What happened
On July 3, 2019, at 15:45 UTC, an Air Tractor AT-802AF operated by Agro-montiar was performing firefighting duties for the National Emergency and Civil Protection Authority (ANEPC). The aircraft, registration EC-JUB, was part of a two-aircraft formation flying from Proença-a-Nova to the Castelo de Bode dam to collect water for fire suppression efforts in the Leiria district.
While approaching the dam, the pilot identified nearby power lines and planned a low-pass maneuver to check the water collection site. The flight plan involved a south-to-north pass in a tailwind, followed by a north-to-south pass for the actual scooping. During the final approach for the water landing, the pilot reported that the aircraft was configured for landing, noting "four blue" lights, which indicates the landing gear is in the up position. However, the investigation confirmed the landing gear was actually in the extended position.
Upon contact with the water, the aircraft experienced a violent impact due to sudden deceleration. The impact was severe enough to activate the on-board emergency locator transmitter. The pilot managed to egress the cockpit and swim to the shore, remaining uninjured. The aircraft, however, suffered substantial damage to the engine, propeller, and fuselage, and the floats were separated from the wings. The aircraft was subsequently declared destroyed.
The investigation
The GPIAAF investigation focused on the configuration of the aircraft's retractable landing gear and the crew's communication procedures. The investigation examined the Wipair 10000 float system, which utilizes electrically driven hydraulic pumps and actuators to manage the gear. Investigators verified that the landing gear was in the extended position, consistent with the physical selector in the cockpit, despite the pilot's verbal confirmation of an "up" configuration.
Findings
- The pilot, an experienced Spanish national with over 4,300 flight hours, was performing the mission according to legal requirements.
- The aircraft's landing gear indicator system uses eight lights: four blue for "gear up" and four green for "gear down."
- The landing gear was extended during the water landing, contradicting the pilot's verbal confirmation of the gear being up.
- The pilot's communication with the wingman (A7) involved alternating between firefighting and flight information frequencies, which deviated from the operator's established procedure of assigning specific radios to specific tasks.
- While the aircraft's cockpit remained intact, providing a survival space, the impact forces were sufficient to cause significant structural failure.
Safety action
Following the accident, the operator, Agro-montiar, and the ANEPC initiated several safety improvements:
- All pilots operating within national territory are now required to maintain ICAO Level IV aeronautical English proficiency.
- The operator has launched a campaign to promote standard phraseology, specifically for VFR operations.
- The landing gear cross-check procedure is being revised to include specific standard phraseology and relative aircraft positions.
- A "Sterile Cockpit" concept is being implemented to prevent external interference during critical flight phases.
- The ANEPC is revising operational instructions to ensure mission radio frequencies are prioritized correctly by crews.