Transcript Minnesota Wing Aircrew Training: Task O-2101

ELT Equipment and detection
Procedures
Minnesota Wing Aircrew Training:
Task O-2101
Task O-2101
Task O-2101
Objectives
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Discuss the various types of ELTs {P; 10.1.1}
Describe how an ELT can be detected {P;
10.2}
Describe how the aircraft DF works in both
the Alarm and DF modes {P; 10.3.1}
Discuss using the DF during a typical ELT
search {P; 10.3.2}
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Response during initial phase, including signal
fade
Response when getting close
Response as you pass over the beacon
Task O-2101
Objectives
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Describe the following ELT search methods:
{P; 10.4 – 10.7}
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Homing
Wing null
Aural
Signal
Discuss signal reflection and interference {P;
10.9}
Describe how to silence an ELT and the legal
issues involved. {P; 10.10}
Task O-2101
Vocabulary
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Glossary of terms
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Direction Finder, DF.
Emergency Locator Transmitter, ELT.
Marine Emergency Position Indicating Radio
Beacon, EPIRB.
Personal Locator Beacon, PLB.
Search And Rescue Satellite, SARSAT.
Task O-2101
Beacons
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100 milliwatts of power
– Roughly equal to that of a
regular flashlight
Normally set off by the impact
of an airplane crash; can be
set off by a hard landing-check 121.5 before engine
shutdown
Remember that the ELT may
be attached to an aircraft or
vessel in distress!
Line of sight Reception.
Subject to deflection and
dispersion.
Task O-2101
The ELT
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Activated by g-force (when armed)
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Three frequencies:
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Some can be activated by the pilot in the cockpit
121.5 MHz (VHF emergency)
243 MHz (UHF emergency – military guard)
406.025 MHz (third generation ELT/EPIRB)
General types:
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General aviation aircraft
Military (“beepers” or “beacons”)
Marine EPIRB
Test station (training practice beacon)
Advanced (406)
Task O-2101
ELT Antenna
Task O-2101
Most aircraft have ELTs installed
But they
don’t
always
survive a
crash
Task O-2101
Most aircraft have ELTs installed
But they
don’t
always
survive a
crash
Task O-2101
Military beacons
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Most common type is the URT-33/C
Personnel ejecting/parachuting will have a
243 MHz beacon
Some downed pilots may be able to
communicate via two-way radio on 243 MHz
using a PRC-90 or later military survival radio
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Beacon mode transmits like an ELT on 243 MHz
Task O-2101
Personal beacons
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Personal Locator Beacon (PLB) or Personal
Emergency Transmitter (PET):
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Intended for hikers and other remote wilderness
travelers
PLB’s operate in the 406.0-406.1 MHz band
Task O-2101
Marine EPIRB
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Emergency Position Indicating Radio Beacon
Similar to an ELT, an EPIRB is used on ships
and boats
Mandatory on certain commercial vessels
Some activate automatically and others are
manually activated
Task O-2101
Advanced ELTs
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Most advanced are TSO C126
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406.025 MHz beacons have data burst encoding that
identifies each (registered) individual beacon to the GOES
SAR satellite system
Many have digital position reporting (GPS)
Still very expensive
Advantages of 406:
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Less chance of inadvertent activation.
Transmits identification.
Some transmits GPS position.
Higher power.
Cockpit indicator.
Will include weak 121.5 transmitter.
Self Test
Task O-2101
Practice Beacon
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Training Practice Beacons
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All should be converted from 121.6 to
121.775 MHz by now (if it isn’t, don’t use it)
During practice searches, avoid calling the
practice beacon an ‘ELT’ when
communicating over the radio
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Includes ones used by CAP
May cause confusion
Always use the term ‘Practice Beacon’
Task O-2101
Testing an Aircraft ELT
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Can test the aircraft’s ELT within the first five
minutes after each hour
Only allowed up to three sweeps
When was the last time you tested the ELT in
your aircraft?
Do you regularly monitor 121.5 MHz after you
land?
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Ensure your ELT didn’t activate
This isn’t considered a test, by the way, but you
can try this excuse if you like
Task O-2101
Inadvertent Activation
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Excessively hard landings (Welcome aboard,
Ensign!)
Inadvertent change of switch position
During removal/installation
Malfunction
Non-ELT source on 121.5 MHz (computers,
broadcast stations, even pizza ovens!)
Monsieur Murphy
Task O-2101
False Alarms
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Approximately 97% of received ELT signals are
