What happened
On July 20, 2018, an experimental RV-10, registration PT-ZMI, was performing a private passenger flight from Corrente, Piauí, to Teresina, Piauí. During the approach to runway 20 at the Senador Petrônio Portella Aerodrome (SBTE), the aircraft experienced a drop in fuel pressure indicated on the digital engine monitoring system. The pilot activated the electric fuel pump for approximately two minutes, which temporarily stabilized the pressure, but the pilot subsequently deactivated the pump.
Shortly after, the engine began making abnormal noises, followed by a gradual loss of power. The pilot attempted to restore engine operation by re-engaging the electric fuel pump and switching fuel tanks, but these actions were unsuccessful. Unable to maintain flight, the pilot performed a forced landing into a wooded area approximately 8 NM from the airport. The aircraft struck trees with the empennage and the right wing, resulting in substantial damage to the airframe. All four occupants—the pilot and three passengers—emerged from the accident uninjured.
The investigation
CENIPA investigators examined the aircraft' and the engine components. The investigation focused on the reliability of the Engine Monitoring System (EMS-D120), which was found to be providing inaccurate fuel quantity readings, showing one tank as full and the other as empty despite actual levels being different.
Technical analysis of the Lycoming engine revealed a fracture in the mechanical fuel pump. While the aircraft's maintenance records were up to date, the investigation noted that the mechanical fuel pump (part number FAA-PMA, serial number AF-15473) had a known service life limit (TLV) of 500 hours for similar models. At the time of the accident, the engine had accumulated approximately 635 hours, suggesting the component may have exceeded its recommended operational life. Additionally, investigators found that the pilot's emergency response regarding the fuel pump did not strictly follow the procedures outlined in the RV-10 flight manual.
Findings
- The investigation identified a fracture in the mechanical fuel pump as a primary factor in the engine failure.
- The EMS-D120 instrument provided unreliable fuel quantity information to the pilot.
- The pilot's actions regarding the electric fuel pump during the initial pressure drop were not in full compliance with the aircraft's emergency procedures.
- There was a lack of traceability regarding the specific life limit of the mechanical fuel pump installed on the aircraft.
Safety action
It is recommended that the National Civil Aviation Agency (ANAC) share the findings of this investigation with the manufacturer, Flyer Indústria Aeronáutica Ltda, to evaluate the feasibility of including bench inspections or overhauls of the fuel pump within the standard maintenance plan for this component.