AS 311 - Exam 3

78 flashcards · Other · by Nicholas Enoul

What type of starter is commonly used to start a ground power unit (GPU)? A. Auxiliary power unit B. Electric C. Pneumatic D. Starter-generator
B. Electric
What type(s) of starter(s) are most likely to deliver compressed air to the engine that is being started? A. Neither a ground power unit nor an auxiliary power unit B. Only a ground power unit C. Only an auxiliary power unit D. Ground power unit and auxiliary power unit
D. Ground power unit and auxiliary power unit Note: A quick thing that helped me memorize this is that the APU is the main source of air for Pneumatic Starter systems. If the APU and GPU can't provide air, then the whole concept of the pneumatic system wouldn't be possible.
What type of starter converts te energy from compressed air into mechanical energy to spin the gearbox? A. Starter-generator B. Ground power unit C. Electrical D. Pneumatic
D. Pneumatic
What type of starter reduces aircraft weight by combining two components into one? A. Electric B. Pneumatic C. Starter-generator D. Auxiliary power unit
C. Starter-generator
How can the pilot disengage a pneumatic starter from the cockpit? A. By manually disengaging the pawls B. Via the pressure-regulating or shut-off valve C. By manually decreasing the starter throttle to idle D. By manually disengaging the sprag clutch ratchet
B. Via the pressure-regulating or shut-off valve Note: The pawls are only operated by centrifugal force, and the sprag clutch in of itself doesn't have a direct mechanism for stopping it. Pilots cannot control it other than a pressure regulating valve. As we can see here, there isn't a stopping mechanism of any sort in this graphic. However, the pressure-regulating valve is *probably* located somewhere before the air inlet.
What is the usual starting sequence for a turbine engine? 1 Engage Starter 2 At specified N2 or Ng, turn on ignition 3 Introduce fuel 4 Starter disengages either manually or automatically
Note: please type in the answer with numbers (1, 2, 3, 4, etc.). Or, if without keyboard, please press "look at answer".
What is/are the primary temperature gauge(s) that are monitored during engine start? 1). EGT or ITT 2). Only EGT 3). Only ITT 4). CHT or TIT
1). EGT or ITT
During the start sequence, the EGT climbs rapidly and exceeds the maximum allowable temperature. What is this called? A. Hung start B. Runaway start C. The EGT is not related to turbine engine operations D. Hot start
D. Hot start
What (most likely) is the name and purpose of the black box in this image? A. Igniter. Convert high voltage electricity into a spark to ignite the fuel-air mixture B. Exciter. Increase aircraft electrical system voltage for use in the igniter. C. Glow igniter. Use low-voltage electricity and resistance to make the igniter coil glow D. Lead. Carry the electrical current to the igniter.
B. Exciter. Increase aircraft electrical system voltage for use in the igniter.
What is the most common number of igniters in each turbine-powered engine? One Two Three Four
Two Note: The reason for two is because it's o̶n̶e̶ f̶o̶r̶ ̶y̶o̶u̶,̶ ̶a̶n̶d̶ ̶o̶n̶e̶ ̶f̶o̶r̶ ̶m̶e̶ for redundancy!
What type of igniter produces a spark? A. Only igniter plugs B. Trick question...turbine engines do not use glow plug igniters C. Igniter plugs and glow plug igniters D. Only glow plug igniters
A. Only igniter plugs
How is the automated starting sequence (most likely) initiated in this Airbus A350? A. Switching the engine master lever to ON without any additional action required B. Switching the start mode switch to IGN START without any additional action required C. Switching the engine master lever to ON after choosing IGN/START with the start mode switch D. Moving the power control levers forward to the START position
C. Switching the engine master lever to ON after choosing IGN/START with the start mode switch
For what type(s) of engine(s) is this the primary power instrument? A. Turbofan and turbojet B. Turboprop and turboshaft C. Turbojet only D. Turbofan only
B. Turboprop and turboshaft Note: If it's a torque meter, it is always (as far as I know) going to be turboprop/turboshaft
What two points in the engine provide the engine pressure ratio (EPR) in most engines? A. Diffuser and engine inlet B. Compressor exit and engine inlet C. N2 compressor pressure and N1 turbine pressure D. High pressure turbine exhaust and engine inlet
D. High pressure turbine exhaust and engine inlet Note: For this one, it is easiest to remember the ratio for EPR EPR = (Turbine discharge pressure) ÷ (compressor inlet or engine inlet pressure) As the high-pressure turbine is furthest aft of the engine, and the compressor inlet is almost synonymous with an engine inlet, (D.) is the only answer.
