Cessna says it understands the "root cause" of a problem that has caused a small number of Corvalis 400 piston singles to be grounded after a fuel leak was discovered in the wing tank of a new aircraft during a post-production flight.

"Working closely with the Federal Aviation Administration, we took immediate steps to understand the root cause," says Cessna in a statement. "We now fully understand the cause and have a solution."

For its part, the FAA issued an emergency airworthiness directive on 10 December, effectively grounding eight aircraft. The agency said the aircraft in question "suffered a significant structural failure", which included a disbonding of a 2.1m (7ft) section of wing skin from the upper forward wing spar. The failure could result "in a catastrophic failure of the wing," says the FAA, adding that it may take "additional AD action as necessary".

Cessna has not provided details on the nature of the fix, or whether the composite components were produced at its facilities in Chihuahua, Mexico. The company last year closed the Corvalis production facility in Bend, Oregon, moving the construction of the wings and fuselage to Mexico and the final assembly to its Independence, Kansas facilities.

Cessna says the AD covers aircraft "produced beginning with serial [number] 1162 or aircraft containing parts produced in the same time frame". As such, the grounding impacts two aircraft delivered outside the company, but neither is in customer service. The other aircraft were awaiting delivery, the airframer says.

Source: Flight International