Rigid Fluid Lines Flashcards
AN fittings have a ______ Connection?
Flared Connection
What degree are AN flared fittings?
37 Degrees
What degree are AC flared fittings?
35 Degrees
What degree are MS flared fittings?
MS fittings do not have flares
When was copper tubing used extensively in aircraft?
During the early days of aviation
How does copper become hard and brittle in aircraft?
Vibration
How do we restore properties in copper?
Annealing
Aluminum allow tubing is used for?
General purpose lines of low or medium fluid pressures such as hydraulic and pneumatic. 1000 PSI - 1500 PSI
What is CRES?
Corrosion resistant steel tubing
Where are steel lines mainly used?
In areas where there is high risk of foreign object damage (FOD) such as the landing gear and wheel well areas.
Where are titanium lines used?
They are used extensively in transport and high performance aircraft and around engines.
True or false: Titanium is 50 percent stronger then steel and 30 percent lighter then steel.
False! Titanium is 30 percent stronger then steel and 50 percent lighter then steel.
How do we positively identify the material used in the original line installation?
Compare code markings on replacement tubing.
On large aluminum alloy tubing the alloy designation can be found where?
Stamped on the surface.
On small aluminum tubing the alloy designation maybe __________; but more often is shown by a __________
MAYBE stamped on the surface, Color code
How do we size rigid tubing lines?
By the outside diameter and wall thickness
OD tubing is sized in what increments?
1/16 inch
A #6 rigid tube is what size?
6/16ths or 3/8ths
Wall thickness is specified in what increment?
Thousandths of an inch
How do we find the OD of a tube?
ID + 2 wall thickness
How do we find the ID of a tube?
OD - 2 wall thickness
How do we find total wall thickness?
OD - ID
How do we find 1 wall thickness?
OD - ID divided by 2
Replacement tubing should be what?
The same sized material as the original line or approved substitute.
How do we ID the material if there are no markings?
Hardness, Acid and Magnetic testing methods
Fabrication of tube assemblies consists of what?
Cutting, deburring, bending and tube joint preparation
How do we cut rigid tubing?
Roll cutters or Fine tooth hacksaw with 32 teeth per inch.
When you cut tubing you should always cut ______ for bending variations.
10% extra material
What is the objective of cutting rigid tubing?
To produce a square end free from burrs.
How do we deburr a tube?
Deburring tool
The objective of tube bending is to obtain what?
A smooth bend without flattening the tube.
Tubing under _____ inch diameter can be bent without the use of a bending tool.
1/4
A small amount of flattening in bends is acceptable but must not be less then ______ percent of the original OD
75%
Fittings for tube connections are made of what materials?
Aluminum alloy, titanium, corrosion resistant steel and brass and bronze
What are the 5 classifications of tube fittings?
Flared, Flareless, Swaged, Beaded, brazed and welded
The two major tube joint fittings are the _______ and ______.
Flared and Flareless
What are the benefits of a double flare over a single flare?
A double flare seals better and is more resistant to the shearing effect of torque.
What tube size are double flares mostly used in?
3/8 and smaller
Presetting is only required on what type of fitting?
MS fittings
What does PHDAN stand for?
Physically Dangerous
What lines are marked as PHDAN?
Lines with oxygen, nitrogen or Freon
What color code and symbol is a fuel line?
Red with Diamonds
What color code and symbol is water injection?
Red and Grey with chevrons pointing down
What color code and symbol is electrical conduit?
Orange with lightning bolts
What color code and symbol is compressed gas?
Orange with diagonal rectangles
What color code and symbol is instrument air?
Orange and blue with crisscrossing lines
What color code and symbol is coolant?
Blue with wavy rectangles
What color code and symbol are hydraulic lines?
Blue and yellow with circles
What color code and symbol are lubrication lines?
Yellow with squares
What color code and symbol is breathing oxygen?
Green with rectangles
What color code and symbol is Deicing?
Grey with triangles
What color code and symbol is fire protection?
Brown with squared diamonds
What color code and symbol is air conditioning?
Brown and grey with random sized circles
What is the warning symbol?
white background with black skull and bones
List the 5 fluid line end fittings?
Universal bulkhead fittings, AN flared, MS flareless, swaged fittings and AC fittings
What color are aluminum alloy fittings?
Blue
What color are carbon steel fittings?
Black
What color are CRES fittings?
Natural
What color are Aluminum-bronze fittings?
Cadmium plate (goldish)
What color are titanium fittings?
Natural to grey
Describe Cryofit fittings.
The sleeve is manufactured 3% smaller, frozen in liquid nitrogen and expanded 5% larger than the line. Sleeve is removed from the liquid nitrogen and inserted on to the tube where the sleeve contracts to its original 3% smaller size and creates a permanent seal.
What color are AC fittings?
Grey or yellow
What is the difference between a AN fitting and a AC fittings?
AN fittings have 37 degree flares and AC fittings have 35 degree flares and are slightly longer.
The liquid medium for proof testing tube assemblies should be what?
Hydraulic fluid, water or oil
What should oxygen tubing be proof tested with?
Dry nitrogen
True or False: You should always apply a compound to the faces of the fitting or flare.
FALSE. You should never apply any compound as it will destroy the metal on metal contact between the fitting and flare.
If an AN flared tube assembly leaks after being tightened to the proper torque what steps do you take next?
Disassemble the line for repair or replace the line completely
What can be done if a flareless tube assembly leaks?
It can be tightened 1/16th turn beyond the noted torque
Leakage of a flared tube assembly is usually caused by what?
Flare distortion in the nut threads, sleeve cracked, flared out of roundness, flare is cracked or split
Tubing that has nicks scratches or dents are acceptable if the dent has a depth of what?
Less than 20% of the tubing diameter unless its in the heel of a short bend radius
A nick or scratch of that has a depth of less then _____ of the wall thickness on aluminum or steel should be reworked before it is acceptable.
10%