Fabricate And Install Flexible Fluid Lines And Fittings

Question 1

What is the function of the lay line (the identification stripe) that runs the length of a flexible hose?

Answer 1

To show the mechanic whether or not the line was twisted when it was installed. The line should be straight, not spiraled.

Question 2

Where are quick-disconnect fluid line couplings normally used in an aircraft hydraulic system?

Answer 2

In the lines that connect the engine-driven pump into the hydraulic system.

Question 3

Is the size of a flexible hose determined by its inside or its outside diameter?

Answer 3

By its inside diameter.

Question 4

What is the minimum amount of slack that must be left when a flexible hose is installed in an aircraft hydraulic system?

Answer 4

The hose should be at least 5% longer than the distance between the fittings. This extra length provides the needed slack.

Question 5

What is the principal advantage of Teflon hose for use in an aircraft hydraulic system?

Answer 5

Teflon hose retains it’s high strength under conditions of high temperature.

Question 6

How much pressure is used to proof-test a flexible hose assembly?

Answer 6

This varies with the hose, but it is generally about two times the recommended operating pressure for the hose.