[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR33.67]

[Page 745-746]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES--Table of Contents
 
      Subpart E--Design and Construction; Turbine Aircraft Engines
 
Sec. 33.67  Fuel system.

    (a) With fuel supplied to the engine at the flow and pressure 
specified by the applicant, the engine must function properly under each 
operating condition required by this part. Each fuel control adjusting 
means that may not be manipulated while the fuel control device is 
mounted on the engine must be secured by a locking device and sealed, or 
otherwise be inaccessible. All other fuel control adjusting means must 
be accessible and marked to indicate the function of the adjustment 
unless the function is obvious.
    (b) There must be a fuel strainer or filter between the engine fuel 
inlet opening and the inlet of either the fuel metering device or the 
engine-driven positive displacement pump whichever is nearer the engine 
fuel inlet. In addition, the following provisions apply to each strainer 
or filter required by this paragraph (b):
    (1) It must be accessible for draining and cleaning and must 
incorporate a screen or element that is easily removable.
    (2) It must have a sediment trap and drain except that it need not 
have a drain if the strainer or filter is easily removable for drain 
purposes.
    (3) It must be mounted so that its weight is not supported by the 
connecting lines or by the inlet or outlet connections of the strainer 
or filter, unless adequate strength margins under all loading conditions 
are provided in the lines and connections.
    (4) It must have the type and degree of fuel filtering specified as 
necessary

[[Page 746]]

for protection of the engine fuel system against foreign particles in 
the fuel. The applicant must show:
    (i) That foreign particles passing through the specified filtering 
means do not impair the engine fuel system functioning; and
    (ii) That the fuel system is capable of sustained operation 
throughout its flow and pressure range with the fuel initially saturated 
with water at 80  deg.F (27  deg.C) and having 0.025 fluid ounces per 
gallon (0.20 milliliters per liter) of free water added and cooled to 
the most critical condition for icing likely to be encountered in 
operation. However, this requirement may be met by demonstrating the 
effectiveness of specified approved fuel anti-icing additives, or that 
the fuel system incorporates a fuel heater which maintains the fuel 
temperature at the fuel strainer or fuel inlet above 32  deg.F (0 
deg.C) under the most critical conditions.
    (5) The applicant must demonstrate that the filtering means has the 
capacity (with respect to engine operating limitations) to ensure that 
the engine will continue to operate within approved limits, with fuel 
contaminated to the maximum degree of particle size and density likely 
to be encountered in service. Operation under these conditions must be 
demonstrated for a period acceptable to the Administrator, beginning 
when indication of impending filter blockage is first given by either:
    (i) Existing engine instrumentation; or
    (ii) Additional means incorporated into the engine fuel system.
    (6) Any strainer or filter bypass must be designed and constructed 
so that the release of collected contaminants is minimized by 
appropriate location of the bypass to ensure that collected contaminants 
are not in the bypass flow path.
    (c) If provided as part of the engine, the applicant must show for 
each fluid injection (other than fuel) system and its controls that the 
flow of the injected fluid is adequately controlled.
    (d) Engines having a 30-second OEI rating must incorporate means for 
automatic availability and automatic control of a 30-second OEI power.

[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR 
6851, Feb. 23, 1984; Amdt. 33-18, 61 FR 31328, June 19, 1996]