Section 7 Pilot’s Operating Handbook
Description of Airplane and Systems EXTRA 500
duct type, which is an integrated part of the removable upper
right band cowling.
The oil cooler has an internal by-pass, which is controlled by a
thermostat, which is fitted direct to the oil cooler which features
a separate port integral with its oil outlet connection for that
purpose.
For a quicker warm up of engine and to prevent oil temperatures
below recommended operation range at low ambient
temperatures, the thermostat starts to close the internal by-pass
of the cooler on rise at an oil temperature of 55 °C (131 °F).
The internal by-pass is totally closed when oil temperature is
above 78 °C (172 °F) so that all oil is leaded through the oil
cooler core. In addition, the thermostat features a pressure
control, which opens the by-pass in case differential pressure
(core to by-pass) will rise above 25-40 psi at 78 °C (186 °F) oil
temperature.
3 Oil Reservoir
The external oil reservoir (oil tank) is attached to the engine
mount tubes, right hand of the engine close to the oil cooler. An
oil access panel is incorporated to the removable part of the
upper right hand cowling to give unrestricted access to the
bayonet type oil tank filler cap, connected with a dip stick,
which is marked with the word "OIL" and the permissible oil
designation.
The full oil volume for the tank is 5.47 quarts (5.18 liter) and an
add mark on the dipstick at 4.31 quarts (4.08 liter).
To reduce foaming on the oil at high altitudes that could result
in slight oil pressure fluctuation and to fulfill requirement for
minimum oil pressure above 93 % N l speeds, the external oil
tank is slightly pressurized by means of check valves in the vent
line. In addition, this check valve features an internal
depressurization bleed hole in the internal poppet head for
relieving the pressure after engine shutdown and is plumbed to
an overboard line leading to the right hand exhaust stack in the
event of a malfunction of the valve.
4 Scavenge Filter System
An external scavenge lube oil filter is installed between the
engine scavenge oil outlet and the oil inlet of the oil cooler. It is
attached to the bottom engine mount by a steel bracket.
An extended red by-pass indicator pin at the bottom of the filter
unit shows flow through its internal by-pass. The indicator can
7-32 26. January 2011
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