Iranian electronic warfare specialists were able to cut off communications links of the American bat-wing RQ-170 Sentinel, says the engineer, who works for one of many Iranian military and civilian teams currently trying to unravel the drone’s stealth and intelligence secrets, and who could not be named for his safety.

Using knowledge gleaned from previous downed American drones and a technique proudly claimed by Iranian commanders in September, the Iranian specialists then reconfigured the drone’s GPS coordinates to make it land in Iran at what the drone thought was its actual home base in Afghanistan.

“The GPS navigation is the weakest point,” the Iranian engineer told the Monitor, giving the most detailed description yet published of Iran’s “electronic ambush” of the highly classified US drone. “By putting noise [jamming] on the communications, you force the bird into autopilot. This is where the bird loses its brain.”