Page 435 - PPL-engelsk 2025

Communication

4.14 Emergency radio equipment

As a rule, emergency radio equipment in an aircraft consists only of a battery-

powered transmitter.

The transmitter is activated either manually or automatically if it is subjected

to strong shocks such as from a crash or a hard landing.

If it is exposed to moisture or water, it will also start.

Emergency transmitters send a signal that can be detected by rescue personnel

and can be heard if we tune to the emergency frequency 121.5 MHz.

In a loudspeaker, the signal will sound like “dijuuuuu dijuuuuu dijuuuuu” etc.

Each “dijuuuuu” is called a sweep.

The signals can also be picked up by special satellites that make precise

measurements of the transmitter’s position and transmit this to a ground

station.

Types of emergency radio equipment include:

- ELBA Emergency Location Beacon Aircraft

- ELT Emergency Location Transmitter. A type of ELBA that is automatically

activated by impact or ingress of water.
Both types of ELBA must be able to transmit for at least 48 hours.

- SARBE Search and Rescue Beacon. Primarily used by the military.

- EPIRB Emergency Position Indicating Radio Beacon. Primarily used by

shipping.

- PLB Personal Locator Beacon. A handheld emergency transmitter.

The frequencies used in the emergency transmitters are the international

emergency frequency 121.5 MHz and / or 243.0 MHz and in certain cases,

where there is a satellite monitoring system, 406 MHz.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 435