flow and pressure conditions for fuel injection' when such injection is not accomplished in a carburetor.

[Supp. 39, 23 F. R. 7482, Sept. 26, 1958] § 4b.432 Fuel system lines and fittings. (a) Fuel lines shall be installed and supported to prevent excessive vibration and to withstand loads due to fuel pressure and due to accelerated flight conditions.

(b) Fuel lines which are connected to components of the airplane between which relative motion could exist shall incorporate provisions for flexibility.

(c) Flexible connections in fuel lines which may be under pressure and subjected to axial loading shall employ flexible hose assemblies rather than hose clamp connections.

(d) Flexible hose shall be of an approved type or shall be shown to be suitable for the particular application.

(e) Flexible hoses which might be adversely affected by exposure to high temperatures shall not be employed in locations where excessive temperatures will exist during operation or after engine shut-down.

[15 F.R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F.R. 1096, Feb. 5, 1952] S4b.433 Fuel lines and fittings in designated fire zones.

Fuel lines and fittings in all designated fire zones (see § 4b.480) shall comply with the provisions of § 4b.483.

§ 4b.434 Fuel valves.

In addition to the requirements of § 4b.482 for shut-off means, all fuel valves shall be provided with positive stops or suitable index provisions in the "on" and "off" positions and shall be supported so that loads resulting from their operation or from accelerated flight conditions are not transmitted to the lines attached to the valve.

1 Fuel injection is a special form of carburetion: the charging of air or gas with volatile carbon compounds. It is either an intermittent charging of air by discrete, metered quantities of fuel such as occurs on a Diesel cylinder or it is a continuous charging of air by fuel, the fuel flow being proportioned to the airflow through the engine. Examples of continuous injection are injections into the supercharger section of a reciprocating engine or into the combustion chambers of a turbine engine.

§ 4b.435 Fuel strainer or filter.

A fuel strainer or filter shall be provided between the fuel tank outlet and the fuel metering device of the engine. The following provisions of this section shall be complied with:

(a) If an engine-driven fuel pump is provided, the strainer or filter shall be located between the tank outlet and the engine-driven pump inlet.

(b) The fuel strainer or filter shall be accessible for drainage and cleaning, and the strainer screen shall be easily removable.

(c) The strainer of filter shall be mounted in a manner not to cause its weight to be supported by the connecting lines or by the inlet or outlet connections of the strainer itself.

(d) When strainers or filters susceptible to icing are incorporated in the fuel system, a means shall be provided to maintain automatically the fuel flow in the event ice particles accumulate and restrict flow by clogging the filter or

screen.

(e) The fuel strainer or filter shall be of adequate capacity, commensurate with operating limitations established to insure proper service and of appropriate mesh to insure proper engine operation with the fuel contaminated to a degree, with respect to particle size and density, which can be reasonably expected to occur in service. The degree of fuel filtering shall be not less than that established for the engine in accordance with Part 13 of this subchapter. [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-3, 21 F.R. 993, Feb. 11, 1956; Amdt. 4b-6, 22 F.R. 5565, July 16, 1957; Amdt. 4b-8, 23 F.R. 2591, Apr. 19, 1958]

§ 4b.436 Fuel system drains.

Drainage of the system shall be accomplished by fuel strainer drains and other drains as provided in § 4.424. The following shall apply:

(a) Drains shall discharge clear of all portions of the airplane and shall incorporate means for positive locking of the drain in the closed position, either manually or automatically.

(b) All fuel system drains shall be accessible.

(c) If drainage of the fuel strainer permits compliance with paragraphs (a) and (b) of this section, no additional drains need be provided unless it is possible for a hazardous quantity of water or

sediment to be trapped therein. (See also § 4b.483 (c).)

§ 4b.437 Fuel jettisoning system.

If the maximum take-off weight for which the airplane is certificated exceeds 105 percent of the certificated maximum landing weight, provision shall be made for the jettisoning of fuel from the maximum take-off to the maximum landing weight.

