SEARCH PLAN VARIABLES CG Addendum Section H.5

Instructor Notes

Objectives Demonstrate the relationship between Track Spacing (S); Corrected Sweep Width (W); Coverage Factor (C) State the factors needed to obtain a corrected visual sweep width Locate the visual sweep width estimate for night detection aids Compute Coverage Factor (C)

The Goal of Search Planning “To cover as much of the search area as possible with a reasonable probability of detection with the ultimate aim to maximize the probability of success.” Section H.5 Search Plan Variables The goal of search planning is to cover as much of the search area as possible with a reasonable POD with the ultimate aim to maximize POS. Area coverage is a function of area size, corrected sweep width, and the number, speed, and endurance of SRUs used. POD and Coverage are measures of the thoroughness of a search.

TRACK SPACING (S) SWEEP WIDTH (W) COVERAGE FACTOR (C) Search Plan Variables TRACK SPACING (S) SWEEP WIDTH (W) COVERAGE FACTOR (C) Read each, and comment briefly.

The distance between two adjacent Track Spacing (S) The distance between two adjacent parallel search legs Simultaneous Sweeps Successive Sweeps s s H.5.4.1 Track spacing (S) is the distance between two adjacent parallel search legs. It directly influences coverage (C). POD can be increased by decreasing track spacing (which increases coverage), but decreased track spacing means that either less area can be covered, that more time is needed to cover the same area with the same number of SRUs, or that more SRUs are needed to cover the same area in the same amount of time. The ideal “compromise” between area covered and POD is the one that produces the maximum POS.

Sweep Width (W) Search objects missed within Sweep Width Search objects detected outside Sweep Width Figure H-22 Sweep Width Search objects missed within Sweep Width SWEEP WIDTH LATERAL RANGE IN SWEEP WIDTHS NOTE: Number of search objects missed in area “A” is equal to number of search objects sighted in area “B” POD H.5.5 Sweep Width H.5.5.1 Sweep width (W) is the width of a swath centered on the SRU’s track where the probability of detecting the search object if it is outside of that swath is equal to the probability of missing the search object if it is inside that swath. It is a measure of detection capability based on search object and sensor characteristics, weather, and other factors. Sweep width is less, often much less, than twice the maximum detection range, which is the farthest range at which the object can be detected

Sweep Width (W) A measure of detection capability Based on scientific study Some must be corrected for weather, fatigue, velocity It is a measure of detection capability based on search object and sensor characteristics, weather, and other factors.

Visual Sweep Widths W = Wu x fw x ff x fv Sweep width corrected (W) = sweep width uncorrected (Wu) x weather correction (fw) x fatigue correction (ff) x speed correction (fv-aircraft only) Corrected sweep width (W) is a measure of detection capability and will vary with search object type, SRU/sensor type, and environmental conditions. For search patterns that use straight, equally spaced parallel tracks, coverage is computed as the ratio of the corrected sweep width to the track spacing (C = W/S). The more difficult an object is to detect, the closer together the search legs must be to achieve a given coverage. H.5.5.3 Visual sweep widths are determined by choosing an uncorrected sweep width based on type of search object and SRU altitude and correcting it for environmental conditions, speed, and fatigue. For maritime SAR, Sweep width corrected (W) = sweep width uncorrected (Wu) x weather correction (fw) x fatigue correction (ff) x speed correction (fv-aircraft only). Emphasize the three correction factors – Weather, Fatigue, Speed

W = Wu x fw x ff x fv Example Visual Sweep Widths W = Wu x fw x ff x fv Example Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 knots Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Review the example specification.

Visual Sweep Widths Search Altitude (e) Search Altitude. For many objects, the available sweep width tables indicate that sweep width increases slightly with increasing altitude up to 3,000 feet under ideal conditions. However, these figures should not be given undue regard as the smaller increases indicated are generally within the estimation error of the methods used to create the tables.

Uncorrected Visual Sweep Width Visual Sweep Widths W = Wu x fw x ff x fv Uncorrected Visual Sweep Width Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Start with uncorrected sweep width.

Uncorrected Visual Sweep Widths Tables H-11 thru H-19, Pages H46- H50

Uncorrected Visual Sweep Widths Note: If using a surface vessel, use Table H-19 pg H-50 NOTE – Difference between a vessel and a small boat. Cutter or Small boat?

Uncorrected Visual Sweep Width Visual Sweep Widths W = Wu x fw x ff x fv Uncorrected Visual Sweep Width Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Wu = 6.3 Uncorrected sweep width is 6.2. Write it down. Stress the importance of organized work sheets so work can be checked by themselves or by others.

W = Wu x fw x ff x fv Weather Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Weather Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts

Weather Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Weather Correction Factor Weather Correction Winds are 14 knots, that row would be selected. The seas are 4’, so that row would be selected. Then depending on what search object you are looking for, you select a column. Since the object we are looking for is 33’, the CG uses Other search Objects. If environmental conditions of more than one row apply, use the smaller of the weather correction factor.

