# 2A251 Volume 3 UREs

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• 1.

### The primary reason a high frequency (HF) radio uses single sideband (SSB) modulation is

• A.

That fidelity is greatly increased

• B.

The system can use a very wide-band pass

• C.

The transmitter output power is 10 watts

• D.

That it provides many channels on which to operate

D. That it provides many channels on which to operate
Explanation
The primary reason a high frequency (HF) radio uses single sideband (SSB) modulation is that it provides many channels on which to operate. SSB modulation allows for more efficient use of the limited available bandwidth in the HF spectrum by eliminating the need for a carrier signal and one sideband. This enables multiple channels to be transmitted within the same frequency range, increasing the number of available communication channels for HF radios.

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• 2.

### What is the transmitted frequency when a high frequency (HF) radio control is set to 25.000-megahertz (MHz), with a signal modulated by a 1000-hertz tone, when the lower sideband mode is selected?

• A.

24.500 MHz

• B.

24.999 MHz

• C.

25.001 MHz

• D.

25.000 MHz

B. 24.999 MHz
Explanation
When the lower sideband mode is selected, the transmitted frequency is slightly lower than the carrier frequency. In this case, the carrier frequency is set to 25.000 MHz and it is modulated by a 1000 Hz tone. The lower sideband will be 1000 Hz below the carrier frequency, resulting in a transmitted frequency of 24.999 MHz.

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• 3.

### Which is not a mode of operation for the ARC-190 high-frequency radio system?

• A.

Frequency modulation (FM)

• B.

Upper sideband (USB) data

• C.

Lower sideband (LSB) voice

• D.

Amplitude modulated equivalent (AME)

A. Frequency modulation (FM)
Explanation
The ARC-190 high-frequency radio system has multiple modes of operation, including upper sideband (USB) data, lower sideband (LSB) voice, and amplitude modulated equivalent (AME). However, frequency modulation (FM) is not one of the modes of operation for this radio system.

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• 4.

### You are using a learned preset for the ARC-190 high-frequency (HF) radio system. For this application, the transmit tune time is less than

• A.

5 milliseconds

• B.

25 milliseconds

• C.

35 milliseconds

• D.

50 microseconds

C. 35 milliseconds
Explanation
The transmit tune time refers to the time it takes for the radio system to adjust its frequency and power settings before transmitting a signal. In this case, the learned preset for the ARC-190 HF radio system has a transmit tune time of 35 milliseconds. This means that it takes 35 milliseconds for the radio system to complete its tuning process and be ready to transmit a signal.

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• 5.

### This version of the ARC-190 high-frequency (HF) radio system receiver-transmitter (RT) only operated properly if the system has a CU-2275(V)1 HF antenna coupler installed?

• A.

RT-1341(V)1

• B.

RT-1341(V)2

• C.

RT-1341(V)3

• D.

RT-1341(V)4

A. RT-1341(V)1
Explanation
The explanation for the correct answer is that the ARC-190 HF radio system receiver-transmitter (RT) only operates properly when it has a CU-2275(V)1 HF antenna coupler installed. This implies that the RT-1341(V)1 is the version of the radio system that is compatible with the CU-2275(V)1 antenna coupler. The other versions, RT-1341(V)2, RT-1341(V)3, and RT-1341(V)4, may not have the necessary compatibility with the antenna coupler, so they would not operate properly with the ARC-190 HF radio system.

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• 6.

### In the ARC-190 high-frequency (HF) radio system, what helps prevent high voltage arcing within the HF coupler at high altitudes?

• A.

Sealed tuner assembly

• B.

Sealed control compartment

• C.

Pressurized tuner assembly

• D.

Pressurized control compartment

C. Pressurized tuner assembly
Explanation
The pressurized tuner assembly helps prevent high voltage arcing within the HF coupler at high altitudes. By maintaining a higher pressure inside the tuner assembly, it creates a barrier that prevents the formation of arcing, which can be caused by the high altitudes and the associated changes in air pressure. This pressurized environment ensures that the HF coupler remains protected and functions properly, allowing for reliable communication in high altitude conditions.

