Questions - Communication and Navigation

Study Aid Questions

Fill in the Blanks

1. Covalent bonds are created when two or more substances share electrons in their ______.

2. Electron flow occurs when there are ______ in the valence shell due to the atom’s preference to have ______ electrons in all of its shell.

3. A four‐layer diode or ______ has three junctions. The behavior of the junctions can be understood by considering it to be two interconnected ______ transistors.

4. SCRs are often used in high ______ situations, such as switching, phase controls, battery chargers, and ______ circuits.

5. The ______ and amount of voltage applied to the gate can widen and narrow the ______ due to expansion or shrinkage of the depletion area at the junction of the semiconductor.

6. Depletion mode MOSFETs are considered normally ______ while enhanced mode MOSFETZs are normally ______.

7. Forward biased ______ give off energy visible in the ______ characteristic unique to the material of the semiconductor being used.

8. Transistors are rated by the ______ of the collector current to the ______ current, or Beta.

9. Common‐ ______ amplifiers are unique because their construction creates a situation where the base current ______ is than the collector or emitter current.

10. If there is to be an output voltage in a ______ gate, then the inputs cannot both have voltage.

11. The primary flight display displays the attitude indicator in the ______ half of the display and the electronic ______ indicator on the other half.

12. The electronic field component and the electromagnetic field component are oriented ______ to each other and at ______ to the direction that the wave is traveling.

13. 2 common methods of modulating ______ waves are amplitude and ______ modulation.

14. FM is considered ______ to AM for carrying and deciphering information on ______ waves.

15. The information signal is separated from the carrier wave portion of the signal by the ______.

16. Antennas are ______. They radiate and receive waves in certain patterns and ______.

17. ______ wire is used to connect transmitters and receivers to their ______.

18. VORs are marked on aeronautical charts along with their name, the ______ to tune, and a ______ designator.

19. On an RDF system, the only way to determine if the aircraft was flying to or from the ______ was the increasing and decreasing strength of the ______ signal.

20. The combination of a magnetic compass, VOR, and ADF into one instrument is found on an ______.

21. Vertical guidance required for an aircraft to descend for landing is provided by the ______ at an angle of about ______.

22. A ______ transponder provides positive identification and ______ of an aircraft on the radar screen of ATC.

23. Traffic collision ______ systems, or TCAS, are ______ based air‐to‐air traffic monitoring and alerting systems.

24. The ______ covering the antenna must only be painted with approved paint to allow radio signals to pass unobstructed.

25. The GPS receiver measure the time it takes for a signal to arrive from ______ transmitting satellites. This two‐dimensional position is expressed in ______ coordinates.


1. Maintenance of avionics is typically done by a technician with an Airframe license. TRUE/FALSE

2. Analog representations are discontinuous. TRUE/FALSE

3. Diodes act as check valves in AC circuits. TRUE/FALSE

4. Tetrodes are used at higher frequencies than triodes. TRUE/FALSE

5. Semiconductors are thought to be the building blocks of modern electronics. TRUE/FALSE

6. A material is an insulator if the electrons in the valence shell are allowed to move freely from one shell to another. TRUE/FALSE

7. N‐type semiconductor material is also known as a donor material. TRUE/FALSE

8. The amount of current that is allowed to pass through a forward biased diode is indirectly proportional to the amount of voltage applied. TRUE/FALSE

9. A transistor is a sandwich of N‐type material between two pieces of P‐type material and vice versa. TRUE/FALSE

10. Current to the collector‐emitter is turned on and off by the voltage applied to the collector. TRUE/FALSE

11. Photodiodes can carry more current than a photon activated transistor. TRUE/FALSE

12. Rectifiers change AC voltage to DC voltage. TRUE/FALSE

13. Common‐emitter circuits are characterized by high power gains. TRUE/FALSE

14. A sine wave is produced by generators when an conductor is rotated in a uniform electric field. TRUE/FALSE

15. Digital logic is based on the binary numbering system. TRUE/FALSE

16. All gates are amplifiers subject to output fluctuations. TRUE/FALSE

17. The negative OR gate is the same as the NOR gate. TRUE/FALSE

18. The relationship between frequency and wavelength is directly proportional. TRUE/FALSE

19. Ground waves are useful for long distance transmissions. TRUE/FALSE

20. VHF communication radios range from 118.0MHz to 336.975MHz. TRUE/FALSE

21. The distance a carrier wave travels is directly related to the amplification of the signal sent to the antenna. TRUE/FALSE

22. Most radio transmitters generate an unstable oscillating frequency that is stabilized by a mixer. TRUE/FALSE

23. A transceiver is a communication radio that transmits and receives. TRUE/FALSE

24. The strongest signals received align directly with the length of the antenna. TRUE/FALSE

25. The course deviation indicator on an OBS is essentially vertical but moves right and left across graduations each representing 5° of course deviation. TRUE/FALSE

