Aircraft Instruments
This quiz will test you for EOC testing.
- 1.
During operation of the EPU-6/E frequency converter it is determined that E and F pin voltage is not needed for the aircraft. The operator places the Loop/bypass/28V to aircraft switch to what position?
- A.
28V to aircraft
- B.
Neutral
- C.
Bypass
- D.
Loop
Correct Answer
C. Bypass -
- 2.
Which of the following components provides 525VAC to the control transformer of the EPU-6/E frequency converter?
- A.
Input auto transformer
- B.
Output auto transformer
- C.
Input phase sequence transformer
- D.
Output phase sequence transformer
Correct Answer
A. Input auto transformer -
- 3.
What EPU-6/E components receive potential directly from the input auto transformer?
- A.
Analog board and alarm display
- B.
Control transformer and voltage control
- C.
Input circuit breakers and display power supply
- D.
SCR voltage regulator and phase sequence transformer
Correct Answer
D. SCR voltage regulator and phase sequence transformer -
- 4.
The control transformer perform on the EPU-6/E frequency converter provides
- A.
28VDC for the aircraft contactor
- B.
240VDC for the aircraft contactor
- C.
120VAC for the operation of E and F line 28VDC power supply
- D.
240VAC for the operation of E and F line 28VDC power supply
Correct Answer
C. 120VAC for the operation of E and F line 28VDC power supply -
- 5.
What EPU-6/E frequency converter components must be inspected prior to use?
- A.
Air inlets for blockage
- B.
Wiring for secure mounting
- C.
Maintenance panels for corrosion
- D.
Interior air vents for secure mounting
Correct Answer
A. Air inlets for blockage -
- 6.
During operation you determine that there is an undervoltage fault problem with the EPU-6/E frequency converter unit. What component could be malfunctioning?
- A.
Analog board has failed
- B.
Output trim potentiometer is centered
- C.
Voltage control board potentiometer is shorted
- D.
Audible alarm switch is in the SILENCE position
Correct Answer
A. Analog board has failed -
- 7.
During operation of the EPU-6/E frequency converter you determine that one phase voltage is lower that the other two phase. What could cause this malfunction?
- A.
Malfunctioning transistor
- B.
Burnt control transformer fuse
- C.
Improper SCR firing adjustment
- D.
Loose push-on connector on the output filter capacitor
Correct Answer
D. Loose push-on connector on the output filter capacitor -
- 8.
What A/M32A-95 gas turbine compressor section supplies high volume, low-pressure air for combustion, cooling, and bleed air output?
- A.
Turbine section
- B.
Accessory section
- C.
Compressor section
- D.
Air regulator section
Correct Answer
C. Compressor section -
- 9.
The function of the deswirl ring on the A/M32A-95 gas turbine compressor is to
- A.
Accelerate air
- B.
Increase air pressure
- C.
Decrease air velocity
- D.
Smooth turbulent air flow
Correct Answer
D. Smooth turbulent air flow -
- 10.
What A/M32A-95 gas turbine compressor component isolates the second-stage air from the operation of the first-stage compressor?
- A.
Interstage ducts
- B.
Interstage seal
- C.
Impellers
- D.
Inducers
Correct Answer
B. Interstage seal -
- 11.
What prevents overpressurization of the bearing cavity on an A/M32A-95 gas turbine compressor?
- A.
Oil jet
- B.
Oil cooler
- C.
Scavenge pump
- D.
Oil tank vent line
Correct Answer
D. Oil tank vent line -
- 12.
What A/M32A-95 gas turbine compressor chambers are pressurized when the butterfly valve is closed?
- A.
1 and 3
- B.
2 and 4
- C.
1,2, and 3
- D.
1,3, and 4
Correct Answer
D. 1,3, and 4 -
- 13.
The A/M32A-95 gas turbine compressor's rate-metering valve prevents the butterfly valve from snapping open by bleeding air through the atmospheric bleed port from chamber
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2 -
- 14.
