Fluid lines and fitting

Question 1

What are aircraft plumbing lines usually made of

Answer 1

Metal tubing or flexible hose and fittings

Question 2

How is metal tubing sized

Answer 2

By outside diameter and wall thickness. Outside diameter is measured fractionally in sixteenths of an inch

Question 3

What material should be selected for high pressure rigid fuel lines

Answer 3

Annealed or 1/4 hard corrosion resistant steal

Question 4

What type of material should fittings be made of when used in stainless steel tubing

Answer 4

Stainless steel

Question 5

What percent of flattening is allowed when bending metal tubing

Answer 5

25% max

Question 6

What precautions should be taken when routing fluid lines adjacent to electrical wiring

Answer 6

Route the Fluid lines below the electrical wiring and maintain clearance of at least sixteenths of an inch whenever possible and in no case should fluid lines and electrical wiring be closer than 1/2 inch. Ensure that both wiring and fluid lines are fastened to the aircraft structure by clamps or other methods that will maintain the separation

Question 7

What is the purpose of the identification strip running along the length of the flexible hose

Answer 7

Delay line and indicates if the hose has twisted during installation. There is no allowable twist

Question 8

What are some synthetic material commonly used to manufacture flexible hose

Answer 8

Buns-N, neoprene, butyl, ethylene propylene diene rubber, And Teflon

Question 9

How are standard AN type and AC Type fluid line fittings identified

Answer 9

AN fluid line fittings are colored either blue or black. While AC type fittings are usually gray and yellow.

AN fittings have courser threadsAnd they have a small shoulder between the threads and the 37° flare cone. The AC fittings are completely threaded all the way to the 35° flare cone

Question 10

What is the purpose of using quick disconnect couplings in Fluid systems

Answer 10

They provide means of quickly disconnecting a line without a loss of fluid or air entering the system.

Quick disconnect couplings are installed at locations where frequent uncoupling of the line is required for inspection and maintenance. Each half has a valve that is open when coupled together and spring loaded to close when disconnected

Question 11

How is a flexible hose sized

Answer 11

By the inside diameter in sixteenths of an inch increments

Question 12

How much slack must be left in a flexible hose during installation

Answer 12

5 to 8% of the total hose length must be allowed for freedom of movement under pressure

Question 13

How often should flexible hose be clamped in place

Answer 13

Every 24 inches

Question 14

Name considerations when installing flexible hose assembly’s

Answer 14

Slack, flexing, twisting, bending, clearance, and clamps

Question 15

What pressure is used to prove test a flexible hose assembly

Answer 15

1.5 times the recommended operating pressure of the hose

Question 16

What are three parts of a military standard tube Fitting

Answer 16

Body, sleeve, nut

Question 17

What will be the result of over tightening of flared tube Fitting

Answer 17

The compression sleeve cutting edge will cut too deep into the tube and cause the tube to be weekend, flareless fittings are made up of the tube, compression sleeve, and nut

Question 18

What are the two kinds Of flares used in aircraft plumbing systems

Answer 18

Single flare and double flare

Question 19

What is the difference between Automotive in aviation flares

Answer 19

Aviation flares should be 37° in automotive are 45°

Question 20

What is the advantage of flexible Teflon hose over rubber hose

Answer 20

Teflon hose have better resistance to chemicals and a higher strength property at higher temperatures

Question 21

What precautions should be taken when deburring and inspecting the flared end of the tube

Answer 21

Can you should be taken that the tube is not cracked or that the wall thickness is not reduced by the deburring process

Question 22

What type of rubber is used in flexible lines that Carrie phosphate Esther Hydraulic fluid

Answer 22

Synthetic

Question 23

What type of information is on a hose lay line

Answer 23

Information found on the lay line will indicate the type of hose, and the quarter and year of manufacture