Fluid lines & fittings

Which statement about Military Standard

(MS) flareless fittings is/are correct?

1. During installation, MS flareless fittings are normally tightened by

turning the nut a specified amount,

rather than being torqued.

1. New MS flareless tubing/fittings should be assembled clean and dry

2. without lubrication

3. During installation, MS flareless
   fittings are normally tightened by applying a specified torque to the

nut.

A. 1.

B. 1 and 2

C. 3

1.

Which statement is true regarding the geometric symbols on identifying color-code bands that are currently used on aircraft plumbing lines?

A. Symbols are composed of various single colors according to line content.

B. Symbols are always black against a white background regardless of line content.

C. Symbols are composed of one to three

Symbols are always black against a white background regardless of line content.

The material specifications for a certain aircraft require that a replacement oil line be fabricated from 3/4-inch 0.072

5052-0 aluminum alloy tubing. What is the inside dimension of this tubing?

A. 0.606

B. 0.688

C. 0.750

0.606

How can you identify fluid lines?

A. By observing the metal tag or color code on the line

B. By tracing the line to a component

C. By servicing the line

By observing the metal tag or color code on the line

In a metal tubing installation,

A. rigid straight line runs are preferable.

B. tension is undesirable because pressurization will cause it to expand and shift.

C. a tube may be pulled in line if the nut will start on the threaded coupling.

tension is undesirable because pressurization will cause it to expand and shift.

Which of the following statements is true regarding minimum allowable bend radii for 1.5 inches OD or less aluminum alloy and steel tubing of the same size?

A. The minimum radiusafor steel is greater than for aluminum.

B. The minimum radius for steel is the same for both steel and aluminum

C. The minimum radius for steel is the same for both steel and aluminum

The minimum radiusafor steel is greater than for aluminum.

Which of the following statements is/are correct in reference to flare fittings?

1. AN fittings have an identifying shoulder between the end of the
   threads and the flare cone.

2. AC and AN fittings are considered identical except for material
   composition and identifying colors.

3. AN fittings are generally interchangeable with AC fittings of
   compatible material composition.

A. 1

B. 1 and 3

C. 1, 2, and 3

1.

What is an advantage of a double flare on aluminum tubing?

A. Ease of construction.

B. It is less resistant to the shearing effect of torque.

C. It is more resistant to the shearing effect of torque.

It is more resistant to the shearing effect of torque.

gas or fluid line marked with the letters PHDAN is

A. a dual-purpose pneumatic and/or hydraulic line for normal and emergency system use.

B. used to carry a hazardous substance.

C. a pneumatic or hydraulic system drain or discharge line.

used to carry a hazardous substance.

How much extra length should be added when fabricating a flexible hose to allow for changes in length when pressure is applied?

A. No slack should be in the hose installation.

B. 1-3/%

C. 5-8%

5-8%

When a Teflon hose has been in service for a time, what condition may have occurred and/or what precaution should be taken when it is temporarily removed from the aircraft?

A. The hose interior must be kept wet with the fluid carried to prevent embrittlement/deterioration.

B. The hose may become stiff and brittle if not flexed or moved regularly.

C. The hose may have developed a set, or have been manufactured with a pre-set shape, and must be supported to maintain its shape

The hose may have developed a set, or have been manufactured with a pre-set shape, and must be supported to maintain its shape

1. Bonded clamps are used for support when installing metal tubing.

2. Unbonded clamps are used for support when installing wiring.

Regarding the above statements,

A. Only no.1 is true

B. Both no. 1 and no. 2 are true

C. Neither no. 1 nor no. 2 is true

Both no. 1 and no. 2 are true

When flaring aluminum tubing for use with

AN fittings, the flare angle must be

A. 45°

B. 35°

C. 37°.

37

The primary purpose of providing suitable bends in fluid and pneumatic metal tubing runs is to

A.prevent excessive stress on the tubing.

B. provide for access within aircraft structures.

C. clear obstacles and make turns in aircraft structures.

prevent excessive stress on the tubing.

Which statement is true regarding flattening of tubing in bends?

A. Flattening by a maximum of 20 percent of the original diameter is

permissible.

B. Flattening by not more than 25 percent of the original diameter is permissible.

C. Flattening by not more than 25 percent of the original diameter is permissible.

Flattening by not more than 25 percent of the original diameter is permissible.

The best tool to use when cutting alumi tubing, or any tubing of moderately soft metal is a

A. hand operated wheel-type tubing cutter.

B. fine-tooth hacksaw.

C. circular-saw equipped with an abrasive cutting wheel.

hand operated wheel-type tubing cutter.

The term "cold flow" is generally associated with

A
B
C

A. the effects of low temperature gasses or liquids flowing in hose or tubing.

B. impressions left in natural or synthetic rubber hose material.

C. flexibility characteristics of various hose materials at low ambient temperatures.

impressions left in natural or synthetic rubber hose material.

certain amount of slack must be left in a flexible hose during installation because, when under pressure, it

A. expands in length and diameter.

B. expands in length and contracts in diameter

C. contracts in length and expands in diameter

contracts in length and expands in diameter

From the following sequences of steps, indicate the proper order you would use to make a single flare on a piece of tubing:

1. Place the tube in the proper size hole in the flaring block.

2. Project the end of the tube slightly from the top of the flaring
   tool, about the thickness of a dime.

3. Slip the fitting nut and sleeve on the tube.

4. Strike the plunger several light blows with a lightweight hammer or
   mallet and turn the plunger one-half

turn after each blow.

