The U.S. Coast Guard is keeping its C-27J aircraft grounded as it checks on cracks found in the fuselage of 14 aircraft, the service said.

The Coast Guard first grounded its fleet of the medium range surveillance aircraft after receiving an alert on Dec. 1 about a possible issue from manufacturer Leonardo.

“The Coast Guard completed the inspections necessitated by the December 1, 2023, C-27J Alert Service Bulletin released by Leonardo Aircraft Division (LAD),” the Coast Guard told Defense News.

“During these inspections, which required operators to visually observe certain sections of the aircraft, the Coast Guard found cracks of varying degrees on all 14 of its C-27Js,” it added. “The Coast Guard will continue to keep its C-27J fleet grounded while working with Leonardo Aircraft Division to determine a path forward.”

Italy’s Leonardo has said the problem with its C-27Js was first reported by an operator of the aircraft, prompting the company to ask all users to check their fleets and recommending a specific repair if cracks were found.

“The implementation of such repair can be performed at customer premises by the Operators and does not require significant effort,” Leonardo said earlier this month.

The Australian Air Force grounded an unspecified number of its 10 C-27Js which were found to contain cracks. But now, the Air Force is flying them again, a Leonardo spokesman told Defense News.

“Other operators identified the problem but fixed it without grounding the aircraft, while others found no problems,” the spokesman said.

The U.S. Army, the Italian Air Force and the Bulgarian Air Force were among the users who did not find cracks, the spokesman added.

In a statement, Leonardo said: “Following the inspections carried out by the C-27J operators, Leonardo immediately issued a measure that allowed the fleets to return to service by prescribing periodic checks and providing repair instructions to be implemented at the first available maintenance check.”

It added, “At the same time, Leonardo is working alongside the (US) Coast Guard to provide additional instructions and requested technical information to facilitate the return to service of the US Coast Guard fleet as already accomplished by the other operators.”

Leonardo said this month that 16 users of the light tactical transport aircraft had flown 250,000 hours.

On Dec. 20, the company announced the delivery of two aircraft to the Slovenian ministry of defense, adding that it had now received 90 orders for the aircraft.