# 2a553a CDC Volume 4

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Volume 4 of the Comm/Nav CDCs

• 1.

### What is the purpose of VOR?

• A.

Determine bearing to a stations

• B.

Indicate distances along the approach

• C.

Determine left/right guidance

• D.

Determine up/down guidance

A. Determine bearing to a stations
Explanation
The purpose of VOR (VHF Omnidirectional Range) is to determine the bearing or direction to a station. VOR uses radio signals to provide pilots with accurate and reliable navigation information. By using VOR, pilots can determine their position in relation to the VOR station and navigate along a specific radial or course. This helps in planning and executing flights, especially during instrument approaches, where pilots need to accurately track and maintain a specific course to reach their destination.

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• 2.

### The basic operating principle of VOR is phase comparing the

• A.

90 and 150 Hz modulated signals

• B.

30 Hz reference and 9,960 Hz FM signals

• C.

30 Hz variable and 9,960 Hz FM signals

• D.

30 Hz reference and 30 Hz variable signals

D. 30 Hz reference and 30 Hz variable signals
Explanation
The VOR (VHF Omnidirectional Range) operates by phase comparing the 30 Hz reference and 30 Hz variable signals. These signals are used to determine the aircraft's bearing in relation to the VOR station. By comparing the phase difference between the two signals, the VOR system can accurately determine the direction of the aircraft from the station. This information is then displayed to the pilot on the instrument panel, allowing for navigation and course corrections.

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• 3.

### If the magnetic bearing to a VOR station is 225 degrees, the phase difference between the 30 Hz reference and 30 Hz variable signal is

• A.

225 degrees

• B.

135 degrees

• C.

15 degrees

• D.

45 degrees

D. 45 degrees
Explanation
The phase difference between the 30 Hz reference and 30 Hz variable signal is determined by the magnetic bearing to the VOR station, which is 225 degrees. The phase difference is equal to the magnetic bearing, so the correct answer is 225 degrees.

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• 4.

### VOR identification (audible) signals are transmitted

• A.

At 20 second intervals

• B.

At specified time intervals

• C.

At 30 second intervals

• D.

Continuously

D. Continuously
Explanation
VOR identification signals are transmitted continuously. This means that the signals are constantly being broadcasted without any interruptions or breaks. The continuous transmission allows pilots and aircraft navigation systems to receive and interpret the signals accurately and in real-time. It ensures a reliable and constant source of navigation information for pilots to determine their position and navigate effectively.

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• 5.

### The ILS localizer course width at a distance of 10 miles from the transmitter is normally

• A.

0.7 degrees

• B.

2.5 degrees

• C.

0.5 degrees

• D.

5 degrees

D. 5 degrees
• 6.

### What frequency is used to transmit ILS glide slope information?

• A.

HF

• B.

VHF

• C.

LF

• D.

UHF

D. UHF
Explanation
UHF (Ultra High Frequency) is the correct answer for this question. ILS (Instrument Landing System) is a radio navigation system used by aircraft to guide them during the approach and landing phases of a flight. The glide slope is a component of the ILS that provides vertical guidance to the aircraft, ensuring a safe descent path. UHF frequency range, typically between 300 MHz and 3 GHz, is commonly used for ILS glide slope transmissions.

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• 7.

### The ILS marker beacon carrier frequency is

• A.

68.1 MHz

• B.

75 kHz

• C.

75 MHz

• D.

68.1 kHz

C. 75 MHz
Explanation
The correct answer is 75 MHz. The Instrument Landing System (ILS) marker beacon carrier frequency is 75 MHz. Marker beacons are used to provide pilots with additional guidance during an approach and landing. They transmit specific signals that indicate the aircraft's position relative to the runway. The carrier frequency of 75 MHz is standardized for marker beacons in aviation.

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• 8.

### What MLS outputs are provided to the pilot's and copilot's HSIs for approach and takeoff?

• A.

Ground station indications

• B.

Azimuth signals

• C.

Steering indications

• D.