5. Tighten the clamp bar securely to prevent slippage.

6. Center the plunger or flaring pin over the tube.

A. 1, 3, 5, 2, 4, 6.

B, 3, 1, 6, 2, 5, 4.

C, 3, 1, 2, 6, 5, 4.

3, 1, 6, 2, 5, 4.

When inspecting a flexible hose, what should you look for?

A Leaks

B Cold flow

C. Both A and B

Both A and B

Hydraulic tubing, which is damaged in a localized area to such an extent that repair is necessary, may be repaired

A. by cutting out the damaged area and utilizing a swaged tube fitting to join the tube ends.

B. only by replacing the entire tubing using the same size and material as the original.

C. by cutting out the damaged section and soldering in a replacement section of tubing.

by cutting out the damaged area and utilizing a swaged tube fitting to join the tube ends.

When installing bonded clamps to support metal tubing,

B
C

A, remove paint or anodizing from tube at clamp location.

B. paint clamp and tube after clamp installation to prevent corrosion.

C paint removal from tube is not A recommended as it will inhibit

corrosion.

remove paint or anodizing from tube at clamp location.

scratch or nick in aluminum tubing can be repaired provided the scratch or nick does not

A. appear in the heel of a bend.

B. appear on the inside of a bend.

C. exceed 10 percent of the tube OD on a straight section.

appear in the heel of a bend.

A 3/8 inch aircraft high pressure flexible hose as compared to 3/8 inch metal tubing used in the same system will

A. usually have interchangeable applications.

B. have equivalent flow characteristics.

C. have about the same OD.

have equivalent flow characteristics.

What is the color of an AN steel flared-tube fitting?

A. Black

B. Blue

C. Red

Black

Which of the following hose materials are compatible with phosphate-ester base hydraulic fluid?

1. Butyl.

2. Teflon.

3. Buna-N.

4. Neoprene.

A. 2 and 4

B. 1 and 2

C. 1 and 3

1 and 2

Flexible lines must be installed with a slack of

A. enough slack to allow maximum flexing during operation.

B. at least 10 to 12 percent of the length.

C. 5 to 8 percent of the length

5 to 8 percent of the length

Flexible hose used in aircraft plumbing is classified in size according to the

A. outside diameter.

B. cross-sectional area.

C. inside diameter.

inside diameter.

If a flared tube coupling nut is overtightened, where is the tube most likely to be weakened/damaged?

A. At the sleeve and flare junction.

B. At the edge of the sleeve and straight portion of the tube.

C. Along the entire length of the sleeve and tube interface.

At the sleeve and flare junction.

Which coupling nut should be selected for use with 1/2-inch aluminum oil lines which are to be assembled using flared tube ends and standard AN nuts, sleeves, and fittings?

A. AN-818-16.

B. AN-818-8.

C. AN-818-5.

AN-818-8.

Which tubings have the characteristics (high strength, abrasion resistance) necessary for use in a high pressure (3,000 PSI) hydraulic system for operation of landing gear and flaps?

A. 2024-T or 5052-0 aluminum alloy.

B. Corrosion resistant steel annealed or 1/4H.

C. 1100-1/2H or 3003-1/2H aluminum alloy.

Corrosion resistant steel annealed or 1/4H.

Which statement is not true regarding hydraulic fluids?

A. Do not expose fluids to high temperature or open flames.

B. Operating pressure of a hydraulic system can vary from a couple hundred psi in smaller aircraft to several thousand psi in larger aircraft.

C. All hydraulic fluids are compatible.

All hydraulic fluids are compatible.

The maximum distance between end fittings to which a straight hose assembly is to be connected is 50 inches. The minimum hose length to make such a connection should be

A 54-1/2 inches.

B. 51-1/2 inches.

C. 52-1/2 inches.

52-1/2 inches.

Scratches or nicks on the straight portion of aluminum alloy tubing may be repaired if they are no deeper than

A. 10 percent of the wall thickness.

B. 1/32 inch or 20 percent of wall thickness, whichever is less.

C. A 20 percent of the wall thickness.

10 percent of the wall thickness.

Metal tubing fluid lines are sized by wall thickness and

A. inside diameter in 1/16 inch increments.

B. outside diameter in 1/16 inch increments.

C. outside diameter in 1/32 inch increments.

outside diameter in 1/16 inch increments.

Which statement (s) about Military Standard

(MS) flareless fittings is/are correct?

1. During installation, MS flareless fittings are normally tightened by

turning the nut a specified amount,

rather than being torqued.

1. New MS flareless tubing/fittings should be assembled clean and dry

2. without lubrication.

3. During installation, MS flareless
   fittings are normally tightened by applying a specified torque to the

nut.

A. 1

B. 1 and 2

C. 3

1

In most aircraft hydraulic systems, two-piece tube connectors consisting of a sleeve and a nut are used when a tubing flare is required. The use of this type connector eliminates

A. the flaring operation prior to assembly.

B. the possibility of reducing the flare thickness by wiping or ironing during the tightening process.

C. wrench damage to the tubing during the tightening process.

the possibility of reducing the flare thickness by wiping or ironing during the tightening process.

Which of the following defects are NOT acceptable for metal lines?

1. Cracked flare.

2. Seams.

3. Dents in the heel of a bend less than 20 percent of tube diameter.

4. Scratches/nicks on the inside of a bend less than 10 percent of wall thickness.

5. Dents in straight sections that are 20 percent of wall thickness.

A. 1, 2, 3, 4, and 5.

B. 1, 2, and 3.

C. 1, 2, 3, and 5.

1, 2, 3, and 5.