What happened
On June 15, 2001, an EMB-721D, registration PT-REJ, departed from Pampulha Airport (SBBH) bound for Guarapari (SNGA) with a pilot and three passengers. During the flight, approximately 20 nautical miles from the destination, the engine failed and seized, followed by a significant oil leak that coated the windshield and windows, severely obstructing the pilot's visibility.
As the sun was setting, the pilot was forced to lean out of the cockpit to identify a suitable landing site. The pilot opted for an emergency landing in a coffee plantation. During the descent and impact, the aircraft's right wing struck a tree, causing the aircraft to spin 180 degrees and catch fire. The impact resulted in two serious injuries among the occupants, while the other two passengers remained uninjured. The aircraft was a total loss.
The investigation
CENIPA's investigation focused on the circumstances surrounding the maintenance of the aircraft prior to the flight. It was established that the aircraft had been undergoing a 100-hour inspection at a maintenance facility, but the service was not officially completed. Due to delays caused by a magneto issue, the aircraft was moved to a different hangar before the inspection was finalized.
To expedite the aircraft's availability for a planned family trip, a private mechanic was hired to perform repairs, including taking a magneto home to work on it overnight. The investigation also noted that the engine had a history of abnormal vibration dating back to 1999. Investigators examined the possibility of fatigue failure in the engine components, specifically looking at the connecting rod.
Findings
- Improvised maintenance: The aircraft was removed from the maintenance facility before the scheduled inspection was completed, and repairs were performed in an ad hoc manner by a private mechanic.
- Mechanical failure: The investigation identified the fatigue failure of the number 4 connecting rod as a key factor, likely caused by increased cylinder pressure or engine vibration.
- Human factors: The pilot and the contracted pilot exhibited excessive confidence and were highly motivated to complete the trip, which compromised their ability to critically assess the unsafe condition of the aircraft.
- Decision making: The decision to authorize improvised maintenance and the failure to address the ongoing engine vibrations contributed to the accident sequence.