What happened
On August 8, 1998, a Bell 47 G2 helicopter, registration PP-HUE, was conducting a local flight for instructor training at the Jacarepaguá Aerodrome in Rio de Janeiro. The flight, operated by Aeroclube do Brasil, involved a pilot undergoing training to become a helicopter instructor, accompanied by an experienced instructor.
During the execution of an autorotation maneuver, the aircraft experienced a loss of control. The pilot allowed the aircraft to descend with a low tail attitude, causing the tail rotor guard to strike the ground. The impact resulted in significant damage to the airframe, including the rotors, tail cone, transmission, and cabin. The instructor sustained minor injuries, while the pilot remained uninjured.
The investigation
CENIPA's investigation focused on the flight dynamics and the operational environment. The investigation established that the wind conditions were calm (null), a condition that both crew members had not previously encountered during this specific exercise. While the aircraft's airworthiness certificate was valid, the investigation revealed that maintenance records were outdated and that recent inspections had been performed by the flying club without proper authorization or official accreditation.
Investigators also examined the human factors, noting a close personal relationship and high level of trust between the instructor and the student. This relationship, combined with the student's successful performance in previous maneuvers, influenced the crew's decision-making and level of vigilance during the flight.