Authored by Scott E. Lanis 28-Aug-1998Modified by Lt Colonel Fred BlundellTX-129 Fort Worth Senior Squadron

For Local Training Rev 5.0 02-Feb-2014

OBJECTIVES

By the end of this course, you should:àKnow what an ELT is, and how it can be activatedàUnderstand why an ELT signal is an emergencyàDescribe how CAP is called out on an electronic searchàBe familiar with these fundamentals:

• Plotting a SARSAT hit on a map (latitude/longitude)• Direction finding - Little L-Per™ Operation• Triangulation• Body shielding• Aircraft coordination/LORAN/GPS operations• Ground Vehicle Operations

Is an Aircraft Missing?

How would we know?Radio distress callMonitored aircraft drops from RADAROverdue Flight PlanReport from friends/relativesELT Signal (maybe!)

How does CAP Searchfor Missing Aircraft?

Purely Visual SearchesVery Difficult: often few clues

àAir - most effective to cover groundàGround

Electronic Searches - “Quick” (24 hrs)àAir - best reception and rangeàGround - autonomous search is slower and more difficult

Advanced TechnologyFew of these resources available directly to CAP

àSynthetic Aperture Radar (SAR), Thermal/Infrared Imagery, Other Remote Sensing (satellites/reconnaissance aircraft)

What Will A CrashedAirplane Look Like?

Air to GroundCoordination

The most effective way to search The only way CAP stays in the SAR business The plan:

CAP aircraft locates crash (visual / electronic)Coordinates to bring ground team on scene

• Radio (transmit the Lat-Longs from LORAN/GPS!)• Radio Out• Lat-Long (LORAN/GPS)

Ground Team effects rescue

Aircraft Limitations

WeatherCan’t pinpoint signal

àRow of hangers

Ground Search Types for Missing Aircraft

Ramp SearchEnsure the missing aircraft has not landed safelyCan be conducted by both air and ground crews

Bastard SearchEnsure the missing person isn’t in a favorite hangout“You bastard!”

How does a search start?

There is the possibility of a missing aircraftàRadio distress call, aircraft drops from RADAR, overdue

flight plan, report from friends/relatives, ELT Signal AFRCC performs a telephone search

àAirport managers, towers, etc. Missing Aircraft Confirmed!

àAFRCC activates the appropriate CAP wing

What if only an ELTsignal is received?

AFRCC Telephone SearchAirports: “Do you hear it too?”

àLikely false alarm at this point; signal silenced by crews on airport

CAP called sooner if “after hours”àNo one else answers the phone!

Is there another indicator of a missing aircraft?If not, AFRCC will wait to see if the signal terminates

àTestsà Inadvertent actuations terminated

What is an ELT anyway?

Emergency Locator TransmitterIt’s an automatic radio beacon!

3 Frequencies of Operation121.5 MHz (VHF)AND 243 MHz (UHF)

(Military Guard)406.025 MHz (new)

Most aircraft have ELTsinstalled

General Types of ELTs

Aircraft (General Aviation) Military (“beepers” or “beacons”) Personal (PELTs or PLBs) Marine EPIRBs Advanced (406/GPS)

Typical Aircraft ELTOperation

3 Switch positions--on, arm/standby, and off G-switch activated (Generally 9G) Activates ELT upon impact when armed May be manually operated by placing the switch in in the ‘ON’

position

Can you test an ELT?

Yes, with restrictions:First 5 minutes of the hour, no more than 3 sweeps

Battery must be replaced after:One cumulative hour of use or50% of useful life has expiredFAR §91.207(c)

Does not apply to our Practice BeaconsCall nearest FSS in advance: 1 (800) WX-BRIEFGive a contact phone-interference happens on 121.775!

Inadvertent Activationof an ELT May

Occur From

Excessively hard landingInadvertent change of switch positionRemoval of the unit

à activating the switch or G-switchMalfunction

à switch shortàbattery leakage

Who is listening?

SARSAT/COSPASFAA Facilities

àFSS, Centers, TowersAirliners

àOnly if pilot choosesMilitary Aircraft

à243 MHz RequiredGeneral Aviation Aircraft

àThat’s us! Help the system work: monitor 121.5 MHzSignal report is relayed to AFRCC

How SARSAT Works

Receive 121.5, 243, 406 MHz Signals Orbiting and Geostationary Satellites

Orbiting: SARSAT/COSPAS àHigh Inclination (polar) orbits

Geostationary: GOES Weather SatellitesàSAR payloads for 406 only

Operated by Canada, France, Russia, USA They give us digital lat-long coordinates

CAP Mission Coordinator plots these and assigns assetsGround teams must interpret for land navigation

System OperationDetails

SARSAT/COSPAS in polar orbit

Calculates location of signal by measuring Doppler shift

This yields a latitude and a distance

Narrowing the Search (SARSAT/COSPAS Only)

First passàAmbiguity

Where Is It? Second Pass

à average 30-45 minute waitàAmbiguity resolvedà5-12 Nautical Mile Average Error

How do Different ELTs stack up?121.5 MHz ELT

à12 NM Radius, 452 Sq MiàAve. 6 Hour Notificationà60 Milliwatt Transmitter

406 MHz ELTà2 NM Radius, 12.5 Sq MiàAve. 1 Hour Notificationà25 Milliwatt 121.5 Beacon

406 ELT with GPSà .05 NM Radius, .008 Sq MiàAve. 5 minute Notificationà25 Milliwatt 121.5 Beacon

System Review ELT, PLB, EPIRB Signal Received AFRCC gets coordinates from SARSAT Appropriate CAP Wing is activated

False Alarms

97% of received ELTs are false alarms121.5 MHz: 1 in 1000 is an actual emergency (0.1%)406 MHz: 1 in 8 is an actual emergency (12.5%)

Why is a False Alarm a big deal?SARSAT can only monitor 10 ELTs at once (within footprint)

àbent-pipe repeaterVERY easy to overload the systemBlocks emergency communications

Blocks the real emergency!

