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Mission Aircrew Course Electronic Search Patterns (APR 2010)

Mission Aircrew Course Electronic Search Patterns (APR 2010). O-2005 OPERATE THE AIRCRAFT DIRECTION FINDER (P) O-2006 PERFORM ELT SEARCHES (P) O-2007 LOCATE AND SILENCE AN ELT ON THE GROUND (P) O-2101 DESCRIBE HOW ELTS ARE DETECTED (P) O-2108 ASSIST IN ELT SEARCHES (O). Aircrew Tasks.

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Mission Aircrew Course Electronic Search Patterns (APR 2010)

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  1. Mission Aircrew CourseElectronic Search Patterns(APR 2010)

  2. O-2005 OPERATE THE AIRCRAFT DIRECTION FINDER (P) O-2006 PERFORM ELT SEARCHES (P) O-2007 LOCATE AND SILENCE AN ELT ON THE GROUND (P) O-2101 DESCRIBE HOW ELTS ARE DETECTED (P) O-2108 ASSIST IN ELT SEARCHES (O) Aircrew Tasks

  3. Discuss the various types of ELTs. Describe how an ELT can be detected. Describe how the aircraft DF works in both the Alarm and DF modes. Discuss using the DF during a typical ELT search Response during initial phase, including signal fade Response when getting close Response as you pass over the beacon Objectives

  4. Describe the following ELT search methods: Homing Wing null Aural Signal Discuss signal reflection and interference. Describe how to silence an ELT and the legal issues involved. Objectives

  5. Emergency Locator Transmitter Direction Finding for Aircrews:use of equipment commonly found in CAP aircraft N98987 ©2000 Scott E. Lanis 5

  6. Objective: The Elusive ELT Automatic radio beacon (100 milliwatts) Roughly equal to that of a regular flashlight Can be heard on a line-of-sight basis. Remember that the ELT may be attached to an aircraft or vessel in distress! Click Icon to Hear an ELT ©2000 Scott E. Lanis 6

  7. Activated by g-force (when armed) Some can be activated by the pilot in the cockpit Three frequencies: 121.5 MHz (VHF emergency) 243 MHz (UHF emergency – military guard) 406 MHz (third generation advanced ELT/EPIRB/PLB) General types: General aviation aircraft Military (“beepers” or “beacons”) Marine EPIRB Personal Locator Beacons (PLBs) Advanced (406) Test station (training practice beacon) The ELT

  8. ELT Antenna

  9. Most aircraft have ELTs installed But they don’t always survive a crash

  10. Most aircraft have ELTs installed But they don’t always survive a crash

  11. Most common type is the URT-33/C Personnel ejecting/parachuting will most likely have a 243.0 MHz beacon Some downed pilots may be able to communicate via two-way radio on 243.0 MHz using a PRC-90 military survival radio Beacon mode transmits like an ELT on 243 MHz You can monitor (and track!) this frequency on your aircraft’s DF unit Military beacons

  12. Personal Locator Beacon (PLB) Sometimes “Personal Emergency Transmitter” (PET) Intended for hikers, hunters, boaters, and other remote wilderness travelers MOST Use a 406 MHz transmitter and a 121.5 MHz homing signal (generally, at only 25 milliwatts) Many are also equipped with a built-in GPS receiver that provides lat/long coordinates Each PLB must be registered with NOAA Personal beacons

  13. 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 By law, all must be 406 capable now Marine EPIRB

  14. Designed to operate with SARSAT/COSPAS 406 MHz beacons have data burst encoding that identifies each (registered) individual beacon Also produces a 121.5 MHz homing signal and may transmit GPS coordinates Sends a coded signal that can be matched to a registration database The owner's name, address and type of aircraft is obtained from database, so AFRCC can call to see if the aircraft is really missing (70% resolved this way) Since geostationary satellites process the digital signal, it will be heard more quickly and allow a much faster response If the unit has a GPS receiver, it can transmit lat/long coordinates to further speed the search. The signal can also penetrate dense cover (e.g., trees). Still very expensive (~ three times as much as a 121.5 MHz ELT Not mandatory in the United States; MAY become mandatory in Canada Advanced ELTs

  15. Training Beacons are registered as Test Stations, and referred to as “Practice Beacons” Includes ones used by CAP All practice beacons should operate on 121.775 MHz (if it uses another frequency, don’t use it) During practice searches, avoid calling the practice beacon an ‘ELT’ when communicating over the radio May cause confusion Always use the term ‘Practice Beacon’ Practice Beacon

  16. 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? Ensure your ELT didn’t activate This isn’t considered a test, by the way, but you can try this excuse if you like Testing an Aircraft ELT

  17. 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 Inadvertent Activation

  18. At least 97%+ of received ELT signals are false alarms Historically, for 121.5 MHz ELTs about 1 in 1000 are actual emergencies For 406 MHz ELTs about 1 in 10 are actual emergencies They block emergency communications on 121.5 and 243.0 MHz (guarded by towers, ARTCC, and the military) False Alarms

