Supplement Airplane Maintenance Manual
Cessna 172 with TAE 125-02-99 / -114
AMM-20-02
Chapter:
Issue:
Issue Date:
Page:
Content:
20-AMM-79-02
3
06.11.2013
4
6
Rev. No:
Rev. Date:
1
25.08.2014
GEARBOX OIL SYSTEM
The gearbox oil system is a wet oil sump system. Gearbox oil is
used for lubrication and cooling of the gearbox and for operation
of the propeller regulation by the Constant Speed Unit. The
bearings of the gearbox are lubricated without pressure, the gear
wheels convey the oil and leak oil from the propeller regulation is
used. The oil pump sucks oil from the sump and leads it to the
micro filter within the single stage pump, then to the pressure
relief valve (mechanically adjusted to 20 +/- 2 bar [290 psi +/- 29
psi]) and thereafter to the regulation valve (electronically
controlled by the FADEC with Pulse-Width-Modulation). The oil is
then reaching the piston of the propeller which is changing the
blade pitch according to the value given by the FADEC. The oil
temperature is measured at the propeller-shaft, leak oil of the
propeller-regulation lubricates the bearings and returns to the
sump.
The system contains 1 liter gearbox oil, the level can be checked
at a viewer at the left lower front side of the gear accessible
through a flap at the front side of the cowling.
A filler screw is installed on top, a screw for draining at the bottom
of the gearbox housing.
For type of gearbox oil refer to Chapter 06 of this supplement.
Following limitations are established for the gearbox oil system:
min. oil temperature: ......................................... -32°C
max. oil temperature: ......................................... 120°C
MAINTENANCE PRACTICES
1.
General
This maintenance practice provides instructions to inspect
the oil system.
2.
Inspecting the oil system
This is a visual inspection. Check all pipes, pipe joints,
supply connections and engine housing separation points
(e.g. cylinder head gasket, cylinder head cover gasket for
leakage, seepage points and correct routing. Visually
inspect oil for water contamination.
WARNING:
Avoid skin contact with the oil as it may result in skin irritation.
WARNING:
No leaks or seepage points are permitted!
Содержание Cessna 172
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