false alarms
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For 121.5 MHz ELTs abut 1 in 1000 are actual
emergencies
For 406 MHz ELTs abut 1 in 8 are actual emergencies
What’s the big deal?
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SARSAT can only monitor 10 ELTs at once
Easy to overload the system
They block emergency communications on 121.5 and
243 MHz (guarded by towers, ARTCC, and the military)
BOTTOM LINE: ELT Signals are calls For help, and
FALSE ALARMS BLOCK REAL EMERGENCIES!
Task O-2101
QUESTIONS?
Task O-2101
Detection Timeline
Task O-2101
Accuracy of
SARSAT/COSPAS
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For a regular 121.5 MHz beacon:
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Said to be a 12 nautical mile radius (452 square nm)
Actually an oval shape with a 50% probability of being
15 nm wide and 7 nm high
System is more accurate North to South (latitude)
Average six-hour notification
For a 406 MHz beacon it’s a 2 nm radius (12.4
square nm) with an average one-hour notification
For a 406 MHz beacon with GPS it’s a 0.05 nm
radius (0.008 square nm) with an average fiveminute notification
Task O-2101
OK, So How Should I Treat an
ELT Mission?
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AS AN EMERGENCY!
Its not possible to know whether an ELT
signal is a distress signal or a false alarm
Although the statistics are against it, you
must act as though it is a distress call
If you take advantage of them, every ELT
mission allow you to keep your skills sharp!
Task O-2101
Locating the ELT Signal
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Route or parallel track to pick up the signal
If no SARSAT hits or definitive LKP:
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4,000 to 10,000 AGL
Large track spacing (start at 60 nm, then do
halves)
Once signal is located, DF the signal
Task O-2101
Direction Finder (DF)
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A direction finder compares signal
strengths from two antenna patterns to
let the user know:
 When
you are “centered” on a signal
– headed
directly towards OR away
from from the signal source
 Which
direction to turn when not centered
 Similar to an ADF needle, but only points
left or right, hence the term “left-right
homing”
Task O-2101
L-Tronics DF
Task O-2101
DF Antenna
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Most operate on VHF 121.5.
Some have additional UHF 243.0 Capability.
Two antennas, some UHF have three. All the
aircraft in Minnesota wing are mounted on the
bottom, but some wings may have aircraft with
DF antennas on the top
Task O-2101
Search Methods
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DF Homing Method
Wing Shadow Method
Aural Search Method
Night and IFR Electronic Search
Task O-2101
DF Homing Method
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Understand the DF Controls.
Know the Search Procedures.
Practice, Practice, Practice.
Task O-2101
Step 1: Acquire the Signal
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To hear the signal you can use your L-Tronics
Air DF or one of your comm radios.
To acquire with a comm radio, turn the squelch
OFF (pull out the volume knob out or flip the appropriate switch)
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The static you hear may be annoying, but it will allow
you to hear the signal at the earliest possible time
Allows for a weak or distant signal to be heard
Task O-2101
Done using Track Line or Parallel
Track pattern
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Proceed to the SARSAT composite hit, or to the
point designated by your incident commander.
Initial altitude is normally 3,000 to 10,000 AGL
Use a search pattern (Track Line (route) search or
Parallel Track) assigned by the Mission Coordinator
Search
Path
Path of missing
aircraft
Path of missing
aircraft
Task O-2101
Beginning The Search: Altitude
Selection
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Higher altitudes allow for reception of the ELT
signal at greater distances.
ELTs transmit on 121.5 MHz and 243.0 MHz,
both of which limit reception to “line of sight.”
Terrain will block ELT signals.
HIGHER is therefore usually BETTER to
acquire a signal.
Medium altitude is generally better for
searching (after signal heard)
– 3,000 to 5,000 AGL
Task O-2101
Beginning The Search: Altitude
Selection
Signal blocked by the
curvature of the earth
Area of Reception
Area of Reception
Task O-2101
Altitude Selection
ELT RECEPTION DISTANCE
40000
35000
30000
25000
20000
15000
10000
5000
DISTANCE, Nautical Miles
26
5
20
0
14
7
12
1
95
69
56
34
30
18
0
0
ALTITUDE, Feet AGL
45000
New Search
Wing Shadow Method
Task O-2101
Wing Shadowing
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40
By flying the airplane in a circle, at some point the
wing will block the ELT signal to the receiver
antenna
– This causes an audible decrease in volume,
called a “null”
Almost any VHF-AM aircraft communications
radio may be used with this method.
Task O-2101
Wing Shadowing: Antennas
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To properly use the Wing Shadowing method,
you MUST know where the antenna for the
radio you are using is installed & located on
the aircraft
Communications radio antennas are usually,
but not always, located above the wings
– Can be above the fuselage, in the tail, etc.
L-Tronics Aircraft DF antennas may be above
or below the aircraft
