Pipes And Unions Flashcards
What are aircraft fluid lines usually made of?
Metal tubing or flexible hose
Three parts of a pipe?
Two end fillings
Tube
What are the dimensions of a pipe determined by?
External diameter
Wall thickness
What is high pressure in rigid and flexible pipes?
Anything over 1500PSI
What is medium pressure in rigid or flexible pipes?
Anything under 1500PSI
What is low pressure in rigid or flexible pipes?
Suction and Return lines
How are pipes identified?
Stencilled or stamped with drawing number or part number
Inspection stamp
Test stamp
Date of manufacture
What is a pipe pressure-tested to?
1 to 1.5 times the normal working pressure
What are the two types of identification?
Colour/symbol
Code (based on ATA100 numbering system)
What does grey with triangles mean?
De-icing
What does orange and blue with diamonds mean?
Instrument Air
What does blue and yellow with circles mean?
Hydraulic
What does yellow with squares mean?
Lubrication
What colour means physically dangerous?
Grey - PHDAN
Two categories of pipe fittings?
Flareless
Flared
What is MS fitting?
What must you never do?
Ball-bush. Sleeve of malleable steel shaped by pre-stressing in a way that it’s cutting edge is pushed over the pipe, sealing it.
Never re-tighten
What is another ball-bush fitting?
Harrison fitting
What is a Harrison fitting?
Pipe swaged in the sleeve to form a tight seal. Special tool moulds sleeve and widens pipe. Suited for thin walled tubes.
What is a Permaswage fitting?
For damaged pipes. Sleeve squeezed on using hyd-driven tool. Only for emergencies e.g military
Advantages of a Harrison fitting?
Easy handling
Simple tooling
Vibration resistant
Advantages of Permaswage fitting?
Disadvantages?
Quick, light, gives a good seal
Cannot be separated
Two types of flared fittings?
Single flare
Double flare
What is a Single Flared Fitting?
Special tool used to make flare, flare seals against cone.
Clear surfaces paramount
Do not overtighten
If a leak is found, dismantle and inspect
What is the flare angle on aircraft?
37 degrees
What is a Double Flared Fitting?
Soft aluminium tubing outside diameter 3/8” or smaller. Smoother and more concentric, gives a better seal, more durable
What is Sharp-Bottomed pipe damage?
Loss of material damage cuts into material to form scratches
What is Round-Bottomed pipe damage?
Loss of material damage at bottom is not sharp edged but rounded (abrasion)
What is Round-Bottomed Impact pipe damage?
Dent in pipe walling
What requirements must hoses meet?
Slack (2-4% length increase under pressure)
Must never be twisted
Where/what are hoses used?
Connect stationary to dynamic
In high vibration areas
What is low pressure in a hose?
Up to 600PSI
What is medium pressure in a hose?
Up to 3000PSI
What is high pressure in a hose?
3000PSI+
What are Lay Lines?
Run along length of hose with twist indicator. Yellow, red, or white stripes incorporate data/information
What is inspected for on hoses?
Deterioration
Leaks
Mechanical damage (rubbing)
What must inner layers of a hose be?
Chemically compatible Neoprene - petroleum based fluid Buna N - petroleum based fluid Butyl - hydraulic fluid Teflon - almost all fluids
What does hose reinforcement include?
Protective outer cover (physical/heat)
Rubber impregnated fabric
Stainless steel braid
What angle is AN?
Colour?
37 degrees
Blue or black
What angle is AC?
Colour?
35 degrees
Grey or yellow
What is the only reusable hose fitting called?
Aeroquip
What to inspect and check on a hose?
Inspect: applicability, length, cleanliness, damage
Check: part number, cure and assembly dates
What must a hose be?
Supported every 24 inches (2 ft)
Never twisted
What fitting can replace a bending pipe?
Elbow fitting
What is an Elbow Fitting?
Largest bend radius preferred. Protective sleeves - heat shrink, nylon spiral wrap, Teflon.
What do some early products contain?
Asbestos
What materials are used for a hydraulic fitting?
Aluminium allly (D)
Cadmium plated steel
CRES
Advantages of fuel/hydraulic fittings?
Easy connection
Speed
Less fuel vapour
Less hazard
Types of fuel/hydraulic fittings?
Screw Insomatic push/pull Quick thread indicator Full grip push/pull Straight flow ball valve Ball-lock
What does yellow with squares mean?
Lubrication
What does red with stars mean?
Fuel
What does red and grey with arrows mean?
Water injection
What does orange with lightning mean?
Electrical conduit
What does grey and brown with dots mean?
Air condition
What does blue with waves mean?
Coolant
What does green and rectangles mean?
Breathing oxygen
What does brown with diamonds mean?
Fire protection
