Fluid Lines and Fittings in Aircraft

The video tutorial covers fluid lines and fittings in aircraft, including types of fluid lines, classification of metal tubing, and fittings for stainless steel tubing. It explains the function and types of flared tube fittings, differences between AN and AC fittings, and how to identify flareless fittings. Installation requirements for metal fuel, oil, and hydraulic lines are discussed, along with identification markings and advantages of flexible hoses. The operation of quick disconnect couplings and precautions for tube installation are also covered.

What are the two main types of fluid lines used in aircraft?

• Plastic and rubber hoses

• Copper and aluminum tubes

• Rigid metal lines and flexible hoses

• Steel and iron pipes

How is metal tubing classified by size?

• By length in feet

• By wall thickness in centimeters

• By outside diameter in sixteenths of an inch

• By inside diameter in millimeters

What is the purpose of the sleeve in a flared tube fitting?

• To provide insulation

• To reduce weight

• To secure the nut and form a seal

• To increase flexibility

Which type of fitting has a shoulder between the flare cone and the end of the threads?

• AN fittings

• AC fittings

• Flareless fittings

• Compression fittings

What are the components of a flareless tube fitting?

• Clamp and gasket

• Cone and thread

• Nut and sleeve or ferrule

• Bolt and washer

What can happen if a flare-type fitting is over-tightened?

• The fitting may become loose

• The sealing surface may be damaged

• The tube may expand

• The fitting may corrode

What is an additional requirement for installing metal fuel, oil, and hydraulic lines?

• They must be flexible

• They must be insulated

• They must be electrically bonded to the structure

• They must be painted

What is a key advantage of Teflon tubing?

• It is lightweight

• It is compatible with nearly every liquid

• It is inexpensive

• It is easy to install

How can you tell if a flexible hose is installed correctly?

• The lay line will be twisted

• The lay line will be straight

• The hose will be rigid

• The hose will be loose

What is the purpose of quick disconnect fittings?

• To permanently seal a fluid line

• To provide a quick means to connect or disconnect a fluid line without fluid loss

• To increase the pressure in the system

• To reduce the weight of the system