(a) The average rate of fuel jettisoning shall be 1 percent of the maximum take-off weight per minute, except that the time required to jettison the fuel need not be less than 10 minutes. Compliance with these provisions shall be shown at maximum take-off weight, with flaps and landing gear up, and in the following flight conditions:

(1) Power-off glide at a speed of 1.4

(2) Climb at the one-engine-inoperative best rate-of-climb speed with the critical engine inoperative, the remaining engine(s) at maximum continuous power.

(3) Level flight at a speed of 1.4 V11, if the results of tests in conditions specified in subparagraphs (1) and (2) of this paragraph indicate that this condition could be critical.

(b) During the flight tests prescribed in paragraph (a) of this section it shall be demonstrated that the fuel jettisoning system complies with the following provisions.

(1) The fuel jettisoning system and its operation shall be free of fire hazard.

(2) The fuel shall discharge clear of all portions of the airplane.

(3) Fuel or fumes shall not enter any portion of the airplane.

(4) The jettisoning operation shall not affect adversely the controllability of the airplane.

(c) The design of the jettisoning system shall be such that it would not be possible to jettison fuel in the tanks used for take-off and landing below the level providing 45 minutes flight at 75 percent maximum continuous power, except that it shall be permissible to jettison all fuel where an auxiliary control is provided independent of the main jettisoning control. For turbine-powered airplanes, the design of the jettisoning system shall be such that it would not be possible to jettison fuel in the tanks used for takeoff and landing below the level providing

climb from sea level to 10,000 feet and thereafter providing 45 minutes cruise at a speed for maximum range.

(d) The fuel jettisoning valve shall permit the flight personnel to close the valve during any portion of the jettisoning operation. (See4b.475 for fuel jettisoning system controls.)

(e) Unless it is demonstrated that lowering of the flaps does not adversely affect fuel jettisoning, a placard shall be provided adjacent to the jettisoning control to warn flight personnel against jettisoning fuel while the flaps are lowered. A notation to this effect shall also be included in the Airplane Flight Manual. (See § 4b.740.)

(f) The design of the fuel jettisoning system shall be such that any reasonably probable single malfunction in the sys-tem will not result in a hazardous condition due to unsymmetrical jettisoning or inability to jettison fuel.

[15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1096, Feb. 5, 1952; Amdt. 4b-3, 21 F.R. 994, Feb. 11, 1956; Amdt. 4b-6, 22 F.R. 5565, July 16, 1957]

§ 4b.437-1 Test procedure for fuel jettisoning (FAA policies which apply to § 4b.437).

(a) Preliminary tests. In the case where the maximum take-off weight exceeds 105 percent of the maximum landing weight, provisions should be available for jettisoning fuel from the maximum takeoff weight to the maximum landing weight at the corresponding altitude range of airports for which certification is sought. If the applicant has made sufficient jettisoning tests 10 prove the safety of the jettisoning system, the tests may be made with fuel only. Otherwise, preliminary tests should be made with noninflammable fluid first and the results then checked using fuel. The following procedures and methods should be observed for demonstrating the operation of the fuel jettisoning system:

(1) Fire hazard.

to

(i) Fuel in liquid

or vapor form should not impinge upon any external surface of the airplane during or after jettisoning. Colored fuel,

10 The basic purpose of these tests is to determine that the required amount of fuel may be safely jettisoned under reasonably anticipated operating conditions within the prescribed time limit without danger from fire, explosion, or adverse effects on the flying qualities.

or surfaces so treated that liquid or vaporous fuel changes the appearance of the airplane surface may be used for detection purposes. Other equivalent methods for detection may be acceptable.

(ii) Fuel in liquid or vapor form should not enter any portion of the airplane during or after jettisoning. The fuel may be detected by its scent, combustible mixture detector or by visual inspection. In supercharged aircraft the presence of liquid or vaporous fuel should be checked with the airplane unpressurized.

(iii) There should be no evidence of fuel valve leakage after it is closed.

