15:10 Basic Lubrication Systems Flashcards
What is the purpose of the lubrication system
To distribute oil to the engine bearing compartments and the gearboxes
What type of lubrication systems do most modern gas turbine engines use
A self contained dry sump lubrication system
The oil is recirculated through this system by pumps. The system keeps the oil in a fit condition to perform its tasks
What 4 subsystems does a basic lubrication system have
- An oil reservoir and supply system
- A scavenge system
- A vent system
- A monitoring system
What is the oil reservoir and supply system also called
The pressure oil system
What are the main components of the pressure oil system
- The oil tank
- The supply lines
- The supply pump
- The supply filter
Where is the oil stored
In the oil tank and pumped by the supply pump through the supply lines to the oil nozzles in the engine bearing compartments and the gearboxes
The oil is filtered before it reaches the nozzle
Where is the oil filter located
Downstream to the supply pump
What is the purpose of the scavenge system
It returns the oil from the bearing compartments and the gearboxes to the oil tank.
This prevents the accumulation of lubrication oil in the bearing compartments and gearbox
What is the purpose of the vent system
It releases air from the lubrication system to the atmosphere
How does the vent system release air to the atmosphere
Bearing compartments have a vent line to release the sealing air and maintain the airflow across the seals
Vent air leaves the shaft at the rear of the engine
What is the purpose of the oil monitoring system
The oil monitoring system measures and indicates oil quantity, oil pressure and oil temperature
What sensors does the oil monitoring system use
- The oil quantity sensor
- The oil pressure sensor
- The oil temperature sensor
- The low oil pressure switch
- The filter clogging switch
What is used to indicate a blocked filter
Mechanical clogging indicators are used to indicate a clogged filter when the engine is stopped. They are also called pop out indicators
Why would you need to check a magnetic chip detector
Contamination can be checked by checking filters and magnetic chip detectors
What is a magnetic chip detector
Small magnets which are in contact with the scavenge oil. They collect particles of magnetic metal which are passing through the oil
Where are magnetic chip indicators located
In the individual scavenge line for each sump. This makes it easy to isolate the source of contamination
The oil quantity transmitter in the tank sends the information via a computer , which performs the measurement. What is this called
The Engine Interface Unit (EIU)
Where is the oil quantity transmitter usually installed
At the top of the oil tank
This allowed the transmitter to be changed with out draining the tank
What two types of quantity transmitter are used
- The capacitance type transmitter
- The reed switch type transmitter
What is the oil pressure transmitter connected to
The oil supply line and to the oil tank vent line
The transmitter senses the pressure difference between the total oil pressure in the oil supply line and the vent pressure in the oil tank
What is the oil low pressure warning always accompanied by in the cockpit
An acoustic warning
Why would an additional pressure switch is also used in the engine oil system
To initiate a low oil pressure warning
What are the two different types of oil temperature sensor
- The thermocouple
- The thermistor
What is used to find out about internal wear of lubricated engine parts
Spectrometric Oil Analysis Program (SOAP) is used
What kind of particles can SOAP find that filters cannot pick up
Particles that range in size from 0.001mm to 0.02mm
The scavenge oil filter element catches larger particles which are the size of?
0.015mm or bigger
Particles are removed and sent for analysis
What is the easiest method of checking for oil contamination
Magnetic chip indicators.
Particles are attracted to the magnets and they are easily removed for inspection
How does an electric magnetic chip detector work
There are two magnets at its tip, the resistance between the two chip detector magnets is monitored by the Electronic Control Unit
The resistance decreases when particles connect with the magnets
How can the oil quantity be checked
At the sight gauges on the oil tanks on the engine, or on the ECAM or EICAS displays in the cockpit
As the oil tank is fitted above the gearbox what is used to prevent the gearbox being filled with oil
An anti siphon device
On engines with out an anti siphon device how quickly do you need to check the oil quantity after the engine has shut down
Between 5-20 mins when all of the oil is in the tank
Why should you wait 5 mins before opening the oil filler cap
Hot oil could spray out
What is the oil filling process called using oil cans
Gravity filling
What is oil filling called when using an oil servicing system
Pressure filling
What safety procedures must be observed for SOAP sampling
- Always use a new plastic bottle and a new hose to prevent contamination of the oil
- Remember to wait at least 5 mins after engine shut down before opening the oil tank filler cap
- Wear gloves to protect your hands as the oil can be hot
- Close the bottle and label immediately after the sample is taken
What must the SOAP sampling bottle label have on it
- Details of aircraft registration
- The engine position
- The engine serial number
- The station where the sample is taken
- Date and time of sample
When removing a mag chip detector what must be done after you have removed it but before checking it
You must check to see the check valve closes behind the detector to prevent a leak
Why can maintenance staff only check one engines mag detector in one day
As the wrong installation could cause an oil leak
The job must be cross checked by a second mechanic to ensure the job has been carried out correctly
What 2 seals can mag chip detectors have
- A reusable seal
- An O ring
