Fluid Lines & Fittings Flashcards
(35 cards)
How are rigid fluid lines sized, and what increments are used?
By outside diameter in 1/16inch increments, and by wall thickness in 1/1000inch increments.
Name the two types of fluid lines used on aircraft.
Rigid and flexible lines.
What markings are found on flexible hoses?
Size, manufacturing date, pressure range, and temperature limits.
Identify the features of flared-tube fittings.
Flared-tube fittings consist of a sleeve and a B-nut, has a cone angle of 37 degrees, and are usually blue.
What caution should be exercised when deburring?
Not to reduce wall thickness.
Name the parts of a standard flare-less fitting.
The body, sleeve, and nut.
Name two kinds of flares.
The single flare and the double flare.
What is the advantage of flexible Teflon?
Extremely broad operating temperature range, compatible with nearly every liquid used, and has an almost limitless shelf and service life.
How are flexible hoses sized?
By inside diameter at 1/16inch increments.
How does a quick disconnect work?
Fluid coupling that incorporates a check valve (valve and spring) to prevent fluid loss when connecting or disconnecting.
How do you determine if a line is twisted after installation?
By the lay line running the length of the hose, line should be straight not spiraled.
What is the minimum amount of slack that must be left when a flexible hose is installed in an aircraft hydraulic system?
Hose should be at least 5% longer than the distance between the fittings, extra length provides the needed slack.
What damage can be caused by overtightening an MS flareless fitting?
Overtightening drives the cutting edge of the sleeve deep into the tube and weakens it.
What kind of fittings should be used on stainless steel lines?
Stainless steel.
How should rigid, oil, fuel, and hydraulic lines be installed?
Routed through the aircraft for shortest practical length, and clamped and bonded to the structure with integrally bonded line support clamps.
What is the purpose of a Quick Disconnect (QD)?
Faster installation or removal, prevents fluid loss, and no air or debris is allowed to enter the system.
What is the difference between AN and AC flared tube fittings?
Cone angle, thread pitch, color, body length, and AN fittings have a shoulder between the end of the flare cone and the first thread while AC fittings do not.
What is the purpose of a sleeve on a flared tube fitting?
The sleeve draws the tubing flare tightly against the male fitting to form a seal.
What are some visual differences between a flare-less fitting and a flared fitting?
Flare-less fittings have no flare cone and no space between threads and the fitting.
What are the effects of over torquing a flared fitting?
Damages the flare, causing a weak point in the tube.
Of what material are most low-pressure rigid fluid lines made?
1100-1/2 hard or 3003-1/2 hard aluminum alloy tubing.
When routing a fluid line parallel to an electrical wire bundle, which should be on top?
The electrical wire bundle should be on top.
Where are quick-disconnect fluid line couplings normally used in an aircraft hydraulic system?
Where the engine-driven pump connects into the hydraulic system.
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.
