Flight History
A flight departing from Angra dos Reis was en route to Campo de Marte Airport when the crew reported an engine problem at the beginning of the descent. They diverted to Ubatuba Airport. After touchdown on runway 09, which is 940 meters long, the crew performed a maneuver intended to exchange speed for altitude. This caused the aircraft to veer off the runway and crash into a swampy area on the left-hand side of the overshoot area. The aircraft struck several trees, losing both wings and the empennage, and was destroyed.
Injuries and Damage
Both crew members and two passengers were injured; six other passengers escaped unharmed. The pilot in command (PIC) sustained serious injuries, while the second in command (SIC) and two passengers were slightly injured. The aircraft sustained substantial damage.
Investigation Findings
The investigation determined that a failure occurred in the aircraft's propeller pitch control system, which tended to feather the engine. Examination of the propeller revealed that the beta ring displacement was outside the manufacturer's specified limits, though it could not be determined whether this resulted from maintenance or impact during the emergency landing. The propeller-governor's internal components were found to be in operating condition. Functional tests of the engine after the occurrence showed normal operating conditions.
Probable Cause
The official probable cause is a failure in the aircraft's propeller pitch control system, which tended to feather the engine.
Contributing Factors
Contributing factors identified by the investigation include:
- Training – undetermined: The PIC had undergone simulator training less than a year prior, but his difficulty in framing the emergency suggests deficiencies in qualification and training. The SIC was not required to undergo such training.
- Instruction – a contributor: The SIC was not sufficiently familiar with emergencies due to the aircraft classification not requiring simulator sessions.
- Piloting judgment – a contributor: Inadequate assessment of flight parameters on final approach made landing feasible given the 940-meter runway.
- Aircraft maintenance – undetermined: The beta ring displacement was outside limits, and the intermittent ENGINE NP warning light issue was not thoroughly investigated before the flight.
- Memory – undetermined: The PIC's ability to associate trained procedures with the emergency landing pattern was unclear.
- Perception – a contributor/undetermined: Inadequate recognition of propeller feathering condition reduced situational awareness.
- Decision-making process – a contributor/undetermined: The crew did not consider runway length, obstacles, or aircraft condition adequately.
- Support systems – a contributor: The Aircraft Manual and QRH did not clearly address propeller feathering in flight.
Other Details
The flight crew held valid medical certificates and ratings. The aircraft had a valid airworthiness certificate and was within weight and balance limits. Meteorological conditions were compatible with the flight. The airframe, engine, and propeller logbooks were up to date. Prior to the accident, the aircraft had undergone maintenance for recurrent ENGINE NP warning light illumination, including compressor washing and pre-flight checks, but the root cause of the warning was not determined.