Thx for replies. I am still wondering how you identify which engine bleed air to isolate when engine fumes are suspected..
If the cabin crew detect the smell before the flight deck crew (or vice versa) does that indicate the engine?
Then does that indicate which pack to shut down, or is there bleed air crossfeed upstream of the packs?
Or is it simply a matter of shutting down each pack in turn and noting any improvement?
Thank you for your patience. My questions are aimed at finding out how quickly the crew can recognise, identify, and shut off the contaminated air supply, and thereby limit their, and the passengers, exposure to the fumes.
Niallo