  19. Initial ELT Detection • Until 1 Feb 2009, most ELTs were initially detected by the SARSAT-COSPAS system • This system no longer monitors 121.5 and 243.0 • SARSAT-COSPAS only listens for 406 MHz signals now • Initial detection for an ELT must come from an airborne or surface-based asset • Airliners, military aircraft, ATC facilities • Participating civil traffic: YOU • Using the Area of Intersection method should get you closer, you may need mission staff to assist

  20. SARSAT Video

  21. GOES 406 ELT Detection GEO Footprint LEO Footprint

  22. QUESTIONS?

  23. 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 it, every ELT mission allows you to keep your skills sharp! OK, So How Should I Treat an ELT Mission?

  24. Route or parallel track to pick up the signal If no SARSAT hits or definitive LKP: 4,000 to 10,000 AGL Large track spacing (start at 60 nm, then do halves) Once signal is located, DF the signal Locating the ELT Signal

  25. Direction Finder (DF) • 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”

  26. L-Tronics DF Normal: Alarm toggle in ‘up’ position DF: toggle is ‘down’

  27. DF Antenna These are mounted on the bottom, but may be on top

  28. Step 1: Acquire the Signal To hear the signal you can use your L-Tronics receiver, the Becker DF, or one of the comm radios To acquire with a comm radio, turn the squelch OFF 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 Proceed at a reasonable altitude to the Intersection Area Or to the SARSAT hit (406 ELT) if you have one or to the point designated by your incident commander ©2000 Scott E. Lanis 29

  29. Beginning The Search: Altitude Selection 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 SIGNAL HEARD! NO SIGNAL NO SIGNAL ELT ©2000 Scott E. Lanis 30

  30. Altitude Selection ©2000 Scott E. Lanis 31

  31. Intersection Area

  32. Step 2: Track (DF) the Signal There are many different ways to DF an ELT signal: Left-Right DF Homing (L-Tronics DF) Wing Shadow Method Aural Search Metered Search Combinations of the above techniques ©2000 Scott E. Lanis 33

  33. Wing Shadowing 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 ©2000 Scott E. Lanis 34

  34. Wing Shadowing: Antennas 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 ©2000 Scott E. Lanis 35

  35. Communications Antennas Above the Wing Antennas Abovethe Wing N98987 ©2000 Scott E. Lanis 36

  36. DF Antennas Below the Wing N98987 Antennas Belowthe Wing ©2000 Scott E. Lanis 37

  37. QUESTIONS?

  38. How To DF by Wing Shadowing(Also Called Wing-Null Method) 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 N 315 45 E W 225 135 S ©2000 Scott E. Lanis 39

  39. Wing Shadowing:Signal BlockingFor Antennas Above the Wings NULL NULL NULL SIGNAL ELT ©2000 Scott E. Lanis 40

  40. Wing Shadowing:Antennas Above the Wing Turn in a circle until you hear the null (significant decrease in volume) The ELT is 90º to your LEFT SUBTRACT 90º from your heading Or, keep it simple—use the90º index W 315 225 N S 45 135 E ELT ©2000 Scott E. Lanis 41

  41. Wing Shadowing: Signal BlockingFor Antennas Below the Wings ELT NULL NULL SIGNAL NULL ©2000 Scott E. Lanis 42

  42. Wing Shadowing:Antennas Below the Wing 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 S 225 135 W E 315 45 N ELT ©2000 Scott E. Lanis 43

  43. Aural (Hearing) Search Method This is based on the assumption that the area of equal beacon signal strength is circular: do NOT adjust volume during this search; you will need it to determine equal levels of signal 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! ©2000 Scott E. Lanis 44

  44. Aural Search ©2000 Scott E. Lanis 45

  45. Metered Search(Build & Fade) Method 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 ©2000 Scott E. Lanis 46

  46. Metered Search 3 2 FADE 6 4 ELT 7 8 2 MAXIMUM SIGNAL THEN DROP 5 9 MAXIMUM 6 8 7 4 SIGNAL 6 5 4 5 4 2 1 FIRST SIGNAL 2 ©2000 Scott E. Lanis 47

  47. Left-Right DF Homing Most CAP corporate aircraft have L-Tronics 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 ©2000 Scott E. Lanis 48

  48. L-Tronics DF Types Single Meter Model Dual Meter Model mSENS ®VOL REC 243 ALARM AUX DF 121.775 121.6 VHF-DF OFF 121.5 L-Tronics DF STRENGTH mSENS ®VOL ALARM 243 AUX 121.775 121.6 VHFDF OFF 121.5 L-Tronics ©2000 Scott E. Lanis 49

  49. Frequency Switch 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 Refer to owners manual for use of the “AUX” position mSENS ®VOL REC 243 ALARM AUX DF 121.775 121.6 VHF-DF OFF 121.5 L-Tronics ©2000 Scott E. Lanis 50

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