Engine failure leads to forced landing of Cessna 150 in Portugal

Casualties unknown • Comporta, PT

A recreational flight experienced an engine failure due to a broken exhaust valve, resulting in a forced landing and substantial aircraft damage near Comporta.

What happened

On May 15, 2014, a Cessna 150, registration CS-AYJ, was conducting a recreational flight from Portimão to Cascais along the Portuguese Atlantic coast. The flight, operated by Aero Vip, included a pilot and one passenger. After climbing to 2,500 feet, the pilot began to experience engine vibrations and a loss of power near Zambujeira do Mar.

As the aircraft flew over Brejos da Carregueira, the vibrations intensified, prompting the pilot to declare an engine failure to Lisbon Air Traffic Control and attempt an emergency landing at the Comporta airstrip. During the approach, the pilot performed two 360-degree turns to manage altitude and speed. Ultimately, the pilot attempted an emergency landing on a dirt road north of the airfield. The aircraft struck a perpendicular road, causing the nose gear to collapse and the aircraft to overturn. While the pilot and passenger sustained minor injuries and evacuated the aircraft, the aircraft suffered substantial damage to the engine, nose gear, fuselage, and wings.

The investigation

The GPIAAF conducted a technical evaluation of the aircraft at the operator's facilities in Cascais. The investigation included a detailed inspection of the fuel system, which showed no anomalies, and a comprehensive teardown of the Continental O-200-A engine by a certified workshop.

Findings

  • The engine power loss was caused by the failure of the cylinder #3 exhaust valve, which broke at the top of the stem near the valve head.
  • The broken valve head dropped into the cylinder, causing deep marks on the piston top due to impact.
  • The pilot was properly licensed and medically fit at the time of the accident.
  • The engine had completed 1,528 hours since its last overhaul and had undergone a 50-hour inspection only 47 hours prior to the event.
  • The investigation concluded that poor energy management during the emergency contributed to the aircraft landing in unprepared terrain, as the pilot's chosen altitude would have been sufficient for a successful landing on the prepared runway if appropriate techniques, such as the use of flaps, had been employed.

Probable cause

The probable cause of the engine power loss was the failure of the #3 cylinder exhaust valve, leading to asymmetric engine operation and increased vibrations. The severity of the landing was exacerbated by inefficient energy management during the emergency approach.

Frequently asked questions

What happened in the 2014-05-15 Cessna F150L accident near Comporta, PT?

A recreational flight experienced an engine failure due to a broken exhaust valve, resulting in a forced landing and substantial aircraft damage near Comporta.

What aircraft was involved and where did it happen?

The accident on 2014-05-15 involved a Cessna F150L, registration CS-AYJ, at Comporta, PT.

What was the probable cause of the accident?

The probable cause of the engine power loss was the failure of the #3 cylinder exhaust valve, leading to asymmetric engine operation and increased vibrations. The severity of the landing was exacerbated by inefficient energy management during the emergency approach.

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