What is/are the most likely power instrument(s) in a turbofan engine? 1). N1 percentage 2). EGT or ITT 3). EPR or N1 percentage 4). Ng percentage
3). EPR or N1 percentage
What is the meaning of "VIB" near the bottom of this image? A. Engine vibration in 1/1000 of an inch B. Oil viscosity index in centistoke format C. Engine vibration in 1/10 of an inch D. Oil viscosity index in SAE format
A. Engine vibration in 1/1000 of an inch Note: if you ever see "VIB" I think we can safely assume it is engine vibration. Additionally, considering what unit, the way I memorized it was actually watching a lot of machine-shop videos. The near-universal measurement for accuracy in the US when machining is in thou (or 1/1000 of an inch).
To what type(s) of engine(s) do these instruments refer? A. Turbojet B. Turboprop C. Turbofan D. Turbofan or turboshaft
B. Turboprop Note: The unique thing we see on this instrument is the TORQ PSI instrument. As we know, torque meters are almost always going to be in turboprops. I am pretty sure it also applies to turboshafts, however, the option for turbo shaft is paired with turbofan - which is incorrect.
What temperature is also called "turbine outlet temperature"? 1). TIT 2). EGT 3). CHT 4). ITT
2). EGT Note: EGT is known as Engine Exhaust Temperature. As the turbine outlet is directly behind/a part of the exhaust, EGT is also coined as "turbine outlet temperature."
The Cessna 441 Conquest is a turboprop. What type of starter is the least likely to be used to start these engines? A. Pneumatic starter B. Electric starter C. Starter-generator D. Auxiliary power unit (APU)
A. Pneumatic starter Note: First things first, starter-generators are the "most widely used starting unit on small gas turbine engines, including turbojets, turbofans, turboprops, and turboshafts." (Textbook p 10-3 in Starter-Generator section). INTERESTING NOTE: The interesting thing about this question though is that two of the answers (electric-starter & APU) are effectively tied together. If, for example, the electric-starter wasn't likely used in the engines, then that also means that the…
A. Electric starter B. Hydraulic starter C. Starter-generator D. Pneumatic starter
A. Electric starter Note: Though the main engines themselves on this aircraft probably use starter-generators or pneumatic starters, the rear end (as seen in the image) looks to be an APU as this specific engine is located in the tail cone. With this, we also need to know that APU systems inherently use Electric Starters as seen in this paragraph in the textbook: "Standalone electric starters...are often used on auxiliary and ground power units but are not typically used on flight engines." (Te…
What is the purpose of the pawls in this image? A. Remain engaged with the starter ratchet at all RPMs B. Engage with the pneumatic starter ratchet until disengaged by centrifugal force C. Engage with the pneumatic starter ratchet at high RPM during air restarts D. Disengage from the starter ratchet at low RPM
B. Engage with the pneumatic starter ratchet until disengaged by centrifugal force Note: The key word to look for is that centrifugal force. The mechanism cannot be disengaged directly (not even by the pilot, the pilot only has control of the pressure regulating/bypass valve) other than by centrifugal force.
How can the pilot disengage this pneumatic starter from the cockpit? A. Manually disengage the starter pawls B. Manually disconnect electrical power to the pneumatic starter. C. Close the starter bypass valve D. Manually disengage the sprag clutch
C. Close the starter bypass valve Note: The pilot's only direct control (as far as I know) over the pneumatic starter is via the bypass/pressure regulating valve.
