Oil Leak on One Plane Leads to Inspection of 104-Jet Fleet
By DOUG CAMERON
The Pentagon temporarily grounded the entire F-35 Joint Strike Fighter fleet at the start of the weekend after one of the advanced jets suffered an engine oil leak and declared an in-flight emergency.
While the suspension of flight and ground testing on Friday was described by F-35 program officials as a precautionary move, it is the second time in 16 months that engine problems have grounded the entire fleet. It comes just two weeks before the plane is due to make its first international appearance.
Engine maker Pratt Whitney, a unit of United Technologies Corp. UTX -0.01% , said most of the 104-jet fleet had been cleared to resume flying by late Saturday following the safety inspections mandated by the F-35 managers on Friday. The F-35 program office said these revealed potential problems on two more jets.
The incident on June 10 involved an F-35B jet, which can take off and land vertically. The pilot declared an in-flight emergency after being alerted to an engine oil problem, and landed safely back at base at Marine Corps Air Station Yuma in Arizona.
Pentagon officials on Friday ordered engines on all three models of the F-35 to be inspected before they could resume flights.
Pratt Whitney said in a statement that it was working to identify the cause of last week’s problem, with jet-by-jet inspections taking around 90 minutes each. Program officials have pointed to problems with an oil-flow-management valve.
The F-35B is one of three variants of the jet built by Lockheed Martin Corp. LMT +0.38% , and scheduled to be the first to be declared combat ready. Program officials last week expressed confidence that it will be ready for the Marine Corps as scheduled in July 2015.
The F-35B is expected to make its international debut on July 4 in a fly-past at the naming ceremony for the British Royal Navy’s new aircraft carrier at a dockyard in Scotland. It is also scheduled to perform at two military air shows in the U.K. later in July. A spokesman for the F-35 program office said the jet is still expected to appear at the air shows.