Block III (1b Engine Components)

What is mounted to the accessory box and provides the initial rotation of the gearbox and compressor to start the engine?

Starter

What two types of starters are used on aircraft?

Pneumatic (air starter) and Mechanical (Jet Fuel Starter 'JFS')

What source can an engine use to pneumatically (air) start?

A. Auxiliary Power Unit (APU)

B. Bleed air from another engine

C. Aerospace Ground Equipment

D. All of the Above

D. All of the Above

What is a Jet Fuel Starter (JFS)?

A mechanical way of starting an aircraft, mostly used on fighters. It is a small internally mounted turbine engine that mechanically turns the compressor of the main engine to start the aircraft.

What does the Ignition/ Exciter Unit do?

Supplies high voltage to igniter plugs

What do igniter plugs do?

Send an electrical charge (spark) across a gap between two pieces of metal so the air/ fuel mixture is ignited

Name the five components in the engine fuel system.

(1) Engine driven fuel pumps

(2) Fuel Control Unit

(3) Fuel Manifold

(4) Fuel Nozzles

(5) Fuel Flow Indicator

What do the engine driven fuel pumps do?

Deliver pressurized fuel to a fuel control unit.

*Always sending as much as possible, is not controlled/ throttled

What does the fuel control unit do?

Controls and regulates amount of fuel based on the throttle position

What does the fuel manifold do?

Collects and distributes fuel flow from fuel control unit to fuel nozzles

(Plumbing/ piping around the outside of the engine)

What do the fuel nozzles do?

Spray/ inject fuel into the combustion area in a highly atomized, precise pattern of spray. Located in the combustion section/ chamber.

What does the fuel flow indicator do?

Indicates fuel flow in pounds per hour to the engine and sends information to a gauge in the cockpit.

What does the engine control system do?

Has throttle levers that provide engine control/ thrust output. Connected via mechanical cables or electronic signals to the engine.

What does an instrument system do?

Instruments (gauges) monitor critical engine operating conditions and normal/ abnormal operating ranges

What four types of instruments did we learn about?

(1) Tachometer

(2) Exhaust Gas Temperature/ Turbine Inlet Temperature

(3) Oil Pressure

(4) Oil Temperature

What does a tachometer do?

Indicates engine power output in PERCENTAGE of engines max RPM

What does an exhaust gas temperature/ turbine inlet temperature instrument do?

Uses thermocouples (temperature sensors) mounted around the engine to indicate the temperature (CELSIUS) of gases in exhaust or turbine inlet section

What does an oil pressure indicator do?

Indicates oil pressure in pounds per square inch (PSI)

What does an oil temperature indicator do?

Indicates temperature of oil

What do thrust reverses do?

Reverse the thrust from rearward to forward. Help slow the aircraft during landing roll or aborted take-offs. Reduces stress on landing gear/ brakes. Only high bypass engines have them.

How does a thrust reverser work?

The throttle position controls actuators which move mechanical doors. Mechanical doors close behind the exhaust section forcing the air forward instead of rearward.

What does a compressor anti-stall system do?

Prevents a compressor stall or surge.

During rapid acceleration or deceleration airflow can be disrupted in the compressor section and cause a build-up of pressure which leads to engine failure.

What are variable inlet guide vanes?

Normally located in the front before the first stage of compression. The angle of vanes directs airflow into the compressor section at the optimal engine performance rate. Helps avoid stalls. Found on Turbofan Engines.

What are variable stator vanes?

Positioned after rotor blades. The angle is changed to allow optimal engine efficiency of the compressor at all engine speeds.

What is the engine anti-ice system?

Uses hot compressor bleed air to prevent formation of ice on fan/ inlet section in front of the compressor section.

What does engine oil do?

Lubricates, cleans and cools bearings and gears

What is a wet sump oil system?

Stores oil in accessory gear box

What is a dry sump oil system?

Stores oil in externally mounted reservoir/ tank.

Utilizes scavenge pump

What is a scavenge pump?

