AIRCRAFT LANDING GEAR SYSTEMS

Exposure to and/or storage near which of the fol- lowing is considered harmful to aircraft tires?

2. Fuel. 3. Oil. 4. Ozone. 6. Electrical equipment. 7. Hydraulic fluid. 8. Solvents. C—2, 3, 4, 6, 7, 8.

The pressure source for power brakes is

A— the main hydraulic system.

If the extended longitudinal axis of the main landing gear wheel assemblies intersects aft of the aircraft, the wheels can be termed as having

A— toe-out.

To prevent a very rapid extension of an oleo shock strut after initial compression resulting from landing impact,

A— various types of valves or orifices are used which restrict the reverse fluid flow.

(Refer to Figure 10.) The trunnion nut on an aircraft landing gear requires a torque of 320 inch-pounds. To reach the nut, a 2-inch straight adapter must be used on an 18-inch torque wrench. How many foot-pounds will be indicated on the torque wrench when the required torque of the nut is reached?

A—24.

The braking action of a Cleveland disk brake is accomplished by compressing a rotating brake disk between two opposite brake linings. How is equal pres- sure on both sides of the rotating disk assured?

B— By allowing the caliper to float to automatically equalize as pressure is applied to the rotor.

Aircraft tire pressure should be checked

B— at least once a week or more often.

If an airplane equipped with master cylinders and single-disk brakes has excessive brake pedal travel, but the brakes are hard and effective, the probable cause is

B— worn brake linings.

A special bolt in a landing gear attachment requires a torque value of 440 inch-pounds. How many foot-pounds are required?

C— 36.6.

Excessive wear in the center of the tread of an aircraft tire is an indication of

C— overinflation.

On an air valve core stem, what indicates high- pressure type?

C—An embossed letter "H".

If it is determined that spongy brake action is not caused by air in the brake system, what is the next most likely cause?

C—Deteriorated flexible hoses.

What should be checked when a shock strut bot- toms during a landing?

C—Fluid level.

What is the purpose of the torque links attached to the cylinder and piston of a landing gear oleo strut?

C—Maintain correct wheel alignment.

What action should be taken whenever mainte- nance is performed that will affect the landing gear system performance?

C—The aircraft should be placed on jacks and a retraction test should be performed.

Extension of an oleo shock strut is measured to determine the

C—proper operating position of the strut.

Debooster valves are used in brake systems primarily to

C—reduce the pressure and release the brakes rapidly.

When installing a chevron-type seal in an aircraft hydraulic cylinder, the open side of the seal should face

C—the direction of fluid pressure.

Internal leakage in a brake master cylinder unit can cause

C—the pedal to slowly creep down while pedal pressure is applied.

The hydraulic packing seals used in a landing gear shock strut are

C—used only with a specific type of fluid.

How is it determined in a master cylinder brake sys- tem that all of the air has been purged from the system?

B— By depressing the brake and noting that the brake is firm and not spongy.

What action, if any, should be taken when there is a difference of more than 5 pounds of air pressure in tires mounted as duals?

B— Correct the discrepancy and enter in the aircraft records.

Which statement is true with respect to an aircraft equipped with hydraulically operated multiple-disk type brake assemblies?

B— Do not set parking brake when brakes are hot.

What condition would most likely cause exces- sive fluctuation of the pressure gauge when the hydraulic pump is operating?

B— Inadequate supply of fluid.

What is the function of a cam incorporated in a nose gear shock strut?

B— Straightens the nosewheel.

When working with high pressure, high perfor- mance tires, why is it recommended to deflate the tires when removing wheels from the axle?

B— To ensure safety in case of a defective wheel or broken tie bolts.

A fully-charged hydraulic accumulator provides

B— a source for additional hydraulic power when heavy demands are placed on the system.

A pilot reports the right brake on an aircraft is spongy when the brake pedal is depressed in a normal manner. The probable cause is

B— air in the brake hydraulic system.

If a brake debooster is used in a hydraulic brake system, its position in the system will be

B— between the brake control valve and the brake actuating cylinder.

On all aircraft equipped with retractable landing gear, some means must be provided to

B— extend the landing gear if the normal operating mechanism fails.

A hydraulic system referred to as a "power pack" system will

B— have all hydraulic power components located in one unit.

An automatic damping action occurs at the steering damper if for any reason the flow of high-pressure fluid is removed from the

B— inlet of the steering damper.

The repair for an out-of-tolerance toe-in condition of main landing gear wheels determined not to be the result of bent or twisted components consists of

B— inserting, removing, or changing the location of washers or spacers at the center pivotal point of the scissor torque links.

A pilot reports that the brake pedals have excessive travel. A probable cause is

B— lack of fluid in the brake system.

A sleeve, spacer, or bumper ring is incorporated in a landing gear oleo shock strut to

B— limit the extension stroke.

In shock struts, chevron seals are used to

B— prevent oil from escaping.

The purpose of an orifice check valve is to

B— restrict flow in one direction and allow free flow in the other.

The metering pins in oleo shock struts serve to

B— retard the flow of oil as the struts are compressed.

The best safeguards against heat buildup in aircraft tires are

B— short ground rolls, slow taxi speeds, minimum braking, and proper tire inflation.