– Below the aircraft is the preferred
installation
Task O-2101
Communications Antennas
Above the Wing
Antennas Above
the Wing
42
Task O-2101
DF Antennas Below the
Wing
Antennas Below
the Wing
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Task O-2101
How To DF by Wing
Shadowing
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N
E
W
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Fly a constant bank angle 360° turn.
the audio will “null,”
or get significantly quieter,
when your wing blocks the
antenna’s reception of the
ELT signal.
S
44
Task O-2101
Wing Shadowing: Signal Blocking
For Antennas Below the Wings
NULL
NULL
SIGNAL
ELT
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Task O-2101
Wing Shadowing:
Antennas Below the Wing
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Turn in a circle until you hear the null (significant
decrease in volume)
The ELT is 90º to your RIGHT: ADD 90º to your
heading
ELT
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Antenna Location
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Antenna on bottom, left
turn, subtract 90
degrees.
220 - 90 = 130
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Antenna on the top, left
turn, add 90 degrees.
040 + 90 = 130
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Antenna on bottom,
right turn = add 90
degrees.
355 + 90 = 085
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Antenna on top, right
turn = subtract 90
degrees.
175 - 90 = 085
Task O-2101
Aural (Hearing) Search Method
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Only Requires a Receiver.
This is based on the assumption that the
area of equal beacon signal strength is
circular:
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do NOT adjust volume during this search; you will
need it to determine equal levels of signal.
Task O-2101
Aural (Hearing) Search Method (cont)
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Begin by plotting your position as soon as
you receive the ELT signal.
Fly that course for a short distance, then turn
90º left or right and proceed until the signal
fades.
Turn around (180º) and mark where the
signal fades on the other side of the circle.
Plot chord lines similar to that of the diagram.
Bisect the chord lines at a perpendicular.
Plot a course to the location where the
perpendicular lines intersect: this should be
the location of the target!
Task O-2101
Aural Metered Search
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Must Have a Signal Strength Meter.
Assumes the Beacon Transmission Pattern is
Circular.
Task O-2101
Aural Metered Search
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This search requires a signal strength meter (like that on the
L-Tronics DF units-if the DF portion of the unit is inoperative
you can still use this type of search as long as RECeive is
OK.
Note your signal strength when beginning the search.
Fly a straight line until the signal gets lower, then increases
to your original level.
Turn 180º and return to the lowest level of signal, then turn
90º left or right.
You should now be headed directly towards or away from
the transmitter.
If the signal increases in strength, you are headed directly
for the ELT.
If the signal decreases in strength, turn 180º
Task O-2101
Left-Right DF Homing
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64
Most CAP corporate aircraft have LTronics LA-Series Left-Right Homing DF
units.
These units operate virtually the same,
but there are two major varieties:
– Single Meter Models
– Dual Meter Models
Task O-2101
L-Tronics DF Types
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Single Meter Model
m SENS
REC
243
ALARM
AUX
121.775
VOL
DF
121.6
VHF-DF
121.5
OFF
L-Tronics
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Dual Meter Model
Task O-2101
Frequency Switch
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Selects frequency to be used.
Use 121.5 MHz for actual ELTs/EPIRBs.
243.0 MHz may also be used for all actual
electronic searches.
Use 121.775 MHz for training (or 121.6 for nonCAP practices).
Refer to owners manual for use of the “AUX”
position.
Task O-2101
Alarm Toggle
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Normal: Alarm toggle in ‘up’ position
DF: toggle is ‘down’
DF is short for Direction Find
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67
DF gives left-right homing to the ELT/EPIRB signal
ALARM is for NON-MISSION flights only
– Use only during normal flying to alert the presence of an
ELT or EPIRB
Task O-2101
Volume & Sensitivity
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Volume controls the audio level to the speaker or headsets
Sensitivity controls the amount of signal that enters into the DF
unit
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It is critical that the proper amount of signal enters
the DF: half-scale, or the middle, is an optimum
starting place
As the signal gets stronger, reduce SENSITIVITY, not volume
– The DF will be unreliable as too much signal is received, so
you must cut out part of it by reducing the sensitivity
– More than three-quarters scale is too much
Task O-2101
PREFLIGHT FUNCTIONAL CHECK
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Just as you preflight the rest of the
aircraft, you should preflight your DF
when going on an ELT electronic search
mission
These procedures are covered in the
Mission Aircrew Reference Text.
Task O-2101
DF SETTINGS FOR
DUAL METER MODELS

