Flexible Hose Fluid Lines

When is it acceptable to reuse a detachable MS-type end fitting?

If it appears serviceable and is not visibly damaged

Why should clamps be checked and re-tightened several days after installation?

Due to material setting from cold flow

Why must flexible hose ends remain straight for at least two hose diameters from the fittings?

To avoid flexure at the fittings

Which material would be inappropriate for use with Skydrol?

Buna-N

A medium-pressure flexible hose in a small diameter is rated to withstand how much pressure?

Up to 3,000 psi

What does "cold flow" indicate during hose inspection?

Permanent hose deformation from clamping pressure

Why is pure rubber never used in the construction of aircraft flexible hoses?

It lacks the necessary strength and durability for aviation use

What primary advantage does Teflon have over rubber when used in flexible hoses?

Practically unlimited shelf and service life

What determines the dash number stenciled on the side of a hose?

The size of tubing it is compatible with

Which material is most suitable for flexible hoses used with phosphate ester base hydraulic fluids?

Butyl

What is the primary function of a torque-limiting wrench during clamp installation?

To prevent over-tightening and hose damage

Why are flexible hoses supported every 24 inches or less during installation?

To limit flexing and chafing during operation

What feature of a flexible hose indicates if it has been twisted during installation?

A spiral in the lay line

What testing method is appropriate for detecting leaks in gas-filled hose assemblies?

Water immersion test

What installation failure does a twisted lay line most likely indicate?

The hose was installed with torsional stress

What precaution should be taken when installing hoses near heat sources?

Locate hoses away from heat or install shrouds

How should a flexible hose be tested after assembly but before installation?

Use hydraulic oil or water for proof testing

Why must flexible hoses be installed with 5% to 8% slack?

To accommodate hose contraction during pressurization

What result could a bend radius that is too sharp cause?

Reduced burst pressure of the hose

What makes Teflon suitable for nearly all aircraft fluid types?

It is chemically inert with broad compatibility

During hose fabrication, what critical step ensures the inside diameter is preserved for flow integrity?

Matching the fitting ID to the hose ID

Which hose type must be replaced completely if failure occurs at a swaged end fitting?

Factory-assembled hose with swaged fittings

What is the most appropriate response to discovering deep, permanent impressions under a hose clamp during inspection?

Consider the hose deteriorated and replace it

What advantage does a rubber-cushioned clamp offer?

Protection from vibration and chafing

Which of the following best explains why preformed Teflon hoses are used in aircraft systems?

They enable shorter routing and eliminate special elbows