Questions | Aircraft Instrument Systems

Study Aid Questions

Fill in the Blanks

1. Pressure may be measured in three ways. These are:
a. __________________ pressure.
b. __________________ pressure.
c. __________________ pressure.

2. Under standard day conditions, atmospheric pressure is ______________ inches of Mercury or ______________ psi.

3. The difference between atmospheric pressure and the pressure being measured is called ______________ pressure.

4. A(n) ______________ type instrument is used to measure high pressures.

5. The two pressures sensed by the airspeed indicator are:
a. ______________
b. ______________

6. The instrument that measures the differential pressure between the tailpipe total pressure and the compressor inlet total pressure of a turbine engine is the _________________________________ indicator.

7. The ______________ measures the absolute pressure of the air surrounding the aircraft.

8. The altitude shown on an altimeter when the local altimeter setting is placed in the barometric window is called ________________________ altitude.

9. All elevations on aeronautical charts are measured from ____________________________.

10. The scale in the barometric window of an altimeter may be calibrated in ______________ of ______________ or ______________.

11. The altitude shown on an altimeter when standard sea level pressure is put into the barometric window is called ______________ altitude.

12. Flight level 320 is a pressure altitude ______________ feet.

13. Pressure altitude may be converted into density altitude by correcting the pressure altitude for non-standard ______________.

14. When static ports are exposed to disturbed air, the results are altimeter system errors known as
______________ error.

15. The tests required for a static system of an aircraft operated under instrument flight rules is described in FAR Part ______________.

16. Altimeters installed in aircraft that operate under instrument flight rules must have their accuracy checked every ______________ (how many) calendar months.

17. The uncorrected reading of an airspeed indicator is called ______________ airspeed.

18. An instrument that measures aircraft speed relative to the speed of sound is called a _________________.

19. Mach ______________ is flight at an airspeed of 95% of the speed of sound.

20. The rate-of-climb indicator is more properly known as the ______________ indicator.

21. Resistance change-type temperature measuring instruments may use either a(n) __________________________ or a(n) __________________________ circuit.

22. A(n) _____________________ instrument is typically used to measure high temperatures.

23. An _____________________ gives the pilot an indication of the load imposed on the aircraft structure in terms of G's.

24. The _____________________ is used by the pilot of a twin-engine aircraft to synchronize the propeller rotations.

25. A(n) _____________________ is an instrument that displays engine RPM.

TRUE or FALSE

1. An aneroid barometer measures gauge pressure. TRUE/FALSE

2. The manifold pressure gauge measures the absolute pressure inside the induction system of a reciprocating engine. TRUE/FALSE

3. Density altitude is not a direct measurement. TRUE/FALSE

4. Radio altimeters provide an indication of the aircraft's absolute altitude above sea level. TRUE/FALSE

5. For navigation and flight planning purposes, a pilot is most interested in calibrated airspeed. TRUE/FALSE

6. A vertical speed indicator measures the rate of change static pressure. TRUE/FALSE

7. It is permissible to cut off excess length of thermocouple leads. TRUE/FALSE

8. Compass variation is caused by the magnetic fields in the aircraft that interfere with those of the earth. TRUE/FALSE

9. Swinging a compass compensates for deviation. TRUE/FALSE

10. The rotor vanes of a dry-type vacuum pump are made of carbon. TRUE/FALSE

11. An A&P maintenance technician can disassemble and repair an aircraft instrument. TRUE/FALSE

12. The alternate source valve in the aircraft flight instrument system is in the static system. TRUE/FALSE

13. The mass type flowmeter is the least accurate method of measuring fuel flow. TRUE/FALSE

14. Shock mounts are used to isolate instruments and equipment from high frequency vibration. TRUE/FALSE

15. A shock-mounted instrument panel must be electrically grounded to the aircraft structure to provide a current return path. TRUE/FALSE

Knowledge Application Questions

1. What instruments in an aircraft are connected to the static system?

2. What types of repairs or alterations can a certificated A&P mechanic make to aircraft instruments?

3. What is the significance of a red radial line on the dial of an aircraft instrument?

4. What is the significance of a yellow arc on the dial of an aircraft instrument?

5. What is the significance of a green arc on the dial of an aircraft instrument?

6. What is the significance of a white arc on the dial of an airspeed indicator?

7. What is used to warn a mechanic that the glass on an aircraft instrument that contains the range marks has slipped?

8. Where can a mechanic find the range markings that are required on the instruments in a particular aircraft?

9. What check must be made if a mechanic replaces any instrument that is connected to the instrument static system?

10. Why are many of the electrical instruments mounted in steel cases?

11. Why must an aircraft instrument panel be electrically bonded to the primary aircraft structure?

12. What error is corrected when an aircraft compass is swung?

13. What fluid is used in an aircraft magnetic compass?

14. What is the maximum amount of deviation error that is allowed when a magnetic compass is installed in an aircraft?

15. What is the maximum amount of leakage that is allowed when checking the static system of an aircraft that is operated under Instrument Flight Rules?