MISSIONS
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NON-MISSION FLIGHTS
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Select 121.5 (or 121.775 for training
missions)
Ensure Alarm Toggle Off
Turn Sensitivity to Maximum (Full Clockwise)
Turn Volume to About Mid-Scale
DF Should Stay About Centered
Strength Meter Will Move Up-Scale to Right
–
Select 121.5
Turn Alarm Toggle On
Turn Sensitivity To Maximum
Task O-2101
SIX STEPS
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Use these 6 steps for locating ELTs and
EPIRBs with L-Tronics LA- series airborne
DF equipment
Use the full procedure every time for the best
results
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71
RECeive
HALF
DF
TURN
CHECK
SHOOT
Each of these steps will be described in
detail in the slides to follow
Task O-2101
Step 1: RECeive
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72
Once you have started to receive the ELT
or EPIRB signal on the proper frequency.
If you have a single-meter unit, turn the
mode selector to RECeive and turn the
volume to a comfortable level.
If you have a dual meter unit, refer to the
STRENGTH window (no need to change
modes).
Task O-2101
RECeive Mode/STRENGTH Window
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In receive mode or in the strength window, the unit
measures signal strength
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Left needle is low, right is high
Values are relative depending on the sensitivity you have
selected.
You may still be able to use the strength meter even if the
DF is not functioning perfectly
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It is possible to locate an ELT using only the Receive Mode
Utilize Aural Search/Metered Search methods to accomplish
If the unit isn’t completely operable, try wing shadowing using one
of the aircraft’s communications radios and use the DF unit’s
strength meter as a backup using the aural/metered methods
Task O-2101
Step 2: HALF

