What happened
On the afternoon of August 20, 2006, a Sova KP-2U ultralight aircraft, registration CS-ULM, was conducting a training flight near Cascais, Portugal. The flight, operated by the Pelicano flight school, carried a pilot and one passenger. After departing Cascais (Tires) aerodrome, the aircraft proceeded to the Cascais bay at an altitude of 1,50 and was observed performing several uncoordinated maneuvers with fluctuating altitudes.
At approximately 15:15 UTC, the aircraft was flying at roughly 800 feet AMSL, about 500 meters offshore. The pilot executed a tight left-hand turn, losing approximately 400 feet of altitude. After regaining altitude, the pilot attempted a second tight turn to the right. During this maneuver, the aircraft experienced a sudden, violent movement and entered a left-hand spin. The aircraft pitched nose-down, completed approximately two and a half rotations around its longitudinal axis, and struck the water in a nearly vertical attitude. The aircraft disappeared beneath the surface immediately upon impact.
The investigation
The GPIAAF investigation examined the aircraft wreckage, which was recovered from a depth of approximately 29 meters. Submerged imagery showed the aircraft hit the water nose-first, causing significant compression damage to the engine, propeller, and windscreen. The investigation also reviewed the pilot's credentials, the aircraft's maintenance history, and local meteorological conditions.
Investigators noted that the pilot had very limited experience, having accumulated only 2 hours and 20 minutes of flight time as a pilot prior to this flight. Meteorological data indicated strong northwest winds of 30 knots with 35-knot gusts, resulting in moderate turbulence near the coastline. While there was ambiguity regarding whether the pilot met the specific flight hour requirements to carry a passenger under certain interpretations of local regulations, the investigation determined that the presence of the passenger was not a primary factor in the accident.
Findings
- The aircraft was in a valid state of airworthiness and had complied with all maintenance programs.
- The pilot demonstrated a lack of flight coordination, characterized by frequent changes in heading and altitude.
- During the final right-hand turn, the pilot likely applied excessive back pressure on the control column to maintain altitude, increasing the angle of attack to a critical level.
- The primary cause of the accident was deficient piloting technique, which led to an aerodynamic stall and the subsequent entry into a spin, followed by an inability to recover before impact.
- Strong winds and moderate turbulence contributed to the difficulty of maintaining aircraft control during the maneuvers.