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• 7.

### The external blower for an ARC-190 high-frequency radio system is overheating. This situation will cause a receiver-transmitter (RT) fault and

• A.

Keep the coupler from tuning

• B.

Reduce the external blower speed

• C.

Cause the RT fault light to turnoff

• D.

Keep the transmitter from functioning

D. Keep the transmitter from functioning
Explanation
If the external blower for an ARC-190 high-frequency radio system is overheating, it can cause the transmitter to stop functioning. This is because the external blower plays a crucial role in cooling down the system, and if it is overheating, it will not be able to effectively cool the transmitter, leading to its malfunctioning.

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• 8.

### A very-high frequency (VHF) frequency modulated (FM) radio is mainly used on aircraft that

• A.

Contact ground forces

• B.

Contacts airborne tankers for fuel

• C.

Uses Air Force controlled airfields

• D.

Is controlled by civilian air traffic controllers

A. Contact ground forces
Explanation
A very-high frequency (VHF) frequency modulated (FM) radio is mainly used on aircraft to contact ground forces. This means that the radio is primarily used for communication between the aircraft and ground personnel, such as military troops or support teams. It allows the aircraft to relay important information, coordinate operations, and receive instructions from the ground forces.

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• 9.

### Which very-high frequency (VHF) radio system would have the best chance of receiving a signal from a station located beyond the line of sight (LOS)?

• A.

VHF amplitude modulated (AM)

• B.

VHF omnirange (VOR)

• C.

VHF frequency modulated (FM)

• D.

Localizer/glideslope

C. VHF frequency modulated (FM)
Explanation
VHF frequency modulated (FM) radio systems would have the best chance of receiving a signal from a station located beyond the line of sight (LOS). This is because FM signals are less affected by obstacles and atmospheric conditions compared to other VHF radio systems. FM signals have a wider bandwidth, which allows them to carry more information and be less susceptible to interference. Additionally, FM signals can be easily demodulated and decoded, making them more reliable for long-distance communication.

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• 10.

### Which very-high frequency (VHF) radio system uses two antennas?

• A.

Frequency modulated (FM) homing

• B.

Amplitude modulated (AM) communications

• C.

FM communications

• D.

AM direction finder

A. Frequency modulated (FM) homing
Explanation
Frequency modulated (FM) homing is the correct answer because it is a VHF radio system that utilizes two antennas. This system is commonly used in aviation and maritime applications for navigation and tracking purposes. By using two antennas, FM homing can determine the direction of a signal source by comparing the strength of the signal received by each antenna. This allows for accurate and reliable tracking of signals in VHF frequencies.

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• 11.

### The frequency range of the ARC-186 very-high frequency (VHF) radio receiver, in only the receive amplitude modulated (AM) mode, is this megahertz (MHz) range

• A.

30 to 87.975

• B.

38 to 87.975

• C.

108 to 151.975

• D.

116 to 151.975

C. 108 to 151.975
Explanation
The correct answer is 108 to 151.975. This range represents the frequency range of the ARC-186 VHF radio receiver in the receive AM mode.

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• 12.

### Which frequencies can the ARC-186 very-high frequency (VHF) radio not transmit with in the amplitude modulated (AM) mode?

• A.

30 to 87.975 megahertz (MHz)

• B.

38 to 87.975 MHz

• C.

108 to 115.975 MHz

• D.

116 to 151.975 MHz

C. 108 to 115.975 MHz
Explanation
The ARC-186 very-high frequency (VHF) radio cannot transmit in the amplitude modulated (AM) mode within the frequency range of 108 to 115.975 MHz.

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• 13.

### We call the C-11029/ARC-186 a true communications/navigation (comm/nav) control box because

• A.

Rivet work force changed its design

• B.

It controls the very-high frequency amplitude-modulated (AM) and frequency modulated (FM) systems

• C.

