An F-35A Joint Strike Fighter preparing for a training mission at Mountain Home Air Force Base, Idaho, caught fire just before takeoff, according to the Air Force.

The Air Force F-35A Lightning II, assigned to the 56th Fighter Wing, experienced what the service said was a “ground emergency” at about 12:20 p.m. eastern Friday at the base, according to a statement.

“The pilot had to egress the aircraft during engine start due to a fire from the aft section of the aircraft,” the statement said.  The fire was extinguished quickly, the service said. The pilot is assigned to the 61st Fighter Squadron at Luke Air Force Base in Arizona.

Officials said as a precaution, the pilot, four 61st Aircraft Maintenance unit airmen, also from Luke, and three airmen from the 366th Maintenance Group from Mountain Home were transported to the base medical center “for evaluation and have since been released.”

Seven of the stealthy fifth-generation fighters have been at Mountain Home since Sept. 10 to use the base’s range for surface-to-air training, the statement said.

The Air Force said the cause of fire is under investigation.

In 2014, U.S. military services stopped flights of the Lockheed Martin Corp.-manufactured fighter jet after one of the aircraft caught fire during takeoff.

Last week, the Air Force ordered a temporary stand-down of 13 out of 104 F-35s in the fleet “due to the discovery of peeling and crumbling insulation in avionics cooling lines inside the fuel tanks,” according to a statement at the time.

Two additional aircraft, belonging to Norway and currently stationed at Luke Air Force Base, Arizona, have also been affected.

The service at the Air Force Association’s annual Air Space & Cyber Conference said it would soon begin additional repairson the grounded F-35s, but did not give an elaborate timeline.