[Code of Federal Regulations]
[Title 14, Volume 2]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR135.89]

[Page 662]
 
                     TITLE 14--AERONAUTICSAND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION 
                               (CONTINUED)
 
PART 135--OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS 
AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT--Table of Contents
 
                      Subpart B--Flight Operations
 
Sec. 135.89  Pilot requirements: Use of oxygen.

    (a) Unpressurized aircraft. Each pilot of an unpressurized aircraft 
shall use oxygen continuously when flying--
    (1) At altitudes above 10,000 feet through 12,000 feet MSL for that 
part of the flight at those altitudes that is of more than 30 minutes 
duration; and
    (2) Above 12,000 feet MSL.
    (b) Pressurized aircraft. (1) Whenever a pressurized aircraft is 
operated with the cabin pressure altitude more than 10,000 feet MSL, 
each pilot shall comply with paragraph (a) of this section.
    (2) Whenever a pressurized aircraft is operated at altitudes above 
25,000 feet through 35,000 feet MSL, unless each pilot has an approved 
quick-donning type oxygen mask--
    (i) At least one pilot at the controls shall wear, secured and 
sealed, an oxygen mask that either supplies oxygen at all times or 
automatically supplies oxygen whenever the cabin pressure altitude 
exceeds 12,000 feet MSL; and
    (ii) During that flight, each other pilot on flight deck duty shall 
have an oxygen mask, connected to an oxygen supply, located so as to 
allow immediate placing of the mask on the pilot's face sealed and 
secured for use.
    (3) Whenever a pressurized aircraft is operated at altitudes above 
35,000 feet MSL, at least one pilot at the controls shall wear, secured 
and sealed, an oxygen mask required by paragraph (b)(2)(i) of this 
section.
    (4) If one pilot leaves a pilot duty station of an aircraft when 
operating at altitudes above 25,000 feet MSL, the remaining pilot at the 
controls shall put on and use an approved oxygen mask until the other 
pilot returns to the pilot duty station of the aircraft.