Elevation signals

C. Steering indications
Explanation
The correct answer is steering indications. The MLS (Microwave Landing System) provides steering indications to both the pilot and copilot's Horizontal Situation Indicators (HSIs) during approach and takeoff. These indications help the pilots maintain the correct path and alignment with the runway. Steering indications are essential for ensuring safe and accurate navigation during critical phases of flight.

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• 9.

### What is not an MLS output?

• A.

Azimuth deviation

• B.

Azimuth warning flag

• C.

Glide slope correction flag

• D.

Glide slope deviation

C. Glide slope correction flag
Explanation
The question asks for something that is not an MLS output. The options provided are azimuth deviation, azimuth warning flag, glide slope correction flag, and glide slope deviation. Azimuth deviation, azimuth warning flag, and glide slope deviation are all outputs of an MLS system, as they provide information about the deviation from the desired azimuth or glide slope. However, the glide slope correction flag is not an output of an MLS system. Therefore, it is the correct answer to the question.

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• 10.

### On how many channels are the MLS receivers capable of operating?

• A.

559

• B.

500

• C.

669

• D.

200

D. 200
Explanation
The MLS receivers are capable of operating on 200 channels.

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• 11.

### What is the frequency range of the MLS receivers?

• A.

5031-5091 MHz

• B.

200-500 MHz

• C.

500-669 MHz

• D.

669-5031 MHz

A. 5031-5091 MHz
Explanation
The frequency range of the MLS receivers is 5031-5091 MHz. This means that the receivers are designed to operate within this specific range of frequencies.

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• 12.

### Which antennas are shared by MLS numbers 1 and 2?

• A.

3 and 4

• B.

3 and 2

• C.

1 and 3

• D.

1 and 2

A. 3 and 4
Explanation
The antennas that are shared by MLS numbers 1 and 2 are 3 and 4.

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• 13.

### Which MLS landing system component allows for selection of system status?

• A.

• B.

Integrated display computer unit

• C.

Flight director mode selector

• D.

Data bus coupler

B. Integrated display computer unit
Explanation
The integrated display computer unit is the component of the MLS landing system that allows for the selection of system status. It is responsible for displaying information and data related to the MLS system, and it provides the user with the ability to choose different system statuses based on their requirements or preferences.

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• 14.

### When an ILS frequency is selected, the ARN-127 VOR receiver parks the HSI bearing pointer at the

• A.

10 o'clock position

• B.

6 o'clock position

• C.

3 o'clock position

• D.

4 o'clock position

D. 4 o'clock position
Explanation
When an ILS frequency is selected, the ARN-127 VOR receiver parks the HSI bearing pointer at the 4 o'clock position. This positioning helps the pilot to easily distinguish between the VOR and ILS indications on the HSI. By placing the bearing pointer at the 4 o'clock position, it allows for a clear separation between the VOR radial and the localizer course, which is typically displayed at the 12 o'clock position. This positioning aids in the pilot's situational awareness and helps in accurately navigating the aircraft during ILS approaches.

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• 15.

### Which radial will the aircraft be positioned on if the aircraft is located north of the VOR station?

• A.

090 degrees

• B.

270 degrees

• C.

000 degrees

• D.

180 degrees

C. 000 degrees
Explanation
If the aircraft is located north of the VOR station, it will be positioned on the 000 degrees radial. The radial is a line extending outward from the VOR station, and the 000 degrees radial is the one that points directly north. Therefore, if the aircraft is north of the VOR station, it will be positioned on the 000 degrees radial.

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• 16.

### To get a FROM flag in view on the HSI when the magnetic bearing to the VOR station is 75 degrees, the selected course should be manually set to

• A.

75 degrees

• B.

360 degrees

• C.

150 degrees

• D.

210 degrees

D. 210 degrees
Explanation
To get a FROM flag in view on the HSI when the magnetic bearing to the VOR station is 75 degrees, the selected course should be manually set to 210 degrees. This is because the HSI displays the reciprocal of the magnetic bearing, which is 180 degrees opposite. By setting the selected course to 210 degrees, the HSI will display the reciprocal as 30 degrees, indicating a FROM flag.