(iv) If there is any evidence that wing flap positions, other than that used for the test may adversely affect the flow pattern, the airplane should be placarded "Fuel should not be jettisoned except when flaps are set at --"."

(v) The applicant should select for demonstration the tanks or tank combinations which are critical for demonstrating the flow rate during jettisoning.

(vi) Fuel jettisoning flow pattern should be demonstrated from all normally used tank or tank combinations on both sides of airplane whether or not both sides are symmetrical.

(vii) Fuel jettisoning rate may be demonstrated from only one side of symmetrical tank or tank combinations which are critical for flow rate.

(viii) Fuel jettisoning rate and flow pattern should be demonstrated when jettisoning from full tanks using fuel.

(2) Control. (1) Changes in the airplane control qualities during the fuel jettisoning tests should be noted.

(ii) Discontinuance of fuel jettisoning should be demonstrated in flight.

(3) Residual fuel. The residual fuel should be measured by draining the tanks from which fuel has been jettisoned in flight, measuring the total drained fuel and subtracting from the total the unusable fuel quantity for each tank to determine if there is sufficient reserve fuel after jettisoning to meet § 4b.437. This may be a ground test.

(b) Configuration. Fuel jettisoning tests should be conducted in the configurations that follow:

(1) Glide.

Weight-Maximum take-off.

C. G. position-Optional.

Wing flaps-Retracted or in a position desired for approval.

(c) Test procedure and required data. When the airplane is trimmed in the configuration specified in paragraph (b) (1) and (2) of this section, the jettisoning valves should be opened and allowed to remain open until all jettisoning liquid has been disposed. If the configuration of paragraph (b) (3) of this section is critical, tests should also be conducted for this condition. This procedure may be carried out in segments if desired. The following data should be recorded: Time to jettison fuel.

Fuel gauge quantity at reasonable time intervals.

of the airplane under critical operating conditions times the approved maximum permissible oil consumption rate of the engine under the same conditions, plus a suitable margin to assure system circulation. In lieu of a rational analysis of airplane range for reciprocating engines, a fuel-oil ratio of 30:1 by volume shall be acceptable for airplanes not provided with a reserve or transfer system.

(c) If either an oil transfer system or a reserve oil system is provided for reciprocating engines, the total oil capacity need not exceed one gallon for each 40 gallons of fuel capacity.

(d) Oil-fuel ratios lower than those prescribed in paragraphs (b) and (c) of this section shall be acceptable if substantiated by data on the actual oil consumption of the engine.

(e) The ability of the oil cooling provisions to maintain the oil inlet temperature to the engine at or below the maximum established value shall be demonstrated in accordance with pertinent provisions of §§ 4b.450 through 4b.454.

[15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1096, Feb. 5, 1952; 17 F.R. 1334, Feb. 12, 1952; Amdt. 4b-6, 22 F.R. 5565, July 16, 1957]

§ 4b.440-1 Procedure for demonstrating oil cooling (FAA policies which apply to § 4b.440(e)).

Procedures for conducting cooling tests are those outlined in §§ 4b.452-1 and 4b.453-1.

[Supp. 24, 19 F. R. 4464, July 20, 1954] § 4b.441

Oil tank construction.

The following requirements shall apply to the construction of the oil tank.

(a) Oil tank expansion space. (1) Oil tanks shall have an expansion space of not less than either 10 percent of the tank capacity or 0.5 gallon, whichever is the greater.

(2) Reserve oil tanks which have no direct connection to any engine shall have an expansion space which is not less than 2 percent of the tank capacity.

(3) It shall not be possible to fill the oil tank expansion space inadvertently when the airplane is in the normal ground attitude.

shall discharge clear of all portions of the airplane.

(2) The oil tank filler cap shall provide an oil-tight seal.

(3) Oil tank filler connections shall be marked as prescribed in § 4b.738 (b).

(c) Oil tank vent. (1) Oil tanks shall be vented from the top portion of the expansion space in such a manner that venting of the tank is effective under all normal flight conditions.