Now that the unit is in RECeive mode and you
have a good signal, turn the Sensitivity Knob to
HALF SCALE
–
This is in the center of the window
If you are flying with a dual-meter unit, turn the
Sensitivity Knob so the needle reads HALF
SCALE in the STRENGTH window
 A half-scale strength reading will prevent too
much signal (oversense) from entering the unit
and will provide you with a good starting point
 It is also the optimum for the DF homing
74 antennas

Task O-2101
Step 3: DF
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75
For signal meter units, turn the mode
selector know to DF.
In DF mode, you can think of the needle
as always pointing Direct to the Flipping
target.
For dual meter models, simply refer to the
DF window (no need to change modes).
Task O-2101
DF Antenna

The aircraft DF unit has a 2 or 3 “element”
antenna
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Commonly, we might call this two or three antennas
It just means there are two or three rods!
This antenna setup is directional
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One element actually receives the signal
The other elements (rods) reflect the signal away
from the first rod
Antenna Elements
Task O-2101
Antenna Reception Pattern

When viewed from the bottom, an
antenna setup like the one pictured on the
previous slide produces a reception
pattern like the one shown here
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77
This pattern is called “carotid,”
which means
“heart-shaped”
The pattern is the same
even if the antennas are
mounted above the
wing
Element 1
2
3
Task O-2101
Direction Finding
Mode/Window
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
The DF mode rapidly alternates the receiving and reflecting antenna
elements
– It chooses one element as the receiver and the other two as the
reflectors, then switches to the other set
This produces a carotid pattern each time
the unit switches
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one is shown in red, the other in yellow
By comparing the two patterns, the unit
will determine when they are equal
When they’re equal, the needle centers!
When the needle is centered,
the target is either directly ahead or
behind you!
Task O-2101
Step 4: TURN
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Turn at least one FULL circle, noting
where the DF needle centers.
Under ideal conditions, the needle will
center twice
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79
When facing directly at the source of the
signal
When facing 180º away from the target
You will solve this problem (called
ambiguity) in the next step.
Task O-2101
DF CENTERS
ELT (Possibility 1)
Alternating
Antenna
Patterns
WHEN THE
PATTERNS
ARE EQUAL,
THE DF NEEDLE
CENTERS!
Alternating
Antenna
Patterns
ELT (Possibility 2)
Task O-2101
Step 5: CHECK
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

Use Turn to Tell
Remembering that in DF mode the needle
always points Direct to the Flipping target
When you have the needle centered, turn
left or right
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81
If you turn left and the needle goes left, the
ELT is 180º from your present heading
If you turn left and the needle turns right, the
ELT is dead ahead
Task O-2101
AMBIGUITY

When Needle Centers
–
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
ELT is Directly
Ahead or Behind
This situation is
called “ambiguity”
To Solve
ambiguity:
Use Turn to Tell
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Make a turn left or right
The needle always points
Direct to the Flipping Target
(DF!)
ELT (Possibility 2)
ELT (Possibility 1)
Task O-2101
ELT
DF NEEDLE

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
Compare the YELLOW
(LEFT)
and the RED (RIGHT)
antenna patterns
In this case, the
LEFT pattern is
stronger than
the RIGHT
In DF mode, the
needle would then
point LEFT
–
The needle always points
Direct to the Flipping
Target!
Task O-2101
SOLVING
AMBIGUITY


ELT (Possibility 1)
Actual ELT position
is unknown to user
Make a small turn
left or right
–
As a teaching
reminder, “Use a
TURN to TELL”
ELT (Possibility 2)
Task O-2101
SOLVING
AMBIGUITY


Actual ELT position
is unknown to user
Make a small turn
left or right
–

ELT (Possibility 1)
As a teaching
reminder, “Use a
TURN to TELL”
Example:
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–
TURN LEFT
needle goes left
ELT (Possibility 2)
Task O-2101
SOLVING AMBIGUITY
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Actual ELT position
is unknown to user
Make a small turn
left or right
–
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As a teaching
reminder, “Use a
TURN to TELL”
Example:
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–
TURN LEFT
If needle goes left
ELT is to your left
(behind you)
ELT (Possibility 2)
Task O-2101
SOLVING
AMBIGUITY


ELT (Possibility 1)
If you turn Left and
the
needle moves Right
The ELT is in
Front of you!
ELT (Possibility 2)
Task O-2101
SOLVING
AMBIGUITY



