SA Flyer — Edition 263 — September 2017

80 SA Flyer Magazine

Oil may be expensive,

but we have often heard

that AMOs say regular

oil changes are the least

expensive maintenance an

aircraft owner can carry out

on his aircraft engine.

A

IRCRAFT engine

manufacturers

have very strict

guidelines as to

when oil changes

should be done,

which include

calendar time

limits, even if the engine has run less than

the recommended hour requirements.

The lubricating oil in your engine has

six major functions and must perform all of

them simultaneously

• and without any
  compromise.

These six functions are:

1. To provide a cushion between
   moving parts


2. Reduce friction between moving
   parts


3. Protect the highly finished internal
   parts of the engine from corrosion


4. Keep the interior of the engine
   clean and free of sludge, dirt,
   varnish and other harmful
   contaminants


5. Provide cooling to internal areas


6. Help seal the piston rings to
   cylinder walls
   Let’s look at each function in more
   detail.

A CUSHION BETWEEN MOVING

PARTS

Severe loads are imposed, not only

on the valve train, but within the cylinders,

crankcase and accessory drive section.

Parts are being thrust open, yanked shut,

spun on static bearings and so on. We can

only imagine

how long

these parts

would last if it was not for the thin layer of

lubricating oil between them.

REDUCING FRICTION

Lubricating oil is distributed to the

moving parts of the engine in a number of

different ways. This oil reduces friction by

having an effect similar to millions of tiny

ball bearings rolling around between the

moving parts. The little ‘ball bearings’ of

the engine oil vary in size depending on

the different viscosities or grades of aircraft

engine oil. It is thus important that the

correct type of oil is used.

PROTECTING INTERNAL PARTS

After engine shutdown, a coating of

oil covers the entire interior of the engine.

This coating provides protection against

corrosion. However, the oil drains off after

time, exposing the interior of the engine to

corrosion damage. Over time, contaminants

get in the oil, for example combustion

gasses that get past

the piston rings,

which cause the

oil to become

saturated with

corrosive

agents.

KNOW YOUR PLANE

Wyndham Ferreira – Ferreira Aviation Bloemfontein

OIL CHANGES

THE IMPORTANCE OF

ABOVE - Regular oil changes save your engine ... and will save you money.