AVIA- Chapter 7 pt. 2

Sections of turbine engines

-Inlet
-Compressor
-Combustion Chambers
-Turbine section
-Exhaust

Compressor type classification of turbine engines

Centrifugal Flow & Axial Flow

Centrifugal flow

Air flows perpendicular to the axis of rotation

Axial flow

Air flows parallel to the axis of rotation

Design type classification of turbine engines

-Turbojet
-Turboprop
-Turbofan
-Turboshaft

Engine Pressure Ratio (EPR)

-Indicates power output
-Ratio of Compressor inlet pressure to turbine discharge --
pressure

Exhaust Gas Temperature (EGT)

-Measures turbine temp. (a limiting factor for turbine engines)
EGT measures this temperature

Other variations of EGT

-Turbine Inlet Temperature (TIT)
-Turbine Outlet Temperature (TOT)
-Turbine Gas Temperature (TGT)

Torquemeter

-Used on Turboshaft & Turboprop engines
-Measures power applied to the shaft

N1 Indicator

-Indicates rotational speed of low pressure compressor in percent (driven by the N1 turbine wheel)

N2 Indicator

-Indicates rotational speed of high pressure compressor in percent (driven by the N2 turbine wheel)

Temperature limits

Turbine Inlet Temperature is the usual limiting factor

Decreases

Lower density (altitude) _________ available thrust

Limit

High ambient temperatures ______ thrust available

Foreign Object Damage (FOD)

Anything other than air that enters a turbine compressor has the potential to cause damage to the engine

Hot start

If EGT exceeds limits during the start, a ___ _____ has occurred

Hot start causal

Excessive fuel present or insufficient air flow

Hung start

If engine does not reach normal speed after ignition, a ____ _____ has occurred

Hung start causal

Insufficient start power or fuel control malfunction

Compressor stall

When inlet velocity and compressor rotational speed become imbalanced a __________ _____ may occur (inlet air flow is disrupted)

Compressor stall causal

Causes fluctuations in the in RPM and EGT

Compressor stall recovery

Reducing power and increasing airspeed

Flameout

Combustion is stopped

Flameout causal

Excessive fuel flow (rich) or fuel starvation (lean), occurs during descent if power is reduced too far

Flameout recovery

Air start can be attempted if time allows

Shaft horsepower or brake horsepower

Turboprops and Turboshaft engines are rated by. . .

Net thrust or thrust horsepower

Turbojet and Turbofan engines are rated by. . .

Two types of fuel systems

Gravity feed & Pressure feed (fuel pump system)

Gravity feed

Gravity Feed: uses gravity to move fuel from tanks to the engine (tanks must be higher than the engine fuel inlet)

Fuel pump system

Uses engine driven pump and auxiliary electric fuel pump

Primer system

Used in both fuel systems for engine starting (may be manual or electric depending on installation)

Fuel tanks

Normally located in the wings, vented to atmosphere to prevent vacuum from forming above fuel (also allows expansion space)

Fuel quantity

Gauges have a sensor in each tank, may be displayed in gallon or pounds

Fuel levels

____ ______ should be manually verified during preflight

Fuel selectors

Allows for fuel management, can be simple ON/OFF, or multiple valves/many tanks

Strainers

Must be drained during preflight to purge water from the system

Red

80/87 fuel color

Green

100/130 fuel color

Blue

100LL fuel color

Clear or straw

Jet A fuel color

Automotive gasoline (MOGAS)

Available at some airports (only for approved aircrafts), no color spec.

Ground

Most important consideration for refueling aircraft is to ______ the aircraft to the fuel pump/truck BEFORE beginning refueling

Light

_____ aircraft use exhaust muff for heating air for cabin and defrosting the windshield

Larger

______ aircraft (twins and larger) use combustion heaters which are fueled from the aircraft’s fuel supply

Bleed air

Turbine aircraft can take _____ ___ from the engine compressor section to heat the cabin

14 volt systems

Use a 12 volt battery

28 volt systems

Use a 24 volt battery

Onboard electrical system

Must provide sufficient power to operate all of the onboard systems, almost all use alternators

Master switch

Controls electrical system, usually split to connect/disconnect the battery and the alternator separately

Hydraulic systems

Use hydraulic pressure to operate brakes, retractable landing gear, flight controls, flaps, spoilers and other systems

Basic components of a hydraulic system

Reservoir, pump, filter, control valves, actuators, and a pressure control system

Different landing gear types

Tricycle (nose wheel), conventional (tail wheel), (fixed or retractable)

Pressurized areas on an aircraft

Typically pressurizes cabin, flight compartment and sometimes the baggage compartment

Pressurized aircraft

-Requires a source of compressed air (usually bleed air from turbine engines)
-Typically maintains a cabin altitude of about 8000 feet
-Prevents hypoxia for crew and passengers

Outflow valve

In a pressurized aircraft pressure is controlled by the _______ _____ which regulates cabin pressure

Oxygen systems

-Required for crew operating at 12,500 ft+ for 30 min+
-Must be provided for all occupants if operating at 15,000 ft+
-Pilots encouraged to use oxygen at 10,00 ft+ in day and 5000 ft+ night.

Two basic types of oxygen systems

Diluter-Demand system (up to 40,000 ft)
Pressure-Demand system (40,000 ft+)

Servicing oxygen systems

-Done outside of hangars
-Cleanliness is critical
-No contact with petroleum products
-Persons servicing must have no dirt, oil, or grease on hands, clothing, or tools

Anti-/de-icing devices (wings)

-Inflatable boots
-Heated leading edges
-Weeping wing

Anti-/de-icing devices (windscreen)

-Deice fluid (alcohol)
-Electrical heating

Anti-/de-icing devices (prop)

-Electrical
-Deice fluid