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6/17/21 

AIM 

can take hours. SAR forces can initiate a response to 
406 MHz alerts in minutes compared to the potential 
delay of hours for a 121.5/243.0 MHz ELT. 
Therefore, due to the obvious advantages of 406 MHz 
beacons and the significant disadvantages to the older 
121.5/243.0 MHz beacons, and considering that the 
International Cospas

Sarsat Program stopped the 

monitoring of 121.5/243.0 MHz by satellites on 
February 1, 2009, all aircraft owners/operators are 
highly encouraged by both NOAA and the FAA to 
consider making the switch to a digital 406 MHz ELT 
beacon.  Further, for non

aircraft owner pilots, check 

the ELT installed in the aircraft you are flying, and as 
appropriate, obtain a personal locator beacon 
transmitting on 406 MHz. 

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 
procedures. 

(b) 

Digital 406 MHz ELTs should only be 

tested in accordance with the unit’s manufacturer’s 
instructions. 

(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 
signals. 

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 

strength. 

(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. 

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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 

Emergency Services Available to Pilots 

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