26. The VOR circuitry is still active on an VOR/ILS receiver when the ILS localizer frequency is tuned in. TRUE/FALSE

27. DME distances are slant distances which is longer than ground distance. TRUE/FALSE

28. Transponder code 7700 is used for hijack situations. TRUE/FALSE

29. A radio altimeter indicates altitude in MSL. TRUE/FALSE

30. The accuracy of GPS is within 20 meters horizontally and can be improved to 7.6 meters with the integration of WAAS to the GPS. TRUE/FALSE

Knowledge Application Questions

1. How are analog electric signals modified?

2. Why were vacuum tubes replaced by solid‐state devices in aircraft radios?

3. Why is silicon one of the primary materials used in the manufacturing of semi‐conductors?

4. When is a semi‐conductor said to be reversed biased and what is the resulting effect of the circuit?

5. What does it mean when a diode is designed with a zener voltage and why are they used?

6. What are the advantages of a UJT over a bipolar transistor?

7. What are Shockley diodes useful for?

8. What are the three basic amplifier types?

9. Explain what a NOT gate does in terms of Logic in and out and what this means in relation to voltage.

10. What is the difference between an EXCLUSIVE OR and an OR?

11. Explain the processes of transmitting radio waves.

12. What is demodulation in amplitude modulation?

13. Why is frequency modulation considered superior to amplitude modulation?

14. What are the three frequencies produced when two AC signals are mixed together?

15. What is the purpose of the receiver and what does it do?

16. What are the three characteristics of concern when considering an antenna?

17. How is the use of one‐quarter of the wavelength antenna possible?

18. What is antenna field directivity?

19. Describe the difference between dipole, Marconi, and loop antennas.

20. How does a VOR receiver interpret the signal generated by the VOR station?

21. Describe each of the radio transmissions used on an ILS approach.

22. What does pressing IDENT do for an ATC controller?en is TCAS II required and what does it provide?

23. When is TCAS II required and what does it provide?

24. What are the advantages of ADS‐B over conventional ground‐based radar?

25. What are the three segments of GPS?

Multiple Choices Questions

1. Installed radio equipment is protected from damage due to jolts and vibration by
a. shock mounts.
b. spring and/or viscous damper mounted racks.
c. rubber or foam cushioning material between circuit chassis and case.

2. (1) Use solder to attach bonding jumpers on radio equipment.
(2) Radio equipment is bonded to the aircraft in order to provide a low impedance ground and to minimize radio interference from static electrical charges.

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

3. When must the radio station license be displayed in an aircraft equipped with a two-way radio?
a. When the aircraft is certified for IFR flight.
b. When the aircraft is operated outside the U.S.
c. When the aircraft is returned to service.

4. When would a U.S. resident NOT be required to hold a Federal Communications Commission (FCC) Restricted Radio Telephone Operator Permit to operate two-way aircraft VKF radio equipment?
a. When flying or communicating within the United States.
b. When flying to or communicating with destinations outside the United States.
c. When the radio equipment is operated in aircraft certified for VFR flight only.

5. Part of the ADF system used on aircraft includes
a. sense and loop antennas.
b. RMI indicator antenna.
c. marker beacon antenna.

6. When installing coaxial cable, it should be secured firmly along its entire length
a. wherever the cable sags.
b. at 1-foot intervals.
c. at 2-foot intervals.

7. When must the emergency locator transmitter (ELT) battery be replaced (other than reading the replacement date)?
a. When the transmitter has been tested more than ten times.
b. When the transmitter has been in use for more than one cumulative hour.
c. Must be replaced annually or if the five G switch has been activated.

8. An emergency locator transmitter (ELT) battery must be capable of furnishing power for signal transmission for at least
a. 48 hours.
b. 36 hours.
c. 72 hours.

9. The preferred location of an ELT is
a. where it is readily accessible to the pilot or a member of the flightcrew while the aircraft is in flight.
b. as far aft as possible, but forward of the vertical fin.
c. as far aft as possible.

10. An emergency locator transmitter (ELT) is normally activated by an inertial switch or equivalent mechanism if subjected to a force of a prescribed intensity and duration. It must activate when the force is applied
a. parallel to the longitudinal axis of the aircraft.
b. in any direction relative to the aircraft axes.
c. parallel to the vertical axis of the aircraft.

11. How may the battery replacement date be verified for an emergency locator transmitter (ELT)?
a. By activating the transmitter and measuring the signal strength.
b. By removing the batteries and testing them under a measured load to determine if 50 percent of the useful life remains.
c. By observing the battery replacement date marked on the outside of the transmitter.

12. How may the operation of an installed emergency locator transmitter (ELT) be verified during aircraft inspection?
a. By moving the deactivating switch from the DISARM position to the ARM position, while monitoring the civil emergency frequency with a communications receiver at five minutes after the hour.
b. By tuning a communications receiver to the civil emergency frequency, and activating the ELT momentarily within five minutes after the hour.
c. By activating the 5 g switch and turning the unit on at five minutes after the hour.