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• 17.

### During ILS operation, a full-scale deflection of the HSI vertical needle indicates the aircraft is off course from the runway centerline by

• A.

2.5 degrees

• B.

200 feet

• C.

400 feet

• D.

0.6 degrees

A. 2.5 degrees
Explanation
A full-scale deflection of the HSI vertical needle during ILS operation indicates that the aircraft is off course from the runway centerline by 2.5 degrees. This means that the aircraft is deviating significantly from the desired path and needs to make corrections to get back on track. The degree of deflection is a crucial indicator for pilots to maintain proper alignment with the runway centerline during instrument landing system operations.

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• 18.

### In ILS operation, a deflection of two dots on the attitude director indicator glide slope deviation scale indicates the aircraft is

• A.

2.5 degrees off glide path

• B.

6.0 degrees off glide path

• C.

0.6 degrees off glide path

• D.

0.25 degrees off glide path

C. 0.6 degrees off glide path
Explanation
A deflection of two dots on the attitude director indicator glide slope deviation scale indicates that the aircraft is 0.6 degrees off the glide path.

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• 19.

### When the ILS marker beacon amber (orange) lamp illuminates, the pilot hears a

• A.

3,000 Hz tone

• B.

1,000 Hz tone

• C.

1,300 Hz tone

• D.

400 Hz tone

C. 1,300 Hz tone
Explanation
When the ILS marker beacon amber lamp illuminates, the pilot hears a 1,300 Hz tone. This is because the 1,300 Hz tone is associated with the middle marker beacon on the Instrument Landing System (ILS). The ILS uses marker beacons to provide guidance to pilots during instrument approaches. Each beacon is associated with a specific frequency tone, and the 1,300 Hz tone indicates the presence of the middle marker. This helps the pilot to confirm their position during the approach and make necessary adjustments.

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• 20.

### The total number of VOR/ILS channels that can be selected by the AN/ARN-147 control box is

• A.

240

• B.

200

• C.

40

• D.

160

B. 200
Explanation
The AN/ARN-147 control box is capable of selecting a total of 200 VOR/ILS channels.

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• 21.

### If the VOR station signal is lost or the receiver malfunctions, the ARN-147 system parks the bearing pointer at the

• A.

12 o'clock position

• B.

3 o'clock position

• C.

9 o'clock position

• D.

6 o'clock position

B. 3 o'clock position
Explanation
The ARN-147 system is designed to provide navigation guidance using the VOR station signal. In the event of signal loss or receiver malfunction, the system parks the bearing pointer at the 3 o'clock position. This indicates that the pilot should continue on the last known course until the signal is regained or the receiver is fixed. The 3 o'clock position is chosen as it is a distinct and easily recognizable reference point on the instrument panel.

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• 22.

### In VOR mode, what information is sent to the HSI by the ARN-147 VOR/localizer receiver?

• A.

• B.

Left/right deviation, flag alarm, and TO/FROM

• C.

Relative bearing, flag alarm, and heading

• D.

Flag alarm, distance, and left/right deviation

B. Left/right deviation, flag alarm, and TO/FROM
Explanation
The ARN-147 VOR/localizer receiver sends left/right deviation, flag alarm, and TO/FROM information to the HSI in VOR mode. This means that the receiver provides the pilot with the deviation from the desired course, alerts the pilot if there is any issue or flag alarm, and indicates whether the aircraft is flying towards or away from the VOR station. This information is crucial for the pilot to navigate accurately and maintain the desired course.

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• 23.

### What glide slope information is provided to the attitude director indicator when the AN/ARN-127 is oeprating in the ILS mode?

• A.

• B.

Audio signals

• C.

Left/right deviations

• D.

