What happened
On the night of May 17, 2011, a PA-34-200 aircraft, registration PT-IFS, was conducting an enroute night instructional flight. The flight originated from Piracicaba Aerodrome (SDPW) with the intention of performing a landing and go-around procedure at São José do Rio Preto (SBSR) before returning to Piracic．
During the return leg, the crew—consisting of an instructor, a student, and two passengers—was cleared by Pirassununga Approach Control to descend. While performing a right turn during the descent, the aircraft's speed increased significantly, approaching its maximum structural limit. The aircraft subsequently entered a steep, high-angle descent and collided with the terrain at Serra do Facão, near the Angeleli Farm. The impact occurred on a southern hillside at an elevation of approximately 930 meters. All four occupants perished in the accident, and the aircraft was destroyed.
The investigation
CENIPA investigators examined the wreckage and found no evidence of mechanical failure. The engines and propellers showed characteristics consistent with power being developed at the time of impact, and the airframe, engines, and propellers logbook records were up to date. Meteorological conditions at the time were favorable for visual flight.
Analysis of radar data revealed that after the aircraft began its descent, it initiated a continuous right-hand curve. During this maneuver, the airspeed accelerated from 100 knots to a level near the aircraft's structural maximum. The investigators determined that the flight trajectory and the high angle of impact were consistent with a graveyard spiral.
Findings
- Spatial disorientation likely caused the crew to lose track of the aircraft's position relative to the ground during the transition from instrument flight to night visual flight.
- The execution of a prolonged, accelerating curve contributed to the loss of control.
- The presence of passengers on an instructional flight was noted as a potential vulnerability in the organizational safety culture.
Safety action
CENIPA issued several recommendations following the investigation:
- A recommendation to Brazil’s National Civil Aviation Agency (ANAC) to evaluate updating the Commercial Pilot Course curriculum to include disciplines related to human physiology and the effects of flight conditions on the crew.
- A recommendation for the operator to be alerted regarding the risks of carrying passengers on instructional flights.
- A call to disseminate lessons learned regarding the risks of spatial disorientation during night operations.