What happened
On January 11, 2013, an Embraer EMB 720 D, registration PT-RIK, was performing a daytime passenger flight from Rio Branco, AC, to Envira, AM. Shortly after departing from runway 06 at Rio Branco Airport, at an altitude of approximately 200 feet, the pilot detected abnormal engine operation. In response to the engine malfunction, the pilot attempted an emergency landing on the same runway.
The aircraft touched down within the final 100 meters of the available runway. Due to the loss of power, the aircraft could not stop within the runway limits, overrunning the far end of the runway and striking rocks and vegetation. The aircraft eventually came to rest in an inverted position approximately 300 meters from the initial touchdown point. The impact resulted in severe damage to the aircraft. The pilot remained uninjured, while the seven passengers sustained minor injuries.
The investigation
CENIPA investigators examined the engine and the maintenance history of the aircraft. While the engine was found to be in normal working condition and operating within manufacturer parameters at the time of testing, investigators discovered a pair of cutting/nippers pliers located in the lower part of the engine compartment, near the fuel metering valve.
Further investigation into the aircraft's maintenance records revealed that a corrective maintenance intervention had been performed immediately prior to takeoff. This maintenance work was not recorded in the aircraft's logbook and was carried out by two mechanics who were not authorized by ANAC, acting at the request of the aircraft owner. While the airframe and propeller records were up to date, the engine records were not.
Findings
- The most probable cause of the engine power reduction was that the pliers left in the engine compartment shifted during the aircraft's nose-up attitude after takeoff, interfering with the fuel metering valve lever and enriching/impoverishing the mixture.
- The maintenance performed prior to the flight was conducted by unauthorized personnel and was not documented in the aircraft logbook.
- The aircraft's engine maintenance records were not up to date.
- The pilot was qualified, held a valid medical certificate, and possessed the necessary experience for the flight.