What happened
On June 21, 2000, a BEECH 95-B55, registration PT-LGL, operated by Jaó Táxi Aéreo, crashed near Agrovilas das Palmeiras, in the municipality of Santo Antônio do Leverger, Mato Grosso. The flight was an instrument flight rules (IFR) mission transporting bank mail from Várzea Grande to Rondonópolis, carrying two crew members and two passengers.
During the flight, witnesses observed the aircraft emerging from cloud cover with a high rate of descent and significant lateral yawing. The aircraft struck a tree at approximately 15 meters in height before impacting the ground at a steep, nearly vertical angle of 79 degrees. All four fatalities occurred upon impact. The aircraft sustained severe damage and was a total loss.
The investigation
CENIPA's investigation revealed a pattern of severe maintenance deficiencies and operational irregularities. Although the aircraft's logs indicated periodic inspections, investigators found that several mechanical issues had persisted for a long time. Specifically, the right engine (M2) was found inoperable at the time of impact, and the left engine (M1) was operating at low power.
Technical examinations of the engines uncovered excessive wear in the fuel controller, fractured valve springs, and fouled spark plugs. Furthermore, the air filter housings allowed unfiltered air to enter the engines due to excessive wear. The investigation also noted that the maintenance shop had used expired grease and uncertified lubricants.
Regarding the crew, the investigation found that the pilot was experiencing significant physiological and psychological stressors, including extreme fatigue from a nocturnal lifestyle and regular alcohol consumption. The pilot also proceeded with the flight despite being alerted to a fuel leak during taxiing.
Findings
- Engine Failure: The primary cause of the accident was the failure of the right engine due to improper maintenance, including faulty fuel delivery and contaminated air intake.
- Aerodynamic Stall: The pilot likely attempted to manage the descent by reducing speed, which led to the aircraft falling below the Minimum Control Speed (VMC) and entering a stall.
- Maintenance Deficiencies: The aircraft was being operated in a precarious mechanical state, with critical components failing to meet airworthiness standards.
- Human Factors: The pilot's decision-making was compromised by fatigue, stress, and a high level of overconfidence, which led to the decision to depart despite known mechanical issues and fuel leaks.
- Organizational Oversight: The operator lacked adequate pilot performance monitoring, training, and safety culture, allowing substandard maintenance and risky operational practices to persist.