13. Static dischargers help eliminate radio interference by dissipating static electricity into the atmosphere at
a. low current levels.
b. high voltage level.
c. high current levels.

14. Long Range Navigation (LORAN) systems determine aircraft location by
a. measuring the inertial forces acting on the aircraft.
b. means of pulsed signals transmitted from ground stations.
c. means of signals transmitted to and from navigation satellites.

15. An aircraft antenna installation must be grounded
a. to the airframe.
b. to the radio rack.
c. to the engine.

16. VHF radio signals are commonly used in
a. both VOR navigation and ATC communications.
b. ATC communications.
c. VOR navigation.

17. On modern large aircraft, what electronic device typically monitors flight parameters and performs autopilot functions?
a. Control/display unit.
b. Transponder.
c. Flight management computer.

18. In the landing configuration GPWS typically monitors the radio (radar) altimeter; air data computer; instrument landing system, and
a. aileron, rudder, and elevator positions.
b. landing gear and flap positions.
c. spoiler, slat, and stabilizer positions.

19. In general, the purpose of an aircraft transponder is to
a. continually transmit heading, speed, and rate of climb/decent etc. information to ATC.
b. monitor aircraft speed, heading, altitude, and attitude whenever the autopilot system is engaged.
c. receive an interrogation signal from a ground station and automatically send a reply back.

20. When an antenna is installed, it should be fastened
a. to the primary structure at the approximate intersection of the three aircraft axes.
b. with a reinforcing doubler on each side of the aircraft skin.
c. so that loads imposed are transmitted to the aircraft structure.

21. After an automatic direction finding antenna has been installed, the
a. loop must be calibrated.
b. antenna must be grounded.
c. transceiver must be compensated.

22. Doublers are used when antennas are installed to
a. prevent oil canning of the skin.
b. eliminate antenna vibration.
c. reinstate the structural strength of the aircraft skin.

23. One antenna can be used for the radio range and standard broadcast bands in light aircraft because the
a. antenna is omnidirectional.
b. antenna length may be electronically adjusted.
c. two ranges are close together.

24. What characteristics of the installation of a rigid antenna on a vertical stabilizer should be evaluated?
a. Polarization and impedance.
b. Flutter and vibration.
c. Impedance and interference.

25. A gasket or sealant is used between the antenna mast and fuselage skin
a. for aircraft pressurization only.
b. to prevent the entry of moisture.
c. to prevent abrasion between the antenna mast and fuselage skin.

26. The preferred location of a VOR antenna on light aircraft is on
a. top of the cabin with the apex of the V pointing forward.
b. top of the vertical stabilizer.
c. the bottom of the fuselage and as far forward as possible.

27. The purpose of a localizer is to
a. set the airplane on the proper approach angle to the runway.
b. indicate the distance the airplane is from the end of the runway.
c. align the airplane with the center of the runway.

28. (Refer to figure 1) What is the approximate drag load on an antenna with a frontal area of .I25 square feet installed on an aircraft with a speed of 225 MPH?
a. 2.080 pounds.
b. 2.069 pounds.
c. 2.073 pounds.

Figure 1

29. (Refer to figure 1) What is the approximate drag load on an antenna with a frontal area of .I37 square feet installed on an aircraft with a speed of 275 MPH?
a. 3.592 pounds.
b. 3.387 pounds.
c. 3.741 pounds.

30. A DME antenna should be located in a position on the aircraft that will
a. permit interruptions in DME operation.
b. not be blanked by the wing when the aircraft is banked.
c. eliminate the possibility of the DME locking on a station.

31. When bending coaxial cable, the bend radius should be at least
a. 10 times the diameter of the cable.
b. 15 times the diameter of the cable.
c. 20 times the diameter of the cable.

32. When installing a DME antenna, it should be aligned with the
a. centerline on the airplane.
b. angle of incidence.
c. null position.

33. (Refer to figure 2) Which of the antennas shown is a typical DME antenna?
a. 1
b. 2
c. 4

Aircraft antenna types
Figure 2

34. (Refer to figure 2) Which of the antennas shown is a typical glideslope antenna?
a. 2
b. 3
c. 4

35. The addition of avionics and associated antenna systems forward of the CG limit will affect
a. CG limits and useful load.
b. useful load and maximum gross weight.
c. empty weight and useful load.

36. How much clearance from the seat bottom is required when installing radio equipment under a seat?
a. No set minimum as long as the equipment receives adequate cooling and damage protection.
b. 3 inches with the seat unoccupied.
c. 1 inch with the seat occupied and subjected to maximum downward seat spring deflection.

37. The purpose of a glideslope system is to
a. indicate the distance the airplane is from the end of the runway.
b. assist the pilot in making a correct angle of descent to the runway.
c. provide for automatic altitude reporting to air traffic control.

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