What happened
During an approach and landing at Cascais aerodrome, a Beechcraft 18 touched down with excessive speed and an improper aircraft attitude, causing the aircraft to bounce on the first runway contact. Following a second touchdown, the aircraft entered a divergent dynamic characterized by successive deviations to the left and right. This resulted in a ground loop that sent the aircraft off the left side of the runway, rotating approximately 220 degrees from its initial heading. During this excursion, the right wingtip of the Beechcraft 18 struck a Cessna 152 that was holding on the taxiway awaiting takeoff for an instructional flight.
The investigation
The GPIAAF investigation examined the aircraft condition, crew data, and environmental factors at the time of the event. The investigation noted that the pilot had not operated this specific aircraft model since 201 runway 17, which featured a 4° APAPI and a negative slope of -1.1%. At the time of landing, the wind was reported as 290/09kt, providing an 8-knot right crosswind component. While the Beechcraft 18 showed signs of degradation likely due to inactivity or lack of preservation, investigators could not link the runway excursion to any mechanical failure. The collision caused the tail wheel of the Beechcraft 18 to collapse upon striking the edge of the taxiway, damaging the rear fuselage, vertical stabilizers, and rudders. The Cessna 152 sustained substantial damage to its left wing and the cockpit area of the fuselage. Both crews were uninjured.
Findings
- The primary cause of the accident was inadequate piloting technique during landing involving excessive directional correction (PIO).
- A contributing factor was the pilot's reduced proficiency with the specific aircraft model under the recorded wind conditions.
- The pilot had not flown the involved aircraft model since 2018.