What happened
On August 30, 2018, an EMB-711 ST, registration PT-RON, was performing a private passenger flight from Aeródromo Paulo Afonso to Aeródromo Deputado Luís Eduardo Magalhães. Approximately 55 minutes into the flight, while cruising at FL 105, the pilot noticed heavy engine vibrations. During an emergency descent, the engine suffered a sudden shutdown at FL 090, accompanied by a loud noise and significant oil leakage onto the windshield.
The pilot performed an emergency landing on highway BR 1 lubricated 110. During the landing roll, the left wing struck a road sign and the right wing collided with a tree, causing the aircraft to spin before coming to a halt. The aircraft sustained substantial damage, including engine block failure and landing gear collapse, but the pilot and two passengers were uninjured.
The investigation
CENIPA investigators examined the engine and found extensive internal damage, including broken pistons, a broken crankshaft, and components that had fused due to extreme heat. The investigation determined that the oil loss occurred specifically through the oil filler neck. At the crash site, the oil filler cap was found displaced.
Technical analysis revealed that the locking mechanism for the filler cap was worn and malfunctioning, which allowed the cap to detach due to engine vibrations. Furthermore, investigators identified discrepancies in maintenance records, noting that service dates in the engine and propeller logbooks did not match the maintenance work order. The investigation also noted that the engine had only flown 37 hours since its last 100-hour inspection, suggesting that the worn locking mechanism might have been overlooked during recent maintenance.
Findings
- The engine oil loss caused a failure in the lubrication system, leading to excessive heat, internal component melting, and total engine failure.
- The locking mechanism of the oil filler cap was worn and failed to secure the cap properly.
- The pilot failed to notice the insecurely placed filler cap during the pre-flight inspection.
- Inaccurate transcription of maintenance data created discrepancies between work orders and aircraft logbooks.