In-Flight Observation of Gamma Ray Glows by ILDAS

An Airbus A340 aircraft flew over Northern Australia with the In-Flight Lightning Damage Assessment System (ILDAS) installed onboard. A long-duration gamma ray emission was detected. The most intense emission was observed at 12km altitude and lasted for 20s. Its intensity was 20 times the background counts, and it was abruptly terminated by a distant lightning flash. In this work we reconstruct the aircraft path and event timeline. The glow-terminating flash triggered a discharge from the aircraft wing that was recorded by a video camera operating onboard. Another count rate increase was observed 6min later and lasted for 30s. The lightning activity as reported by ground networks in this region was analyzed. The measured spectra characteristics of the emission were estimated.