The use of the O2 mask above
FL250 when a pilot leaves his/her station has changed. Effective immediately, pilots are not required to don an O2 mask on our aircraft when one pilot leaves his/her station and the aircraft is at or below
FL410. However, the regulation still requires one pilot to always wear an O2 mask whenever operating above
FL410. See 14CFR,121.333(c)(2)(i)(A).