OPERATION MANUAL
SILA 450 c
AERO EAST EUROPE
Date 01.09.2015.
Revision 00
Page | 44
AIRPLANE & SYSTEMS DESCRIPTION
Before checking the oil level, make sure that there is not excess residue oil in the
crankcase.
Prior to oil level check, turn the propeller several times by hand in direction of
engine rotation to pump all the oil from the engine to the oil tank. This process is
completed when air flows back to the oil tank cover of the oil tank of the oil tank is
removed.
Pull out the oil dipstick.
The oil in the oil tank should be between the two marks (min./max) on the oil
dipstick, but must never fall below the min mark.
For longer flights replenish oil to max. mark to warrant more oil reserve.
It is important to remember how oil temperature, pressure and type are important factors
for the correct and safe use of the aircraft.
Constant behavior of temperatures and parameters (say “as usual” but of course
within the constructor’s limits) indicates generally safe and health engine service. For this
reason any unexpected change in what the user is judging as “unusual” must be carefully
considered.
Oil participate to the fluids cooling action of the engine and its temperature must be in line
with that of the cooling liquid. Usually friction (RPM) make oil temperature to raise while
CHT raise with EGT and MAP. Oil pressure is highly dependent from viscosity so it is normal
that the oil temperature decrease after the worming up of the engine to stabilize on a fixed
value. Because of the presence of an oil circuit separated from the engine case through
radiator and pipeline it is very important the constant monitoring in occasion of the pre-
flight inspections verifying eventual leaking, or critical points as the connections along the
pipeline; more no contact points between the engine parts must be in the potential
condition to impair trough vibrations any element of the pipeline including the radiator.
The characteristics of the oil must take into account the prevalent kind of fuel used
(detergent properties of the oil itself) as well as the climatic area in which the aircraft is
supposed to operate. Temperature steps which the user must remember are the following:
About 50°C = the minimal temperature necessary for a sufficient engine lubrication.
About 90 – 110°C = desirable working temperature.
About 120 °C = limit for almost mineral oils (above this value lubrication is not
guaranteed).
About 130 °C = limit for almost synthetic oils (above this value lubrication is not
guaranteed).
When during the flight it happens to be unable to maintain the oil temperature within
the limits the following actions must be undertaken:
Temperature is increasing = reduce RPM and change aircraft attitude and speed
(rate of climb).
Temperature is too low = increase RPM , interrupt a descent or decrease the rate
of descent, increase aerodynamic drag.
A sudden fall of the oil temperature is equally dangerous as an excess of its raising.
