What happened
On October 22, 2004, an EMB-721C, registration PT-EOO, was performing a ferry flight from Goiânia, GO, to Cuiabá, MT. The flight was being conducted under Visual Flight Rules (VFR) at a planned altitude of 6,50 and feet. However, due to deteriorating weather conditions, the pilot was forced to descend to 4,500 feet and eventually to 2,500 feet to maintain VFR conditions.
Approximately one hour into the flight, the engine failed and subsequently stopped completely. At the time of the failure, the aircraft was at an altitude of approximately 1,200 feet. The pilot attempted an emergency landing in an unprepared area of cerrado vegetation. During the landing sequence, the left wing struck a tree at an altitude of about two meters, causing the aircraft to slide 64.5 meters across the terrain. The impact was severe enough to tear the wings from the fuselage. The pilot survived the accident uninjured, though the aircraft sustained severe damage.
The investigation
CENIPA's investigation into the engine failure revealed significant maintenance irregularities. Post-accident inspections of the engine and propeller showed that the lubrication system was contaminated with foreign objects, including cloth residues and a ballpoint pen refill found inside the engine sump and oil filter. Additionally, the investigation found that the engine's camshafts were worn and there was friction in the oil pump gear housing.
Further examination of the electrical system revealed that the original alternator had been replaced with a Wapsa model that was not approved for use on this specific aircraft type, and no documentation existed for this installation. The investigation also noted that the aircraft's maintenance logs were outdated regarding flight hours and refueling entries.
Findings
- Adverse weather conditions forced the aircraft to fly at a lower altitude, which limited the pilot's time to execute engine restart checklists.
- Inadequate pilot judgment regarding weather planning contributed to the lack of time available to manage the emergency.
- Improper maintenance practices and inadequate management supervision likely contributed to the engine failure, evidenced by the presence of foreign object debris (FOD) and unapproved parts in the engine and electrical systems.
Safety action
Following the investigation, several safety recommendations were issued:
- The maintenance facility was advised to retrain specialized personnel to ensure all aircraft documentation is correctly completed before return to service.
- A recommendation was made for a maintenance audit of the service provider to verify technical procedures and quality control.
- CENIPA recommended that ANAC disseminate the report to general aviation operators to emphasize the importance of proper maintenance execution.