What A/M32A-95 gas turbine compressor component closes to complete the electrical circuit to the fuel solenoid and ignition unit?
- A.
Load switch
- B.
Oil pressure switch
- C.
Turbine start switch
- D.
35 percent centrifugal speed switch
Correct Answer
B. Oil pressure switch -
- 15.
Refer to foldout 2. The A/M32A-95 runs up to 60 percent but the battery is not charging. What is the probable cause of this trouble?
- A.
K4 energized and its contacts closed
- B.
K3 de-energized and its contacts opened
- C.
K4 de-energized and its contacts closed
- D.
K3 de-energized and the contacts did not remain closed
Correct Answer
D. K3 de-energized and the contacts did not remain closed -
- 16.
Refer to foldout 2. During an operational check of an A/M32A-95 gas turbine compressor, you place the air load switch S2 in the ON position. The butterfly valve starts to open at 95 percent. What do you check?
- A.
SV2
- B.
S10
- C.
TD2
- D.
K6
Correct Answer
C. TD2 -
- 17.
Refer to foldout 2. What A/M32A-95 gas turbine compressor component energizes SV4?
- A.
Master switch
- B.
Air load valve
- C.
Air load switch
- D.
Oil pressure switch
Correct Answer
C. Air load switch -
- 18.
What preliminary set-up step, if skipped, prevents the A/M32A-95 gas turbine compressor from starting?
- A.
Set-up controls
- B.
Set parking brake
- C.
Open and secure the exhaust door
- D.
Ensure the turbine air inlet and exhaust outlets are free of obstructions
Correct Answer
C. Open and secure the exhaust door -
- 19.
On the A/M32A-95 gas turbine compressor, discharge air pressure at 100 percent engine speed should indicate
- A.
55 +2psig
- B.
45 +2psig
- C.
35 +2psig
- D.
25 +2psig
Correct Answer
C. 35 +2psig -
- 20.
Refer to foldout 2. The A/M32A-95 engine cranks but does not start. What is the probable cause of this trouble?
- A.
CB3 is open
- B.
S9 is shorted
- C.
SV1 coil is open
- D.
K7 is not energizing
Correct Answer
C. SV1 coil is open -
- 21.
The A/M32A-95 gas turbine compressor does not shut down when the charging rate decreases to 12 amperes. What is the probable cause of this trouble?
- A.
Air load switch
- B.
Fuel level relay K5
- C.
2 speed solenoid SV4
- D.
Battery charging module
Correct Answer
D. Battery charging module -
- 22.
When heat is applied to an ice cube and teh ice starts to melt, it is
- A.
Super heat
- B.
Latent heat
- C.
Sensible heat
- D.
Convention heat
Correct Answer
B. Latent heat -
- 23.
The three methods of heat transfer are
- A.
Sensible, latent, and super heat
- B.
Sensible, convention, and conduction
- C.
Conduction, convention, radiation
- D.
Conduction, convention, and super heat
Correct Answer
C. Conduction, convention, radiation -
- 24.
The air flowing through an air conditioner is also called
- A.
Heat
- B.
Heat load
- C.
Pounds per minute(ppm)
- D.
Cubic feet per minute(cfm)
Correct Answer
B. Heat load -
- 25.
While you are doing an operational check of an air conditioner, you notice the unit is short cycling. What do you do to correct this trouble?
- A.
Increase the heat load
- B.
Lower the refrigerant charge
- C.
Check the receiver outlet valve
- D.
Decrease the setting of the LPCO
Correct Answer
C. Check the receiver outlet valve -
- 26.
Bubbles in an air conditioner refrigeration system sight glass probably indicate
- A.
Refrigerant overcharge
- B.
A low refrigerant charge
- C.
High discharge temperature
- D.
Low discharge air temperature
Correct Answer
B. A low refrigerant charge -
- 27.
