2 - Communications

2 - Communications

1. What is radio?

   • Frequency, amplitude, attenuation of pressure wave
   • Pressure waves at speed of sound, radio waves are electromagnetic waves that travel at the speed of light
   • VHF transmissions are direct (line of sight)
     • Below 5,000ft 60nm range
     • 5,000-10,000ft 90nm range

2. Use of the VHF COM

   • Squelch control, radio test and frequency selection

3. Communicating

   • Mic directly in front of mouth so can be touched with puckered lips.
   • Listen first, decide what to say, then say it without hesitation.
   • Be clear - the most important aspect is that the message gets across clearly and quickly and that the frequency in not unnecessarily blocked.

4. Standard Words and Phrases

   • Called phraseology. Standard phrases exist for common aircraft communication. Practice it in the shower.

5. The ADF

   • For navigation to a point but can also be used to receive (but not send) voice transmissions.

6. Radar

   • Primary radar - non-discriminatory, eg. weather
   • Secondary radar - Needs transponder but better, stronger more detailed information including callsign, altitude and speed.
   • Transponder codes
     • 1200 - VFR not participating in Radar Information Services (RIS)
     • 7600 - Radio failure
     • 7700 - Serious emergency
     • Switch to SBY before changing code

7. Emergency radio procedures

   • Mayday - Distress Panpan - Urgency Security - Safety
   • 121.5 - "Guard" frequency for emergencies only
   • Aerodrome Lights in loss of radio contact
     • Steady green - land if no collision risk
     • Stead red - Give way and continue circling
     • Flashing green - return for immediate landing
     • Flashing red - aerodrome unsafe, do not land
     • White flashes - no meaning
     • Flash landing lights to attract attention

8. Introduction

   • Aviate, navigate, communicate
   • See and be seen
   • ICAO radio procedures

9. Radio installation in the cockpit

   • Avionic (aviation electronics). Navaids and radio-navaids.