What happened
On February 4, 1978, at approximately 15:20, a Tiger Moth (registration CS-AAA) was performing a local aerobatic training flight departing from the Cascais aerodrome (Tires). The aircraft, owned by the Direcção-Geral da Aeronáutica Civil and operated by the Aero Clube de Portugal, began the flight with an aggressive left-hand turn.
During the maneuvers, the crew executed a series of loops, totaling six vertical maneuvers, reaching an estimated altitude of 1,500 feet. Following these maneuvers, the aircraft entered a series of approximately five spins (vrille). During the final stages of the flight, the aircraft was flying into the wind at a low airspeed. The pilot attempted to recover from the spin by applying full throttle on two separate occasions; however, the recovery occurred at an altitude too low to prevent impact. The aircraft struck the ground approximately 20 and 300 meters west of the runway at an angle between 45 and 60 degrees.
Both the pilot and the passenger sustained serious injuries and were transported to a hospital in Lisbon.
The investigation
The investigation examined the airworthiness of the aircraft and the flight profiles executed by the crew. The aircraft was found to be properly certified, equipped, and maintained in accordance with regulations. The pilot held a valid commercial pilot license with approximately 1,700 flight hours. Investigators also reviewed witness accounts, including a passenger who noted that the flight maneuvers were performed differently than usual and were particularly intense.
Findings
- The aircraft was in a legal and airworthy condition for the flight.
- No mechanical anomalies or system failures were detected in the aircraft's components that contributed to the accident.
- The aircraft was destroyed upon impact, with significant damage to the fuselage, wings, and landing gear.
- The spin was performed at an altitude that left insufficient margin for recovery before ground impact.