40 Questions
What is the primary function of the engine fuel system?
To maintain a steady running state and ensure smooth maximum rate accelerations
What is represented by the normal running line in the fuel system?
The fuel requirement for a given rpm
What effect does an increase in fuel flow initially have on the engine?
It restricts compressor air delivery, leading to unstable airflow and engine surge
What must be maintained to avoid flameout in the engine?
Sufficient fuel flow
What happens when the available energy in the gas stream decreases?
The engine decelerates
What is the metering requirement of the fuel system related to?
Pumping and metering clean, ice-free fuel to the engine in accordance with EEC demands
What is the function of the Fuel Metering Unit (FMU)?
To convert electrical signals to servo pressures
At what point is the Fuel Flow Transmitter reading inaccurate?
At fuel flows lower than 500 pph
What occurs when the COSS control circuit commands the fuel switch to the 'OFF' position?
The PRSOV is forced to close
How is deceleration achieved in the FMU operation during engine running?
By increasing the pressure drop across the FMV
What is the purpose of the differential pressure transducer signals supplied to the EEC (channel A)?
To provide indication of engine health monitoring
What happens when the aircraft fuel control switch is in the 'ON' position during engine running?
The EEC command increases fuel flow, directing HP servo fuel to the FMV bottom piston
What is the purpose of controlling fuel spill in the HP pump?
To minimize fuel spill at engine start point
What is the function of the LP fuel filter differential pressure transducer?
To measure the differential pressure across the LP fuel filter
What is the main purpose of the LP fuel filter assembly?
To remove debris from the fuel prior to entering the HP pump
What does the LP fuel DP transducer do when the differential pressure rises above the first EEC-predetermined threshold?
Displays a maintenance message in the cockpit
What are the two functions of the LP fuel DP transducer?
Measurement of absolute pressure and measurement of differential pressure
What is the purpose of the Fuel Return To Tank (FRTT) differential pressure transducer?
To convert measurements into electrical signals for EEC
What is the purpose of the HP Fuel Filter?
To prevent adverse engine effects from unfiltered fuel in case of LP Fuel Filter bypass valve opening
What is the filtration rating of the filter element in the HP Fuel Filter?
250 micron
What is the purpose of the Fuel Temperature Transducer?
To provide an electrical signal representative of the fuel delivery temperature at the FCOC fuel outlet
What is the function of the Overspeed and Splitter Unit (OSU)?
To divide the engine metered fuel flow equally between the upper and lower burner manifold
What is the purpose of the upper and lower fuel manifolds?
To distribute fuel to 20 fuel nozzles on the upper and lower halves of the engine
What occurs when the splitter valve in the Overspeed and Splitter Unit (OSU) is in the closed position?
A groove around the piston allows the upper manifold to drain into the lower manifold
Which component of the fuel spray nozzles is responsible for atomizing the fuel for efficient combustion?
The fuel orifice
What happens to the fuel in the fuel burner nozzles and manifold during engine shutdown?
It is collected in the drains tank due to back pressure in the combustor chamber
Which display window presentation provides digital readings of engine fuel flow and indicates the difference in fuel flow between the two engines?
Fuelsynoptic 213 window
What CAS message is associated with LP Pump outlet indicating insufficient fuel pressure for the HP fuel system?
Low fuel pressure detected
What condition causes the FRTT (Fuel Return To Tank) system to cease operation?
Pulling of either FIRE handle
What does the High Pressure Shutoff Valve (HPSOV) do when FUEL CONTROL switch selection is OFF?
Remains closed
What is the purpose of alternating the ignition systems for each ground start sequence?
To ensure equal usage of igniter plugs and to detect dormant faults
What triggers both of the ignition systems on the ground?
A failure to ignite indicating a failed ignition system
What is the purpose of energizing both ignition systems in case of water ingestion or surge in stall detection?
To increase the likelihood of a successful lightoff
What detects electrical faults in the Electronic Engine Controller (EEC)?
Internal voltage and current monitors
What is the purpose of the Input Electromagnetic Interference (EMI) Filter in the ignition unit?
To filter out high-frequency elements and prevent contamination of the aircraft DC power supply
What is the function of the Power Control Section in the ignition unit?
To change DC input voltage into a pulsating voltage that is then supplied to the discharge section
What are the components of the Ignition System?
High Energy Ignition Units, High Temperature Ignition Leads, and Igniter Plugs
What is the role of Z diodes in the ignition unit?
To protect the unit from overvoltage and voltage transients
What causes ignition of the fuel-air mixture in the combustion chamber?
Igniter Plugs
What is contained in a sealed case to protect it from damage and moisture?
Ignition Unit
Test your knowledge about the output of flowmeters and the requirements for High-Pressure (HP) Fuel Filters in engines. Questions may cover topics such as voltage pulses, mass flow rate, and the purpose of HP Fuel Filters in relation to LP Fuel Filters.
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