What happened
On September 11, 2008, an EMB-711C aircraft, registration PT-NNM, was performing a multi-stop flight service to distribute and collect mail near Santarém, Brazil. While flying the final leg from Alenquer to Santarém at an altitude of 1,200 feet, the engine failed.
With approximately five minutes remaining until the scheduled landing, the pilot declared an emergency and informed air traffic control that an emergency landing on the Tapaj andós River would be necessary. The pilot executed a successful water landing at an altitude of 800 feet. Following the impact, the pilot and one passenger remained on the wing of the aircraft until it became fully submerged. While the pilot and one passenger were rescued by a passing fishing boat, one passenger was lost in the river; their body was recovered 48 hours later. The aircraft sustained substantial damage and remained submerged for ten days before being recovered.
The investigation
CENIPA investigators examined the engine components, specifically the mechanical fuel pump, electric fuel pump, and the servo-injector. While the mechanical pump and servo-injector were found to be functioning normally, the electric fuel pump was found to be non-functional at the time of the engine failure, though its condition was heavily degraded by oxidation due to the aircraft's submersion.
The investigation also reviewed the aircraft's maintenance logs and the operator's management practices. Investigators found that the aircraft's fuel level indicators were unavailable, preventing the pilot from monitoring the fuel imbalance between tanks. Furthermore, the investigation looked into the company's training programs and flight planning procedures.
Findings
- Fuel exhaustion/imbalance: The engine failure was caused by a lack of fuel, exacerbated by an inability to monitor the fuel levels between tanks.
- Maintenance deficiencies: The lack of functional fuel level indicators prevented the pilot from identifying a fuel imbalance that exceeded the manufacturer's maximum allowable limit.
- Inadequate flight planning: Fuel consumption was calculated using empirical estimates that failed to account for the higher fuel burn during takeoff, climb, and taxiing, leading to less fuel on board than anticipated.
- Organizational and training failures: The operator had not implemented a standardized flight safety policy regarding fuel management. Additionally, the pilot had been assigned as commander without completing the company's required training program.
- Management oversight: The company allowed the pilot to operate the aircraft without meeting all regulatory training and operational check requirements.