ABSTRACT
Figure 7.3 ELT transmitter and modulator printed circuit board (the crystal oscillator is located on the right with the dual-frequency output stages on the left)
Figure 7.1 Type-W ELT with attachment cord secured by water-soluble tape (the antenna has been removed)
Figure 7.2 Interior view of the ELT shown in Figure 7.1. Note how the battery occupies approximately 50% of the internal volume
Figure 7.4 ELT test switch and test light (the antenna base connector is in the centre of the unit)
In order to safeguard the equipment and to ensure
that it is available for operation should the need
arise, various considerations should be observed
when placing and mounting an ELT and its
associated antenna system in an aircraft. The
following requirements apply to Type-F, AF, AP
ELT installations in fixed wing aircraft and
rotorcraft:
1. When installed in a fixed wing aircraft, ELT
should be mounted with its sensitive axis
pointing in the direction of flight
2. When installed in a rotorcraft ELT should be
mounted with its sensitive axis pointing
Table 7.2 Typical Type-AF ELT specification
Figure 7.5 Type-AF ELT control panel (note the three switch positions marked ON, ARMED and TEST/RESET)
approximately 45° downward from the
normal forward direction of flight
3. ELT should be installed to withstand
ultimate inertia forces of 10 g upward,
22.5 g downward, 45 g forward and 7.5 g
sideways
4. The location chosen for the ELT should be
sufficiently free from vibration to prevent
involuntary activation of the transmitter
5. ELT should be located and mounted so as to
minimise the probability of damage to the
transmitter and antenna by fire or crushing
as a result of a crash impact
6. ELT should be accessible for manual
activation and deactivation. If it is equipped
with an antenna for portable operation, the
ELT should be easily detachable from inside
the aircraft
7. The external surface of the aircraft should be
marked to indicate the location of the ELT
8. Where an ELT has provision for remote
operation it is important to ensure that
appropriate notices are displayed.
