What happened
On January 9, 2002, an EMB-201 aircraft, registration PT-GNV, operated by AGROVEL - Agroaérea Vila Velha Ltda, was performing agricultural spraying operations near Fazenda Dallarosa in Primavera do Este, Mato Grosso. While executing a left turn to intercept a spraying line, the engine suffered a loss of power. The pilot attempted an emergency forced landing, but during the approach, the aircraft struck a fence. This impact caused a loss of control and a violent collision with the ground. The aircraft sustained severe structural damage, including the separation of the engine assembly and the tail section, but the pilot emerged uninjured.
The investigation
CENIPA investigators examined the engine and the fuel system to determine the cause of the power loss. While fuel samples were analyzed by PETROBRAS, they did not show irregularities, though the investigation noted that the pilot had not performed fuel tank drainage that day despite recent heavy rains. Upon inspecting the engine, investigators discovered the presence of graphite grease on all spark plugs. According to the engine manufacturer, this specific material is not approved for use in the ignition system as it can compromise performance. The investigation also noted that while the aircraft's maintenance records were up to date, the maintenance services performed were considered periodic but inadequate.
Findings
- The primary cause of the engine failure was inadequate spark plug ignition due to the use of graphite grease, a material not specified by the manufacturer.
- The use of non-compliant lubricant on the spark plugs compromised the engine's performance.
- Maintenance practices were found to be insufficient, specifically regarding the use of unauthorized materials in the ignition system.
- The lack of fuel tank drainage following heavy rainfall was identified as a potential, though less likely, contributing factor to engine power loss.