What is the usual starting sequence for a turbine engine? 1 Engage starter and begin turning compressor 2 Turn on igniters 3 Introduce fuel 4 Disengage starter at designated N2 or Ng speed
Note: please type in the answer with numbers (1, 2, 3, 4, etc.). Or, if without keyboard, please press "look at answer".
What type of start has occurred if the Ng speed increases only to 49% during the engine starting sequence in a Cessna 208 Caravan (Pratt & Whitney PT6)? A. Runaway start B. Hung start C. Normal start D. Hot start
B. Hung start Note: A runaway start is a start where RPM just runs out of the limits, Hot start is when the turbine goes past temperature limits, and a hung start is when the turbine cannot reach the RPM needed for normal start. A hung start could lead to a hot one, but it is initially just a hung start.
What is the name and purpose of the black box in this image? A. Igniter plug housing. Contain the igniter spark for use in the combustor. B. Lead. Carry the electrical current from the exciter to the igniter plug. C. Exciter. Increase voltage to create a spark in the igniter plug. D. Igniter plug. Create a high voltage spark for use in the combustor.
C. Exciter. Increase voltage to create a spark in the igniter plug.
What is the operational purpose of the ITT engine instrument? A. Primary temperature instrument to monitor inlet for icing conditions B. Primary temperature instrument to monitor propeller governor operation C. Primary temperature instrument to monitor accessory gearbox operation D. Primary temperature instrument to identify a hot start
D. Primary temperature instrument to identify a hot start Note: For Hot starts: monitor ITT and EGT For Hung starts: monitor N2 or Ng
What is the primary power instrument for a turboprop engine? A. ITT B. Propeller RPM C. Torque D. Engine RPM
C. Torque
What is the primary instrument to identify a hung start? A. Turbine RPM B. Torque C. ITT D. Propeller RPM
A. Turbine RPM
How do you determine which types of fuel are acceptable for the engine(s) on your aircraft? A. Check the AFM or POH B. Turbine-powered engines can burn an equal or lower rating of fuel C. Turbine-powered engines can burn an equal or higher rating of fuel D. All turbine-powered engines can burn any type of jet fuel
A. Check the AFM or POH
What is the primary difference between Jet A and Jet A1 fuels? 1). Jet A has a lower freezing point 2). Jet A has a higher flashpoint 3). Jet A1 has a lower freezing point 4). Jet A1 includes renewable biomass additives
3). Jet A1 has a lower freezing point
What type of fuel is designed specifically for high-altitude and/or cold weather operations? 1). Jet A 2). Prist 3). JP-5 4). Jet A1
4). Jet A1
Calculate Thrust Specific Fuel Consumption (TSFC) per engine for the Pilatus PC-24 airplane with the Williams FJ44 turbofan engine: **Round answer to the nearest 1/100 and do not enter units** Fuel flow: 877 lbs/hr. Fn: 2,300 lbf
Answer: 0.38 Notes: TSFC = Fuel Flow / Gross or Net thrust Units are in lbs/hr and lbf
What is the name and numerical value of the ideal ratio of fuel to air weight for combustion? A. There is no ideal ratio because it changes for each engine B. Stoichiometric ratio. 15:1 C. Hydropneumatic. 5:1 D. Vapor ratio. 1:5
