What aircraft was involved and where did it happen?

The accident on 2022-03-18 involved a Europa XS, registration G-CHAH, at Welshpool Airport, Powys, GB.

What was the probable cause of the accident?

The engine power loss was caused by an air leak in the induction system resulting from a displaced O-ring seal.

Engine power loss leads to runway excursion in Europa XS

A private flight in a Europa XS experienced a sudden loss of engine power during takeoff at Welshpool Airport, resulting in aircraft damage.

What happened

On 18 March 2022, a Europa XS, registration G-CHAH, was performing a private flight from Welshpool Airport in Powys. Shortly after takeoff, while the aircraft was at approximately 60 feet altitude and 60 knots, the engine experienced a significant loss of power. At the moment of the failure, the pilot was in the process of retracting the flaps and landing gear.

Despite the power loss, the engine continued to run with noticeable roughness. The pilot responded by pushing the nose down and closing the throttle to prevent any unexpected acceleration or climb should the engine have recovered. The aircraft subsequently landed on the remaining portion of the runway. During the landing, the partially retracted main wheel was forced into its well, and the aircraft came to a halt on the right side of the runway. The incident resulted in no injuries to the pilot, though the aircraft sustained damage to the propeller, the engine cowl, and the right wingtip.

The investigation

Investigators examined the Jabiru 3300A piston engine to determine the cause of the power loss. The inspection of the induction system revealed that one of the four O-ring seals, which secures the induction pipes to the plenum chamber, had become displaced. This displacement prevented the system from maintaining an airtight seal.

Engineers noted that the induction system relies on these O-rings and gasket sealant to function correctly. The investigation considered that the displacement might have been caused by the shrinkage or movement of a neoprene flexible joint over time. Furthermore, the maintenance organization involved noted that while the assembly method follows the manual, the instructions can be prone to misinterpretation, leading to similar issues in other Jabiru engines.

Findings

The primary cause of the power loss was a displaced O-ring seal within the induction system.
This displacement allowed air to leak into the induction system, which disrupted the necessary fuel-air ratio for stable engine operation.
The pilot's decision to close the throttle and land on the runway prevented a more serious outcome by mitigating the risk of an unexpected climb or re-acceleration.
The maintenance organization is developing illustrated guidance for owners to prevent assembly errors.