Up/down deviations

D. Up/down deviations
Explanation
When the AN/ARN-127 is operating in the ILS mode, it provides up/down deviations information to the attitude director indicator. This means that the AN/ARN-127 is responsible for indicating whether the aircraft is above or below the desired glide slope. It does not provide left/right deviations or audio signals, but rather focuses on vertical guidance.

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• 24.

### The main reference burst is transmitted when the main lobe of the TACAN surface beacon radiation pattern is due

• A.

South

• B.

North

• C.

West

• D.

East

D. East
Explanation
The main reference burst is transmitted when the main lobe of the TACAN surface beacon radiation pattern is due East.

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• 25.

### A TACAN beacon provides a station identification code every

• A.

7.5 seconds

• B.

20 seconds

• C.

40 seconds

• D.

30 seconds

D. 30 seconds
Explanation
A TACAN beacon provides a station identification code every 30 seconds. This means that every 30 seconds, the TACAN beacon transmits a unique code that identifies the station. This code is used by aircraft or other receivers to determine their distance and bearing from the station. By transmitting the code every 30 seconds, the TACAN beacon ensures that aircraft and receivers have updated and accurate information for navigation purposes.

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• 26.

### During TACAN operation, the two signals phased compared to produce the fine bearing (+- 1 degree) are the

• A.

1135 Hz variable and MRB

• B.

15 Hz reference and MRB

• C.

15 Hz reference and ARB

• D.

35 Hz variable and ARB

D. 35 Hz variable and ARB
Explanation
During TACAN operation, the fine bearing (+- 1 degree) is produced by comparing the phase of the 35 Hz variable signal and the ARB (Azimuth Reference Bit) signal. The 35 Hz variable signal represents the angular displacement between the aircraft and the ground station, while the ARB signal provides the reference for the bearing calculation. By comparing the phase of these two signals, the TACAN system can accurately determine the fine bearing of the aircraft.

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• 27.

### When the TACAN main reference burst occurs at the minimum amplitude of the 15 Hz variable signal, the azimuth to the station is

• A.

270 degrees

• B.

180 degrees

• C.

90 degrees

• D.

0 degrees

C. 90 degrees
Explanation
When the TACAN main reference burst occurs at the minimum amplitude of the 15 Hz variable signal, it indicates that the station is directly to the east or west of the observer. In this case, the azimuth to the station would be 90 degrees, as it is perpendicular to the observer's line of sight.

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• 28.

### If the HSI indicator displays a magnetic heading of 45 degrees and magnetic bearing of 5 degrees to the tactical air navigation station, the the relative bearing is

• A.

45 degrees

• B.

225 degrees

• C.

320 degrees

• D.

40 degrees

C. 320 degrees
Explanation
The relative bearing is the angle between the aircraft's heading and the position of the object being observed. In this case, the HSI indicator displays a magnetic heading of 45 degrees and a magnetic bearing of 5 degrees to the tactical air navigation station. To determine the relative bearing, we subtract the magnetic bearing from the magnetic heading. Therefore, 45 degrees - 5 degrees = 40 degrees. However, since the relative bearing is always measured clockwise from the aircraft's nose, we add 360 degrees to the result. Hence, the correct answer is 320 degrees.

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• 29.

### In the tactical air navigation mode, each dot on the HSI represents an error from the selected course of

• A.

10.0 degrees

• B.

1.25 degrees

• C.

2.50 degrees

• D.

5.0 degrees

D. 5.0 degrees
Explanation
In tactical air navigation mode, each dot on the HSI represents an error from the selected course of 5.0 degrees. This means that if the aircraft is deviating from the selected course, the HSI will display the extent of the deviation by showing the number of dots away from the desired course. For example, if the aircraft is one dot to the right of the course, it means that it is off by 5.0 degrees to the right. This information helps pilots make necessary corrections to stay on track during their flight.

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• 30.

### If the horizontal situation indicator bearing pointer indicates 50 degrees during tactical air navigation operation, waht selected couse should be selected to get the FROM arrow

• A.

330 degrees

• B.

0 degrees

• C.

120 degrees

• D.

