June 26 (Bloomberg) -- The U.S. Air Force today grounded its fleet of F-35 fighter jets made by Lockheed Martin Corp. as a safety precaution after a fire on one of the planes forced an aborted takeoff.
The temporary suspension of flight operations applies to the Air Force’s 45 “A model” planes. The Defense Department didn’t direct a halt to tests of the Marine Corps and Navy versions of the jet, known as the Joint Strike Fighter.
The grounding was the latest setback for the F-35, the costliest U.S. weapons system, which is being built even as it’s still being developed. The order was issued after an emergency at Eglin Air Force Base in Florida on June 23, when a fire in the rear of one plane forced the pilot to abort a takeoff.
“As a precautionary measure, the Air Force has decided to temporarily suspend all F-35A operations until it is determined that flights can resume safely,” the Air Force said in a statement. “This is not an uncommon practice following a mishap. It ensures the safety of our crews and our aircraft so we can determine there is no fleet-wide issue that needs to be addressed.”
The cause of the Eglin incident remains under investigation, Army Colonel Steve Warren, a Pentagon spokesman, told reporters today.
The Marine Corps hasn’t flown its 31 F-35s for the last two days and is assessing whether to suspend flight operations on a daily basis, said Captain Richard Ulsh, a Marine Corps spokesman. The Navy is still assessing whether to issue a service-wide suspension, although some of its planes have been temporarily grounded, said Lieutenant Jackie Pau, a Navy spokeswoman.
The F-35 has been plagued by a costly redesign, bulkhead cracks, excessive weight and delays in software. Building all 2,443 planes is projected to cost $398.6 billion, a 71 percent increase in inflation-adjusted dollars since the contract with Lockheed, the largest U.S. defense contractor, was signed in 2001.
The Air Force’s F-35s are at four bases: Luke Air Force Base in Arizona, Nellis Air Force Base in Nevada, Edwards Air Force Base in California, and Eglin, said Major Natasha Waggoner, an Air Force spokeswoman.
Lockheed will assist in any investigation of the fire at Eglin, said Gordon Johndroe, a spokesman for the Bethesda, Maryland-based company. He referred any further comments to the Air Force.
Two weeks ago, the Pentagon ordered that all F-35 engines must be inspected before the planes could resume flying. That order, issued June 13, came in response to an “in-flight emergency” on June 10, when a Marine Corps F-35 had to return to base at Air Station Yuma, Arizona, after its engine lost oil. There were no injuries. Inspections of three other planes at the station revealed “suspect findings,” the Defense Department said in a statement.
Last year, the Pentagon grounded all F-35s after a routine engine inspection revealed a crack on a turbine blade in a test aircraft at Edwards Air Force Base. Flights resumed about a week later after further inspections found no other problems.
While defense officials have cited progress for the F-35, Frank Kendall, the Pentagon’s top weapons buyer, has said it hasn’t yet demonstrated sufficient reliability improvements. There’s “some marginal evidence of improvement, but it’s not enough,” Kendall told reporters June 12.