History of the Flight
On 15 December 2010, at 15:11 UTC, a Tecnam P-96 Golf ultralight aircraft, registration CS-UOO, departed from Cascais Municipal Aerodrome (LPCS) for a leisure flight. The flight was planned to proceed north at 1500 feet, with a touch-and-go landing at Tojeira, then to Ericeira, and return to Cascais via Cabo da Roca. The aircraft had two occupants: a pilot and a passenger, both male. The estimated flight duration was 1 hour 15 minutes, and the aircraft carried fuel for 3 hours. The call sign was CLP357.
At 15:22, while under radar monitoring by the Lisbon Military Flight Information Service and in radio contact with Approach Control at Base Aérea Nº 1 (Sintra), the pilot declared a Mayday, reporting a total engine failure and stating he could not reach Tojeira airstrip. The controller asked for the exact position, and the pilot requested a moment to confirm but did not re-establish contact.
Witnesses on the beach of Aguda reported seeing the aircraft approach from the sea, heading north-south. It touched down in a three-point attitude near the middle of the beach, rose to about 5 meters, glided to the end of the beach, veered slightly right to avoid rocks, and struck the water. The aircraft nosed over and floated inverted approximately 15 meters from the surf. Three witnesses attempted to pull the aircraft to dry sand by the tail and left flap but could not due to wave action and sand entering the broken canopy. Firefighters from Colares arrived, extracted the occupants, and administered resuscitation. The pilot responded and was airlifted to Hospital de São Francisco Xavier. The passenger was pronounced dead at the scene by an INEM physician.
Injuries and Damage
The passenger was killed, and the pilot sustained serious injuries. The aircraft suffered substantial damage from impact with sand and waves, including destruction of the cockpit, fuselage, wings, horizontal and vertical stabilizers, propeller, engine, and engine mountings. Additional damage occurred during removal.
Investigation Findings
The investigation determined that the primary cause of the accident was a fatigue fracture of the engine crankshaft, resulting from continuous overload or reduction in material properties. A contributing factor was the use of engine oil with viscosity and performance classification not conforming to the manufacturer's specifications.
Probable Cause
The primary cause was a fatigue fracture of the crankshaft, resulting from continuous overload or reduction in material properties. A contributing factor was the use of engine oil with viscosity and performance classification not conforming to the manufacturer's specifications.