270 degrees

D. 270 degrees
Explanation
In tactical air navigation, the horizontal situation indicator bearing pointer indicates the direction to a selected course. To get the FROM arrow, the selected course should be opposite to the bearing pointer. Since the bearing pointer indicates 50 degrees, the opposite direction would be 180 degrees away from it. Therefore, the selected course should be 180 degrees + 90 degrees (to get the FROM arrow) which equals 270 degrees.

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• 31.

### The purpose of the TACAN system is to provide the pilot with accurate

• A.

Distance, bearing, and aural information

• B.

Aircraft heading, bearing, and distance information

• C.

Distance, aircraft heading, and aural information

• D.

Magnetic heading, aural, and distance information

A. Distance, bearing, and aural information
Explanation
The TACAN system is designed to provide the pilot with accurate distance, bearing, and aural information. This means that it can determine the distance between the aircraft and a ground station, the direction or bearing to that station, and also provide aural cues or signals to assist the pilot in navigation. This information is crucial for pilots to accurately navigate and maintain situational awareness during flights.

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• 32.

### The maximum number of tactical air navigation channels available for use by the AN/ARN-118 system is

• A.

200

• B.

390

• C.

252

• D.

126

C. 252
Explanation
The AN/ARN-118 system has a maximum of 252 tactical air navigation channels available for use.

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• 33.

### The AN/ARN-118 is controlled by the area navigation system when the TACAN control box channel selector (X or Y) is set to

• A.

10

• B.

00

• C.

11

• D.

01

B. 00
Explanation
The correct answer is "00". The AN/ARN-118 is controlled by the area navigation system when the TACAN control box channel selector is set to "00". This indicates that the AN/ARN-118 is integrated with the area navigation system and will receive guidance and navigation information from it. The other options do not specify the correct setting for the TACAN control box channel selector, so they are not the correct answer.

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• 34.

### What signals are produced when the AN/ARN-118 is in the transmit-receiver mode?

• A.

Only distance and BIT from a CA

• B.

Bearing, slant range distance, and BIT from a surface beacon

• C.

Only slant range distance and beacon identity tone from a surface beacon

• D.

Bearing and distance from a cooperating aircraft (CA)

B. Bearing, slant range distance, and BIT from a surface beacon
Explanation
When the AN/ARN-118 is in the transmit-receiver mode, it produces signals that include the bearing, slant range distance, and BIT (Built-In Test) from a surface beacon. This means that the device is able to provide information about the direction, distance, and status of a surface beacon. It does not provide signals related to a cooperating aircraft (CA) or only distance and BIT from a CA.

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• 35.

### For two aircraft to communicate using the AN/ARN-118 in air-to-air mode when one aircraft is on channel 37Y, the other aircraft must be on channel

• A.

100Y

• B.

37X

• C.

37Y

• D.

100X

A. 100Y
Explanation
In order for two aircraft to communicate using the AN/ARN-118 in air-to-air mode, they must be on the same channel. The first aircraft is on channel 37Y, therefore the other aircraft must also be on the same channel, which is 37Y. The answer 100Y is incorrect because it is a different channel. Similarly, 37X and 100X are also incorrect as they do not match the channel of the first aircraft.

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• 36.

• A.

Warning flag

• B.

TO/FROM

• C.

Bearing

• D.

Distance

B. TO/FROM
Explanation
The information that is not sent to the tactical air navigation adapter from the receiver-transmitter is the TO/FROM indication. This means that the adapter does not receive any indication of whether the aircraft is heading towards or away from the navigational beacon.

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• 37.

### In the TACAN receiver-transmitter adapter, TO/FROM information is developed by combine magnetic bearing with

• A.

• B.

Relative bearing

• C.

Course deviation

• D.

Explanation
The TO/FROM information in the TACAN receiver-transmitter adapter is developed by combining the magnetic bearing with the magnetic heading. The magnetic bearing refers to the direction towards a specific point relative to magnetic north, while the magnetic heading refers to the direction in which the aircraft's nose is pointing relative to magnetic north. By combining these two pieces of information, the adapter can determine whether the aircraft is heading towards or away from the desired point.