B. Stoichiometric ratio. 15:1 Note: If you see stoichiometric, it is likely the right answer for these questions.
A fuel control unit (FCU) that uses air pressure to create mechanical motion is known as what type of FCU? A. Hydromechanical B. Pneumato-hydraulic C. Electromechanical D. Pneumatic
D. Pneumatic
A FCU that uses hydraulic pressure to create mechanical motion is known as what type of FCU? A. Hydromechanical B. Electromechanical C. Pneumatic D. Pneumato-hydraulic
A. Hydromechanical
What conditions lead to a low thrust specific fuel consumption (TSFC)? A. Equal fuel consumption per pound of thrust B. Fuel consumption and thrust are not related C. High fuel consumption per pound of thrust D. Low fuel consumption per pound of thrust
D. Low fuel consumption per pound of thrust Note: If we think of this mathematically, it starts to make sense. Since TSFC = Fuel Flow / Thrust, we can see that if we have a very extremely low fuel flow (or consumption), and very extremely high thrust, it would be an incredibly low number ex: 1/10000 = 0.001 On the other hand, if we have very high fuel flow and very low thrust, we can see that it is extremely high ex: 1000/1 = 1000
What is more desirable...high or low TSFC? A. High TSFC because fuel consumption is minimized B. Low TSFC because fuel consumption is minimized C. High TSFC because fuel consumption is maximized D. Low TSFC because fuel consumption is maximized
B. Low TSFC because fuel consumption is minimized Note: Mathematically speaking, this makes sense because if TSFC = Fuel Flow / Thrust, we want fuel flow to be low and thrust to be high. Since this means the final number would be lower, we want a lower TSFC. ex: 1 (fuel flow) / 1000 (thrust) = 0.001 TSFC
Which type of engine generally has the lowest TSFC? A. Turbojet B. Medium-bypass turbofan C. Low-bypass turbofan D. High-bypass turbofan
D. High-bypass turbofan Note: What's most efficient? High-bypass! :D
What is the purpose of the fuel-oil heat exchanger? A. Oil cools the fuel while fuel heats the oil to prevent viscosity changes B. Fuel cools the oil while oil heats the fuel to prevent fuel icing C. Fuel cools the oil to decrease the oil's viscosity D. Oil heats the fuel to decrease the fuel's freezing temperature
B. Fuel cools the oil while oil heats the fuel to prevent fuel icing
What is the purpose of the combustor drain? A. Allow unburned fuel to return to the fuel tank during flight B. Allow excess fuel pressure to vent during high power settings C. Allow unburned fuel to return to the combustor during idle engine power D. Decrease the risk of hot starts or exhaust pipe fires
D. Decrease the risk of hot starts or exhaust pipe fires
What is the purpose of variable inlet or stator guide vanes? A. Reduce engine airflow at low RPM B. Increase engine airflow at low RPM. C. Reduce engine airflow at high RPM. D. Increase engine airflow at all RPM.
A. Reduce engine airflow at low RPM
What is the purpose of anti-stall bleed systems? A. Reduce pressure in the aft compressor stages B. Reduce pressure in the forward compressor stages C. Increase pressure in the aft compressor stages D. Increase pressure in the forward compressor stages
A. Reduce pressure in the aft compressor stages
When are variable inlet or stator guide vanes at the lowest pitch setting when compared to the relative wind entering the compressor? In other words, when are VIGV closed? A. Low engine RPM B. High engine RPM C. All engine RPM D. The pitch setting does not change
A. Low engine RPM
When are anti-stall bleed systems open? A. Low engine RPM B. High engine RPM C. All engine RPM D. They do not open or close
A. Low engine RPM
How does a pilot control engine anti-stall systems from the cockpit? A. Anti-stall systems are automated and are not directly controlled from the cockpit B. By pushing the BLEED VALVE OPEN button C. By moving the VANE PITCH lever to HIGH PITCH D. By programming the ECU
A. Anti-stall systems are automated and are not directly controlled from the cockpit
Why are turbine engines more likely to stall at low RPM? A. The mass airflow and compressor pressure ratio are too low B. The mass airflow is too high for the compression ratio C. The compression ratio is too high for the mass airflow D. The pressure is too high in the forward sections of the compressor
C. The compression ratio is too high for the mass airflow -- Note -- **THIS IS AN ABSOLUTE GUESS AND IS PROBABLY WRONG** as I'll need to verify this, but my guess for why this is the case is that: at low rpm, air gets too compressed aft compressor stages can't spin fast enough because it doesn't have the necessary mass airflow (MA was compressed too much), causing stagnation Stagnation leads to compressor stall (reaches critical angle of attack) --> Additionally, too much mass airflow probably…
How does outside air temperature affect the operation of variable inlet or stator guide vanes? A. Colder temperatures cause them to open or move to higher pitch at a lower N2 speed B. Colder temperatures cause them to close or move to a lower pitch at a lower N2 speed C. Colder temperatures cause them to open or move to a higher pitch at a higher N2 speed D. Temperature does not affect variable inlet or stator guide vanes
A. Colder temperatures cause them to open or move to higher pitch at a lower N2 speed Note: The colder the air, the denser it is --> allowing for higher pitches as we have more lee-way with compression ratio and mass airflow without stalling the engine.
