Turkey may have used its S-400s to detect U.S.-made F-16 fighter jets returning from the Eunomia exercise held in August.
The Trump administration should impose new economic sanctions on Turkey buying and activating Russian S-400 Triumf air defense systems: this is the opinion of a bipartisan pair of U.S. senators concerned that Turkey is allowing Russia access to sensitive data on NATO aircraft.
As reported by Air Force Magazine, Senate appropriators Chris Van Hollen (D-Md.) and Sen. James Lankford (R-Okla.) raised concerns in a Oct. 7 letter to Secretary of State Michael R. Pompeo that Turkey may have used its S-400s “to detect U.S.-made F-16 fighter jets returning from the Eunomia exercise” held in August.
According to the lawmakers the drill was a “response to Turkey’s unwarranted aggression in the Eastern Mediterranean,” and involved Cyprus, France, Greece, and Italy. Turkey had sent oil exploration vessels into disputed areas around Cyprus.
If the S-400 missile system (the delivery of which began in July 2019) was used to surveil American F-16s, it would be one of the first publicized instances that Turkey has wielded the air defense system’s radar against a U.S. asset.
“Last year, Turkish F-16 jets flew over Ankara as a part of a test of the S-400, which administration officials have indicated could allow Russia a backdoor to spy on NATO allies,” wrote the senators, who both serve on the powerful Senate Appropriations Committee. “Turkey’s recent activation of the S-400 system to detect the U.S. F-16 underscores our grave concerns about Russia’s ability to access sensitive data.”
A “sense of Congress” act in 2019 demanded that President Donald J. Trump enforce Countering America’s Adversaries Through Sanctions Act (CAATSA) sanctions on Turkey, but the administration has not complied. According to Air Force Magazine, Van Hollen has warned that Congress will take action if the executive branch does not.

A press release accompanying the letter said Trump’s delays “would further endanger the security of NATO operations.”
The Trump administration decided to kick Turkey out of the F-35 program in July 2019. White House press secretary Stephanie Grisham then said, in a statement that the country’s involvement in the program had become “impossible.”
“Unfortunately, Turkey’s decision to purchase Russian S-400 air defense systems renders its continued involvement with the F-35 impossible. The F-35 cannot coexist with a Russian intelligence collection platform that will be used to learn about its advanced capabilities. The United States has been actively working with Turkey to provide air defense solutions to meet its legitimate air defense needs, and this Administration has made multiple offers to move Turkey to the front of the line to receive the U.S. PATRIOT air defense system. Turkey has been a longstanding and trusted partner and NATO Ally for over 65 years, but accepting the S-400 undermines the commitments all NATO Allies made to each other to move away from Russian systems. This will have detrimental impacts on Turkish interoperability with the Alliance.”
However the statement continued by saying that “The United States still greatly values our strategic relationship with Turkey. As NATO Allies, our relationship is multi-layered, and not solely focused on the F-35. Our military-to-military relationship is strong, and we will continue to cooperate with Turkey extensively, mindful of constraints due to the presence of the S-400 system in Turkey.”

Photo credit: Ministry of Defence of the Russian Federation, U.S. Air Force and Vitaly V. Kuzmin via Wikipedia