It controls both the very-high frequency (VHF) radio and the VHF-omnirange/instrument landing system (VOR/ILS) receiver

• D.

Automatic direction finding and homing share similar communication and navigation systems' characteristics

C. It controls both the very-high frequency (VHF) radio and the VHF-omnirange/instrument landing system (VOR/ILS) receiver
Explanation
The correct answer is that the C-11029/ARC-186 is considered a true communications/navigation control box because it controls both the very-high frequency (VHF) radio and the VHF-omnirange/instrument landing system (VOR/ILS) receiver. This implies that it has the capability to manage and regulate both the communication and navigation functions of the aircraft.

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• 14.

### How many frequencies are available for the tunable main receiver to use in the ARC-164 ultra-high frequency (UHF) radio?

• A.

10000

• B.

7000

• C.

3500

• D.

700

B. 7000
Explanation
The correct answer is 7000 because the question asks about the number of frequencies available for the tunable main receiver in the ARC-164 ultra-high frequency (UHF) radio. Therefore, out of the given options, 7000 is the most suitable choice as it represents the number of frequencies available for use.

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• 15.

### How do Have Quick (HQ) radios resist jamming?

• A.

Frequency-hopping

• B.

Retransmission

• C.

Encryption

• D.

Phase shifting

A. Frequency-hopping
Explanation
Frequency-hopping is a technique used by Have Quick (HQ) radios to resist jamming. This technique involves rapidly changing the frequency of the radio signals over a wide range of frequencies. By constantly switching frequencies, the radios make it difficult for jammers to interfere with the communication. This is because the jammers would need to continuously adjust their frequency to match the hopping pattern, which is challenging to achieve in real-time. Therefore, frequency-hopping helps to ensure secure and uninterrupted communication for HQ radios.

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• 16.

### The Have Quick II radios' frequency-hopping pattern and rate is programmed using this feature

• A.

Time-of-day

• B.

Word-of-day

• C.

Net number used

• D.

Universal time coordinated

B. Word-of-day
Explanation
The word-of-day feature is used to program the frequency-hopping pattern and rate of Have Quick II radios. This feature involves assigning a specific word for each day, which is then used to determine the frequency-hopping sequence for that day. By programming the radios with the word-of-day, the radios can synchronize their frequency-hopping patterns, ensuring secure and reliable communication.

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• 17.

### Have Quick II radios frequency hop at the same instant in time because they

• A.

Use the same net number

• B.

Use time-of-day information

• C.

Have the same word-of-day entered

• D.

Are equipped with internal atomic clocks

B. Use time-of-day information
Explanation
The correct answer is "use time-of-day information". Have Quick II radios frequency hop at the same instant in time because they synchronize their frequency hopping patterns based on time-of-day information. This ensures that all radios within a network hop to the same frequency at the same time, allowing for secure and coordinated communication. By using time-of-day information, the radios can maintain synchronization even if they are located in different time zones or have different internal clocks.

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• 18.

### The Have Quick II radio's entry point in the frequency-hopping pattern is established by the word-of-day; however, it is actually programmed using the

• A.

Time-of-day

• B.

Net number

• C.

Multiple word-of-day

• D.

Universal time coordinated

B. Net number
Explanation
The correct answer is "net number". The Have Quick II radio's entry point in the frequency-hopping pattern is established by the word-of-day, but it is actually programmed using the net number. The net number is a unique identifier assigned to each radio net or network, and it helps in determining the specific frequency-hopping pattern to be used. By programming the net number, the radio can synchronize with other radios in the network and ensure secure and reliable communication.

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• 19.

### When two signals are received simultaneoulsy on the same operating net, the Have Quick II radio automatically goes into conferencing. It does this by

• A.

Resetting the net number for communication

• B.

Setting the receiver to narrowband reception

• C.

Injecting a beat frequency to prevent loss of intelligence

• D.