How are most turbine engines protected from ice? A. Compressor bleed air B. Combustor bleed air C. Turbine bleed air D. Electric heating coils
A. Compressor bleed air
What is the maximum temperature at which ice is likely to form in a turbine engine inlet? A. 40°F in dry air and 45°F in visible moisture B. 40°C in dry air and 45°C in visible moisture C. 70°F in dry air and 75°F in visible moisture D. 32°F in both dry air and visible moisture
A. 40°F in dry air and 45°F in visible moisture
Where are turbine engine anti-ice systems most likely to be found? A. Engine inlet, compressor inlet guide vanes, and compressor fan spinner B. Compressor fan and N2 compressor C. Compressor, combustor, and turbine D. Engine inlet and N2 compressor
A. Engine inlet, compressor inlet guide vanes, and compressor fan spinner
What is the location and purpose of a variable bleed valve system (VBV)? A. Between the N1 and N2 compressor. Helps protect the N2 compressor from debris and ice. B. Engine inlet. Helps protect the compressor fan and N1 compressor from debris and ice. C. Between the N2 compressor and combustor. Regulates combustor airflow during icing conditions. D. Between the compressor fan and N1 compressor. Helps regulate N2 compressor airflow during icing conditions.
A. Between the N1 and N2 compressor. Helps protect the N2 compressor from debris and ice.
What are the elements of the fire triangle? (this can have multiple answers) Oxygen Heat Fuel Fire
Oxygen, Heat, & Fuel
Considering the fire or combustion triangle, what is "fuel"? A. Any combustible material B. Only aircraft fuel like Jet A or 100LL C. Only fuel (e.g. Jet A or 100LL) or oil D. Only combustible liquids like fuel (Jet A), oil, or hydraulic fluid
A. Any combustible material
Considering aircraft fire mitigation, what are considered the primary sources of fuel for a fire? A. Aircraft fuel (e.g. Jet A or 100LL), oil, or hydraulic fluid B. Only aircraft fuel (e.g. Jet A or 100LL) C. Only aircraft fuel (e.g. Jet A or 100LL) or oil D. Only hydraulic fluid or oil
A. Aircraft fuel (e.g. Jet A or 100LL), oil, or hydraulic fluid
The act of physically separating fuel from an ignition source is referred to as what method of fire hazard mitigation? A. Compartmentation or isolation B. Fire detection zones C. Dual loop detection systems D. Single loop detection systems
A. Compartmentation or isolation
What is a squib? A. An explosive charge to rapidly discharge extinguishing agent B. A non-magical wizard or witch C. An electrical circuit that releases fire extinguishing agent D. A pneumatic valve that releases fire extinguishing agent
B̶.̶ ̶A̶ ̶n̶o̶n̶-̶m̶a̶g̶i̶c̶a̶l̶ ̶w̶i̶z̶a̶r̶d̶ ̶o̶r̶ ̶w̶i̶t̶c̶h̶ ̶ <-- sadly not the right answer A. An explosive charge to rapidly discharge extinguishing agent
Regarding fire hazard mitigation, what aircraft system(s) should be shut down during a fire to remove an ignition source? A. Electrical system B. Fuel and hydraulic systems C. Oil system D. Environmental system
A. Electrical system Note: I initially thought it would be B. as the first thing you do in an engine fire is to get the fuel shutoff valve. However, I think it is mainly the "hydraulic systems" part of that question that was wrong. Will verify ASAP.
