Aeronautical Information Manual (AIM), page 423

Index   422 -- Page 423 -- 424


121.5 MHz or 243.0 MHz ELT's onboard will have
to depend upon either a nearby Air Traffic Control
facility receiving the alert signal or an overflying

aircraft monitoring 121.5 MHz or 243.0 MHz
detecting the alert. To ensure adequate monitoring of
these frequencies and timely alerts after 2009, all
airborne pilots should periodically monitor these
frequencies to try and detect an activated
121.5/243.0 MHz ELT.

b. Testing.
1. ELTs should be tested in accordance with the
manufacturer's instructions, preferably in a shielded
or screened room or specially designed test container
to prevent the broadcast of signals which could
trigger a false alert.
2. When this cannot be done, aircraft operation-
al testing is authorized as follows:

(a) Analog 121.5/243 MHz ELTs should only
be tested during the first 5 minutes after any hour. If
operational tests must be made outside of this period,
they should be coordinated with the nearest FAA
Control Tower. Tests should be no longer than three
audible sweeps. If the antenna is removable, a
dummy load should be substituted during test
(b) Digital 406 MHz ELTs should only be
tested in accordance with the unit's manufacturer's

(c) Airborne tests are not authorized.

c. False Alarms.

1. Caution should be exercised to prevent the
inadvertent activation of ELTs in the air or while they
are being handled on the ground. Accidental or
unauthorized activation will generate an emergency
signal that cannot be distinguished from the real
thing, leading to expensive and frustrating searches.
A false ELT signal could also interfere with genuine
emergency transmissions and hinder or prevent the
timely location of crash sites. Frequent false alarms
could also result in complacency and decrease the
vigorous reaction that must be attached to all ELT

2. Numerous cases of inadvertent activation
have occurred as a result of aerobatics, hard landings,
movement by ground crews and aircraft mainte-

nance. These false alarms can be minimized by
monitoring 121.5 MHz and/or 243.0 MHz as follows:

(a) In flight when a receiver is available.

(b) Before engine shut down at the end of
each flight.
(c) When the ELT is handled during installa-
tion or maintenance.

(d) When maintenance is being performed
near the ELT.
(e) When a ground crew moves the aircraft.
(f) If an ELT signal is heard, turn off the
aircraft's ELT to determine if it is transmitting. If it
has been activated, maintenance might be required
before the unit is returned to the "ARMED" position.
You should contact the nearest Air Traffic facility and
notify it of the inadvertent activation.
d. Inflight Monitoring and Reporting.

1. Pilots are encouraged to monitor 121.5 MHz
and/or 243.0 MHz while inflight to assist in
identifying possible emergency ELT transmissions.
On receiving a signal, report the following
information to the nearest air traffic facility:
(a) Your position at the time the signal was
first heard.
(b) Your position at the time the signal was
last heard.

(c) Your position at maximum signal

(d) Your flight altitudes and frequency on
which the emergency signal was heard: 121.5 MHz or
243.0 MHz. If possible, positions should be given
relative to a navigation aid. If the aircraft has homing
equipment, provide the bearing to the emergency
signal with each reported position.

6-2-5. FAA K-9 Explosives Detection
Team Program

a. The FAA's Office of Civil Aviation Security
Operations manages the FAA K-9 Explosives
Detection Team Program which was established in
1972. Through a unique agreement with law
enforcement agencies and airport authorities, the
FAA has strategically placed FAA-certified K-9
teams (a team is one handler and one dog) at airports
throughout the country. If a bomb threat is received

Emergency Services Available to Pilots 6-2-3

Page 423 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   422 -- Page 423 -- 424