The correct inflation pressure for an aircraft tire can be obtained from

B— the aircraft service manual.

When an air/oil type of landing gear shock strut is used, the initial shock of landing is cushioned by

B— the fluid being forced through a metered opening.

In brake service work, the term "bleeding brakes" is the process of ?

B— withdrawing fluid from the system for the purpose of removing air that has entered the system.

Excessive wear in the shoulder area of an aircraft tire is an indication of

C— underinflation.

What type of valve is used in the brake actuating line to isolate the emergency brake system from the nor- mal power brake control valve system?

C—A shuttle valve.

Many brake types can be adapted to operate mechanically or hydraulically. Which type is not adapt- able to mechanical operation?

C—Expander-tube type.

What device in a hydraulic system with a constant- delivery pump allows circulation of the fluid when no demands are on the system?

C—Pressure regulator.

What would be the effect if the piston return spring broke in a brake master cylinder?

C—The brakes would drag.

What is one effect a restricted compensator port of a master cylinder will have on a brake system?

C—The restriction will cause slow release of the brakes.

A high-speed aircraft tire with a sound cord body and bead may be recapped

C—an indefinite number of times.

Nose gear centering cams are used in many retractable landing gear systems. The primary purpose of the centering device is to

C—center the nosewheel before it enters the wheel well.

The purpose of a relief valve in a brake system is to

C—compensate for thermal expansion.

Chines are used on some aircraft nose wheel tires to help

C—deflect water away from the fuselage.

The purpose of a sequence valve in a hydraulic retractable landing gear system is to

C—ensure operation of the landing gear and gear doors in the proper order.

When bleeding aircraft brakes, one of the indica- tions that the air has been purged from the system is

C—firm brake pedals

Instructions concerning the type of fluid and amount of air pressure to be put in a shock strut are found

C—in the aircraft manufacturer's service manual.

The fusible plugs installed in some aircraft wheels will

C—melt at a specified elevated temperature.

A filter incorporating specially treated cellulose paper is identified as a

C—micronic filter.

The removal, installation, and repair of landing gear tires by the holder of a private pilot certificate on an aircraft owned or operated is considered to be

C—preventive maintenance.

When servicing an empty shock strut with fluid, the strut should be completely compressed and extended several times to ensure

C—proper packing ring seating and removal of air bubbles.

Debooster cylinders are used in brake systems primarily to

C—reduce the pressure to the brake and increase the volume of fluid flow.

On most aircraft, the oil level of an air and oil shock strut is checked by

C—releasing the air and seeing that the oil is to the level of the filler plug

An electric motor used to raise and lower a landing gear would most likely be a

C—split field series-wound motor.

If a shock strut bottoms after it has been properly serviced, the

C—strut should be removed, disassembled, and inspected.

Aircraft brakes requiring a large volume of fluid to operate the brakes generally

C—use power brake control valves.

Overinflated aircraft tires may cause damage to the

C—wheel flange.

How long should you wait after a flight before checking tire pressure?

A— At least 2 hours (3 hours in hot weather).

What is the purpose of a compensating port or valve in a brake master cylinder of an independent brake system?

A— Permits the fluid to flow toward or away from the reservoir as temperature changes.

A close inspection of a fusible plug reveals the core has experienced some deformation. What is the appropri- ate maintenance procedure?

A— Replace all the fusible plugs.

Why do most aircraft tire manufacturers recom- mend that the tubes in newly installed tires be first inflated, fully deflated, and then reinflated to the correct pressure?

A— To allow the tube to position itself correctly inside the tire.

An O-ring intended for use in a hydraulic system using MIL-H-5606 (mineral base) fluid will be marked with

A— a blue stripe or dot.

Lockout deboosters are primarily pressure reduc- ing valves that

A— allow full debooster piston travel without fluid from the high pressure side entering the low pressure chamber.

When servicing an air/oil shock strut with MIL-5606 the strut should be

A— collapsed and fluid added at the filler opening.

The left brake is dragging excessively on an air- plane on which no recent brake service work has been performed. The most probable cause is

A— foreign particles stuck in the master cylinder compensating port.

Power boost brake systems are used on aircraft that have

A— high landing speeds.

A flexible hydraulic hose identified as MIL-H-8788 will have a strip running the length of the hose. This stripe is

A— installed without excessive twisting.

If an aircraft shock strut (air/oil type) bottoms upon initial landing contact, but functions correctly during taxi, the most probable cause is

A— low fluid.

The primary purpose for balancing aircraft wheel assemblies is to

A— prevent heavy spots and reduce vibration.

A stripe or mark applied to a wheel rim and extend- ing onto the sidewall of a tube-type tire is a

A— slippage mark.

A brake debooster valve is installed in systems where the high pressure of the hydraulic system (3000 psi) is used to operate brakes

A— that are designed to work with lower pressure.

What is the minimum amount of time to wait for tires to cool before checking tire pressure?

A— 3 hours.

Aside from an external leak in the line, what will cause parking brakes to continually bleed off pressure?

A— An internal leak in the master cylinder.

When will a continuous horn provide a warning in the cockpit?

A— When the throttle is retarded and gear is not down and locked.