Fluid Lines & Fittings Flashcards
14 Questions
Of what material are most low-pressure rigid fluid lines made?
1100-1/2 hard or 3003-1/2 hard aluminum alloy tubing.
Is the size of a rigid fluid line determined by its inside or its outside diameter?
By its outside diameter.
When routing a fluid line parallel to an electrical wire bundle, which should be on top?
The electrical wire bundle should be on top.
What is the function of the lay line (the identification stripe) that runs the length of a flexible hose?
This line shows the mechanic whether or not the line has been twisted when it was installed. The line should be straight, not spiraled.
How can you distinguish an AN fluid line fitting from an AC fitting?
The AN fitting has a shoulder between the end of the flare cone and the first thread. The threads of an AC fitting extend all of the way to the flare cone.
Where are quick-disconnect fluid line couplings normally used in an aircraft hydraulic system?
Quick disconnect couplings are normally used where the engine-driven pump connects into the hydraulic system.
Is the size of a flexible hose determined by its inside or its outside diameter?
By its inside diameter.
What is the minimum amount of slack that must be left when a flexible hose is installed in an aircraft hydraulic system?
The hose should be at least 5% longer than the distance between the fittings. This extra length provides the needed slack.
How tight should an MS flareless fitting be tightened?
Tighten the fitting by hand until it is snug, and then turn it with a wrench for 1/6-turn to 1/3-turn. Never turn it more than 1/3-turn with a wrench.
What damage can be caused by over tightening an MS flareless fitting?
Overtightening drives the cutting edge of the sleeve deeply into the tube and weakens it.
What kind of rigid tubing can be flared with a double flare?
5052-0 and 6061-T aluminum alloy tubing in sizes from 1/8-inch to 3/8-inch OD.
What is the principal advantage of Teflon hose for use in an aircraft hydraulic system?
Teflon hose retains its high strength under conditions of high temperature.
What precautions should be taken when flaring a piece of aluminum alloy tubing?
The end of the tubing must be polished so it will not crack when it is stretched with the flaring tool.
How much pressure is used to proof test a flexible hose assembly?
This varies with the hose, but it is generally about two times the recommended operating pressure for the hose.
