AC ENGINEERING (FLUID LINES & FITTING)

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

Only by replacing the tubing section run (connection to connection) using the same size and material as the original

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

By cutting out the damaged section and soldering in a replacement section of tubing

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

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

Along the entire length of the sleeve and tube interface

At the sleeve and flare junction

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

51-1/2 inches

54-1/2 inches

52-1/2 inches

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

2. New MS flareless tubing/fittings should be assembled clean and dry without lubrication

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

1 and 2

Which statement is true regarding flattening of tubing in bends?

The small diameter portion in the bend cannot exceed more than 75 percent of the diameter of straight tubing

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

Flattening by a maximum of 20 percent of the original diameter is permissible

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. Tightened the clamp bar securely to prevent slippage

6. Center the plunger or flaring pin over the tube

3,1,6,2,5,4

1,3,5,2,4,6

3,1,2,6,5,4

A gas or fluid line marked with the letters PHDAN is

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

A pneumatic or hydraulic system drain or discharge line

Used to carry a hazardous substance

Which statement concerning Bernoulli's principle is true?

The pressure of a fluid decreases at points where the velocity of the fluid increases

The pressure of a fluid increases at points where the velocity of the fluid increases

It applies only to gases and vaporized liquids

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

Wrench damage to the tubing during the tightening process

The flaring operation prior to assembly

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

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

Clear obstacle and make turns in aircraft structures

Provides for access within aircraft structures

Prevent excessing stress on the tubing

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?

0.688 inch

0.606 inch

0.750 inch

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?

Corrosion-resistant steel annealed or 1/4H

2024-T or 5052-0 aluminum alloy

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

(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

Only No.1 is true

Both No.1 and No.2 are true

Neither o.1 nor No.2 is true

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

Have equivalent flow characteristics

Have higher flow capabilities

Usually have interchangeable applications

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

20 percent of the wall thickness

10 percent of the wall thickness

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

When installing bonded clamps to support metal tubing

Remove paint or anodizing from tube at clamp location

Paint clamp and tube after clamp installation to prevent corrosion

Paint removal from tube is not recommended as it will inhibit corrosion

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?

The minimum radius for steel is less than for aluminum

The minimum radius for steel is greater than for aluminum

The minimum radius is the same both steel and aluminum

Excessive stress on fluid or pneumatic metal tubing caused by expansion and contraction due to temperature changes can best be avoided by

Using short, straight sections of tubing between fixed parts of the aircraft

Providing bends in the tubing

Using tubing of the same material as the majority of the adjoining structure

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

Symbols are composed of various single colors according to line content

Symbols are composed of one to three contrasting colors according to line content

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

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

1 and 3

1,2 and 3

The term 'cold flow' is generally associated with

Impressions left in natural or synthetic rubber hose material

The effects of low temperature gasses or liquids flowing in hose or tubing

Flexibility characteristics of various hose materials at low ambient temperatures

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

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

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

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

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

Expands in length and contracts in diameter

Expands in length and diameter

Contracts in length and expands in diameter

In a metal tubing installation

Tension is undesirable because pressurization will cause it to expand and shift

Rigid straight line runs are preferable

A tube may be pulled in line if the nut will start on the threaded coupling

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