The US Defence Secretary Jim Mattis is weighing a Navy request to delay for at least six years the shock testing intended to determine how well its new $12.9 billion aircraft carrier, USS Gerald R. Ford, could withstand attack.

Despite the warnings of Pentagon’s testing office that the USS Gerald R. Ford shouldn’t be deployed for initial combat duty until it’s gone through the tests, which involve setting off underwater charges to check the resilience of a ship’s key systems, the US Navy wants to deploy the carrier as soon as possible.

In its proposed budget for fiscal 2019, the Navy removed funding for the test, which had been scheduled to start late next year. The Ford is now scheduled to be ready for initial combat duty in 2022. The service wants to put off the shock testing and do it on the second carrier in the new class, the USS John F. Kennedy, which is scheduled for delivery in September 2024.