Chapter 6 - Section 1: Basic principles of Selective Calling

Question 1

What is the purpose of SELCAL?

Answer 1

Tell the flight crew when a ground station wants to contact them on a radio

Reduces pilot workload and distractions by making continuous monitoring of the radio system unnecessary

Question 2

What is the construction of the SELCAL signal?

Answer 2

AM set of four audio tones that agree with the airplane’s assigned SELCAL code

Question 3

What occurs on the flight deck when the SELCAL code is recognised?

Answer 3

The decoder sounds the warning electronics unit to chime and illuminates the pilot’s call panel lamp

Question 4

What does the SELCAL system consist of?

Answer 4

• A single 5 channel decoder
• A shorting receptacle wired for the code assigned to that aircraft
• Pilot’s call panel

Question 5

What causes the decoder to be reset?

Answer 5

Pressing the lamp/switch on the pilot’s call panel

or

Press-to-talk mic signals from the associated transceiver

Question 6

Describe the input codes to the decoder from the VHF and HF transceivers?

Answer 6

Two spaced audio bursts, each one-second long and consisting of two superimposed audio tones in accordance with ARINC 714

Question 7

Describe the output chime of the warning electronic unit when signalled by the decoder?

Answer 7

A single HI (587 Hz) chime for any channel activated

Question 8

How many audio tones are used in SELCAL calling?

Answer 8

16