Aeroplane Systems: Speakers and Microphones

What is the primary function of an amplifier in an audio system?

To increase the small audio input voltage to a higher power audio signal

What happens when the push-to-talk button is pushed?

The microphone signal is input to the intercom amplifier

What is the main disadvantage of using hot mikes?

Any background noise is transferred over the intercom

What converts electrical signals into sound in a speaker?

The coils of wire in the speaker Signup and view all the answers

What controls the speaker volume?

The volume knob Signup and view all the answers

What type of signal does a microphone produce?

A low voltage signal Signup and view all the answers

What is a major drawback of satellite communications in terms of latency?

0.25 second delay in all communications Signup and view all the answers

What is a limitation of satellite communications in terms of coverage?

Lack of coverage at high latitudes Signup and view all the answers

What is the primary reason why HF communications and data systems are still favored over satellite communications?

Higher cost of satellite communications Signup and view all the answers

What is a potential application of satellite communications in the future?

Passenger communications Signup and view all the answers

How many geostationary satellites were part of the INMARSAT system launched in the early 1980s?

3 Signup and view all the answers

What is a limitation of fitting satellite communications on aircraft?

Size of the avionics package Signup and view all the answers

What is the primary function of the headphone jack in the CVR system?

To perform audio checks during testing Signup and view all the answers

What is the purpose of the erase button in the CVR system?

To completely erase the memory Signup and view all the answers

What are the preconditions for erasing the memory in the CVR system?

Weight on wheels, park brake set, and erase button pressed for greater than a set time Signup and view all the answers

What is recorded on Channel 1 of the CVR system?

The flight interphone and passenger address Signup and view all the answers

What is the function of the LED status indicator in the CVR system?

To indicate serviceability during tests Signup and view all the answers

What is the purpose of a microphone in the CVR system?

To record cockpit area communication Signup and view all the answers

What is the main advantage of HF radios over VHF communications?

Capability of transmitting worldwide Signup and view all the answers

How do HF radios achieve long-range communication?

By using sky waves refracted through the ionosphere Signup and view all the answers

What is a characteristic of HF transmitters in aircraft?

High output power of 80-200 watts Signup and view all the answers

What can affect HF communication in an aircraft?

Atmospheric interference and thunderstorms Signup and view all the answers

What type of antenna is commonly used on modern aircraft with HF?

Long wire antenna Signup and view all the answers

Why are long wire antennas rarely used on jet aircraft?

Due to vibration and increased risk of damage at high speeds Signup and view all the answers

What is the primary function of an underwater locator beacon?

To act as a homing signal for emergency services Signup and view all the answers

What frequency do underwater locator beacons transmit on?

37.5 kHz Signup and view all the answers

What is the purpose of the self-erecting antenna in an emergency locator transmitter?

To erect the antenna when the ELB is activated Signup and view all the answers

Where is the emergency underwater locator beacon typically located?

As part of the flight data recorder Signup and view all the answers

What type of signal does an underwater locator beacon emit?

A constant beeping Signup and view all the answers

What is the primary function of a cockpit voice recorder?

To monitor all signals and conversations in the cockpit Signup and view all the answers