What happened
On September 25, 2010, a Robinson R44 helicopter, registration PT-YPW, was performing a private passenger flight from Formosa, Goiás, to Novo Gama, Goiás. The flight was conducted under Visual Flight Rules (VFR) without a filed flight plan.
During the landing phase at a local soccer field, the pilot attempted a landing in a restricted area using a steep approach angle. As the aircraft descended at a high rate, the low rotor RPM warning horn activated. The pilot misinterpreted this warning as engine power loss and continued the descent, resulting in a heavy impact with the ground. The impact caused the tail boom to strike the terrain, leading to the separation of the tail rotor and a subsequent loss of control. The aircraft sustained substantial damage to the airframe, engine, transmission, and electrical systems, but the pilot and two passengers escaped without injury.
The investigation
CENIPA investigators examined the aircraft's weight and balance records and found that the helicopter was operating well beyond its operational limits. Although the takeoff weight was approximately 1,050kg, the performance charts for the prevailing temperature (32°C) and pressure (1017 hPa) indicated a maximum takeoff weight of only 970kg, representing an excess of 80kg. By the time of the landing, the aircraft was approximately 120kg overweight for the atmospheric conditions.
The investigation also scrutinized the pilot's training records. Discrepancies were found in the pilot's flight log, including entries made in pencil and missing dates. Investigators noted contradictions regarding the pilot's initial check flight and found that certain regulatory requirements for initial training, such as flight planning and air traffic control communications, may not have been properly evaluated. Furthermore, while engine components were functional, evidence of oil in the left magneto and damaged wiring was found, though these were likely results of the impact rather than the cause of the descent.
Findings
- The pilot was qualified but lacked sufficient experience for the type of operation being performed.
- The aircraft was operating exceeding the maximum takeoff weight for the prevailing temperature and pressure.
- The pilot failed to properly manage the rotor RPM by not lowering the collective when the low RPM warning sounded.
- Inadequate flight planning and failure to consider critical environmental variables such as temperature and altitude.
- Deficiencies in pilot training supervision and flight instruction standards.