Friendly Fire in Ukraine - How Can a Patriot Shoot Down an F-16?

Aren’t there guardrails in place to ensure this doesn’t happen? Like Identification Friend or Foe (IFF) Interrogators?

A US Air Force F-16 Fighting Falcon “Triple Nickel” aircraft assigned to the 555th Expeditionary Fighter Squadron from Aviano Air Base, Italy, takes off from Bagram Air Field, Afghanistan, June 21, 2015. (U.S. Air Force photo by Tech. Sgt. Joseph Swafford/Released) Public domain

Last week, a Ukrainian F-16 fighter jet crashed during a Russian missile att…