FYI
NTSB Special Investigation Report
Wing Failure of Boeing 747-131
Near Madrid, Spain
May 9, 1976
http://libraryonline.erau.edu/online...s/AAR78-12.pdf
On May 9, 1976, an Imperial Iranian Air Force Boeing 747-131 crashed as it approached Madrid, Spain. Witnesses observed lightning strike the aircraft followed by fire, explosion, and separation of the left wing. The report includes fire pattern studies, structural failure descriptions, trajectory analysis, fuel flammability calculations, gust loading analysis, and an analytical treatment of several hypotheses.