What happened
On January 11, 2006, a Cessna 150M, registration CS-ASX, was conducting a training mission near Cascais, Portugal. The flight, operated by Leávia Aviation School, involved an instructor and a student pilot practicing engine failure simulations and emergency landings.
At approximately 15:20 UTC, while operating near the coast at Guincho, the instructor initiated a simulated engine failure and water landing maneuver. After reaching an altitude of 300 feet, the instructor began a recovery turn to the left, heading inland toward the mountains. As the aircraft climbed, the pilot opted to fly through a narrow valley between the Figueira do Guincho and Biscaia hills.
However, the aircraft's performance was severely compromised by orographic downdrafts caused by the terrain. The climb gradient of the valley (approximately 21.5%) far exceeded the aircraft's maximum achievable climb gradient (approximately 9.4%). Unable to clear the obstacles or execute a 180-degree turn back to the sea, the pilot attempted an emergency landing on the mountainside. During this maneuver, the right wing struck a tree, causing the aircraft to spin and impact the ground nearly vertically in a residential yard.
The investigation
The GPIAAF investigation examined the flight history, aircraft maintenance records, and meteorological conditions. The investigation established that the aircraft was airworthy and the crew was properly licensed. Investigators analyzed the aircraft's performance capabilities against the terrain gradients and identified that the recovery maneuver placed the aircraft in a flight condition incompatible with its performance limits. The investigation also noted that the emergency landing was poorly prepared, as the flaps were not extended, and the execution was flawed, leading to the collision with the tree.
Findings
- The primary cause was inadequate piloting technique during the recovery from the simulated engine failure.
- The pilot chose a recovery route over rugged terrain that was impossible to traverse given the aircraft's performance limitations.
- The aircraft's climb capability was further degraded by downdrafts created by the terrain.
- The emergency landing on unprepared ground was poorly executed and lacked proper configuration, specifically the failure to deploy flaps.
- The impact resulted in the total loss of the aircraft, though both pilots escaped with only minor abrasions and contusions.