Chp 4 ( Compressor Washing) Flashcards
What is the purpose of Compressor Washing?
To remove the accumulation of salt, dust, and industrial products from the air duct and compressor, which can affect aerodynamic characteristics and engine performance.
Why must compressors be washed periodically?
To remove deposits from dirty compressor blades and corrosion, which may cause a deterioration in engine performance.
Which type of compressor is more likely to lose performance?
The axial compressor is more likely to lose performance due to the shape and size of the blades than the centrifugal compressor.
What factors determine the periodicity of compressor washing?
Location and atmospheric conditions as laid down in the aircraft maintenance manual (AMM - Topic 1).
In what environments is more frequent washing required?
In salt-laden atmospheres, industrial areas, and during a sudden drop in engine performance.
What fluids are used for normal washing?
a. ZOK 27 (Detergent)
b. Demineralised water
c. For cold conditions, an anti-icing inhibitor (Methanol)
d. Precise details will be laid down in the relevant aircraft publication
What is the warning associated with ZOK-27?
WARNING 1: Fluid compressor washing ZOK-27 is a dangerous material.
What is the warning associated with Methanol?
WARNING 2: Fluid Methanol pure AL-14 is a dangerous material.
What is the caution regarding water/methanol mix?
WARNING 3: Fluid water/methanol mix is a dangerous material.
What should be checked before starting the engine?
Make sure that the air intake and surrounding area is clear of loose articles prior to starting the engine.
What is the purpose of washing fluid ZOK-27?
Washing fluid ZOK-27 is used as a deposit remover and is to be diluted using water (distilled, demineralised or drinking).
NOTE 1: The ratio of the chemical to water must be prepared IAW the Maintenance Manual.
What should be ensured regarding air services?
Ensure all air services are switched off (cabin heating etc.).
NOTE 3
What happens if the delivery valve on the washing rig is opened too quickly?
Opening the delivery valve on the washing rig too quickly will slow the engine down and possibly flame out.
NOTE 4
What is a typical compressor washing procedure for Gazelle Aircraft?
a. If installed, remove the anti-icing shield and/or sand filter
b. Ensure that the intake debris guard is fitted
c. Remove the engine cowlings
d. Remove the safety pin and open the fastener
e. Open the securing strap. Install the wash rig around the intake with the distribution pipe positioned in the centre of the intake duct and fastener positioned vertically
f. Close the fastener and secure with the safety pin
g. Thoroughly mix the ingredients and pour the mixture into the juniper rig (minimum 25 litres).
What is the first step in connecting the wash rig?
Connect the wash rig to the juniper rig, ensuring the delivery valve on the rig is closed and pressurising the rig to between 35 lbs in² and 40 lbs in².
What should be done after connecting the wash rig?
Start the engine in accordance with current instructions and accelerate to maximum.
How long should fluid flow after opening the delivery valve?
Allow fluid to flow for two minutes.
What is the next step after allowing fluid to flow?
Close the delivery valve and continue the engine run for a further two minutes (drying out run).
What should be done after the drying out run?
Stop the engine.
What is the procedure for disconnecting the juniper rig?
Disconnect the juniper rig from the washing rig and remove the washing rig in the reverse order to fitting.
What are the final operations after washing?
Install the anti-icing shield, sand filter or silencer as applicable, install the engine cowlings, ensure the work area is clean and free of loose objects, and remove all tools and equipment from the aircraft.
What is important about the washing ring installation?
Ensure that a nominal gap exists between the support frame and intake washing ring.
How is the delivery equipment configured in some aircraft?
Some aircraft have the delivery equipment fitted permanently into the intake area of the engine, connected via a panel on the intake cowlings.