What MA-3D air conditioner component controls refrigerant flow into the evaporator?
- A.
Quench valve
- B.
TXV solenoid valve
- C.
Hot gas bypass circuit
- D.
Electric expansion valve
Correct Answer
D. Electric expansion valve -
- 28.
The temperature controller on an MA-3D air conditioner opens the hot gas bypass valve if the
- A.
Air pressure is too low so the boiler point of the R134a must be increased
- B.
Suction air pressure is too high so the boiling point of the refrigerant can be decreased
- C.
Suction pressure is too low so the boiling point of the refrigerant must be increased to increase the output air temperature
- D.
Suction pressure is too high so the boiling point of the refrigerant must be decreased to decrease the output air temperature
Correct Answer
C. Suction pressure is too low so the boiling point of the refrigerant must be increased to increase the output air temperature -
- 29.
You place the MA-3D air conditioner SW1 in the START position, but the engine does not operate. What is the probable cause of this trouble?
- A.
K7 contacts are closed
- B.
Overspeed switch is closed
- C.
Oil pressure switch is closed
- D.
Override switch is not closed
Correct Answer
D. Override switch is not closed -
- 30.
Refer to foldouts 4 and 5. What relay prevents the MA-3D air conditioner pumpdown light from illuminating in the cool mode?
- A.
K8
- B.
K2
- C.
TC
- D.
S4
Correct Answer
A. K8 -
- 31.
The engine on the MA-3D air conditioner is operating at 1,250 rpm, but the blower clutch does not engage. What do you do?
- A.
Replace SW2
- B.
Replace the engine speed control
- C.
Nothing, this is normal operation; the blower clutch energizes at governed speed
- D.
Check the MPU to make sure it's sending the proper signal to the engine speed control
Correct Answer
C. Nothing, this is normal operation; the blower clutch energizes at governed speed -
- 32.
What MA-3D air conditioner component provides 24 VAC for operation of the temperature controller?
- A.
Generator G1
- B.
Alternator G2
- C.
Power monitor relay PMR
- D.
Transformer rectifier TR1
Correct Answer
C. Power monitor relay PMR -
- 33.
The MA-3D air conditioner radiator fan stops operating. Where do you start troubleshooting?
- A.
K2
- B.
K4
- C.
G2
- D.
CB2
Correct Answer
B. K4 -
- 34.
While you are operating an MA-3D air conditioner, the output air temperature is too high, so you set the temperature control to maximum cooling. The Temperature controller sends a signal to
- A.
B7 which steps closed to meter R134a into the evaporator
- B.
B7 which steps open to meter R134a into the evaporator
- C.
The quench valve which opens to aid in cooling
- D.
S1 and S2 which open to aid in cooling
Correct Answer
B. B7 which steps open to meter R134a into the evaporator -
- 35.
What MA-3D air conditioner safety component de-energizes the compressor clutch?
- A.
Low-pressure cutout (LOCO) closing
- B.
Oil pressure cutout (OPCO) closing
- C.
Temperature controller (TC) breaking the circuit to K2
- D.
Suction pressure rising to 5 psi
Correct Answer
C. Temperature controller (TC) breaking the circuit to K2 -
- 36.
What type of refrigeration system leak occurs when the pressure within the system is less than atmospheric pressure?
- A.
Vaccum leaks
- B.
Inward leaks
- C.
Outward leaks
- D.
Pressure leaks
Correct Answer
B. Inward leaks -
- 37.
What type of engine starter does the ACE 802S air conditioner use?
- A.
Air
- B.
Manual
- C.
Electric
- D.
Hydraulic
Correct Answer
A. Air -
- 38.
What medium is used to lubricate the engine starter on the ACE 802S air conditioner?
- A.
Air
- B.
Oil
- C.
Fuel
- D.
Coolant
Correct Answer
C. Fuel -
- 39.