Offsetting the second transmitter frequency by 25 kilohertz

D. Offsetting the second transmitter frequency by 25 kilohertz
Explanation
The correct answer is offsetting the second transmitter frequency by 25 kilohertz. When two signals are received simultaneously on the same operating net, the Have Quick II radio automatically goes into conferencing by offsetting the frequency of the second transmitter by 25 kilohertz. This helps to prevent interference and ensure clear communication between the two signals. By offsetting the frequency, the radio is able to distinguish between the two signals and maintain effective communication.

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• 20.

### The HAVE QUICK II panel-mount configuration is primarily used in

• A.

Retrofit situations

• B.

Bomber aircraft

• C.

Cargo aircraft

• D.

New aircraft

D. New aircraft
Explanation
The HAVE QUICK II panel-mount configuration is primarily used in new aircraft. This suggests that this configuration is specifically designed and implemented in newly manufactured aircraft rather than being used for retrofitting older aircraft. This could be because the panel-mount configuration is more easily integrated into the design and construction process of new aircraft, ensuring optimal functionality and compatibility with other systems.

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• 21.

### What is the advantage of the remote Have Quick II configuration over the panel mount configuration in an aircraft?

• A.

More convenient for maintenance

• B.

Can be used with a remote channel indicator

• C.

Reduced cost by using existing aircraft wiring

• D.

Can be used with a ultra-high frequency direction finding system

C. Reduced cost by using existing aircraft wiring
Explanation
The advantage of the remote Have Quick II configuration over the panel mount configuration in an aircraft is that it reduces cost by utilizing the existing aircraft wiring. This means that there is no need for additional wiring installation, resulting in cost savings for the aircraft owner.

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• 22.

### The HAVE QUICK II multiple word-of-day (MWOD) modification provided loading capability to allow entering up to how many words for what number of days usage, respectively?

• A.

Two; 2 days use

• B.

Four; 4 days use

• C.

Six; 6 days use

• D.

Eight; 8 days use

C. Six; 6 days use
Explanation
The HAVE QUICK II multiple word-of-day (MWOD) modification allows for entering up to six words for a usage period of six days. This modification provides loading capability for a specific number of words and days, allowing for efficient communication and operation within a set time frame.

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• 23.

### Which component takes over control in the event of an ARC-210 radio system remote tuning panel's failure?

• A.

• B.

Control display unit

• C.

Remote tuning panel

• D.

Remote volume control

B. Control display unit
Explanation
In the event of an ARC-210 radio system remote tuning panel's failure, the control display unit takes over control. The control display unit is responsible for managing and controlling the radio set, including tuning and adjusting frequencies. Therefore, if the remote tuning panel fails, the control display unit will step in to ensure that the radio system continues to function properly.

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• 24.

### The remote tuning panel can not control the ARC-210 radio system if the

• A.

Radio set control is turned on

• B.

Radio set control is turned off

• C.

Remote volume control is turned on

• D.

Remote volume control is turned off

A. Radio set control is turned on
Explanation
If the radio set control is turned on, the remote tuning panel cannot control the ARC-210 radio system. This means that the radio system is being controlled directly by the radio set control and not through the remote tuning panel.

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• 25.

### A high pass filter is installed on the ARC-210 radio system to

• A.

Attenuate frequency-modulated (FM) commercial stations below 108 megahertz (MHz)

• B.

Attenuate FM commercial stations above 108 MHz

• C.

Bleed over aircraft FM transmissions below 108 MHz

• D.

Bleed over airraft FM transmissions below 108 MHz

A. Attenuate frequency-modulated (FM) commercial stations below 108 megahertz (MHz)
Explanation
The high pass filter is installed on the ARC-210 radio system to attenuate frequency-modulated (FM) commercial stations below 108 megahertz (MHz). This means that the filter is designed to reduce the strength or intensity of FM signals from commercial stations that are below the frequency of 108 MHz. By doing so, the filter helps to prevent interference from these stations and ensures that the radio system can effectively transmit and receive signals within its intended frequency range.

