[Code of Federal Regulations]

[Title 14, Volume 1]

[Revised as of January 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 14CFR33.67]



[Page 778-779]

 

                     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 779]]



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]