(2) Oil tank vents shall be arranged so that condensation of water vapor which might freeze and obstruct the line cannot accumulate at any point. (See also § 4b.483 (c).)

(d) Oil tank outlet. Provision shall be made either to prevent entrance into the tank itself or into the tank outlet of any foreign object which might obstruct the flow of oil through the system. The oil tank outlet shall not be enclosed by any screen or guard which would reduce the flow of oil below a safe value at any operating temperature condition.

(e) Flexible oil tank liners. Flexible oil tank liners shall be of an approved type or shall be shown to be suitable for the particular application.

[15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1096, Feb. 5, 1952] § 4b.442

Oil tank tests.

The oil tank installation shall comply with the provisions of § 4b.422, except that the location of an engine oil tank in a designated fire zone shall be acceptable if the tank and its supports are of fireproof construction to the extent that damage by fire to any nonfireproof parts would not result in leakage or spillage of oil.

[Amdt. 4b-6, 17 F. R. 1096, Feb. 5, 1952] § 4b.444 Oil lines and fittings.

(a) General. The provisions of § 4b.432 shall be applicable to oil lines.

(b) Lines and fittings in designated fire zones. Oil lines and fittings in all designated fire zones (see § 4b.480) shall comply with the provisions of § 4b.483.

(c) Engine breather lines. (1) Engine breather lines shall be arranged so that condensation of water vapor which might freeze and obstruct the line cannot accumulate at any point.

(2) Breathers shall discharge in a location which will not constitute a fire hazard in case foaming occurs and in a manner so that the emitted oil will not impinge upon the pilot windshield.

(3) The breather shall not discharge into the engine air induction system. (See also § 4b.483 (c).)

§ 4b.445 Oil valves.

(a) The requirements of § 4b.482 for shut-off means shall be complied with. Closing of oil shut-off means shall not prevent feathering the propeller.

(b) All oil valves shall be provided with positive stops or suitable index provisions in the "on" and "off" positions, and they shall be supported so that loads resulting from their operation or from accelerated flight conditions are not transmitted to the lines attached to the valve.

§ 4b.449

Propeller feathering system.

(a) If the propeller feathering system is dependent upon the use of the engine oil supply, provision shall be made to trap a quantity of oil in the tank in case the supply becomes depleted due to failure of any portion of the lubricating system other than the tank itself.

(b) The quantity of trapped oil shall be sufficient to accomplish the feathering operation and shall be available only to the feathering pump.

(c) The ability of the system to accomplish feathering with the trapped supply of oil shall be demonstrated. It shall be acceptable to make this demonstration on the ground.

§ 4b.449-1 Procedure for demonstrating propeller feathering (FAA policies which apply to § 4b.449).

Tests should be conducted to demonstrate that the oil reserve for propeller feathering is adequate to accomplish the feathering procedure. This may be done on the ground by using an auxiliary source of oil for lubricating the engine during its operation.

[Supp. 24, 19 F. R. 4464, July 20, 1954] COOLING SYSTEM General.

§ 4b.450

The powerplant cooling provisions shall be capable of maintaining the temperatures of major powerplant components, engine fluids, and the carburetor intake air within the established safe values under all conditions of ground and flight operation. (For cooling system instruments see §§ 4b.604 and 4b.734.)

§ 4b.450-1

Cooling with reverse thrust (FAA policies which apply to § 4b.450).

The policies outlined in § 4b.402-1(j) will apply.

[Supp. 25, 20 F. R. 2280, Apr. 8, 1955]

§ 4b.451 Cooling tests.

(a) General. Compliance with the provisions of § 4b.450 shall be demonstrated under critical ground, water, and flight operating conditions. If the tests are conducted under conditions which deviate from the maximum anticipated air temperature (see paragraph (b) of this section), the recorded powerplant temperatures shall be corrected in accordance with the provisions of paragraphs (c) and (d) of this sec