[Code of Federal Regulations]
[Title 14, Volume 2]
[Revised as of January 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR121.227]

[Page 763]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION 
                               (CONTINUED)
 
PART 121_OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS--
 
              Subpart J_Special Airworthiness Requirements
 
Sec. 121.227  Pressure cross-feed arrangements.

    (a) Pressure cross-feed lines may not pass through parts of the 
airplane used for carrying persons or cargo unless--
    (1) There is a means to allow crewmembers to shut off the supply of 
fuel to these lines; or
    (2) The lines are enclosed in a fuel and fume-proof enclosure that 
is ventilated and drained to the exterior of the airplane.

However, such an enclosure need not be used if those lines incorporate 
no fittings on or within the personnel or cargo areas and are suitably 
routed or protected to prevent accidental damage.
    (b) Lines that can be isolated from the rest of the fuel system by 
valves at each end must incorporate provisions for relieving excessive 
pressures that may result from exposure of the isolated line to high 
temperatures.