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• 26.

### What component is used to control the ARC-210 radio system if dual integrating processing center (IPC) fails?

• A.

• B.

Control display unit

• C.

Remote tuning panel

• D.

Remote volume control

Explanation
The component used to control the ARC-210 radio system if the dual integrating processing center (IPC) fails is the Radio set control. This control allows the user to manage and operate the radio system directly, bypassing the IPC. In the event of a failure in the IPC, the radio set control ensures that communication can still be maintained and controlled effectively.

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• 27.

### You swap the active and stanby frequencies on the ARC-210 radio system, using the remote tuning panel (RTP), by

• A.

Pressing the outer knob

• B.

Pressing the inner knob

• C.

Rotating the outer knob

• D.

Rotating the inner knob

B. Pressing the inner knob
Explanation
The correct answer is pressing the inner knob. When swapping the active and standby frequencies on the ARC-210 radio system using the remote tuning panel (RTP), you need to press the inner knob. This action will switch the frequencies, allowing the standby frequency to become the active frequency and vice versa.

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• 28.

### Which one of the following frequencies is not reserved for emergency use?

• A.

8.0 megahertz (MHz)

• B.

40.5 MHz

• C.

121.5 MHz

• D.

243.0 Mhz

A. 8.0 megahertz (MHz)
Explanation
The correct answer is 8.0 megahertz (MHz). This frequency is not reserved for emergency use. The other frequencies listed, 40.5 MHz, 121.5 MHz, and 243.0 MHz, are all reserved for emergency communication purposes.

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• 29.

### Which one of the following is not a PRC-90 emergency radio operating mode?

• A.

Morse code

• B.

Two-way voice communications

• C.

Three-way voice communications

• D.

Variable audio modulation between 1000 and 300 hertz

C. Three-way voice communications
Explanation
The PRC-90 emergency radio is designed for search and rescue operations. It is capable of Morse code communication, two-way voice communication, and variable audio modulation between 1000 and 300 hertz. However, three-way voice communication is not a feature of the PRC-90 emergency radio.

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• 30.

### The emergency communications system that deploys from an aircraft before or at impact, to give it a better chance of surviving the crash, is the

• A.

• B.

Crash position indicator (CPI)

• C.

Underwater acoustical beacon (UAB)

• D.

Emergency locator transmitter (ELT)

B. Crash position indicator (CPI)
Explanation
The crash position indicator (CPI) is an emergency communications system that is deployed from an aircraft before or at impact to increase its chances of surviving a crash. It is designed to help locate the aircraft in the event of a crash by emitting a distress signal. The CPI is typically equipped with a radio transmitter and a GPS system, allowing search and rescue teams to quickly and accurately locate the crash site. Unlike the other options, the CPI specifically refers to a system used for indicating the position of the aircraft during a crash.

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• 31.

### The emergency communications aircraft system that emits pulses of high-frequency (HF) sound is the

• A.

• B.

Crash position indicator (CPI)

• C.

Underwater acoustical beacon (UAB)

• D.

Emergency locator transmitter (ELT)

C. Underwater acoustical beacon (UAB)
Explanation
The correct answer is the underwater acoustical beacon (UAB). This system emits pulses of high-frequency sound and is used for emergency communications. It is specifically designed to be used underwater, making it ideal for situations where an aircraft has crashed into water and needs to be located. The UAB emits these sound pulses, which can be detected by search and rescue teams using specialized equipment, allowing them to locate the aircraft and initiate rescue operations.

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• 32.

### Approximately how many days can the underwater acoustical beacon transmit before battery power is depleted?

• A.

10

• B.

20

• C.

25

• D.

30

D. 30
Explanation
The correct answer is 30. This suggests that the underwater acoustical beacon can transmit for approximately 30 days before its battery power is depleted.

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• 33.

### When activated, the emergency locator transmitter (ELT) continues transmitting on frequencies

• A.