Multiple Choices Questions

1. An aircraft magnetic compass is swung to up-date the compass correction card when
a. the compass is serviced.
b. equipment is added that could effect compass deviation.
c. an annual inspection is accomplished on the aircraft.

2. The operating mechanism of most hydraulic pressure gauges is
a. a Bourdon tube.
b. an evacuated bellows filled with an inert gas to which suitable arms, levers, and gears are attached.
c. an airtight diaphragm.

3. What is the fixed line mark attached to the compass bowl of a magnetic compass called?
a. Reference line.
b. Lubber line.
c. Reeder line.

4. (1) Aircraft instruments are color-coded to direct attention to operational ranges and limitations.
(2) Aircraft instruments range markings are not specified by Title 14 of the Code of Federal Regulations but are standardized by aircraft manufacturers.

Regarding the above statements,
a. only No. 1 is true.
b. both No. 1 and No. 2 are true.
c. only No. 2 is true.

5. When swinging a magnetic compass, the compensators are adjusted to correct for
a. magnetic variations.
b. compass card oscillations.
c. magnetic influence deviation.

6. What will be the result if the instrument static pressure line becomes disconnected inside a pressurized cabin during cruising flight?
a. The altimeter will read low and the airspeed indicator will read high.
b. The altimeter and airspeed indicator will both read low.
c. The altimeter and airspeed indicator will both read high.

7. The maximum deviation (during level flight] permitted in a compensated magnetic direction indicator installed on an aircraft certificated under Federal Aviation Regulation Part 23 is
a. 100
b. 60
c. 80

8. Magnetic compass bowls are filled with a liquid to
a. dampen the oscillation of the float.
b. reduce deviation errors.
c. retard precession of the float.

9. Instrument static system leakage can be detected by observing the rate of change in indication of the
a. airspeed indicator after suction has been applied to the static system to cause a prescribed equivalent airspeed to be indicated.
b. altimeter after suction has been applied to the static system to cause a prescribed equivalent altitude to be indicated.
c. altimeter after pressure has been applied to the static system to cause a prescribed equivalent altitude to be indicated.

10. The maximum altitude loss permitted during an unpressurized aircraft instrument static pressure system integrity check is
a. 200 feet in 1 minute.
b. 100 feet in 1 minute.
c. 50 feet in 1 minute.

11. Which statement regarding an aircraft instrument vacuum system is true?
a. If the air inlet to each vacuum instrument is connected to a common atmospheric pressure manifold, the system generally will be equipped with individual instrument filters only.
b. Vacuum systems are generally more effective at high altitudes than positive pressure systems.
c. Dry type vacuum pumps with carbon vanes are very susceptible to damage from solid airborne particles and must take in only filtered air.

12. When an aircraft altimeter is set at 29.92" Hg on the ground, the altimeter will read
a. field elevation.
b. density altitude.
c. pressure altitude.

13. Which of the following instrument discrepancies could be corrected by an aviation mechanic?
1. Red line missing.
2. Case leaking.
3. Glass cracked.
4. Mounting screws loose.
5. Case paint chipped.
6. Leaking at line B nut.
7. Will not adjust.
8. Fogged.

a. 1,4,6
b. 1,4,5,6
c. 3,4,5,6

14. Which of the following instrument discrepancies would require replacement of the instrument?
1. Red line missing.
2. Case leaking.
3. Glass cracked.
4. Mounting screws loose.
5. Case paint chipped.
6. Leaking at line B nut.
7. Will not zero out.
8. Fogged.

a. 1,3,5,8
b. 1,4,6,7
c. 2,3,7,8

15. Which of the following instrument conditions is acceptable and would not require correction?
1. Red line missing.
2. Case leaking.
3. Glass cracked.
4. Mounting screws loose.
5. Case paint chipped.
6. Leaking at line B nut.
7. Will not zero out.
8. Fogged.

a. None
b. 1
c. 5

16. A barometric altimeter indicates pressure altitude when the barometric scale is set at
a. field elevation.
b. 14.7" Hg.
c. 29.92" Hg.

17. A Bourdon tube instrument may be used to indicate
1. pressure.
2. temperature.
3. position.

a. 1
b. 2 and 3
c. 1 and 2

18. A turn coordinator instrument indicates
a. both roll and yaw.
b. the need for corrections in pitch and bank.
c. the longitudinal attitude of the aircraft during climb and descent.

