Originally Posted by
yanrair
Thats what happened though like Papa India, the design was poor. It allowed you to fire the bottles without having fully pulled the fire handle. My memory is that it was partly pulled.
According to the accident report - the handle was never pulled. See Page 20.
"On this occasion the difference between the two drills, was in advertently obscured by the Flight Engineer, who went for, but did not pull, the fire shut-off handle whilst carrying out the Engine Overheat or Failure Drill; it appears that this not only gave him the impression that he had pulled the fire shut-off handle as part of the fire drill, but also gave the same impression to the First Officer."
BOAC had 2 similar procedures then - with the vital difference of pulling or not pulling the FCH. The crew started one procedure - then changed when they realised the fire warning. They thought the handle had been pulled - but actually it had not.
Later the two procedures were were amalgamated into one - to make it simpler.
KISS principal again.