NIFE ENGINE EXAM QUESTIONS
WITH 100% CORRECT ANSWERS
(GRADED A+)
Workings of a Turbojet - Answer-Creates thrust by accelerating a small mass of air
through the engine and out the exhaust
Propulsive force is dependent on the amount of fuel
Workings of a Turbofan - Answer-Thrust is created by using that of the turbojet but also
by accelerating bypassed or ducted air through a duct-enclosed fan driven by the
turbine
Bypass Air - Answer-Airflow that goes around the gas generator
Bypass Ratio - Answer-The amount of air that bypasses the gas generator in
comparison with the amount of air that passes through the gas generator
Higher bypass ratios yield lower TSFC and are more efficient
Advantages and Disadvantages of a Turbofan Engine Compared to a Turbojet -
Answer-Advantages: higher thrust at low airspeeds, lower TSFC, shorter takeoff
distances, consideration noise reduction
Disadvantages: higher specific weight, larger frontal area, inefficient at higher altitudes
Workings of a Turboprop - Answer-Propeller acts as wings producing horizontal lift, aka
thrust. It imparts a small acceleration to a large mass of air
Propeller Main Components - Answer-Pitch change/dome assembly: changes pitch of
blades
Blades: installed into hub
Hub: attached to propeller shaft
Reduction Gear Box (RGB) - Answer-Converts the high RPM, low torque of gas
generator to low RPM, high torque needed for the propeller
Prevents propeller blades from reaching supersonic speeds
,Turboprop Alpha Range - Answer-PCL is positioned from flight idle to full power
PCL sends fuel flow signals to FCU
Propeller governor controls blade angle
FCU controls fuel flow
Turboprop Beta Range - Answer-PCL is positioned from flight idle to max reverse
PCL is mechanically to FCU and pitch change assembly
Only used during ground operations
Advantages and Disadvantages of a Turboprop - Answer-Advantages: develops high
thrust at low speeds, excellent takeoff, slow speed, and low altitude characteristics,
superior for lifting heavy loads off shorter runways, lowest TSFC for gas turbines
Disadvantages: heavier and more complicated, limited speeds
Workings of a Turboshaft - Answer-Similar to a turboprop except all energy not used to
drive the compressor is converted to shaft horsepower
Pascal's Law - Answer-Pressure applied to a confined liquid is transmitted equally in all
directions without loss of pressure and acts with equal force on all surfaces
Pressure - Answer-Force per unit area.
Workings of Hydraulics - Answer-If input and output area are the same, then the force
and distance displaced will be the same.
If they are different, the force will vary based on F1=A1*F2/A2. This is based on the
basic pressure equation P=F/A. The displacement will be inversely proportional
Power Control System - Answer-Supplies fluid pressure to the flight controls only
Utility Control System - Answer-Supplies fluid pressure to the utility systems as well as
the flight controls
Ex. Landing gear, wing fold, wheel brakes
Reservoir Functions - Answer-S torage space for hydraulic fluid
H eat dissipation
A eration
F oreign matter trapping
T hermal expansion
Non-Pressurized Reservoirs - Answer-Vented to ambient air
Balances reservoir pressure with atmospheric
Located in pressurized compartment
, Pressurized Reservoirs - Answer-Designed for high altitude operation
Pressurized by bleed air from compressor or by hydraulic system pressure
Pressurization ensures positive fluid flow for any aircraft attitude
Types of Pumps - Answer-Hand pumps: backup hydraulic system, provides alternative
hydraulic power, mainly used for emergency systems
Variable displacement pump: regulates fluid volume delivery in accordance with system
flow
Constant displacement pump: delivers constant fluid output for any rotational speed,
delivers steady flow regardless of system pressure, must incorporate a pressure
regulator/unloader valve
Pressure Regulator/Unloader Valve - Answer-Maintains a set pressure by diverting
excess pump flow back to reservoir
Check Valve - Answer-Allows free flow of hydraulic fluid from pumps but prevents back
flow of system pressure
Accumulator Functions - Answer-S hock absorber
E mergency pressure use
A ssist peak operations
M aintain pressure during shutdown
Filters - Answer-Ensure delivery of contaminant free hydraulic fluid by preventing dust,
grit, and undesirable impurities from entering the system
Relief Valve - Answer-safety valve installed to prevent pressure to build up to the point
where a seal might burst or a damage may occur
Pressure Gauges - Answer-Indicate the amount of pressure in the hydraulic system
Pressure Switches - Answer-Used to indicate a hydraulic pressure drop that falls below
allowable limits
Hydraulic Fuses - Answer-Safety devices that detect ruptures, failed fittings, or other
leak producing failures/damage
Prevents loss of fluids while allowing rest of system to remain in operation
Selector Control Valves - Answer-Redirects fluid flow for system operation
Changing the direction reverses the flow changing the direction of fluid flow to the
