Aircraft Communication Systems Flashcards

Which SELCAL code format is used to alert a specific aircraft on HF or VHF radio?

Answer: A four-letter code using characters A through S (excluding I, N, O)

SELCAL codes consist of four letters chosen from A through S, excluding I, N, and O, to uniquely identify an aircraft.

When an aircraft loses all radio communication in VFR conditions, the pilot should squawk transponder code:

Answer: 7600

Squawk 7600 indicates loss of communications (NORDO); 7500 is hijacking and 7700 is emergency.

A dispatcher notices ATIS information 'Kilo' is current. What does this indicate?

Answer: The current ATIS identifier is the 11th sequential letter of the alphabet

ATIS identifiers cycle through the phonetic alphabet; 'Kilo' is the 11th letter, indicating the 11th update.

What is the primary purpose of ACARS (Aircraft Communications Addressing and Reporting System)?

Answer: To relay digital data messages between aircraft and ground stations

ACARS is a digital datalink system used to exchange pre-formatted and free-text messages between aircraft and ground operations or ATC.

Under FAR Part 121, the dispatcher must be able to communicate with the aircraft at all times during flight. What system is required for extended overwater operations beyond VHF range?

Answer: HF radio or an approved satellite communication system

FAR 121.99 requires HF radio or satellite communication for flights beyond the range of VHF ground stations.

Which frequency is designated as the international aeronautical emergency frequency?

Answer: 121.5 MHz

121.5 MHz is the international VHF emergency and guard frequency monitored by ATC and military facilities.

A flight crew reports they are unable to contact dispatch via ACARS. As dispatcher, what is your FIRST action?

Answer: Attempt contact via an alternate means such as HF radio, SATCOM, or relay through ATC

The dispatcher should attempt contact through any available alternate communication path before escalating to emergency procedures.