JS1 / KC135 airprox – important information
All glider pilots who fly cross-country should read this news item which includes a link to the UK Airprox Board’s report.
On the 8th Apr 2025 at 4nm west of Ely in East Anglia, a JS1 and a KC135 (an airline sized tanker aircraft) that were flying in class G airspace passed within 50′ of each other.
In assessing the effectiveness of the safety barriers associated with this incident, the UK airprox board concluded that the key factors had been:
Flight Tactical Planning and Execution was assessed as ineffective because, given the location that the JS1 pilot was operating in, it would have been prudent to have relayed their intentions to the Mildenhall controller.
Situational Awareness of the Conflicting Aircraft and Action were assessed as ineffective because the JS1 pilot had no situational awareness of the position of the KC135 and the pilot of the KC135 had had only generic situational awareness of the presence of the glider from the Traffic Information passed to them by the Mildenhall controller.
Electronic Warning System Operation and Compliance were assessed as ineffective because the EC device fitted to the JS1 would not have been expected to have detected the KC135. Additionally, the TCAS fitted to the KC135 had been unable to detect either the EC device or the non-operative transponder equipment in the JS1.
See and Avoid were assessed as ineffective because the KC135 pilot had not seen the JS1 and the JS1 pilot had not seen the KC135.
You can read the UKAB report here.
