What happened
On August 9, 2006, at approximately 12:45 local time, an Air Tractor AT-802A, registration EC-IQC, was performing aerial firefighting operations in the Ría de Pontevedra, near the port of Raxo, Spain. The aircraft, operated by CEGISA, had previously flown from Rosinos to Vigo Airport before departing for the water-loading mission.
While the pilot was performing a water-loading maneuver on the surface of the water, the aircraft experienced a sudden, violent deceleration. This force caused the nose of the aircraft to pitch downward abruptly, resulting in the propeller striking the water. The pilot, the sole occupant of the aircraft, was uninjured and was able to exit the aircraft safely. The impact caused significant damage to the aircraft, including the loss of the propeller, damage to the lower engine cowling, and the breakage of the forward strut connecting the two floats.
The investigation
The investigation focused on determining why the aircraft's nose pitched down so sharply upon contact with the water. Investigators examined the aircraft's landing gear system, which utilizes hydraulic pumps and actuators to retract the wheels into the floats. The system uses a specific light configuration (blue for up, green for down) to indicate position, with red lights indicating the gear is in transition.
Physical inspection of the aircraft revealed no evidence of impact with submerged objects. The damage to the engine cowling and the float strut appeared consistent with being struck by the propeller as it detached. Furthermore, when the aircraft was recovered from the water, the landing gear was found in the retracted position, and subsequent testing of the extension and retraction cycles showed the mechanism was functioning correctly.
Findings
- The investigation established that the aircraft likely landed on the water with the landing gear extended or in the process of retracting.
- The sudden drag created by the extended gear caused the nose to pitch down and the propeller to strike the water.
- The cockpit light system used to indicate gear position is not highly intuitive, as the blue and green lights can be easily confused in bright sunlight.
- The significant time required for a full gear transition (approximately 35 seconds) may lead to uncertainty regarding the gear's actual position.
- While the pilot possessed extensive firefighting experience, they had relatively limited experience (190 hours) specifically with the amphibious Air Tractor AT-802A.
- As the aircraft had performed only land-based takeoffs and landings earlier that day, the pilot may have had an incorrect estimation of the gear status during the first water landing of the day.