What happened
On July 17, 2016, at 19:42 local time, a PZL W-3AS helicopter, registration EC-LQA, operated by Hispánica de Aviación (HASA), was performing aerial firefighting duties near Villanueva de la Cañada, Madrid. The aircraft was returning from an active firefighting mission with 2 pilots and 10 firefighting specialists on board.
During a routine procedure, the pilot inadvertently closed the fuel shutoff valve for engine 1. While the engine initially stopped, the investigation found that the engine had actually restarted and was running at idle speed approximately 50 seconds after the valve closure. However, the crew did not identify that the engine was functioning and continued to believe the engine was shut down. After attempting an in-flight restart, the crew decided to perform an emergency landing in a nearby field to attempt a proper engine start. During the approach and landing maneuver, the helicopter failed to maintain appropriate speed, altitude, and flight path, causing the aircraft to roll onto its right side.
All 12 occupants evacuated the aircraft. The 2 pilots and 5 of the specialists sustained minor injuries, while the remaining 5 specialists were uninjured.
The investigation
The CIAIAC examined the flight data, cockpit voice recordings, and maintenance history of the aircraft. The investigation focused on the sequence of events leading to the engine shutdown, the crew's failure to recognize the engine's operational status, and the execution of the emergency landing. The investigators also reviewed the operator's firefighting procedures, crew training, and the adequacy of the aircraft's flight manual regarding engine restart and motoring procedures.