90 Questions
What is the main purpose of Engine Pressure Ratio (EPR) system?
To indicate engine thrust
In the EPR formula, what does Pt2 represent?
Compressor inlet pressure
Which company uses station Pt2 and station Pt7 to identify EPR tap-off points?
Pratt & Whitney
What is the EPR ratio formula according to the text?
(Pt2 / Pt7) - 1
How would an increase in Pt7 value affect the EPR value calculated using the formula?
Decrease
What are the two main performance instruments mentioned in the text for monitoring engine output?
Engine Pressure Ratio (EPR) and torque
What does an EPR indication of 2.4 mean?
The turbine discharge pressure is 2.4 times greater than the compressor inlet pressure
When should aircrew refer to EPR graphs according to the text?
Before planning flights
Why may fuel and cargo loadings need to be reduced in high ambient air temperatures?
To maintain safe operating conditions due to reduced engine performance
What does the Take-off EPR value of 2.6 indicate?
The EPR value needed for take-off under specific conditions
What does the EPR reflect about the engine?
The amount of work the engine is doing in the air
What is the main purpose of using Engine Pressure Ratio (EPR) as an engine performance indicator?
To account for turbine discharge total pressure and compressor inlet total pressure
Which type of engines are primarily focused on producing thrust?
Turbojet engines
What is the most common power indication for Turbo-propeller and turboshaft engines?
Torque
If an engine is performing at rated take-off power but indicates an exhaust gas temperature 20°C above comparable engines, what could this indicate?
Inefficient compressor or bleed air loss
What do engine condition instruments enable operators to monitor specifically?
Oil temperature and exhaust gas temperature
In modern aircraft, what is the trend regarding cockpit instrument displays?
They are shifting towards multi-functional digital displays
What happens to the torque-shaft when the engine is delivering power to the gearbox?
It twists slightly.
What is the function of the phase detector in the torque indicator system?
Calculates the difference between signals from pick-up assemblies.
How does the torque indicator system use the output from the phase detector?
To drive a pointer in the torque indicator.
What effect does misalignment of teeth on the torque-shaft with the reference shaft have on the torque-shaft indication system?
It results in inaccurate torque measurement.
In the torque-shaft indication system, what component calculates the difference between signals from pick-up assemblies?
Phase detector
What drives a pointer in the torque indicator of a complete torque indicator system?
Phase detector output
What is the main function of a torquemeter indicator system in a turbo-propeller engine?
Measures and indicates torque transmitted to the propeller
How does the hydraulic torque indication system determine torque in a turbo-propeller powerplant?
By measuring hydraulic pressure
What effect does aerodynamic resistance have on the torquemeter system in a turbo-propeller engine?
Transfers torque from the planet gears to the stationary ring gear
How is torque typically transmitted in a rotary wing configuration from the engine to the main and tail rotor assemblies?
Via an engine reduction gearbox and then to the main rotor gearbox
In what way do torquemeter systems differ based on the type of engine used?
In the principle of operation but not in construction
Which component converts rotational force into thrust in a turbo-propeller engine?
Propeller shaft
How does the hydraulic torque indicating system generate a torque signal?
By detecting resistance between gears
What translates resistance between gears into a torque signal in the hydraulic torque indicating system?
Piston displacement
In the hydraulic torque indicating system, what is used to sense the oil pressure proportional to the torque applied to the propeller shaft?
Bourdon tube
What is the role of the ring gear movement in the hydraulic torque indicating system?
To resist piston movement
Which component is responsible for displaying the torque information in the cockpit in the hydraulic torque indicating system?
Cockpit indicator
What is the purpose of oil pressure in the hydraulic torque indicating system?
To be proportional to applied torque
What do engine condition instruments NOT include?
Hydraulic system pressure
Why would an operator monitor engine condition instruments?
To troubleshoot specific engine sections or components
If an operator notices low oil quantity and high oil temperature in an engine, what is a likely deduction?
The low oil quantity caused the high oil temperature
What might a pilot do if they observe a high torque indication from one engine in a twin-engine helicopter?
Scan the condition instruments of the other engine
How do engine condition instruments help in troubleshooting?
By providing data for maintenance schedules
What is the significance of noticing a high torque indication from one engine in a twin-engine helicopter?
It indicates a possible issue with that specific engine
How does monitoring condition instruments aid in maintaining optimal engine performance?
By allowing for early detection of potential issues
What is the main purpose of performance instruments in the engine cockpit?
Allow an operator to monitor engine output at a glance
If Pt2 is at 14.7 PSI absolute and Pt7 is at 28.52 PSI absolute, what would be the EPR value based on the formula provided?
2.0
What do pressure transmitters do in a typical EPR system as discussed in the text?
Sense and interpret compressor inlet and turbine discharge pressures
What distinguishes performance instruments from condition instruments in the engine cockpit?
