What happened
On August 23, 1995, at approximately 19:45 local time, a PA-31 Navajo, registration PT-IHH, was operating a flight from Fortaleza to Teresina. While approaching Teresina, the pilot experienced a significant electrical failure, which disabled the aircraft's radio communications and navigation equipment. Unable to contact air traffic control via radio, the pilot used a mobile phone to communicate with the Teresina controller.
During the approach, the pilot reported a suspicion that the landing gear might not be properly extended and locked. Following a suggestion from the controller, the pilot performed a low pass over the airfield to visually verify the gear. While the gear appeared to be down, the landing gear doors were observed to be open.
In an attempt to re-verify the aircraft's status, the pilot initiated a go-around. However, because the electrical failure had rendered the electric fuel pumps inoperable, the engine failed to maintain power. The aircraft subsequently struck the terrain approximately 6 km northeast of the airport. The impact resulted in the total destruction of the aircraft and the deaths of all seven occupants (one pilot and six passengers).
The investigation
CENIPA's investigation revealed that the aircraft was operating with several pre-existing mechanical discrepancies. A note found in the pilot's belongings detailed numerous issues, including an inoperative left alternator, malfunctioning VOR/Derm navigation equipment, and inconsistent fuel pump pressure. The investigation established that the pilot was a "free-lancer" with limited experience as a commander in the PA-31 model.
Investigators found that the aircraft's electrical system was under extreme strain, as the failure of the left alternator meant the entire load was being drawn from the battery. The investigation also noted that the aircraft's logbook and emergency checklists were not found at the crash site. Furthermore, the investigation highlighted that the pilot faced significant pressure from the passengers—who were high-ranking company executives—to proceed with the flight despite the deteriorating technical conditions and the transition into night operations.
Findings
- Inadequate decision-making: The pilot failed to follow the manufacturer's emergency procedures, which mandated landing as soon as possible following an electrical failure.
- Operational pressure: The pilot accepted a high-risk flight profile, including operating without a co-pilot and during nighttime, due to professional pressure to secure permanent employment with the operator.
- Maintenance deficiencies: The operator failed to perform necessary corrective maintenance on known discrepancies, such as the inoperative alternator and navigation equipment.
- Loss of control: The decision to perform a go-around while relying on battery power—which was nearing exhaustion—led to the failure of the electric fuel pumps, causing engine power loss and subsequent loss of control.
- Lack of experience: The pilot's limited experience as a commander in this specific aircraft type contributed to the inability to manage the complex emergency effectively.