ELT (Possibility 1)
If you turn Left and the
needle moves Right
The ELT is in
Front of you!
Example:
– Turn left
– Needle goes
right
ELT (Possibility 2)
Task O-2101
SOLVING
AMBIGUITY

Solution:
– If you turn Left
and the needle
moves Right
– The ELT is in
Front of you!
ELT (Possibility 1)
Task O-2101
N
Step 6: SHOOT

W
–

90
S

Use your DG to determine a
bearing to the target & follow it
You may need to fly through a
zone of signal dropout
Be watchful for signs of signal passage
E

If you get signal passage, consider using the
“pinpointing the target” techniques listed in this
presentation
Frequently repeat the full six steps to ensure
you are heading in the right direction and that
you didn’t inadvertently overfly the ELT
Task O-2101
How A DF Unit Works: Summary

Two Main Modes of Operation
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RECeive Mode is a Strength Meter
–

Left is low, right is high
DF Mode Centers on Signal
–
–

RECeive
DF
Always points to the signal
Use a Turn to Tell when solving ambiguity
Aircraft and ground units work the same
way
Task O-2101
Reflections
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
Reflections of an ELT signal work just like
a flashlight off of a mirror
Any flat, hard, or wet object can cause
signal reflections
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–
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92
Mountains, especially cliff faces
Hangars and other metal structures
Wet grass or snow
Large bodies of water or ice
Powerlines can also have a large effect
on a low-powered signal such as an ELT
Task O-2101
Beating Reflections

Check your sensitivity at half-scale or lower
–


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Reflections will generally be weaker than the most direct
path to the target
Following reflections will generally take your closer to the
target
If sensitivity is set to minimum, try DFing on a different
frequency
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
93
But ensure that its high enough to receive adequate signal
For example, if you are trying to locate an actual ELT on 121.5
MHz, try locating it on 121.6 or 121.775 MHz when you get close
When all else fails, fly somewhere else to get a good DF
bearing-or try that at the first sign of problems!
Task O-2101
Carrier-Only Signals
–
You don’t always need to hear the ELT or EPIRB to find it

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–
–
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A carrier-only signal may be broadcasting with no audible sweep
This is especially true with low or old batteries, damaged
ELTs, or spurious transmissions
You can identify a carrier-only signal by DEFLECTION
Good needle deflection generally indicates a signal that is
strong enough to DF
Compare your deflection to another frequency
 If
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–
94
you are using 121.5 MHz, try it on 121.775 MHz
If deflection is the same in both frequencies, you DON’T
have a signal, just random noise
If deflection is different, keep at it! You have the signal.
Task O-2101
Vertical Reflections & Signal Dropout





95
The transmission pattern (similar to the reception
pattern of the DF antennas, only for
transmission) of an ELT is not a perfect circle or
sphere
It has lobes, or, stronger and weaker points
This is accentuated when the ELT is transmitting
from a location above the surrounding ground
When you get a good DF heading and the signal
fades or drops out completely you may just be
outside of one of the signal lobes
When you reacquire the signal, it should be
stronger than when you lost it
Task O-2101
Signal Dropout


If you encounter a signal dropout, continue to fly on your last
good DF heading
You should reacquire the signal in a few minutes
–

Actual time will depend upon your distance to the target
If you are unable to reacquire, return to where you last heard
the signal and re-DF
NO SIGNAL
SIGNAL
HEARD
96
Task O-2101
Signal Strength


The rate of change in signal strength increases as you get
closer to the transmitter, and RECeive mode or the
STRENGTH window measures signal strength
This is due to Maxwell’s inverse square law.
–

