Air Canada co-pilot falls ill during flight

[PJ2]

India Four Two;

Thanks, that settles it I think - no mask required in this circumstance.

Decades ago, we were required to don an Ox mask when the other crew member momentarily left the cockpit. That requirement was discontinued and the only requirement now is when operating above 410; - the P1, (pilot flying) is required to wear the mask. This all assumes quick-donning equipment.