Fluid Lines and Fittings Flashcards
Which coupling nut should be selected for used with 1/2 inch aluminum oil lines which are to be assembled using flared tube ends and standard AN nuts, sleeves and fittings?
AN-818-8
Metal tubing fluid lines are sized by wall thickness and
outside diameter in 1/16 inch increments
Rolling type flaring tools are used to flare ____, ____, and _____ tubing?
Soft copper, aluminium, brass
Which coupling nut should be selected for used with 3/8 inch aluminum oil lines which are to be assembled using flared tube ends and standard AN nuts, sleeves and fittings?
AN-818-6
From the following sequences of steps, indicate the proper order you would use to make a single flare on a piece of tubing:
1. Place the tube in the proper size hole in the flaring block
2. Project the end of the tube slightly from the top of the flaring tool, about the thickness of a dime
3. Slip the fitting nut and sleeve on the tube
4. Strike the plunger several light blows with a lightweight hammer or mallet and turn the plunger one half turn after each blow
5. Tighten the clamp bar securely to prevent slippage
6. Centre ther plunger or flaring pin over the tube
3, 1, 6, 2, 5, 4
Hydraulic tubing, which is damaged in a localized area to such an extent that repair is necessary, may be repaired
by cutting out the damaged area and utilizing a swaged tube fitting to join the tube ends
What is an advantage of a double flare on aluminum tubing?
More resistant to damage when the joint is tightened
A certain amount of slack must be left in a flexible hose during installation beacusrm when under pressure, it
contracts in length and expands in diameter
What precautions should be taken when removing a flexible hose from an aircraft?
Hoses should not be straightened and should rely on a wire to support their shape
What type of hose should be used in areas of high vibration?
Flexible
The term ‘cold flow’ is generally associated with
impressions left in natural or synthetic rubber hose material
What is the color of an AN steel flared-tube fitting?
Black
Which of the following statements is/are correct in reference to flare fittings?
1. AN fittings have an identifying shoulder between the end of the threads and the flare cone
1
Flexible lines must be installed with
a slack of 5 to 8 percent of the length
The maximum distance between end fittings to which a straight hose assembly is to be connected due to temperature changes can best be avoided by
providing bends in the tubing
The material specifications for a certain aircraft require that a replacement oil line be fabricated from 3/4-inch 0.072 5052-0 aluminum alloy tubing. What is the inside dimension of this tubing?
0.606 inch
In most aircraft hydraulic systems, two piece tube connectors consisting of a sleeve and a nut are used when a tubing flare is required. The use of this type connector eliminates
the possibility of reducing the flare thickness by wiping or ironing during the tightening process
During installation, MS flareless fittings
are normally tightened by turning the nut in a specified amount, unless the manufacturer lists the torque values
When flaring aluminum tubing for use with AN fittings, the flare angle must be
37 degrees
Scratches or nicks on the straight portion of aluminum alloy tubing may be repaired if they are not deeper than
10 percent of the wall thickenss
Flexible hose are used in aircraft systems (plumbing) is classified in size according to the
inside diameter
When a Teflon hose has been in service for a time, what condition may have occurred and/or what precaution should be taken when it is temporarily removed from the aircraft?
The hose may have developed a set or have been manufactured with pre-set shape, and must be supported to maintain its shape
What does the dash number on a hose signify?
Inside diameter
A scratch or nick in aluminium tubing can be repaired provided it does not
appear in the heel of a bend in the tube
Which of the following hose materials are compatible with phosphate-ester base hydraulic fluids?
Butyl and Teflon
Which tubings have the characteristics (high strengths, abrasion resistance) necessary for use in a high pressure (3,000 PSI) hydraulic system for operation of landing gear and flaps?
Corrosion resistant steel or 1/4H
When installing bonding clamps to support metal tubing
remove paint or anodizing from the tube at clamp location
In a metal tubing installation,
tension is undesirable because pressurization will cause it to expand and shift
The best tool to use when cutting aluminum tubing, or any tubing of moderately soft metal is a
hand operated wheel-type tubing cutter
Which of the following tools is best to use when cutting aluminium tubing?
hand operated wheel type tubing cutter
The primary purpose of providing suitable bends in fluid and pneumatic metal tubing runs is to
prevent excessive stress on tubing
Which of the following statements is true regarding minimum aluminum allowable bend radii for 1.5 inches OD or less aluminium alloy and steel tubing for the same size?
The minimum radius for steel is greater than for aluminum
Which of the following statements is/are true in reference to the flare fittings?
1. AN fittings have an identifying shoulder between the ends of the threads and the flare cone
1.
A gas or fluid line marked with the letters PHDAN
used to carry hazardous substances
Which statement is true regarding the variety of utilized on identifying color-code bands that are currently used on aircraft plumbing lines?
Symbols are always black against a white background regardless of line content
If a flared tube coupling nut is over torqued, where is the tube most likely to be weakened to damaged?
At the sleeve or flare junction
When installing a castle nut, and the nut castellation does not align with the the cotter pin in the bolt within the torque range, the acceptable practice is to
change the nut or washer and try again
Which statement is true concerning Bernoulli’s principle is true?
The pressure of a fluid decreases at points where the velocity increases
- Bonded clamps are used for support when installing metal tubing
- Unbonded clamps are used for supports when installing wiring
Both No.1 and No.2 are true
Which statement is true regarding flattening of tubing in bends?
The small diameter of the flattened portion must not be less than 75 percent of the original outside diameter
Which statement is true regarding flattening of tubing in bends?
Flattening by not more than 25 percent of the original diameter is permissible
A 3/8 inch aircraft high pressure flexible hose as compared to 3/8 inch metal tubing is used to in the same system will
have higher flow characteristics
