What functions does the audio selector panel provide?

• It connects the microphone to the selected communication system and all the selected audio signals to the headphones.

• Frequency tuning for HF- and VHF-communication systems.

• It amplifies the microphone signal for the passenger address system.

• It converts the analogue audio signals into Digital signals to the selected communication system

Which priority sequence is used in a Passenger Address (PA) amplifier?

• 1. cabin crew, 2. cockpit crew, 3. pre-recorded announcements, 4. boarding music

• The highest priority is the system that is first switched on.

• 1. cockpit crew, 2. cabin crew, 3. pre-recorded announcements, 4. boarding music

• 1. boarding music, 2. pre-recorded announcements, 3. cabin crew, 4. cockpit crew

Why are three VHF systems installed?

• One for the captain, one for the first officer and one for the observer

• One to transmit, one to receive and one for spare

• Two systems are required for commercial airline operation and the third one is normally used by ACARS.

• One main system and 2 for redundancy

What is the SATCOM system used for?

• For voice communication only

• For voice communication and data transfer between the ground and the aircraft

• For ACARS data transfer only

• For positional navigation downlink

What is the primary purpose of radio communication?

• To detect nearby objects

• To exchange information using radio waves

• To stream video

• To listen to music

What is the main function of a resonator in a radio?

• To amplify the radio signal

• To amplify a specific frequency while ignoring all others

• To filter specific audio frequencies

• To amplify the audio signal

Which layer of the atmosphere is most crucial for long-distance point-to-point communications?

• Ionosphere
• Mesosphere
• Stratosphere
• Thermosphere

What is the HF band radio transmission often referred to, and why are they suitable for long-distance communication?

• Ultrawave radio, because they have the highest frequency and speed

• Longwave radio, because they can penetrate through solid objects easily

• Shortwave radio, because they can be refracted back to Earth by the ionosphere layer in the atmosphere

• Microwave radio, because they are not absorbed by solid objects so travel further

How do space waves travel to the receiving antenna?

• They diffract from high points on the surface or buildings.

• They travel along the contour of the Earth

• They are refracted back to the Earth by the ionosphere

• They travel through the air directly in 'line of sight' or can be reflected from the surface of the Earth

Which type of surface has the best conductivity for surface wave propagation?

• Jungle

• Desert

• Sea water

• Rocky Terrain