Engine associated "flash & thermal event"?
Airtours 732 at Manchester and 777 at LAX?
On ground, no airflow and no significant dynamic loading.
Luckily (for some) rapidly attended to by Fire/Rescue services.
Now try the same at 30,000ft, with the N1s and N2s at maximum, sometimes over 100% in the case of the N1s and a healthy draught to propagate the inferno and see what happens?
Just a thought from an old geezer who's read too many accident reports, in 40+ years associated with the profession with some memory chips still readable...........................
