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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