What happened
On August 6, 2010, a Cessna T188C was performing its fourth agricultural spraying mission of the day at the Olepalma estate in the Quinindé sector. While returning to the operator's base at the “El Limón” airstrip, the aircraft experienced a sudden loss of engine power.
The pilot attempted to maintain flight by activating the auxiliary fuel pump, which temporarily restored power. However, whenever the auxiliary pump was deactivated, the engine would lose power again. This unstable condition persisted for approximately eight minutes. During this period, the pilot reported hearing three sounds similar to explosions before the engine ceased functioning entirely.
Facing total power loss, the pilot performed an emergency landing in a flat, grassy area at the “Las Marunaillas” estate. The aircraft traveled 275 meters along a heading of 290 degrees before impacting vegetation and spraying equipment, which caused damage to the propeller blades and the left wing. The pilot sustained no injuries.
The investigation
The investigation focused on the mechanical failure of the engine and the operational practices of the company. Investigators conducted a ground run of the Continental TSIO-520T engine using the fuel remaining in the aircraft's wings. During this test, the engine operated within normal parameters, and no leaks or immediate failures were detected.
Regarding the operator, the board identified several organizational deficiencies. The company was operating without an approved Operations Manual, as required by regulations. Furthermore, the person appointed as Chief of Operations was also an active pilot, making it impossible to perform the necessary flight monitoring duties. The investigation also noted a lack of fuel control procedures and the absence of a system to verify the quality of fuel during replenishment.
Findings
- The primary cause of the engine failure was a momentary malfunction of the mechanical fuel pump, which reduced fuel flow to the engine.
- It is probable that the engine eventually stopped due to flooding (over-priming) caused by the prolonged use of the auxiliary fuel pump, which is intended only for very short durations.
- The aircraft maintained sufficient forward speed at the time of impact with the vegetation, as evidenced by the deformation of the propeller blades.
- Operational risks were present due to the lack of a flight planning system and inadequate fuel contamination prevention measures, such as unprotected refueling nozzles.