Use of oxygen when one pilot is on break

[FDMII]

CanadianAirbusPilot;

http://www.pprune.org/tech-log/57233...ml#post9220664
"Never heard of that in Canada"

One carrier in Canada used to require it when one pilot left the FD. That same carrier now requires both pilots to wear O2 masks when above FL410 and the masks are the quick-donning type.