W = Wu x fw x ff x fv Weather Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Weather Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts The first correction factor for weather. Fw = 0.9

W = Wu x fw x ff x fv Fatigue Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Fatigue Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Correcting for Fatigue The second correction factor is for fatigue. Either “YES” or “NO” Coast Guard Addendum Paragraph H.5.5.4(c) If feedback from on scene SRUs indicates search crews were excessively fatigued, reduce sweep width values by 10 percent (multiply by 0.9). How do we know if excessive fatigue is present? An SRU does NOT have to be in fatigue status for this to apply. If the crew has been underway / airborne in heavy weather for a significant amount f time, go ahead and apply this factor. You are giving the search object the benefit.

W = Wu x fw x ff x fv Fatigue Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Fatigue Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts In this example fatigue is excessive so the factor is 0.9. Next factor is velocity. Ff = 0.9

W = Wu x fw x ff x fv Speed Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Speed Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Speed correction factor applies to aircraft only.

W = Wu x fw x ff x fv Speed Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Speed Correction Factor Note – fixed wing and helicopter speed correction factors.

W = Wu x fw x ff x fv Speed Correction Factor Visual Sweep Widths W = Wu x fw x ff x fv Speed Correction Factor Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts In this example the velocity correction factor is .9 Fv = 0.9

W = Wu x fw x ff x fv Example Visual Sweep Widths W = Wu x fw x ff x fv Example Search Object 33 ft Power Boat SRU Type HH-65 Altitude 1000 ft Visibility 10 nm Wind 14 kts Seas 4 ft Crew fatigue Yes SRU Speed 120 kts Wu = 6.3 fw = 0.9 ff = 0.9 fv = 0.9 W = 4.59 Review the example specification. Make sure the class is with you.

Uncorrected Visual Sweep Width Visual Sweep Widths Uncorrected Visual Sweep Width Wu = 6.3 fw = 0.9 ff = 0.9 fv = 0.9 W = 4.59 SRU track Effect of correction. Uncorrected we had a sweep width of over six miles.

Uncorrected Visual Sweep Width Visual Sweep Widths Uncorrected Visual Sweep Width Wu = 6.3 fw = 0.9 ff = 0.9 fv = 0.9 W = 4.59 SRU track Corrected, it is less than five miles. THE PROCESS IS IMPORTANT!

Visual Distress Signaling Devices (VDSD) Orange smoke Red flare Star shell Dye markers Tracers Signal mirrors Sweep widths for VDSD are never corrected. Use them right out of the table. Active targets are designed to attract our attention. VDSD do not require correction, their Sweep Widths are used as listed. Of course, if the visibility is 4 miles in haze and the sweep width for a target is 10NM, make the correction as necessary. H.5.5.6 Visual Distress Signaling Devices (VDSDs). When estimating sweep widths for VDSDs, such as pyrotechnics, dye markers, tracer bullets, or signal mirrors, use either twice the range at which survivors can be expected to detect the SRU, or the value given in Tables H-20, H-21, H-22, H-23 or H-24, whichever is smaller.

Electronic Search Sensors EPIRB/ELT* Surface Radar FLAR SLAR FLIR NVG* EPIRB / ELT Sweep widths require minor corrections. Radar search sensors do not require correction either, their Sweep Widths are used as listed. NVG’s require very complex calculations, allow the SMC to utilize computer systems to calculate.

Coverage Factor (C) C = W/S Measure of search thoroughness or how well an area was searched. Entering argument when calculating Probability of Detection. C = W/S H.5.6 Coverage Factor (C) Coverage Factor (C) is a measure of search thoroughness or how well an area was searched. It is used as an entering argument when calculating POD. For search pattern that uses straight, equally spaced parallel tracks, coverage is computed as the ratio of the corrected sweep width to the track spacing (C = W/S). Coverage (C) = Corrected Sweep Width (W) / Track Spacing (S)

How to use the Bookmark W / / Demonstrate the use of the pyramid C S X

Track Spacing and Sweep Width are equal. C = 1.0 S = W (1: 1 Ratio) Sweep Width Track Spacing SRU track 3.4.2.1 Initial Response Search Area. When the search object is not located upon arrival on scene, the default initial response is to conduct a search with an average coverage of 1.0. In this search, SWEEP WIDTH equals TRACK SPACING. Which factor do you have control of? Track Spacing. Track Spacing and Sweep Width are equal.

Track Spacing is greater than the Sweep Width. W < S (1:2 Ratio) Sweep Width Track Spacing Coverage factor LESS THAN 1 leaves areas that are not searched or not searched well. TRACK SPACING is greater than SWEEP WIDTH. Ask students when might a search like this be used?? (perfect conditions, large target, large area to search, little time, few resources) Sweep Width Track Spacing is greater than the Sweep Width.

Track Spacing is less than the Sweep Width. W > S (3:2 Ratio) Sweep Width Coverage factor is GREATER THAN 1. TRACK SPACING is less than SWEEP WIDTH, which causes overlap. When might this search be used?? (small object (PIW), small area, many resources, good datum , lots of time) Track Spacing Sweep Width Track Spacing is less than the Sweep Width.

Review Distance between two adjacent search legs Width of a swath centered on an SRU’s track where probability of detecting object outside that swath is equal to missing the object inside the swath Measure of search thoroughness or how well an area was searched Track Spacing Sweep Width Coverage Factor

Review What are the factors for correcting a Visual Sweep Width? What is the correction factor for a VDSD? Sweep Width divided by Track Spacing = ?? Weather, fatigue, A/C Speed None Coverage

And that is all there is to it! LAB TIME