8.0 and 121.5 megahertz (MHz)

• B.

243.0 and 282.8 Mhz

• C.

254.5 and 282.8 MHz

• D.

121.5 and 243.0 MHz

D. 121.5 and 243.0 MHz
Explanation
The emergency locator transmitter (ELT) is a device that is activated in emergency situations to transmit distress signals and help rescuers locate the aircraft or vessel in distress. The correct answer states that when activated, the ELT continues transmitting on frequencies 121.5 and 243.0 MHz. These frequencies are commonly used for emergency distress signals and are monitored by search and rescue organizations. By transmitting on these frequencies, the ELT increases the chances of being detected and located by rescue teams.

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• 34.

### The emergency locator transmitter (ELT) is designed to survive an impact of up to

• A.

50 gravitational forces or Gs

• B.

100 Gs

• C.

125 Gs

• D.

135 Gs

B. 100 Gs
Explanation
The emergency locator transmitter (ELT) is designed to survive an impact of up to 100 Gs. Gs, or gravitational forces, are a unit of measurement used to describe the force experienced by an object during acceleration or deceleration. In the case of an ELT, it is crucial for it to withstand high impact forces in the event of a crash or accident. A rating of 100 Gs indicates that the ELT is built to withstand a significant amount of force, ensuring its functionality and ability to transmit distress signals even in severe conditions.

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• 35.

### All interphone audio common lines are connected to ground at a single point in order to

• A.

Amplify stray audio frequencies

• B.

Eliminate audio frequencies above 16,000 kilohertz (kHz)

• C.

Ensure that high-voltage potentials are not detected in the audio circuits

• D.

Minimize the stray electromagnetic radiation from being picked up by the system

D. Minimize the stray electromagnetic radiation from being picked up by the system
Explanation
Connecting all interphone audio common lines to ground at a single point helps to minimize the stray electromagnetic radiation from being picked up by the system. By grounding the common lines, any stray electromagnetic radiation that may be present is directed away from the audio circuits, reducing the chances of interference or noise being introduced into the system. This grounding technique helps to maintain the integrity and quality of the audio signals transmitted through the interphone system.

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• 36.

### This term describes the lines used to determine whether a transceiver connected to the intercom system will be in a transmit or receive condition

• A.

Control

• B.

• C.

System ground

• D.

Microphone audio

A. Control
Explanation
The term "control" is used to describe the lines that determine whether a transceiver connected to the intercom system will be in a transmit or receive condition. These control lines play a crucial role in managing the communication flow between the transceiver and the intercom system, allowing the user to switch between transmitting and receiving audio signals as needed.

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• 37.

### The seven-position ROTARY SELECT switch, on the C-6567 interphone control panel, allows the operator to select, monitor, key and modulate any one of this number of different radios through the intercom system

• A.

Four

• B.

Five

• C.

Six

• D.

Seven

C. Six
Explanation
The explanation for the correct answer, "Six," is that the seven-position ROTARY SELECT switch on the C-6567 interphone control panel allows the operator to select, monitor, key, and modulate any one of six different radios through the intercom system.

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• 38.

### The purpose of the +17 to +19-voltage direct current (VDC) on the CALL control line of the C-6567 interphone set control is to

• A.

Reduce the level of CALL audio input

• B.

Disable the mic amplifier during CALL operation

• C.

Energive the CALL switch on the front panel of the c-6624

• D.

Activate the automatic gain control (AGC) circuits in the headset amplifiers

D. Activate the automatic gain control (AGC) circuits in the headset amplifiers
Explanation
The +17 to +19-voltage direct current (VDC) on the CALL control line of the C-6567 interphone set control is used to activate the automatic gain control (AGC) circuits in the headset amplifiers. This voltage is necessary to regulate and adjust the amplification levels of the audio signals in order to maintain a consistent and optimal volume for the user. By activating the AGC circuits, the interphone set can automatically adjust the amplification based on the incoming audio signal, ensuring clear and balanced communication.