Collects and returns oil to reservoir/ tank for reuse

What happens when an oil filter is blocked/ dirty?

An internal bypass valve is opened to allow oil to bypass the filter regardless of contaminants

What is a differential pressure pin (Delta-P) used for?

A red indicator pin extends to indicate a contaminated/ clogged filter

How does engine oil get cooled?

An oil cooler passes oil near streams of ram air or fuel. The heat energy is transferred from the oil to the air or fuel, and the oil exits the cooler at a lower temperature

What is the purpose of a pressure/ breather vent?

When oil heats up in the bearing cases, vapors are created. The vent system removes oil vapors by venting bearing compartments, oil tanks, and accessory gearboxes

How/ when do you service the oil system on an aircraft?

Oil levels are checked after each flight and serviced IAW Technical Order.

If oil levels are low, use either unopened cans poured into a filler neck (unpressurized), or use a service cart connected to an oil connection port (pressurized)

What are five safety precautions when servicing the oil on an aircraft?

(1) Wear PPE

(2) Operating temps can cause burns

(3) Oil is toxic, can cause fetal hazards (consult SDS)

(4) Wash if skin contact occurs

(5) Seek medical attention if ingested

What component rotates the gearbox and compressor on engine start?

A. Crank

B. Starter

C. Ignition

D. Flywheel

B. Starter

Which component contains the gap necessary for a spark to ignite the fuel/air mixture?

A. Ignition unit

B. Igniter plugs

C. Igniter gapper

D. Igniter exciter

B. Igniter Plugs

What unit of measure is used for a fuel flow indicator?

A. Pound per square inch

B. Gallons per hour

C. Miles per gallon

D. Pounds per hour

D. Pounds per hour

What component in the fuel system controls and regulates fuel based on throttle position and engine condition?

A. Fuel pump

B. Fuel nozzles

C. Fuel control unit

D. Fuel manifold tubing

C. Fuel control unit

How is oil pressure measured?

A. Pounds per hour

B. Degrees of Celsius

C. Pounds per square inch

D. Revolutions per minute

C. pounds per square inch

What does the engine tachometer indicate?

A. Power output in percentage of RPM rating

B. Power output in pound per square inch

C. Power input to engine inlet intake

D. Pounds of thrust

A. Power output in percentage of RPM rating

What are mechanical doors that redirect engine thrust forward?

A. Exhaust closer

B. Thrust forward

C. Thrust reversers

D. Exhaust reversers

C. Thrust reversers

What maintains efficiency of the compressor at all engine speeds?

A. Variable stator vanes

B. Engine anti-ice system

C. Variable inlet guide vanes

D. Compressor anti-stall system

A. Variable stator vanes

What uses engine bleed air to prevent the formation of ice on fan/inlet section?

A. Engine anti-ice system

B. Aircraft air conditioning

C. Engine inlet heater probe system

D. Engine intake Rapid Air Movement (RAM) system

A. Engine anti-ice system

What stores oil for oil system use?

A. Oil pump

B. Reservoir/tank

C. Oil compressor

D. Breather/release valve

B. Reservoir/ tank

Which type of pump returns oil from the engine back to a reservoir/tank?

A. Dry

B. Pressure

C. Scavenge

D. Backflow

C. Scavenge

Which valve opens to allow oil to bypass a blocked/dirty filter element?

A. Bypass

B. Pressure

C. Oil cooler

D. Red indicator

A. Bypass

What is the purpose of the oil pressure/breather vent?

A. Relieve excess pressure in the system

B. Return oil to reservoir/tank in wet sumps

C. Provide bypassed oil to return to dry sumps

D. Remove oil vapors from bearing compartments and accessory gearbox

D. Remove oil vapors from bearing compartments and accessory gearbox

What is required if oil is ingested?

A. Notify Commander

B. Seek medical attention

C. Allow sufficient time for oil to air dry

D. Leave clothing on to prevent further contamination

B. Seek medical attention

What hazard is present by the oil operating temperatures?

A. Rash

B. Burns

C. Irritation

D. Excessive dryness

B. Burns