Post on 15-Jan-2016
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Emergency Services Electronic Searches
Mission Pilot CAPR 50-15
Attachment 10Paragraph b
Richard ShulakWasatch Sqdn.
RMR-UT-008January 2000
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Used to augment search Track line search (route) Parallel track search
Standard equipment can be used
CAP planes equipped with DF ELTs on 121.5 or 243 mhz
Electronic Searches
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Homing Method
Used with DF equipment Start at 5000 to 10000 ft AGL Keep needle centered Determine if heading
towards or away from target Crossover indications Problems
Stray signals Other aircraft Low altitude reflections
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Signal Null Search
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Signal Null Methods
Requires two conditions Metal wings Requires several nulls to locate
target Null direction differs for
different wing and antenna configurations High wing Low wing
Calibrate using DG Use lower altitudes as you
approach suspect area No nulls
Descend to search altitude
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Signal Null SearchCrew Requirements
1. Crew skilled in executing steep turns Close to the ground Possibility of a spin No recovery possible Not recommended below
1000 to 2000 ft AGL 2. Know aircraft position
when null occurs Plot vectors
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Signal Null SearchCrew Requirements
3. Lost signal procedures Return to last known signal Requires charting
4. Approach to the search area Watch for other aircraft Non CAP aircraft may be
involved
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Aural Search Methods
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Aural Search MethodProcedure Assumption that area of
equal beacon strength is circular
Procedure Observer plots position
when signal is first heard Pilot turns 90 degrees
Either left or right All subsequent turns are
made in the same direction (left or right)
Continue until signal fades (SF). Do not touch volume
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Aural Search MethodProcedure
Pilot executes 180 degree turn
Plot the new signal heard point (SH)
Fly until signal fades (SF) Generates second vector
Pilot flies to indicated point and executes low altitude search
Notes Calculations are approximate Bisectors seldom intersect
over target
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Metered Search
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Metered Search Requires a signal strength
meter Procedure
Find two points of equal strength
Fly to mid point At mid point, turn left or right If signal drops, turn 180
degrees Observer plots two more points
of equal strength Turn and fly to max reading Start low level search
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Electronic Searches Conclusions
Requires training Works best in flat terrain Signals reflect
Can cause DF equipment to indicate different directions
Flying higher can help In mountainous areas,
canyons, crevices etc will block signals
In above examples, plotting where signals are heard and lost can help identify possible ELT locations