M7.9 Flashcards
What pressure are high pressure lines?
Over 1500 PSI
What pressure are medium pressure lines?
Under 1500 PSI
What pressure are low pressure lines?
Suction and return
What are medium and low pressure lines made out of?
Aluminium alloys for weight saving
What are lines in the engine, landing gear, high chance of fire or stone damage made out of?
Steel or titanium
What should be done when cleaning pipes and hoses?
blow compressed air in both ends
How are pipes and hoses tested?
Tested at 1.5 of its normal working pressure with one end capped
Why are support clamps used?
To secure to the aircraft structure or assemblies in the engine nacelle
Why are rubber cushioned clamps used
To support pipes in high vibration areas
What are cushioned clamps made from in high contamination areas?
Teflon
What are bonded clamps used for?
To secure metal fuel, oil, hydraulic lines (it has electrical lead connecting to the structure)
What is the flare angle for aircraft fittings?
37 degrees (45 for vehicle-types)
What are the two way you can form a single flare?
Impact and roll (preferred)
What is important to remember about AN fittings?
- 37 degrees
- has a recess
- coarser
- blue or black
- longer
What is important to remember about AC fittings?
- 35 degrees
- no recess
- finer
- grey or yellow
- shorter
When double flaring what is the largest diameter you can do?
3/8 or smaller
Who normally produces hoses?
Manufacturer
Where are hoses used?
High vibration areas and moving parts
What are the three types of hoses?
- low pressure (up to 600 PSI)
- medium pressure (up to 3000 PSI)
- high pressure (3000+)
What are the job of lay lines?
To see if it is twisted or not (yellow, red or white)
What is the difference between hose length and assembly length?
Hose length is just the hose and assembly is including the fittings
Why should there be some slack in a hose?
Because when it is pressurised it will reduce in length and increase in diameter
What should you do if a part shows any sign of damage?
Reject it
