This course is designed to give a basic introduction to how electronic searches for downed aircraft are conducted. It includes use of the L-Tronics “Little L-Per™,” triangulation, body shielding, and activation of CAP. This course is mainly focused on the ground team member aspect of electronic search. Authored by Scott E. Lanis 28-Aug-1998 Modified by Lt Colonel Fred Blundell TX-129 Fort Worth Senior Squadron For Local Training Rev 5.0 02-Feb-2014

OBJECTIVES By the end of this course, you should: Know what an ELT is, and how it can be activated Understand why an ELT signal is an emergency Describe how CAP is called out on an electronic search Be 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 call Monitored aircraft drops from RADAR Overdue Flight Plan Report from friends/relatives ELT Signal (maybe!)

How does CAP Search for Missing Aircraft? Purely Visual Searches Very Difficult: often few clues Air - most effective to cover ground Ground Electronic Searches - “Quick” (24 hrs) Air - best reception and range Ground - autonomous search is slower and more difficult Advanced Technology Few of these resources available directly to CAP Synthetic Aperture Radar (SAR), Thermal/Infrared Imagery, Other Remote Sensing (satellites/reconnaissance aircraft) A purely visual search is often a nearly impossible task when the range and speed of a missing aircraft is considered. An airborne search covers the most ground per period of time. Ground searches by themselves are ineffective. (not including ramp and bastard searches) This “cutting edge” technology was heavily utilized in Colorado’s search for Craig Buttons’ A-10.

What Will A Crashed Airplane Look Like? Your second most likely place to find a Bonanza. JOKE! I love Bonanzas. An aircraft like this is likely to have survivors-and they’ve likely already gone home and left the ELT operating! (I’ve seen this twice)

Air to Ground Coordination 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 Weather Can’t pinpoint signal Row of hangers

Ground Search Types for Missing Aircraft Ramp Search Ensure the missing aircraft has not landed safely Can be conducted by both air and ground crews Bastard Search Ensure the missing person isn’t in a favorite hangout “You bastard!”

How does a search start? There is the possibility of a missing aircraft Radio distress call, aircraft drops from RADAR, overdue flight plan, report from friends/relatives, ELT Signal AFRCC performs a telephone search Airport managers, towers, etc. Missing Aircraft Confirmed! AFRCC activates the appropriate CAP wing AFRCC will try to resolve the ELT AFRCC will call airport managers to see if they receive a signal that seems to be near an airfield if a signal is received on the field, the manager will responsibly disable the ELT If no airports are in the vicinity, a CAP search is initiated after a set period of time has passed If the signal coincides with an overdue aircraft or unclosed flight plan, search begins faster CAP often is called out “after hours” when there are no airport managers left at work! CAP answers the call because everyone else has gone home.

What if only an ELT signal is received? AFRCC Telephone Search Airports: “Do you hear it too?” Likely false alarm at this point; signal silenced by crews on airport CAP called sooner if “after hours” No one else answers the phone! Is there another indicator of a missing aircraft? If not, AFRCC will wait to see if the signal terminates Tests Inadvertent actuations terminated

What is an ELT anyway? Emergency Locator Transmitter It’s an automatic radio beacon! 3 Frequencies of Operation 121.5 MHz (VHF) AND 243 MHz (UHF) (Military Guard) 406.025 MHz (new) Most aircraft have ELTs installed

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

Typical Aircraft ELT Operation 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 or 50% of useful life has expired FAR §91.207(c) Does not apply to our Practice Beacons Call nearest FSS in advance: 1 (800) WX-BRIEF Give a contact phone-interference happens on 121.775!

Inadvertent Activation of an ELT May Occur From Excessively hard landing Inadvertent change of switch position Removal of the unit activating the switch or G-switch Malfunction switch short battery leakage

Who is listening? SARSAT/COSPAS FAA Facilities FSS, Centers, Towers Airliners Only if pilot chooses Military Aircraft 243 MHz Required General Aviation Aircraft That’s us! Help the system work: monitor 121.5 MHz Signal report is relayed to AFRCC

How SARSAT Works Receive 121.5, 243, 406 MHz Signals Orbiting and Geostationary Satellites Orbiting: SARSAT/COSPAS High Inclination (polar) orbits Geostationary: GOES Weather Satellites SAR payloads for 406 only Operated by Canada, France, Russia, USA They give us digital lat-long coordinates CAP Mission Coordinator plots these and assigns assets Ground teams must interpret for land navigation

System Operation Details 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 pass Ambiguity

Where Is It? Second Pass average 30-45 minute wait Ambiguity resolved 5-12 Nautical Mile Average Error

How do Different ELTs stack up? 121.5 MHz ELT 12 NM Radius, 452 Sq Mi Ave. 6 Hour Notification 60 Milliwatt Transmitter 406 MHz ELT 2 NM Radius, 12.5 Sq Mi Ave. 1 Hour Notification 25 Milliwatt 121.5 Beacon 406 ELT with GPS .05 NM Radius, .008 Sq Mi Ave. 5 minute Notification Diagram and information adapted from NOAA Pamphlet, with the exception of 25 milliwatt beacon. Note that hunting ELTs by signal alone will become much more difficult with less than 1/2 the power (inverse square law says less than 1/4 the effective radius from previous ELTs) but hopefully uncommon Food for thought: how common will the GPS portion of an ELT fail with the 121.5 beacon operating?? That’s anyone’s guess.

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 alarms 121.5 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) bent-pipe repeater VERY easy to overload the system Blocks emergency communications Blocks the real emergency!

How should we treat 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 triangulate Close 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 the Little L-Per 6 Steps: use the full procedure every time! Turn the unit to Receive, check proper frequency and volume Turn the Sensitivity Knob to HALF SCALE This will prevent oversense and a good starting point Turn the unit to DF (Direct to the Flipping target) Turn at least one FULL circle, stopping and calling, “Center!” Check: Use Turn to Tell: the needle will point Direct to the Flipping target Use 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 only From a direction of the arrows on the antenna (to your left) Use it with multiple centers (more than 2) to verify strongest path Due Reflections That’s most likely the true direction to the ELT

Reflections Caused by flat surfaces Hangars are notorious Rock wall, cliff, or mountains To beat reflections Check sensitivity half scale often Use RECeive mode Rubber ducky antenna Off-frequency tuning Usually 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 signal Center up DF unit on the signal Take the magnetic bearing (shoot an azimuth) Correct for magnetic variation East is least, West is best Plot your bearings (draw a line) on map The ELT should be where the lines cross!

Let’s See That

Body Shielding The BEST method of beating reflections at close range Can 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 will probably not identify a particular hangar Body blocks out the signal Called a NULL Null should be at your BACK

Off-Frequency Tuning Decrease sensitivity when: Sensitivity (L-Per™) is at the minimum and signal is still too strong (full scale on receive) You don’t get a null during body shielding You don’t have a sensitivity knob (Jetstream) Shortening (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 propagation You don’t always need to hear the ELT Carrier wave may be broadcasting with no audible sweep Especially true in low batteries, or odd transmissions You can tell by DEFLECTION Good needle deflection generally indicates a signal that is strong enough to DF

What else can affect an ELT signal? Power lines EM Radiation If 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 ground DF mode (most common) Wing Null Method (body shielding with the wing!) Signal Strength Aural 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 tent Grounding wire Remove battery Remove antenna The Sheriff is required for forcible entry Most folks will be very cooperative Ensure the aircraft operator is notified you disabled the ELT!

Summary You Should Now: Know what an ELT is and how it can be activated Understand why an ELT signal is an emergency Describe how CAP is called out on an electronic search Be 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!