The compressor switch on the ACE 802S must be held in the HOLD position when engaging the compressor in order to
- A.
Build up oil pressure
- B.
Defrost the evaporator
- C.
Allow the oil and discharge pressures to stabilize
- D.
Ensure the engine is at governed speed before engaging compressor
Correct Answer
C. Allow the oil and discharge pressures to stabilize -
- 40.
When the ACE 802S compressor is in the HOLD position, what is the compressor displacement?
- A.
Erratic
- B.
Constant
- C.
Minimum
- D.
Maximum
Correct Answer
B. Constant -
- 41.
What does the heat boost system on the ACE 802S air conditioner uses to trim output air temperature?
- A.
Air
- B.
Refrigerant
- C.
Engine coolant
- D.
Electric heater
Correct Answer
C. Engine coolant -
- 42.
What ACE 802S air conditioner components divide the refrigerant system high-pressure side from the low-pressure side?
- A.
Compressor and expansion valve
- B.
Condenser and expansion valve
- C.
Compressor and condenser
- D.
Condenser and evaporator
Correct Answer
A. Compressor and expansion valve -
- 43.
What ACE 802S air conditioner system "supercharges" the compressor?
- A.
Defrost
- B.
Heat boost
- C.
Vapor injection
- D.
Liquid injection
Correct Answer
C. Vapor injection -
- 44.
What valve must be opened prior to starting the engine on the ACE 802S air conditioner system?
- A.
Air shutoff
- B.
Fuel shutoff
- C.
Coolant control
- D.
Refrigerant flow
Correct Answer
A. Air shutoff -
- 45.
What is the first troubleshooting step that must be completed when a unit comes in with a write-up in the forms?
- A.
Perform a service inspection
- B.
Perform an operational check
- C.
Verify the problem actually exists
- D.
Recognize the write-up as a malfunction
Correct Answer
D. Recognize the write-up as a malfunction -
- 46.
What power source operates the heater/combustion section of the new generation heater (NGH)?
- A.
12 VDC
- B.
120 VAC
- C.
Hydraulic motor
- D.
Diesel engine only
Correct Answer
B. 120 VAC -
- 47.
How does the new generation heater (NGH) keep output air temperature within programmed limits?
- A.
Burner control unit (BCU) uss outlet air sensors to compare air temperature with programmed value, cycling the fuel burner on and off to maintain temperature
- B.
Heater Control Unit (HCU) uses outlet air sensors to compare air temperature with programmed value, cycling the fuel burner on and off to maintain temperature
- C.
A photocell monitors combustion and activates the BCU to cycle the fuel burner on and off to maintain temperature
- D.
An electronic thermostat cycles the main air fan on and off to maintain temperture
Correct Answer
B. Heater Control Unit (HCU) uses outlet air sensors to compare air temperature with programmed value, cycling the fuel burner on and off to maintain temperature -
- 48.
What adjustment on the new generation heater (NGH) prevents coking in the combustion section?
- A.
Fuel pressure
- B.
Air/fuel ratio
- C.
Igniter timing
- D.
Fuel spray pattern
Correct Answer
B. Air/fuel ratio -
- 49.
How does the photocell on the new generation heater (NGH) verify the flame in the burner tube?
- A.
The photocell's thermal contacts open when heat increases
- B.
The photocell's thermal contacts close when heat increases
- C.
The photocell's resistance decreases in the presence of light
- D.
The photocell's resistance increases in the presence of light
Correct Answer
C. The photocell's resistance decreases in the presence of light -
- 50.
When troubleshooting a defective new generation heater (NGH) charging system, what component do you check first?
- A.
Charge coil
- B.
Alternator G1
- C.
Ignition switch
- D.
Charge regulator
Correct Answer
C. Ignition switch -
Quiz Review Timeline +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
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Current Version
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Jan 19, 2017Quiz Edited by
ProProfs Editorial Team -
Jan 11, 2011Quiz Created by
Haybird29
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