Smoke: Mask 100% or EMER?
I'm in ground school (again) for the B737, and brought this up to my instructor today:
"Why does the memory item for smoke/fumes say Oxygen Mask . . . On/100% and not On/EMER"?
Having talked to an engineer from Avox/Scott years ago I came away with the impression that the 100% is meant as 100% O2 at 100% pressure (EMER), not simply 100% O2 content.
The engineer explained that the pressure in the mask helps to seal the mask and provide a positive pressure to keep irritants out.
We're got the EROS masks in our 737s, but I'd imagine the concept is the same.
Thoughts?