INSTALLATION MANUAL OPERATION MANUAL INSPECTION LOG
KANNAD 406 AF / AF-H / AF (6D)
PAGE: 2
JUN 23/2008
B. World coverage with the COSPAS-SARSAT system
The major improvement is the use of the COSPAS-SARSAT system for
processing aeronautical emergencies.
The difference with the 121.5 / 243 MHz is that the 406 MHz transmission
carries digital data which enable the identification of the aircraft in distress and
facilitate SAR operation (type of the aircraft, number of passengers, type of
emergency).
The 406 MHz message is transmitted to the COSPAS-SARSAT satellites. This
message is downloaded to one of the 64 ground stations (44 LEOLUTs and 20
GEOLUTS).
The aircraft is located by Doppler effect by the LEO satellites with a precision
better than 2 NM (4 km) at any point of the earth.
C. Environmental improvements of ELTs
The certification of an ELT includes a range of severe mechanical tests:
• resistance to flame;
• impact and crush tests;
• resistance to 100 G and 500 G shocks;
• watertightness;
• antideflagration;
• extreme temperatures (-20°C to 55°C for more than 48 hours).
D. G-Switch (shock detectors)
The shock detectors currently equipping automatic ELTs are the cause of a
large number of false alarms. Major work has consisted in studying aircraft
crashes (study made by the " Crash Research Institute ") and evaluating the
acceleration amplitudes involved. As a consequence, G-Switch specifications
have been modified to optimize the accuracy of the crash detection.
