WorksheetsAMT 105 Fluid Lines and Fittings
Total questions: 33
Worksheet time: 17mins
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. Center the plunger or flaring pin over the tube.
1,3,5,2,4,6
3,1,6,2,5,4
3,1,2,6,5,4
A certain amount of slack must be left in a flexible hose during installation because, when under pressure, it
expands in length and diameter
expands in length and contracts in diameter
contracts in length and expands in diameter
What is the color of an AN steel flared-tube fitting?
black
blue
red
Which coupling nut should be selected for use with 1/2-inch aluminum oil lines which are to be assembled using flared tube ends and standard AN nuts, sleeves, and fittings?
AN-818-5
AN-818-16
AN-818-8
Which statement(s) about Military Standard (MS) flareless fittings is/are correct?
1. During installation, MS flareless fittings are normally tightened by turning the nut a specified amount, rather than being torqued.
2. New MS flareless tubing/fittings should be assembled clean and dry without lubrication.
3. During installation, MS flareless fittings are normally tightened by applying a specified torque to the nut
1
1 and 2
3
Which of the following hose materials are compatible with phosphate-ester base hydraulic fluids?
1. Butyl.
2. Teflon.
3. Buna-N.
4. Neoprene.
1 and 2
2 and 4
1 and 3
When flaring aluminum tubing for use with AN fittings, the flare angle must be
37 degrees
39 degrees
45 degrees
When installing bonded clamps to support metal tubing,
paint removal from tube is not recommended as it will inhibit corrosion
paint clamp and tube after clamp installation to prevent corrosion
remove paint or anodizing from tube at clamp location
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 flaring operation prior to assembly
the possibility of reducing the flare thickness by wiping or ironing during the tightening process
wrench damage to the tubing during the tightening process
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
0.688 inch
0.750 inch
The primary purpose of providing suitable bends in fluid and pneumatic metal tubing runs is to
clear obstacles and make turns in aircraft structures
provide for access within aircraft structures
prevent excessive stress on tubing
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.
2. AC and AN fittings are considered identical except for material composition and identifying colors.
3. AN fittings are generally interchangeable with AC fittings of compatible material composition.
1
1 and 3
1, 2 and 3
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
only by replacing the tubing section run (connection to connection) using the same size and material as the original
by cutting out the damaged section and soldering in a replacement section of tubing
Scratches or nicks on the straight portion of aluminum alloy tubing may be repaired if they are no deeper than
20% of the wall thickness
1/32 inch or 20% of the wall thickness, whichever is less
10% of the wall thickness
Which tubings have the characteristics (high strength, abrasion resistance) necessary for use in a high-pressure (3,000 PSI) hydraulic system for operation of landing gear and flaps?
2024-T or 5052-O aluminum alloy
corrosion resistant steel annealed or 1/4 hard
1100-1/2H or 3003-1/2H aluminum alloy
What is an advantage of a double flare on aluminum tubing?
ease of construction
more resistant to damage when the joint is tightened
can be applied to any size wall thickness of tubing
In a metal tubing installation,
rigid straight line runs are preferable
tension is undesirable because pressurization will cause it to expand and shift
a tube may be pulled in line if the nut will start on the threaded coupling
The best tool to use when cutting aluminum tubing, or any tubing of moderately soft metal is a
hand operated wheel type tubing cutter
fine toothed hacksaw
circular-saw equipped with an abrasive cutting wheel
Metal tubing fluid lines are sized by wall thickness and
outside diameter in 1/16 inch increments
inside diameter in 1/16 inch increments
outside diameter in 1/32 inch increments
The maximum distance between end fittings to which a straight hose assembly is to be connected is 50 inches. The minimum hose length to make such a connection should be
54-1/2 inches
51-1/2 inches
52-1/2 inches
Flexible hose used in aircraft systems is classified in size according to the
outside diameter
wall thickness
inside diameter
The term 'cold flow' is generally associated with
the effects of low temperature gasses or liquids flowing in hose or tubing.
impressions left in natural or synthetic rubber hose material.
flexibility characteristics of various hose materials at low ambient temperatures.
Flexible lines must be installed with
a slack of 5 to 8 percent of the length.
a slack of at least 10 to 12 percent of the length.
enough slack to allow maximum flexing during operation.
A scratch or nick in aluminum tubing can be repaired provided it does not
appear in the heel of a bend.
appear on the inside of a bend.
exceed 10 percent of the tube OD on a straight section.
Excessive stress on fluid or pneumatic metal tubing caused by expansion and contraction due to temperature changes can best be avoided by
using short, straight sections of tubing between fixed parts of the aircraft.
using tubing of the same material as the majority of the adjoining structure.
providing bends in the tubing.
A gas or fluid line marked with the letters PHDAN is
a dual-purpose pneumatic and/or hydraulic line for normal and emergency system use.
used to carry a hazardous substance.
a pneumatic or hydraulic system drain or discharge line.
Which statement is true regarding the variety of symbols utilized on the identifying color-code bands that are currently used on aircraft plumbing lines?
Symbols are composed of various single colors according to line content.
Symbols are always black against a white background regardless of line content.
Symbols are composed of one to three contrasting colors according to line content.
If a flared tube coupling nut is overtightened, where is the tube most likely to be weakened/damaged?
Along the entire length of the sleeve and tube interface.
At the edge of the sleeve and straight portion of the tube.
At the sleeve and flare junction.
Which statement concerning Bernoulli's principle is true?
The pressure of a fluid increases at points where the velocity of the fluid increases.
The pressure of a fluid decreases at points where the velocity of the fluid increases.
It applies only to gases and vaporized liquids.
(1) Bonded clamps are used for support when installing metal tubing.
(2) Unbonded clamps are used for support when installing wiring.
Regarding the above statements,
only No. 1 is true.
both No. 1 and No. 2 are true.
neither No. 1 nor No. 2 is true.
Which statement is true regarding flattening of tubing in bends?
Flattening by a maximum of 20 percent of the original diameter is permissible.
Flattening by not more than 25 percent of the original diameter is permissible.
The small diameter portion in the bend cannot exceed more than 75 percent of the diameter of straight tubing.
A 3/8 inch aircraft high pressure flexible hose as compared to 3/8 inch metal tubing used in the same system will
have higher flow capabilities.
have equivalent flow characteristics.
usually have interchangeable applications.
Which of the following statements is true regarding minimum allowable bend radii for 1.5 inches OD or less aluminum alloy and steel tubing of the same size?
The minimum radius for steel is greater than for aluminum.
The minimum radius for steel is less than for aluminum.
The minimum radius is the same for both steel and aluminum.