When you double the distance from an object, the energy it you
receive from it is 1/4 of what you originally received, or the inverse
square: 1/(22) = 1/4
 After Scottish Physicist James Clerk Maxwell, 1831-1879
You will therefore need to turn down the sensitivity to keep the
unit at half scale in the RECeive mode or STRENGTH window
much more often as you get close to the source of the signal
– This should let you know that you’re getting close
97
Task O-2101
Signal Strength Rate of Change
70
DISTANCE FROM
TRANSMITTER (NM)
SENSITIVITY KNOB
DEACREASES EXPONENTIALLY AS
DISTANCE DECREASES
4
3
60
50
5
40
2
6
1
30
7
20
10
0
7
6
5
4
3
SENSITIVITY UNITS
98
2
1
Task O-2101
Cone of Confusion


Antennas receive best when the
pole is perpendicular to the signal
When you approach the directly
overhead position on an ELT, your
DF will become unreliable
–
–

You should practice to see what this
“station passage” reading looks like
–
99
It may swing left and right
It may center regardless of your heading
It is similar to crossing a VOR
Cone of
Confusion
Task O-2101
Reception in the “Cone of Silence”


You may also get a significant drop in ELT signal since the
antennas don’t receive well directly off of their tips
Although called a cone of silence, you will probably only see &
hear a large decrease in signal instead of complete silence
POOR
antenna
signal
10
0
GOOD
Task O-2101
Pinpointing the ELT



If you get a station passage indication, make an
approximate 180 degree turn and DF back to the target
Repeat this process using different approach angles
each time, remembering that
your path may be curved due
to wind (like uncorrected
NDB holding)
The point where station
passage is received
several times
should be the
location of
the target
3
1
10
1
2
Task O-2101
Pinpointing the ELT

After you think you have the target
located
–
–
–

10
2
make a low pass over the suspected location
and visually scan
if signal strength decreases significantly or
drops out, climb back and try again
this is not the target: sometimes false targets
will appear due to reflections or other
interference
If you hear the ELT at low altitude, you
probably have the right place
–
a low pass down a runway might be a good
idea if you suspect a particular airport
Task O-2101
Night and IFR Electronic Search




10
3
Observe Altitudes Closely.
Ensure Clearance from Towers.
Electronic Search Only (No Visual).
Maintain Contact With FAA Facility (If Possible).
Task O-2101
Coordination with ATC




10
4
Monitor and Advise Traffic if Searching Near an
Uncontrolled Airport.
Advise Approach Control and/or Tower Near a
Controlled Airport.
Advise ATC if You Hear an ELT.
Advise ATC if You No Longer Hear the ELT.
Task O-2101
QUESTIONS?
Task O-2101
After Locating The ELT





After location, coordinate with ground teams to
bring them on-scene.
Use radio communication and relay GPS
coordinates.
Pick up the ground team at a predetermined
location and lead them to the target.
Alternately, coordinate a pick up point on the
radio.
Practice your air to ground coordination skills
often
10 – try it both with and without radio communication
6  Air-to-Ground is CAP’s best unique ES skill!
Task O-2101
DF upon Landing




Many times the ELT is located at an airfield
where it is easier for you to land and locate
the ELT than it is to get a ground team to the
scene
You can use a hand-held radio or hand-held
DF unit
The most commonly used in CAP is the Little
L-Per
You did remember to put one of these (with
charged batteries) in the aircraft before you
left, didn’t you?
Task O-2101
Little L-Per

Six Steps
–
–
–
–
–
–
Receive
Half
DF
Center
Turn
Shoot
Task O-2101
OK, which of these planes is it in?



You land at an airport with multiple hangers
and each hanger is full of aircraft
This can make it difficult to find the ELT
Two methods can help:
–
–
Signal-offset
Using a hand-held radio without its antenna
Task O-2101
OK, which of these planes is it in?

Signal-offset: reflected signals are generally
weaker so by tuning your radio further away
from the primary frequency you can isolate
the signal:
–
–
–
Assume ELT transmitting on 121.5; set to 121.55
As you home in set in 121.6 (you may even work
up to 121.7)
As you get further away from 121.5 the area
where the signal will break through the squelch
becomes smaller and smaller (you can even turn
up the squelch to get further isolation)
Task O-2101
OK, which of these planes is it in?