Regarding fire hazard mitigation, what aircraft system(s) should be shut down to due to the toxic gases produced during a fire? A. Environmental system B. Electrical system C. Fuel and hydraulic systems D. Oil system
A. Environmental system
What fire detection system(s) rely on electrical resistance to detect a fire? A. Single-loop and dual-loop systems B. Pneumatic systems C. Single-loop and pneumatic systems D. The EICAS
A. Single-loop and dual-loop systems Note: EICAS btw is "Engine Indicating and Crew Alerting System"
What fire detection system(s) rely on changing gas pressure to detect a fire? A. Pneumatic system B. Single-loop and dual-loop systems C. Dual-loop and pneumatic systems D. The EICAS
A. Pneumatic system Note: The way I got this was by thinking "gas has/is pressure, pressure is pneumatic, this is a pneumatic system". Additionally, EICAS is "Engine Indicating and Crew Alerting System"
What is/are the most common fire extinguishing agent(s) in on-board aircraft fire suppression systems? A. Carbon dioxide and halon B. Water C. Foam D. Hydrogen
A. Carbon dioxide and halon Note: These are the only two agents in almost all modern aircraft fire extinguishing systems
Original: Edited due to pixalization: Based on the following METAR, is inlet icing likely to form? Assume there is no visible moisture. A. No. I expect inlet icing up to 40°F in dry air. B. Yes. I expect inlet icing up to 45°F in dry air. C. No. I expect inlet icing up to 32°F in dry air. D. No. I expect inlet icing up to 32°F in both dry and moist air
A. No. I expect inlet icing up to 40°F in dry air. -- Note -- This might seem a bit dumb, but the reason we choose this answer is that: No visible moisture (makes sense so far) The temperature on METAR is 41°F, a single degree above freezing. Even though it may feel like we should activate anti-ice as we are only a single degree above our limit, we (probably) won't be using it as the tolerance for icing is actually pretty accurate (40 dry 45 with moisture). As the textbook says: "It might seem…
Where is engine ice most likely to accumulate? A. Inlet cowl, inlet guide vanes, and spinner. B. Compressor fan and N1 compressor C. Bypass air duct and inlet compressor fan D. Only the compressor fan
A. Inlet cowl, inlet guide vanes, and spinner.
What are the location and purpose of transient bleed valves? A. Between the N1 and N2 compressor to remove debris B. Between the compressor fan and N1 compressor to provide de-ice air C. In the engine inlet to remove ice before entering the compressor fan D. Between the N2 compressor and combustor to deliver high energy air to the turbine
D. Between the N2 compressor and combustor to deliver high energy air to the turbine
What is/are the most common sources of engine anti-ice heat? A. Bleed air and electric B. Oil heat exchanger C. Coolant system heat exchanger D. De-ice fluid
A. Bleed air and electric Note: In-class, we may not have gone over it too much, but the electric component of the answer comes from electric coils/strips that are sometimes used on some turbines. As the textbook indicates: "Some smaller turboprop and turboshaft engines use electric heat strip systems, which are classed as electro-thermal anti-icing systems".
What is an indication of a compressor stall? A. Fluctuation in engine RPM B. Decrease in EGT C. Decrease in ITT D. Increase in EPR
A. Fluctuation in engine RPM
What pilot action is appropriate if a compressor stall is suspected? A. Decrease engine power B. Increase engine power C. Increase EPR D. Decrease aircraft angle of attack
A. Decrease engine power Note: Legit, this is the only way (as far as I know) for the pilot to directly alleviate/eliminate compressor stall.
Based on the current METAR at KJFK in New York (altitude = sea level), do you expect the variable inlet guide vanes to open at a higher or lower N2 RPM than standard? KJFK 092051Z 19009KT 10SM FEW250 18/13 A3029 RMK AO2 SLP255 T01780133 55007 $ A. Lower N2 because the air density is lower than standard. B. Higher N2 because the air density is lower than standard. C. Lower N2 because the air density is higher than standard. D. Higher N2 because the air density is higher than standard.
B. Higher N2 because the air density is lower than standard. Note: The way I went about this was looking at the altimeter setting. Since the higher the altimeter setting, the higher the altitude. With this being above 29.92, that would mean that we are operating as if the altitude were higher than standard. This all culminates in the variable inlet guide vanes opening later than usual because it would: Open the inlet sooner if density is higher (colder temperatures) Open the inlet a lot later i…
When do you expect anti-stall bleed valves to be closed? A. High engine RPM B. Low engine RPM C. All engine RPMs greater than ground idle D. After engine shut-down and during engine start
A. High engine RPM
When do you expect variable inlet guide vanes to be open so that they allow the greatest amount of airflow through the compressor? A. High engine RPM B. Low engine RPM C. All engine RPMs greater than ground idle. D. After engine shut-down and during engine start.
