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Communication Equipment Technical Problems

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Article Information
Category: Air Ground Communication Air Ground Communication
Content source: Skybrary skybrary
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Sound communications rely on reliable and efficient communication equipment. This briefing note deals with technical problems involving communication equipment.

Types of Equipment Problem

The problems which contribute most commonly to communication breakdown are:

  • Airborne radio equipment malfunction;
  • Ground equipment malfunction; and,
  • Stuck microphone.


Impairment of communication, or complete or partial loss of communication.


Duplication of equipment makes complete loss of communication an extremely rare event.

Typical Scenarios

  • Sleeping receiver. Pilot realises that he/she has heard no communication from ATC or from other aircraft for some time. Pilot investigates and finds that ATC have been trying unsuccessfully to contact him/her for some time. Post-flight investigation reveals no fault in the radio equipment.
  • Airborne Equipment. Pilot select a new frequency but equipment does not respond to change, so pilot is unable to transmit or receive on this frequency.
  • Stuck Microphone. Microphone remains live after transmit switch has been released, blocking other transmissions on this frequency.


  • Pilots and ATCOs report any equipment malfunction, including suspected sleeping receiver, using the national occurrence reporting system, to enable trends to be detected.
  • Operators and ATCUs report equipment malfunctions to the manufacturer to allow improvements to be made to equipment.
  • National authorities continue to investigate sleeping receivers in order to develop solutions.

Further Reading

AGC Safety Letters:

  • Safety Letter 1;
  • Safety Letter 2;
  • Safety Letter 3.

EUROCONTROL Action Plan for Air-Ground Communications Safety, including:

  • Briefing Note AGC3 – Loss of Communication;

EUROCONTROL Level Bust Toolkit:

  • Briefing Note GEN2 - Pilot-Controller Communications;


  • Investigation into Loss of Communication;
  • AGC Safety Study – Causes and Recommendations;
  • An Analysis of Pilot-Controller Occurrences.