19. Aircraft temperature thermocouple leads may
a. not be altered and are designed for a specific installation.
b. be repaired using solderless connectors.
c. be installed with either lead to either post of the indicator.

20. A synchro transmitter is connected to a synchro receiver
a. electrically with wires.
b. mechanically through linkage.
c. electromagnetically without wires.

21. The operation of an angle of attack indicating system is based on detection of differential pressure at a point where the airstream flows in a direction
a. parallel to the longitudinal axis of the aircraft.
b. parallel to the angle of attack of the aircraft.
c. not parallel to the true angle of attack of the aircraft.

22. Turbine engine exhaust gas temperatures are measured by using
a. iron/constantan thermocouples.
b. chromel/alumel thermocouples.
c. ratiometer electrical resistance thermometers.

23. Fuel flow transmitters are designed to transmit data
a. mechanically.
b. utilizing fluid power.
c. electrically.

24. Which of the following causes of aircraft magnetic compass inaccuracies may be compensated for by mechanics?
a. Variation.
b. Magnetic compass current.
c. Deviation.

25. Who is authorized to repair an aircraft instrument?
1. A certified mechanic with an airframe rating.
2. A certificated repairman with an airframe rating.
3. A certificated repair station approved for that class instrument.
4. A certificated airframe repair station.

a. 3 and 4
b. 3
c. 1, 2, 3, and 4

26. What does a reciprocating engine manifold pressure gauge indicate when the engine is not operating?
a. Zero pressure.
b. The differential between the manifold pressure and the atmospheric pressure.
c. The existing atmospheric pressure.

27. The requirements for testing and inspection of instrument static systems required by Section 91.411 are contained in
a. AC 43.13-1A
b. Type Certificate Data Sheets.
c. Part 43, appendix E.

28. Which condition would be most likely to cause excessive vacuum in a vacuum system?
a. Vacuum relief valve improperly adjusted.
b. Vacuum pump overspeed.
c. Vacuum relief valve spring weak.

29. Data transmitted between components in an EFIS are converted into
a. digital signals.
b. analog signals.
c. carrier wave signals.

30. The function of a CRT in an EFIS is to
a. allow the pilot to select the appropriate system configuration for the current flight situation.
b. display alphanumeric data and representations of aircraft instruments.
c. receive and process input signals from aircraft and engine sensors and send the data to the appropriate display.

31. The function of a symbol generator (SG) in an EFIS is to
a. receive and process input signals from aircraft and engine sensors and send the data to the appropriate display.
b. allow the pilot to select the appropriate system configuration for the current flight situation.
c. display alphanumeric data and representations of aircraft instruments.

32. The function of a display controller in an EFIS is to
a. display alphanumeric data and representations of aircraft instruments.
b. receive and process input signals from aircraft and engine sensors and send the data to the appropriate display.
c. allow the pilot to select the appropriate system configuration for the current flight situation.

33. A radar altimeter determines altitude by
a. means of transponder interrogation.
b. receiving signals transmitted from ground radar stations.
c. transmitting a signal and receiving back a reflected signal.

34. A radar altimeter indicates
a. altitude above ground level.
b. altitude above sea level.
c. flight level (pressure) altitude.

35. Resistance-type temperature indicators using Wheatstone bridge or ratiometer circuits may be used to indicate the temperatures of which of the following?
1. Free air.
2. Exhaust gas temperature.
3. Carburetor air.
4. Coolant (engine).
5. Oil temperature.
6. Cylinder head temperature.

a. 1, 2, 3, 4, 5, and 6
b. 1, 2, 3, and 6
c. 1, 3,4, and 5

36. When flags such as NAV, HDG, or GS are displayed on an HSI, the indication is
a. that function is operating.
b. that function is inoperative.
c. to call attention to deviation from the desired setting, or flight path, or heading, etc.

37. Instrument panel shock mounts absorb
a. low frequency, high-amplitude shocks.
b. high G shock loads imposed by turbulent air.
c. high energy impact shocks caused by had landings.

38. Which procedure should you use if you find a vacuum operated instrument glass loose?
a. Mark the case and glass with a slippage mark.
b. Replace the glass.
c. Install another instrument.

39. Which instruments are connected to an aircraft's pitot static system?
1. Vertical speed indicator.
2. Cabin altimeter.
3. Altimeter.
4. Cabin rate-of-change indicator.
5. Airspeed indicator.

a. 1, 2, 3, 4, and 5
b. 1, 2, and 4
c. 1, 3, and 5

40. Which of the following instruments will normally have range markings?
a. Altimeter.
b. Altimeter, airspeed indicator.

c. Cylinder head temperature gauge, airspeed indicator.

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