective. This action failed to interrupt the rolling tendency and contributed to the rotor strike.
Findings
- The instructor failed to correctly judge the student's altitude and did not maintain the necessary level of supervision to prevent the student from flying below the recommended safety height.
- The instructor applied incorrect control inputs during the emergency, following a procedure that contradicted the manufacturer's manual.
- The student's limited experience in the aircraft type contributed to the initial loss of altitude and subsequent skid strike.