Unintended Flight and Forced Landing of Modified Avid Flyer

Casualties unknown • IE

An aircraft became unexpectedly airborne during a high-speed taxi test, leading to an engine failure and a heavy forced landing near Trevet Airfield.

What happened

On 2 July 2011, an Avid Flyer, registration G-BTKG, was undergoing maintenance to restore it to airworthy status. The aircraft had recently been fitted with new, larger wings. During a high-power engine run and high-speed taxi test at Trevet Airfield, the aircraft unexpectedly lifted off the runway. The pilot, who had not intended to fly the aircraft, attempted to fly a circuit to avoid landing on the runway after drifting off course. During this maneuver, the engine experienced power fluctuations and eventually lost power, necessitating a forced landing in a nearby pasture. The subsequent heavy impact caused the nose wheel to detach, the propeller to be destroyed, and the left main gear to collapse. The pilot escaped the substantial damage without injury.

The investigation

The AAIU examined the aircraft and the circumstances surrounding the flight. The investigation established that the aircraft was being prepared for a technical inspection to renew its UK Permit-to-Fly and was not currently certified for flight. The pilot's flying license had expired, and he had not flown for approximately six months. Investigators looked into the engine's performance and found no mechanical defects or fuel contamination. They also analyzed the weather conditions, noting gusty winds at the time of the incident. The investigation also considered the impact of the recent modifications, specifically the installation of larger wings, on the aircraft's aerodynamic behavior during the taxi test.

Findings

  • The installation of larger wings significantly reduced the aircraft's take-off speed.
  • The combination of high power settings during the taxi test and the increased lift from the new wings caused the aircraft to become airborne unintentionally.
  • The pilot's lack of recent flying experience and unfamiliarity with the modified aircraft's handling characteristics hindered the ability to manage the emergency.
  • Engine power fluctuations, potentially caused by carburetor icing following prolonged ground running, contributed to the forced landing.
  • The aircraft was being operated without a valid Permit-to-Fly.

Probable cause

The primary cause was the installation of larger wings which lowered the take-off speed, combined with a high-power taxi test that generated enough lift to unexpectedly lift the aircraft off the ground. This was compounded by the pilot's lack of currency and familiarity with the modified aircraft.

Frequently asked questions

What happened in the null aircraft accident near IE?

An aircraft became unexpectedly airborne during a high-speed taxi test, leading to an engine failure and a heavy forced landing near Trevet Airfield.

What aircraft was involved and where did it happen?

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

What was the probable cause of the accident?

The primary cause was the installation of larger wings which lowered the take-off speed, combined with a high-power taxi test that generated enough lift to unexpectedly lift the aircraft off the ground. This was compounded by the pilot's lack of currency and familiarity with the modified aircraft.

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