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• 39.

### The CALL switch applies a direct current (DC) voltage to the CALL control line and activates the automatic gain control (AGC) circuits in all aircraft control panels' headset amplifiers. This causes the CALL audio to be heard at least

• A.

2 decibel (dB) louder than any other signals present

• B.

4 dB louder than any other signals present

• C.

6 dB louder than any other signals present

• D.

8 dB louder than any other signals present

C. 6 dB louder than any other signals present
Explanation
The CALL switch activates the AGC circuits in all aircraft control panels' headset amplifiers, which results in the CALL audio being heard 6 dB louder than any other signals present.

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• 40.

### This INTERPHONE FUNCTION switch allows crewmembers to talk to other aircraft positions without pressing the mic button

• A.

CALL

• B.

Hot-mic

• C.

Monitor

• D.

Interphone

B. Hot-mic
Explanation
The correct answer is "Hot-mic." The hot-mic function allows crewmembers to communicate with other aircraft positions without having to press the microphone button. This means that their microphone is always active, allowing for constant communication without the need to manually activate the microphone.

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• 41.

### The radio TRANSMITTER SELECTION switch is a seven-position rotary switch that allows the aircrew to

• A.

Select and transmit on each radio system and the interphone

• B.

Select and monitor the aircraft emergency warning tones

• C.

Tune each radio system and key the interphone

• D.

A. Select and transmit on each radio system and the interphone
Explanation
The radio TRANSMITTER SELECTION switch is a crucial component in an aircraft's communication system. It is a seven-position rotary switch that enables the aircrew to select and transmit on each radio system and the interphone. This means that the switch allows the crew to choose which radio system they want to use for communication and also enables them to transmit their messages through the interphone system. Additionally, the switch also allows the crew to monitor the aircraft emergency warning tones, tune each radio system, and select the radio transmitter frequencies.

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• 42.

### Which interphone system transmission operation is most advantageous to pilots/copilots and why is it important?

• A.

One-button operation; it is less time consuming

• B.

One-button operation; it allows them to talk on radios and maintain communication with the crew

• C.

Two-button operation; it is less time consuming

• D.

Two-button operation; it allows them to talk on radios and maintain communication with the crew

D. Two-button operation; it allows them to talk on radios and maintain communication with the crew
Explanation
The correct answer is two-button operation because it allows pilots and copilots to talk on radios and maintain communication with the crew. This is important because effective communication is crucial in aviation for ensuring safety and coordinating actions between the flight crew. Having a two-button operation enables pilots and copilots to easily switch between interphone communication and radio communication, allowing them to stay connected with the crew and external parties simultaneously.

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• 43.

### The major difference between the U92A/U the U94A/U jack, on the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone, is the

• A.

U92A/U has a push-to-talk (PTT) button

• B.

U94A/U has a PTT button

• C.

U94A/U is located on the pilot's throttle grip

• D.

U92A/U requires an additional wire for the TALK switch

B. U94A/U has a PTT button
Explanation
The major difference between the U92A/U and the U94A/U jack on the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone is that the U94A/U has a PTT button located on the pilot's throttle grip. In contrast, the U92A/U requires an additional wire for the TALK switch. This means that the U94A/U allows the pilot to easily activate the push-to-talk function without needing an extra wire, making it more convenient to use in the cockpit.

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• 44.

### What wire color is connected to the push-to-talk (PTT) button, on the U-94A/U of the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone, when you connect the WM-85/U interphone cable to the U-94A/U jack?

• A.

White

• B.

Green

• C.

Black

• D.

Yellow

D. Yellow
Explanation
When connecting the WM-85/U interphone cable to the U-94A/U jack on the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone, the wire color that is connected to the push-to-talk (PTT) button is yellow.

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• 45.

### To what pins on the U-92A/U headset/microphone, of the C-6624/AIC-25 interphone station, are the MIKE HIGH (red) and MIKE LOW (green) amplifier wires connected?

• A.