How should wetreat an ELT?

As an EMERGENCY!You can’t know which ones are Distress ELTs

And even the false ones are good training!

Transportation to Target

Ground Teams generally will use vehicles for transportation to and from mission base

Aircraft Coordination will get the Ground Team to the target the fastest

If no aircraft is available:Vehicles provide enough speed and range to triangulateClose range may be required for signal acquisition

Direction Finding

DF unit Measures equal strengths of signal• not wholly accurate, but good enough!

Therefore, when needle is centered, ELT could be either direction

Needle always POINTS to the ELT (DF=Direct to the Flipping target)

Use a TURN to TELL if the ELT is in front or behind you

DFing with theLittle L-Per

6 Steps: use the full procedure every time!àTurn the unit to Receive, check proper frequency and volumeàTurn the Sensitivity Knob to HALF SCALE

• This will prevent oversense and a good starting pointàTurn the unit to DF (Direct to the Flipping target)àTurn at least one FULL circle, stopping and calling, “Center!”àCheck: Use Turn to Tell: the needle will point Direct to the

Flipping targetàUse your compass, shoot an azimuth to get a bearing to the

ELT

Direct to the Flipping, Turn to Tell

REC 1/2 DF Center Turn Shoot

Little L-Per Receive Mode

Measures Signal Strength onlyàFrom a direction of the arrows on the antenna (to your left)

Use it with multiple centers (more than 2) to verify strongest pathàDue ReflectionsàThat’s most likely the

true direction to the ELT

Reflections

Caused by flat surfacesHangars are notoriousRock wall, cliff, or mountains

To beat reflectionsCheck sensitivity half scale oftenUse RECeive modeRubber ducky antennaOff-frequency tuningUsually strongest DF center is not a reflection

Triangulation

Best method for ground troops to get an accurate fix when search aircraft support is unavailable

You must be able to receive the signalàCenter up DF unit on the signalàTake the magnetic bearing (shoot an azimuth)àCorrect for magnetic variation

• East is least, West is best

àPlot your bearings (draw a line) on map

àThe ELT should be where the lines cross!

Let’s See That

Body Shielding

The BEST method of beating reflections at close rangeCan use L-Per™Radio Shack JETSTREAM radio is better and CHEAP!At extremely close range, a 2m VHF radio unsquelched may work

• This works ok when trying to figure out a particular aircraft on a flight line, it willprobably not identify a particular hangar

Body blocks out the signalàCalled a NULLàNull should be at your BACK

Off-Frequency Tuning

Decrease sensitivity when:àSensitivity (L-Per™) is at the minimum and signal is still too

strong (full scale on receive) àYou don’t get a null during body shieldingàYou don’t have a sensitivity knob (Jetstream) àShortening (Jetstream) or removing (Little L-Per™) the

antenna will also decrease sensitivity Off-Frequency tuning may be used any time you have too much

signal, but this technique is especially effective during body shielding

I can’t hear the signal!ELTs are limited to Line of Sight propagationYou don’t always need to hear the ELT

àCarrier wave may be broadcasting with no audible sweepEspecially true in low batteries, or odd transmissionsYou can tell by DEFLECTIONGood needle deflection generally indicates a signal that is strong

enough to DF

What else can affect an ELT signal?

Power lines EM RadiationIf you get an actual ELT during a practice search, shut down

all practice beacons. The signal on 121.5 may be frequency shifted from your practice beacon! (often due to power lines)

Fence Line (signal can follow) Coffee Can/Stovepipe effect Hangars Moving Target

How does an aircraft perform an electronic search?

Aircraft use the same type of methods as used on the groundàDF mode (most common)àWing Null Method (body shielding with the wing!)àSignal StrengthàAural Search (rare)

Before going home,silence the signal!

Sometimes that’s the only goal! Methods of disabling an ELT:

Switch off (not always effective!)Foil tentGrounding wireRemove batteryRemove antennaThe Sheriff is required for forcible entry

àMost folks will be very cooperative Ensure the aircraft operator is notified you disabled the ELT!

Summary

You Should Now:àKnow what an ELT is and how it can be activatedàUnderstand why an ELT signal is an emergencyàDescribe how CAP is called out on an electronic searchàBe familiar with these fundamentals:

• Plotting a SARSAT hit on a map (latitude/longitude)• Direction finding - Little L-Per™ Operation• Triangulation• Body shielding• Aircraft coordination/LORAN/GPS operations• Ground Vehicle Operations

QUESTIONS?

Always Think Safety!