What happened
On August 13, 1995, a Hughes 369 HS helicopter, registration PT-HIU, was conducting sightseeing flights from a shopping center parking lot in São Roque, São Paulo. During the tenth flight of the day, while on final approach at an altitude of approximately five meters, the engine experienced a loss of power.
The pilot attempted to execute an autorotation; however, due to the presence of obstacles and people in the landing area, the pilot had to adjust the flight path. In an attempt to avoid a utility pole, the pilot applied significant cyclic input. This maneuver, combined with low rotor RPM, caused the main rotor to strike the tail boom, leading to a loss of control and the tail cone striking the ground. The aircraft subsequently rolled onto its left side.
The accident resulted in one fatality (a passenger who died 40 days after the event), one serious injury, and three minor injuries. The pilot was uninjured. The aircraft sustained severe damage.
The investigation
CENIPA's investigation focused on the fuel system and operational procedures. Investigators discovered significant contamination within the fuel system, including water and solid particles found in the fuel tank, the fuel filter, and the fuel control unit (FCU). Specifically, water was found at the bottom of the screen filter, and debris was present in the microfilter, which caused restricted fuel flow.
The investigation also revealed that the aircraft had been inactive for a long period, operating only about 68 hours over nearly two years. Maintenance records lacked evidence of proper fuel tank cleaning or filter replacements. Furthermore, the investigation found that the aircraft was operating in an unauthorized area without permission from the local aviation authority (SERAC-4) and was carrying five passengers despite being certified for only four.