What happened
On April 16, 2011, an Embraer EMB-712 Neiva, registration PT-VCU, was performing a ferry flight from Pará de Minas, MG, to Vila Velha, ES. The aircraft was returning to the Aeroclube do Espírito Santo following a 100-hour inspection, annual maintenance, and an engine overhaul.
After approximately two hours and ten minutes of flight, the engine stopped. The pilot attempted emergency procedures, including activating the electric pump and switching fuel tanks, but was unable to restart the engine. The pilot subsequently performed a forced landing in an unprepared field at Fazenda Rui Moreira. During the landing, the aircraft struck a tree approximately 3.5 meters tall, which caused the left wing to detach from the fuselage. The aircraft slid 24.3 meters before coming to a stop in a ditch. The pilot and one passenger sustained light injuries, and the aircraft suffered substantial damage.
The investigation
CENIPA's investigation focused on the fuel exhaustion and the electrical state of the aircraft. Investigators found that the aircraft's battery was discharged at the time of engine start, and the maintenance facility had performed an "assisted" start by charging the battery in parallel with another battery rather than replacing the faulty unit.
Furthermore, the investigation identified significant discrepancies in fuel consumption calculations. While the flight club's internal estimates suggested a consumption of 33 liters per hour, the aircraft's Operations Manual indicated that at 75% power, consumption was approximately 38 liters per hour (10 Gal/Hr) when using a corrected mixture. Because the pilot did not adjust the mixture during the flight, the actual fuel consumption exceeded the planned estimates, leading to the depletion of the fuel supply.
Findings
- Fuel exhaustion occurred because the actual fuel consumption rate was higher than the pilot's calculated estimate due to the failure to adjust the mixture.
- The depleted battery prevented the electric fuel pump from functioning, which would have been necessary to deliver fuel from the right tank to the carburetor after the left tank was exhausted.
- The decision to depart with a low-charge battery contributed to the inability to maintain fuel flow during the emergency.
- Inadequate fuel consumption studies and flight planning practices within the flight club's operations.