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Authored by Scott E. Lanis 28-Aug-1998 Modified by Lt Colonel Fred Blundell

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

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Authored by Scott E. Lanis 28-Aug-1998 Modified by Lt Colonel Fred Blundell

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  1. 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

  2. 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

  3. 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!)

  4. How does CAP Searchfor 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)

  5. What Will A CrashedAirplane Look Like?

  6. 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

  7. Aircraft Limitations • Weather • Can’t pinpoint signal • Row of hangers

  8. 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!”

  9. 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

  10. What if only an ELTsignal 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

  11. 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 ELTsinstalled

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

  13. 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

  14. 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!

  15. Inadvertent Activationof an ELT MayOccur From • Excessively hard landing • Inadvertent change of switch position • Removal of the unit • activating the switch or G-switch • Malfunction • switch short • battery leakage

  16. 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

  17. 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

  18. System OperationDetails • SARSAT/COSPAS in polar orbit • Calculates location of signal by measuring Doppler shift • This yields a latitude and a distance

  19. Narrowing the Search (SARSAT/COSPAS Only) • First pass • Ambiguity

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

  21. 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 • 25 Milliwatt 121.5 Beacon

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

  23. 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!

  24. 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!

  25. 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

  26. 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

  27. DFing with theLittle 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

  28. Direct to the Flipping, Turn to Tell

  29. REC • 1/2 • DF • Center • Turn • Shoot

  30. 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 thetrue direction to the ELT

  31. 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

  32. 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!

  33. Let’s See That

  34. 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 willprobably not identify a particular hangar • Body blocks out the signal • Called a NULL • Null should be at your BACK

  35. 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

  36. 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

  37. 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

  38. 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)

  39. 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!

  40. 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

  41. QUESTIONS? Always Think Safety!

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