1 and 2, respectively

• B.

2 and 4, respectively

• C.

3 and 1, respectively

• D.

3 and 4, respectively

C. 3 and 1, respectively
Explanation
The MIKE HIGH (red) and MIKE LOW (green) amplifier wires are connected to pins 3 and 1, respectively, on the U-92A/U headset/microphone of the C-6624/AIC-25 interphone station.

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• 46.

### When the wires easily pull loose from the U-94A/U headset/microphone connection on the C-6624/AIC-25 interphone station, it is typically because

• A.

The internal clamp is missing

• B.

The wires were cut to incorrect length

• C.

The wires have weak solder connections

• D.

The screws have not been tightened completely

A. The internal clamp is missing
Explanation
The correct answer is that the internal clamp is missing. This means that there is no mechanism in place to secure the wires in the U-94A/U headset/microphone connection on the C-6624/AIC-25 interphone station. Without the clamp, the wires can easily pull loose, resulting in a loose connection.

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• 47.

### The airborne digital interphone system (ADIS) combined audio interface unit (CIAU) provides continuous operation using

• A.

Two internal audio interface units

• B.

Three internal audio interface units

• C.

Two external backup audio interface units

• D.

Three external backup audio interface units

A. Two internal audio interface units
Explanation
The correct answer is two internal audio interface units. The ADIS combined audio interface unit (CIAU) ensures continuous operation by utilizing two internal audio interface units. These units are integrated into the system and are designed to handle the audio communication requirements. Having two internal units provides redundancy and ensures that the system can continue functioning even if one unit fails. This redundancy is crucial in critical communication systems to maintain uninterrupted communication during airborne operations.

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• 48.

### The VOL adjustment on the airborne digital interphone system (ADIS) interphone audio control panel (IACP) allows the operator to

• A.

• B.

• C.

• D.

Explanation
The VOL adjustment on the airborne digital interphone system (ADIS) interphone audio control panel (IACP) allows the operator to adjust the volume of the combined received signals. This means that the operator can increase or decrease the volume of all the received signals at once. Additionally, the operator also has the option to adjust the volume of each individual received signal separately. This provides flexibility and control over the audio levels, allowing the operator to customize the listening experience according to their preferences and needs.

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• 49.

### Which built-in-test (BIT) is activated by pressing the BIT pushbutton switch on the airborne digital interphone system (ADIS) interphone audio control panel (IACP)?

• A.

Continuous BIT (CBIT)

• B.

• C.

Maintenance BIT (MBIT)

• D.

Power-up BIT (PBIT)

C. Maintenance BIT (MBIT)
Explanation
The correct answer is Maintenance BIT (MBIT). This is the built-in-test that is activated by pressing the BIT pushbutton switch on the airborne digital interphone system (ADIS) interphone audio control panel (IACP). MBIT is a self-diagnostic feature that allows for the continuous monitoring and testing of the system's components and functions. By pressing the BIT pushbutton switch, the system initiates the MBIT process to identify any faults or failures in the interphone audio control panel and its associated components. This helps in ensuring the system's reliability and performance during flight operations.

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• 50.

### The airborne digital interphone system (ADIS) intercom control panel (ICP) has provisions for these operational functions

• A.

Only talk and listen on the interphone circuit

• B.

Hot-mic and CALL on the interphone circuit

• C.

Hot-mic, talk, and listen on the interphone circuit

• D.

Only talk, listen, and CALL on the interphone circuit

D. Only talk, listen, and CALL on the interphone circuit
Explanation
The correct answer is "Only talk, listen, and CALL on the interphone circuit." This means that the ADIS intercom control panel allows the user to engage in conversation (talk and listen) on the interphone circuit, as well as initiate a call. The other options either exclude one or more of these functions or include additional functions not mentioned in the question.

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• Current Version
• Mar 21, 2023
Quiz Edited by
ProProfs Editorial Team
• Mar 24, 2016
Quiz Created by
Catherine Halcomb

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