A. High engine RPM
What anti-stall system(s) decreases EPR? A. VIGV and anti-stall bleed valves B. Only VIGV C. Only anti-stall bleed valves D. Neither VIGV nor anti-stall bleed valves
A. VIGV and anti-stall bleed valves Note: One way or another, pressure is going to be decreased. The VIGV's goal is to lower the N1 compression ratio so as to not overload the N2 compressor, while the bleed valves literally bleed air in order to maintain nominal operation.
Calculate the thrust specific fuel consumption (TSFC) for the Pratt & Whitney 535A turbofan engine given the following conditions: **Round all answers to the nearest 1/100** Gross thrust: 3,400 lbs. Fuel flow: 1,481 lbs/hr
Answer: 0.44 Note: Remember that for the TSFC equation, it should look like this: TSFC = Fuel Flow ÷ Thrust <--- (either gross or net depending on condition) With this, all we need to do for this formula is divide our fuel flow by gross thrust. I'm not sure if it is always going to be in lbs/hr, but this is the unit that worked for the quiz. 1481/3400 = 0.44
Gulfstream 700 (TSFC = 0.38) [shown above] Honda Jet (TSFC = 0.42) [shown above] Which airplane consumes more fuel per pound of thrust based on the following TSFC values? A. The Honda Jet because the thrust produced is lower B. The Gulfstream 700 because the TSFC is lower C. The Gulfstream 700 because the thrust produced is greater D. The Honda Jet because the TSFC is higher
D. The Honda Jet because the TSFC is higher Note: TSFC is one of the only units where it is overly simple in concept. If it is higher, 'tis means it consumes more fuel. If lower, then it's lower :D I may or may not have overthought this question and then realized my mistake, please do not replicate what I did...
What fuel system component is specifically designed to help prevent hot starts and tail pipe fires during starting? A. Filter bypass B. FCU C. Heat exchanger D. Combustor drain valve
D. Combustor drain valve
Regarding the fuel system, what is the purpose of the fuel/oil heat exchanger in the upper-left part of the image? A. Help prevent ice in the fuel system B. Cool the fuel after being pressurized by the high-pressure fuel pumps C. Help prevent ice in the lubrication system D. Cool the fuel before returning to the fuel tanks
A. Help prevent ice in the fuel system Note: the key thing to remember is that the fuel/oil heat exchanger has two purposes: Cool the oil Pre-heat the fuel As the only answer that even insinuates the heating of fuel, (A.) is the only answer that makes sense. Additionally, with this correct answer, I believe we can safely assume that the fuel heating component from this heat exchanger is specifically meant for ice prevention purposes (even though the textbook doesn't seem to directly suggest so).
What type of fuel control unit (FCU) uses mechanical linkages and fuel pressure to regulate fuel flow? A. Pneumatic B. Hydromechanical C. Pneumatic-mechanical D. Mechanical
B. Hydromechanical
What type of fuel control unit (FCU) uses gas pressures from the engine to regulate fuel flow? A. Mechanical B. Electro-mechanical C. Pneumatic D. Hydromechanical
C. Pneumatic
What is the purpose of the relief valve on the left side of the image? A. Allow fuel that was unused in the atomizer to return to the fuel tank B. Allow fuel to bypass the filter C. Close when fuel pressure exceeds spring pressure D. Open when fuel pressure exceeds spring pressure
D. Open when fuel pressure exceeds spring pressure Note: The graph in of itself doesn't really tell us the function of the relieve valve. The main way to answer this question seems to be memorizing what the purpose of a relief valve is, which in the power point presentation states: "Opens when fuel pressure exceeds spring pressure to bypass" (Ch 7 Fuel Systems PPTX page #20)