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• 38.

### TACAN channel data and selected mode information are routed to the receiver-transmitter as a

• A.

16-bit ternary word

• B.

32-bit ternary word

• C.

32-bit serial word

• D.

16-bit serial word

A. 16-bit ternary word
Explanation
The TACAN channel data and selected mode information are routed to the receiver-transmitter as a 16-bit ternary word. This means that the information is transmitted using a 16-bit binary code, where each bit can have three possible values (0, 1, or 2). This allows for a higher level of data transmission and accuracy compared to a binary word. The use of a ternary word ensures that the receiver-transmitter can accurately interpret and process the channel data and mode information.

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• 39.

• A.

A 24-bit serial word into a 32-bit data output

• B.

Digital distance information into an analog output

• C.

Analog distance information into a digital output

• D.

A 32-bit ternary word into an analog output

B. Digital distance information into an analog output
Explanation
The TACAN receiver-transmitter adapter is designed to convert digital distance information into an analog output. This means that it takes the digital distance information, which is typically represented as a series of bits, and converts it into an analog signal that can be used to provide distance information. This analog output can then be used by other systems or devices to determine the distance between the TACAN receiver and the target location.

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• 40.

### Which acronym is used for the system that determines if an aircraft is a friend or foe?

• A.

TACAN

• B.

IFF

• C.

• D.

B. IFF
Explanation
IFF stands for Identification Friend or Foe, which is a system used in military and civilian aircraft to determine whether an unknown aircraft is friendly or hostile. It allows aircraft to exchange identification codes and signals to prevent friendly fire incidents and enhance situational awareness. TACAN, ADF, and RADAR are all different systems used in aviation for navigation and surveillance purposes, but they do not specifically address the identification of friend or foe aircraft.

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• 41.

### The ground radar and identification, friend or foe interrogator transmissions are synchronized so the radar returns can be

• A.

Used to display altitude information

• B.

Displayed on the PPI independent of the IFF reply

• C.

Displayed on the PPI with the IFF reply

• D.

Displayed on a separate plan position indicator

C. Displayed on the PPI with the IFF reply
Explanation
The ground radar and identification, friend or foe interrogator transmissions are synchronized so that the radar returns can be displayed on the PPI (Plan Position Indicator) together with the IFF (Identification Friend or Foe) reply. This means that the altitude information gathered from the radar returns can be displayed alongside the identification information obtained from the IFF reply, providing a comprehensive display of both altitude and identification on the same screen.

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• 42.

### What acronym is used for the system developed to include identification, altitude, and cryptographic secure-coded reply from an aircraft?

• A.

IFF

• B.

AFSATCOM

• C.

ATCRBS

• D.

AIMS

D. AIMS
Explanation
AIMS stands for Aircraft Identification, Altitude, and Cryptographic Secure-Coded Reply System. This system is developed to include identification, altitude, and a secure-coded reply from an aircraft. It is used for communication and identification purposes in aviation.

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• 43.

### The identification, friend or foe mode 4 interrogation consists of

• A.

Four 0.8-Âµ sec pulses, spaced 21 Âµ sec apart

• B.

Two 0.8 Âµ-sec pulses, spaced 21 Âµ sec apart

• C.

Four 0.5-Âµ sec pulses, spaced 2 Âµ sec apart

• D.

Two 0.5-Âµ sec pulses, spaced 2 Âµ sec apart

C. Four 0.5-Âµ sec pulses, spaced 2 Âµ sec apart
Explanation
The correct answer is four 0.5-Âµ sec pulses, spaced 2 Âµ sec apart. This is because the identification, friend or foe mode 4 interrogation consists of four pulses that are 0.5 microseconds in duration and spaced 2 microseconds apart. This specific pattern of pulses is used to distinguish between friendly and hostile aircraft.

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• 44.

### For the IFF system to sense side lobe interrogations, the interrogating station transmits

• A.

