Originally Posted by
4Greens
Beards may interfere with the use of an oxygen mask.
disproven in the university study “The efficacy of oxygen Delivery masks for Commercial Pilots with facial hair” by Sherri Ferguson SFU Canada.
Their summary; “The policy of a clean-shaven face is based on outdated research on obsolete equipment and testing on respirators not intended for aircrew oxygen delivery.”
This study tested oxygen masks from a320 and b767 so not military masks.