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oil system inspection AnD servicing
Oil Temperature and Colour
High oil temperature will accelerate the accumulation of carbon particles
in the oil and the deterioration of oil additives. Oil colour will darken with
usage and exposure to light. The rate of colour change is dependent upon
the oil manufacturer’s formula. A darkening of the oil does not indicate
deterioration in the lubricity of the base stock. Additives are replenished
with the addition of oil during level servicing.
Chip Detectors
All PT6A engines are fitted with an RGB chip detector, while some models
also have a chip detector in the AGB housing. AGB chip detectors are not
equipped with a self-closing valve. When the chip detector is removed,
the oil in the accessory gearbox will drain from the engine. During normal
operation, there will be approximately ½ litre (17 oz.) of residual oil.
Chip detectors should be checked regularly for continuity and any foreign
material. If the aircraft is equipped with a cockpit indication of the chip
detector, the whole system should also be checked regularly. Refer to the
applicable maintenance manuals for inspection intervals.
Oil Filter Debris Analysis
The oil filter must be changed or cleaned at scheduled intervals. At the
same time a visual inspection of the oil filter and chip detectors should
be done. This is a simple and reliable method of assessing the wear of
oil-wetted parts. As an extra step, a solvent may be used to flush trapped
particles from the engine oil filter. The solvent is poured through filter paper
to collect the debris. This is referred to as a filter “patch” check.
The filter paper is sent to a laboratory for analysis. Laboratory techniques
can be used to determine the alloy of the particles which helps determine
their source. With successive samples, a wear trend for oil-wetted parts
can be established.
oil system inspection AnD servicing
Oil Temperature and Colour
High oil temperature will accelerate the accumulation of carbon particles
in the oil and the deterioration of oil additives. Oil colour will darken with
usage and exposure to light. The rate of colour change is dependent upon
the oil manufacturer’s formula. A darkening of the oil does not indicate
deterioration in the lubricity of the base stock. Additives are replenished
with the addition of oil during level servicing.
Chip Detectors
All PT6A engines are fitted with an RGB chip detector, while some models
also have a chip detector in the AGB housing. AGB chip detectors are not
equipped with a self-closing valve. When the chip detector is removed,
the oil in the accessory gearbox will drain from the engine. During normal
operation, there will be approximately ½ litre (17 oz.) of residual oil.
Chip detectors should be checked regularly for continuity and any foreign
material. If the aircraft is equipped with a cockpit indication of the chip
detector, the whole system should also be checked regularly. Refer to the
applicable maintenance manuals for inspection intervals.
Oil Filter Debris Analysis
The oil filter must be changed or cleaned at scheduled intervals. At the
same time a visual inspection of the oil filter and chip detectors should
be done. This is a simple and reliable method of assessing the wear of
oil-wetted parts. As an extra step, a solvent may be used to flush trapped
particles from the engine oil filter. The solvent is poured through filter paper
to collect the debris. This is referred to as a filter “patch” check.
The filter paper is sent to a laboratory for analysis. Laboratory techniques
can be used to determine the alloy of the particles which helps determine
their source. With successive samples, a wear trend for oil-wetted parts
can be established.
Summary of Contents for PT6A Turboprop
Page 1: ...Key NEW OWNER WISDOm YOUR PT6A turboprop ...
Page 5: ......