Using a hand-held radio without its antenna:
–
–
–
–
–
–
Once you’ve narrowed the suspects down to one
or two aircraft (usually side-by-side), remove the
radio’s antenna and hold it next to one of the ELT
antennas
Turn the volume down until you just hear the
signal
Move to the other aircraft’s ELT antenna
If the signal is stronger you probably have it; if
weaker, its probably the other aircraft
Can also combine this with the signal-offset
method
Don’t key the radio’s transmitter with the antenna
removed!
Task O-2101
OK, where is the thing?

ELTs are usually located in or near the rear of the aircraft.
Also look for remote switches.
–
–
–
–
–
Single-engine Cessna: right side of the upper baggage area
immediately aft of the baggage door
Multi-engine Cessna: left side of the fuselage just forward of the
horizontal stabilizer. Accessed through a small push-plate on the
side of the fuselage.
Single- and multi-engine Piper: in the aft fuselage. Accessed
through a small access panel on the aft bulkhead of the baggage
compartment.
Single- and multi-engine Bonanza: in the aft fuselage. Accessed
through a small access plate on the right side of the fuselage.
Large piston twins (e.g., King Air) and small jets: if installed its
probably in the rear section. No visible antenna. May have a small
round push-plate that lets you manipulate the ELT switch.
Task O-2101
Silencing the ELT


The preferred method is to have the owner
(or someone designated by the owner) turn it
off and disconnect the battery
Second best is to just turn it off
–
–

The owner may take the switch to ‘Off’ and then
back to ‘Armed’
If this is done, stick around and monitor 121.5 to
ensure it doesn’t go off again
If you can’t find the owner, you may have to
build a foil ‘tent’ (refer to CAPP-2)
Task O-2101
Silencing the ELT

Foil Tent

1’ x 5’
Encloses
antenna
Flaps at least
18” beyond
antenna on
fuselage
Securely taped
(masking tape
preferred)



Task O-2101
Silencing the ELT


Ensure that the owner is notified that the ELT was
disabled
If you can’t get a phone number, you can place a
note on the aircraft (not the window)
Task O-2101
Legal Issues



Per CAPR 60-1 Chapter 1, CAP members will
not enter private property and should not do
anything that could cause harm or damage to
the distress beacon or aircraft/boat
Entry to the ELT should be made by the
owner or operator or law enforcement
A transmitting ELT is under the legal authority
of the FCC, and federal law requires that it be
deactivated ASAP (a crashed aircraft is under
the authority of the NTSB)
Task O-2101
Legal Issues


CAP members do not have the authority to
trespass onto private property, either to gain
access to the aircraft or to enter the aircraft to
gain access to the ELT
Besides the owner/operator, some owners
give FBO personnel permission to enter their
aircraft
Task O-2101
Legal Issues


While entry upon private property may be
justified if such an act is for the purpose of
saving life, every effort should be made to
obtain the controlling agency's and/or the
property owner's consent
If you need entry onto private property in
order to search for an ELT, law enforcement
authorities such as local police, the county
sheriff's office or game wardens may be
contacted for assistance.
Task O-2101
Legal Issues


Normally, local law enforcement officials are
happy to assist you; if they are not familiar
with CAP and your responsibilities, a simple
explanation often suffices
If this doesn't work, try calling AFRCC and
have them explain the situation
Task O-2101
Legal Issues



The most important aspect is the manner in
which you approach the matter
The local civil authorities are in charge, but if
the AFRCC tasks you to search, you go
search and offer assistance to the civil
authorities when the opportunity presents
itself
If they tell you go home, then phone the IC
and/or AFRCC and close the mission
Task O-2101
Where to get more information



12
1
CAP Emergency Services Training and
Operational Missions, CAPR 60-3.
Operational and Maintenance Practices for
Emergency Locator Transmitters and Receivers,
AC91-44A.
ELT/EPIRB Search, CAPP2.
Observer Course #3/Mission Pilot Course #5
QUESTIONS?
Good Hunting!