A P1 pulse 6 Âµ sec before the first interrogation pulse

• B.

An interrogation pulse (P1) 2 Âµ sec after the first interrogation pulse

• C.

A P2 pulse 6 Âµ sec before the first interrogation pulse

• D.

A side lobe suppression pulse (P2) 2 Âµ sec after the first interrogation pulse

D. A side lobe suppression pulse (P2) 2 Âµ sec after the first interrogation pulse
Explanation
The correct answer is a side lobe suppression pulse (P2) 2 Âµ sec after the first interrogation pulse. In order for the IFF system to sense side lobe interrogations, a side lobe suppression pulse (P2) needs to be transmitted after the first interrogation pulse. This pulse helps to suppress any side lobe signals that may interfere with the accurate detection and identification of the target. By transmitting the P2 pulse after the first interrogation pulse, the system can effectively filter out any unwanted side lobe signals and improve the overall performance and reliability of the IFF system.

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• 45.

### The IFF information pulses used for mode 1 replies are

• A.

A1, A22, A4, B1, and B2

• B.

A1, A2, A3, B1, and B4

• C.

A1, B1, B2, B4, and C1

• D.

A1, A4, B1, B4, and C1

A. A1, A22, A4, B1, and B2
Explanation
The correct answer is A1, A22, A4, B1, and B2. These are the IFF (Identification Friend or Foe) information pulses used for mode 1 replies. Mode 1 is a military-specific mode of operation for IFF systems. The specific pulses listed in the answer are the ones used to transmit information and identify friendly aircraft.

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• 46.

### The maximum number of IFF reply codes that can be selected in mode 1 is

• A.

1064

• B.

73

• C.

77

• D.

32

D. 32
Explanation
In mode 1, there is a limit to the number of IFF reply codes that can be selected. The correct answer is 32, which means that in mode 1, only 32 different IFF reply codes can be chosen.

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• 47.

### When the IDENT switch is activated, the IFF transponder automatically transmits an identification of position reply for

• A.

10 seconds

• B.

30 seconds

• C.

20 seconds

• D.

25 seconds

C. 20 seconds
Explanation
When the IDENT switch is activated, the IFF transponder automatically transmits an identification of position reply for 20 seconds. This means that for a duration of 20 seconds, the transponder will send out a signal that identifies the position of the aircraft. This can be useful in situations where the aircraft needs to be easily identified or located by air traffic control or other aircraft.

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• 48.

### What happens when the IFF system fails to reply to a mode 4 interrogation?

• A.

The IFF CAUTION light on the pilot's instrument panel illuminates

• B.

The TEST light on the IFF control box illuminates

• C.

The TEST light on the IFF control box does not illuminate

• D.

The REPLY light on the IFF control box illuminates

A. The IFF CAUTION light on the pilot's instrument panel illuminates
Explanation
When the IFF system fails to reply to a mode 4 interrogation, the IFF CAUTION light on the pilot's instrument panel illuminates.

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• 49.

### When the IDENT-OUT-MIC switch is in the MIC position, identification, friend or foe system identification of position replies are triggered every time the

• A.

• B.

• C.

• D.

Explanation
When the IDENT-OUT-MIC switch is in the MIC position, the identification, friend or foe system triggers position replies every time the UHF radio is keyed. This means that whenever the UHF radio is activated, the system will send out identification signals to determine the position of friendly or enemy forces.

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• 50.

### Which position of the IFF mode 4 code selection switch is spring loaded?

• A.

EMER

• B.

ZERO

• C.

NORM

• D.

HOLD

D. HOLD
Explanation
The position of the IFF mode 4 code selection switch that is spring loaded is "HOLD". This means that when the switch is released, it will automatically return to the "HOLD" position. This feature ensures that the switch remains in a specific position unless intentionally moved by the operator, preventing accidental changes to the code selection.

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• Current Version
• Mar 19, 2023
Quiz Edited by
ProProfs Editorial Team
• Feb 05, 2010
Quiz Created by
Egramza

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