actuator
WITH 100% CORRECT ANSWERS
(GRADED A+)
Workings of a Turbojet - Answer-Creates thrust by accelerating a small mass of air
through the engine and out the exhaust
Propulsive force is dependent on the amount of fuel
Workings of a Turbofan - Answer-Thrust is created by using that of the turbojet but also
by accelerating bypassed or ducted air through a duct-enclosed fan driven by the
turbine
Bypass Air - Answer-Airflow that goes around the gas generator
Bypass Ratio - Answer-The amount of air that bypasses the gas generator in
comparison with the amount of air that passes through the gas generator
Higher bypass ratios yield lower TSFC and are more efficient
Advantages and Disadvantages of a Turbofan Engine Compared to a Turbojet -
Answer-Advantages: higher thrust at low airspeeds, lower TSFC, shorter takeoff
distances, consideration noise reduction
Disadvantages: higher specific weight, larger frontal area, inefficient at higher altitudes
Workings of a Turboprop - Answer-Propeller acts as wings producing horizontal lift, aka
thrust. It imparts a small acceleration to a large mass of air
Propeller Main Components - Answer-Pitch change/dome assembly: changes pitch of
blades
Blades: installed into hub
Hub: attached to propeller shaft
Reduction Gear Box (RGB) - Answer-Converts the high RPM, low torque of gas
generator to low RPM, high torque needed for the propeller
Prevents propeller blades from reaching supersonic speeds
,Turboprop Alpha Range - Answer-PCL is positioned from flight idle to full power
PCL sends fuel flow signals to FCU
Propeller governor controls blade angle
FCU controls fuel flow
Turboprop Beta Range - Answer-PCL is positioned from flight idle to max reverse
PCL is mechanically to FCU and pitch change assembly
Only used during ground operations
Advantages and Disadvantages of a Turboprop - Answer-Advantages: develops high
thrust at low speeds, excellent takeoff, slow speed, and low altitude characteristics,
superior for lifting heavy loads off shorter runways, lowest TSFC for gas turbines
Disadvantages: heavier and more complicated, limited speeds
Workings of a Turboshaft - Answer-Similar to a turboprop except all energy not used to
drive the compressor is converted to shaft horsepower
Pascal's Law - Answer-Pressure applied to a confined liquid is transmitted equally in all
directions without loss of pressure and acts with equal force on all surfaces
Pressure - Answer-Force per unit area.
Workings of Hydraulics - Answer-If input and output area are the same, then the force
and distance displaced will be the same.
If they are different, the force will vary based on F1=A1*F2/A2. This is based on the
basic pressure equation P=F/A. The displacement will be inversely proportional
Power Control System - Answer-Supplies fluid pressure to the flight controls only
Utility Control System - Answer-Supplies fluid pressure to the utility systems as well as
the flight controls
Ex. Landing gear, wing fold, wheel brakes
Reservoir Functions - Answer-S torage space for hydraulic fluid
H eat dissipation
A eration
F oreign matter trapping
T hermal expansion
Non-Pressurized Reservoirs - Answer-Vented to ambient air
Balances reservoir pressure with atmospheric
Located in pressurized compartment
, Pressurized Reservoirs - Answer-Designed for high altitude operation
Pressurized by bleed air from compressor or by hydraulic system pressure
Pressurization ensures positive fluid flow for any aircraft attitude
Types of Pumps - Answer-Hand pumps: backup hydraulic system, provides alternative
hydraulic power, mainly used for emergency systems
Variable displacement pump: regulates fluid volume delivery in accordance with system
flow
Constant displacement pump: delivers constant fluid output for any rotational speed,
delivers steady flow regardless of system pressure, must incorporate a pressure
regulator/unloader valve
Pressure Regulator/Unloader Valve - Answer-Maintains a set pressure by diverting
excess pump flow back to reservoir
Check Valve - Answer-Allows free flow of hydraulic fluid from pumps but prevents back
flow of system pressure
Accumulator Functions - Answer-S hock absorber
E mergency pressure use
A ssist peak operations
M aintain pressure during shutdown
Filters - Answer-Ensure delivery of contaminant free hydraulic fluid by preventing dust,
grit, and undesirable impurities from entering the system
Relief Valve - Answer-safety valve installed to prevent pressure to build up to the point
where a seal might burst or a damage may occur
Pressure Gauges - Answer-Indicate the amount of pressure in the hydraulic system
Pressure Switches - Answer-Used to indicate a hydraulic pressure drop that falls below
allowable limits
Hydraulic Fuses - Answer-Safety devices that detect ruptures, failed fittings, or other
leak producing failures/damage
Prevents loss of fluids while allowing rest of system to remain in operation
Selector Control Valves - Answer-Redirects fluid flow for system operation
Changing the direction reverses the flow changing the direction of fluid flow to the
actuator
