turbine test

Gas Turbine Engine Maintenance Notes

Page 1:

  • Gas turbine oil:

    • Fully synthetic

    • Using turbine oil in a recip engine leads to inadequate lubrication due to its thinness.

  • Oil pumps:

    • Turbine engines have positive displacement oil pumps.

  • Types of oils:

    • Type 3 oils allow higher temperatures.

    • Type 2 oils are for high heat operations but may diminish in low heat operations.

    • Type 1 oils are suitable for colder environments.

  • Cooling methods:

    • Fuel can be used to cool engine oil.

    • Ram air and bleed air can be used to cool oil in a turbine engine.

  • Sealing methods:

    • Common ways of sealing turbine engines are carbon seal and labyrinth seal.

  • Lubrication:

    • Bearings in the turbine engine are the most critical parts to lubricate.

    • The bearing supporting the rear of the engine (#3 bearing) is the hottest.

  • Oil types:

    • Gas turbine engines in extremely cold environments use type 1 oil.

  • Components:

    • Chip detector detects ferrous metal.

    • Pressure relief valve maintains oil pressure.

  • Oil system:

    • Most turbine engines have a dry sump system.

    • Oil filters have a bypass for clogged filters.

  • Maintenance:

    • Last chance oil strainers are cleaned at engine overhaul.

  • Fuel controls:

    • Electronic fuel controls can be full authority or supervisory.

  • FADEC and supervisory controls:

    • FADEC has 2 channels, supervisory has 1.

  • Pressurization dump valve:

    • Removes excess fuel to prevent coking.

  • Fuel properties:

    • Kerosene has more heat energy per gallon than per pound.

    • Kerosene is oilier and better for engine lubrication than gasoline.

  • Filters and dividers:

    • Very fine filters are called micron filters.

    • Fuel divider opens based on fuel pressure.

  • Failures and actions:

    • Supervisory EDC failure leads to manual control.

    • Fuel ice light turning on requires turning on fuel heat.

Page 2:

  • Fuel system:

    • Fuel heater opens a bleed air valve for heat exchange.

    • Turbine engine fuel flow meter is calibrated in pounds per hour.

    • Duplex fuel nozzles have primary orifices for idle fuel spraying.

  • Inputs and controls:

    • Hydromechanical fuel control uses power lever angle, inlet pressure, and burner pressure inputs.

    • FADEC cross-checks inputs if one is lost.

  • Ignition system: