What happened
On April 17, at 11:04 UTC, a Piper PA-31 Cheyenne II, registered HBLTI, departed from runway 17 at the Cascais aerodrome (LPCS) on an IFR flight toward Marseille airport (LFML). The aircraft was carrying one pilot and three passengers at the time of the accident.
Following departure, witnesses observed the twin-engine aircraft begin a left-hand turn while climbing to an altitude of approximately 300 feet. During this maneuver, the aircraft's left wing dipped, and the bank angle increased as airspeed dropped. This loss of speed resulted in an aerodynamic stall, sending the plane into a steep descent. The aircraft struck the ground approximately 700 meters from the runway threshold, near a supermarket logistics dock located southeast of the airfield.
The impact and subsequent explosion triggered a significant fire that spread to a nearby house, a truck, and the logistics facility. The aircraft was destroyed by the force of the collision and the resulting flames. All four occupants on the aircraft perished in the accident. Additionally, the driver of the truck involved in the explosion was also killed.
Findings
Investigation of the wreckage revealed that the fuselage, engines, propellers, and wings sustained severe damage due to the impact and the post-collision fire. The structural damage was consistent with heavy loads experienced during the crash sequence and the intensity of the fire. No pre-existing structural defects were identified in the aircraft. At the time of the impact, the landing gear and flaps were found in the retracted position. The primary cause of the accident was an aerodynamic stall following an increasing left bank during the initial climb.