Performance instruments allow for quick monitoring of engine output, while condition instruments focus on overall health assessment
What do high fuel flow and high turbine gas temperature indicate in the context provided?
Compressor air loss
Which of the following is NOT mentioned as an engine condition instrument in the text?
Turbine gas pressure
What does engine vibration indicate based on the information provided?
Mechanical imbalance
What does the fuel flow indicator primarily display according to the text?
Amount of fuel consumed
What is the main purpose of the In-flight Engine Condition Monitoring System (IECMS) discussed in the text?
Diagnosing engine malfunctions
What is the function of the maintenance signal data converter (MSDC) discussed in the text?
Converts analogue signals to a common digital format
Which system converts the analogue signals from engine sensors to a common digital format?
Maintenance Signal Data Converter (MSDC)
What type of data can be downloaded and used by maintenance crews to diagnose and rectify faults?
Fault isolation data
Which component receives signals from engine sensors in the context of the text provided?
Maintenance Signal Data Converter (MSDC)
What is the primary role of the microcomputer trend monitoring data display mentioned in the text?
Providing trend monitoring data
What type of failure modes is the process unable to detect?
Catastrophic failures
Which component is NOT included in the typical sources of wear found in detected failures?
Compressor blades
What is the main advantage of 'on-condition' maintenance for engine modules?
It saves money by reducing the need for scheduled overhauls.
What type of failures may occur where metal particles are too big to be detected by the process?
Catastrophic failures
Why is monitoring engine performance trends crucial for engines maintained on an 'on-condition' basis?
To identify potential faults early and prevent major issues.
What is the main consideration for taking special samples according to the text?
Based on unit maintenance activity directives
What is the purpose of the Spectrometric Oil Analysis Program (SOAP) in engine maintenance?
To detect potential engine failures through oil analysis.
When should routine sampling intervals be as specified?
As mentioned in the technical reference documentation
How does 'on-condition' maintenance differ from traditional scheduled overhauls?
On-condition maintenance eliminates scheduled overhauls unless a fault occurs.
Which component is NOT included in the sources of wear on reciprocating engines?
Compressor blades
How does accurate trend monitoring benefit aircraft operators using 'on-condition' maintenance?
It reduces the need for spares and manpower.
Why are most modern engines manufactured to be modular?
To facilitate 'on-condition' maintenance and easy part replacement.
What type of maintenance is described in the text for modern engines?
On-condition maintenance
Why is monitoring engine performance trends crucial for engines under 'on-condition' maintenance?
To accurately determine maintenance needs
What is the primary purpose of Early Failure Detection (EFD) in engine monitoring?
To detect failures before they cause major issues
What does the Spectrometric Oil Analysis Program (SOAP) primarily focus on in engine maintenance?
Detecting metal particles in oil
Which type of monitoring system evaluates engine performance while the aircraft is in flight?
In-flight Engine Condition Monitoring System (IECMS)
What distinguishes engines maintained through 'on-condition' maintenance from those with scheduled overhaul intervals?
Modular maintenance approach
What is one of the limiting factors of a gas turbine engine mentioned in the text?
Turbine Inlet Temperature (TIT)
Why is it important to measure Turbine Inlet Temperature (TIT) in a gas turbine engine?
To ensure the turbine operates within safe temperature limits
What is the purpose of comparing engine operating parameters?
To diagnose the engine's condition
What is the significance of monitoring engine performance trends?
To assess the engine's condition over time
How does measuring Turbine Inlet Temperature (TIT) aid in engine performance monitoring?
By ensuring safe turbine temperature operation
What does comparing engine operating parameters help to determine?
Engine's condition
What critical information do engine performance instruments provide to engine operators?
Gas temperature information
How does the Spectrometric Oil Analysis Program (SOAP) benefit engine maintenance according to the text?
By detecting early failures
In the context provided, what does the term 'on-condition' maintenance refer to?
'As-needed' maintenance triggered by specific conditions
What component in a turbo-propeller engine receives signals from engine sensors as mentioned in the text?
Torquemeter indicator system
Why are most modern engines manufactured to be modular based on the text?
To facilitate easier maintenance and repairs
What is the main advantage of monitoring condition instruments in maintaining optimal engine performance?
To ensure early failure detection
What does a high torque indication from one engine in a twin-engine helicopter signify based on the information provided?
Potential mechanical failure
How does the hydraulic torque indicating system generate torque signals in a turbo-propeller engine?
By converting oil pressure into torque signals
What is the primary role of the MSDC (Maintenance Signal Data Converter) as discussed in the text?
To convert analogue signals to digital format
What does the EPR system reflect about the engine according to the text?
Gas turbine efficiency
Test your knowledge on engine cockpit performance instruments which help operators monitor engine output or performance easily. This quiz covers topics like Engine Pressure Ratio (EPR) and torque indicators.
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