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Flashcards in Fluid Lines and Fittings Deck (19)
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1
Q

Describe the method of classifying metal tube according to size.

A

Metal tubing is sized according to wall thickness and outside diameter. Outside diameter is measured in 1/16th-inch increments.

2
Q

When installing stainless steel tubing, what type of fittings should be used?

A

Stainless steel fittings

3
Q

What is the function of the sleeve on a flared tube fitting?

A

The nut fits over the sleeve and draws the sleeve and the tubing flare tightly against the male fitting to form a seal.

4
Q

Describe the two types of flares commonly used on aircraft tubing.

A

The single flare and double flare.

5
Q

How can you determine if a fitting is an AN type rather than an AC type?

A

AN fittings have a shoulder between the flare cone and the end of the threads, AC fittings do not.

6
Q

What are the most significant differences between AN and AC fittings?

A

Sleeve length, thread pitch, and the shoulder between the threads and the flare cone on AN fittings.

7
Q

What are the names of the parts of a flareless tube fitting?

A

The nut and the ferrule or sleeve

8
Q

How do you tell a flareless fitting from a flare-type fitting?

A

Flareless fittings don’t have a flare cone and there is no space between the threads and the end of the fitting.

9
Q

What is the effect of over-tightening a flare type fitting?

A

The sealing surface may be damaged or the flare cut off.

10
Q

In addition to being securely clamped, what is an additional requirement for installing metal fuel, oil, and hydraulic lines?

A

The lines must be electrically bonded to the structure.

11
Q

What are some of the important advantages of Teflon tubing?

A

It is compatible with nearly every liquid, has a broad operating temperature range, low resistance to fluid flow and has a very long shelf and service life.

12
Q

Describe the identification markings commonly found on flexible hoses.

A

A lay line, identification such as a Mil Spec number, the manufacturer’s name or symbol, the hose size, and a date code.

13
Q

How can you determine if a flexible hose has been correctly or incorrectly installed?

A

The lay line will be straight if the hose is properly installed. A twisted lay line indicates an incorrect installation.

14
Q

How are flexible hoses designated?

A

By the inside diameter, measured in 1/16th-inch increments.

15
Q

What precautions must be observed when deburring the end of a tube after it is cut?

A

The wall thickness must not be reduced in size or fractured.

16
Q

Describe the operation of quick disconnect couplings.

A

Each half has a valve that is held open when coupled and is spring loaded closed when disconnected.

17
Q

If you fabricate a replacement for a flexible hose, what percentage of the total length must be added to allow for movement under pressure?

A

5 to 8 percent

18
Q

What happens to the tube when a flareless fitting is over-tightened?

A

The tube is weakened when the nut drives the cutting edge of the sleeve too deeply into the tube.

19
Q

Why are quick disconnect fittings used?

A

To provide a quick means to connect or disconnect a fluid line without loss of fluid or entrance of air into the system.