Fluid Lines and Fittings Flashcards
What are aircraft plumbing lines usually made of?
Metal tubing and fittings, or flexible hose.
How is metal tubing sized?
By outside diameter which is measured fractionally in sixteenths of an inch, and by wall thickness measured in thousandths.
What precautions should be taken when routing fluid lines adjacent to electrical wiring?
Route the fluid lines below the electrical wiring and maintain a clearance of at least six inches whenever possible. In no case should fluid lines and electrical wiring be closer than one-half inch. Ensure that both the wiring and the fluid lines are fastened to the aircraft structure by clamps or other methods that will maintain the separation.
What is the purpose of the identification stripe running along the length of a flexible hose?
The stripe is used to determine if the hose has twisted during installation. The stripe should not spiral around the hose after installation is completed.
How are standard AN-type fluid line fittings identified?
AN fluid line fittings are colored either blue or black while AC type fittings are usually gray or yellow. AN fittings have coarser threads than AC fittings, and they also have a small shoulder between the threads and the flare cone. The AC fittings are completely threaded from the shoulder all the way to the flare cone.
What is the purpose of using quick disconnect couplings in fluid systems?
Quick disconnect couplings are installed at locations where frequent uncoupling of the lines is required for inspection or maintenance. Each half has a valve that is open when coupled together and spring loaded closed when disconnected. They provide a means of quickly disconnecting a line without a loss of fluid or air entering the system.
How is flexible hose sized?
By the inside diameter in sixteenths of an inch increments.
How much slack must be left in a flexible hose during installation?
Five to eight percent of the total hose length must be allowed for freedom of movement under pressure.
What are the three parts of a Military Standard (MS) flareless-tube fitting?
The body, the sleeve, and a nut.
What will be the result of over tightening a flareless tube fitting?
The sleeve’s cutting edge will cut too deeply into the tube and cause the tube to be weakened.
What are the two kinds of flares used in aircraft plumbing systems?
A single flare and a double flare.
What is the advantage of flexible teflon hose over rubber hose?
It can be used in the same manner as rubber hose and it has a better operating strength
. What precaution should be taken when deburring the cut end of a tube?
Care should be taken that the tubing is not cracked or that the wall thickness is not reduced by the deburring process.
. What are the identifying features of AN fluid line fittings?
The AN fitting has a shoulder between the end of the threads and the flare cone.
How can you tell that a flexible hose has been installed in a twisted position?
By the identification stripe (Lay-Line) running along the hose length.
