EGLIN AFB – The 33rd Fighter Wing is winding down its F-35 Lightning II fighter jet maintenance training for Turkish students as Turkey, a longtime NATO ally, pursues the purchase of a Russian-made surface-to-air missile system.

According to U.S. defense officials, procuring the Russian S-400 missile system while also operating the F-35 would mean that Turkey could gain insights into how the missile system tracks the fifth-generation stealth fighter jet.  

"The S-400 is incompatible with the F-35," Under Secretary of Defense Ellen M. Lord said in a recent news briefing on a letter from Acting Secretary of Defense Patrick Shanahan to Turkish Defense Minister Hulusi Akar. The letter notified Akar that if the Turkish government continues to work to acquire the S-400, U.S. training of Turkish personnel on piloting and maintaining the F-35 will stop by July 31.

"As we have very clearly communicated at all levels, Turkey will not receive the F-35 if Turkey takes delivery of the S-400 system," Lord told reporters.

Also in the Department of Defense news briefing, Lord told reporters that the U.S. has learned that Turkey has already sent personnel to Russia for training on the S-400 system.

While defense officials indicated that the decision to halt F-35 training could be reversed if Turkey halts its pursuit of the Russian missile system, Lord said in the news briefing that for the immediate future, "we need to begin unwinding Turkey's participation in the F-35 program."

While Eglin Air Force Base does train F-35 pilots, it does not train Turkish student pilots, said Lt. Savannah Stephens, public affairs officer for the 33rd Fighter Wing. All Turkish F-35 pilots are trained at Luke Air Force Baes, where Brig. Gen. Todd Canterbury, commander of the 56th Fighter Wing, already has halted training of Turkish personnel.

At Eglin, maintenance training is limited to the jet's engine, and that training is done on mock-ups and on computers, according to Stephens.

"They're not actually touching an F-35," said Stephens, who added that there is no classified component to any of the work done by the Turkish maintenance students.

The current round of F-35 maintenance training at Eglin already was scheduled to end a few days before the July 31 deadline, Stephens said, and the Turkish leadership team on the base is slated to leave July 29.

In all, there are 12 Turkish students and leaders involved in the maintenance training, Stephens said. According to a report in Defense News, there is a total of 42 pilot and maintenance trainees at Eglin and Luke.

Beyond getting the Turkish maintenance and pilot trainees out of the F-35 program, U.S. defense officials also are working out what to do with the four F-35s already purchased by Turkey that are now at Luke, according to information from the news conference. Also, two major contractors in the F-35 program, Lockheed Martin and Pratt & Whitney, are searching for alternate sources for the more than 900 parts produced for the F-35 by Turkish industries.