Engine failure leads to forced landing on Tory Island

Casualties unknown • IE

A microlight aircraft experienced an uncommanded engine shutdown over Tory Island, resulting in a forced landing on rough terrain and substantial aircraft damage.

What happened

On 9 May 2016, a CFM Streak Shadow, registration G-BVTD, was conducting a private flight from Finn Valley Airfield toward Tory Island, Co. Donegal. After flying approximately 40 minutes and performing several orbits near a lighthouse at 1,200 feet, the aircraft's engine suddenly lost power and cut out. The pilot, who was the sole occupant, attempted to restart the engine three times using the pull cord but was unsuccessful.

Unable to maintain altitude, the pilot sought a landing site. Due to the rocky terrain, the pilot attempted to land on a road leading to the lighthouse. After an unsuccessful attempt to land in one direction, the pilot turned the aircraft to approach the road from the opposite direction. However, there was insufficient height to reach the pavement, and the aircraft landed on rough ground east of the roadway. The impact caused substantial damage to the aircraft, including the separation of the undercarriage and damage to the wings and fuel tanks. The pilot sustained minor injuries but was able to exit the aircraft without assistance.

The investigation

Investigators examined the aircraft's fuel system and the fuel used during the flight. The aircraft utilized a two-tank system, including a composite "slipper" tank. Laboratory analysis of the fuel used—unleaded automotive petrol (Mogas)—revealed an ethanol content of approximately 5.5%, which slightly exceeded the 5% limit specified by EN228 standards.

Upon inspecting the fuel tanks, investigators found significant deterioration and flaking of the internal coating within the lower slipper tank. The investigation focused on the interaction between the ethanol-blended fuel and the composite materials used in the tank's construction.

Findings

  • The engine shutdown was caused by fuel starvation.
  • This starvation was triggered by fragments of detached internal tank coating blocking the fuel flow.
  • The coating failure was due to sub-optimal adhesion between the epoxy and phenoxy resin layers.
  • The presence of ethanol in the Mogas likely contributed to the degradation of the composite fuel tank's internal coating materials.

Probable cause

The engine failure was caused by fuel starvation resulting from debris from the internal fuel tank coating obstructing the fuel flow, a process exacerbated by the effects of ethanol on the composite tank's lining.

Frequently asked questions

What happened in the null aircraft accident near IE?

A microlight aircraft experienced an uncommanded engine shutdown over Tory Island, resulting in a forced landing on rough terrain and substantial aircraft damage.

What aircraft was involved and where did it happen?

The accident on null involved a aircraft, registration G-BVTD, at IE.

What was the probable cause of the accident?

The engine failure was caused by fuel starvation resulting from debris from the internal fuel tank coating obstructing the fuel flow, a process exacerbated by the effects of ethanol on the composite tank's lining.

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