Duk da haka, wani musamman tsanani high-gudun flutter matsala da aka warware kawai ta hanyar saka depleted uranium counterweights matsayin ballast a cikin outboard engine nacelles na farkon 747s. Wannan mataki ya sa tashin hankali a lokacin da wadannan jirgin sama ya fadi, misali El Al Flight 1862 a Amsterdam a 1992 tare da 282 kilogram (622 lb) na uranium a cikin tailplane (a kwance stabilizer). The jirgin gwajin shirin da aka hampered da matsaloli tare da 747 ta JT9D injuna.
engine stalls lalacewa ta hanyar sauri throttle ƙungiyoyi da kuma karkatarwa na injin turbin casings bayan wani gajeren lokaci na sabis