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Search Effort. The Balancing Act. Limited Resources Planning Time in Search Area – how much time does it take to complete a search assignment?. Time in Search Area. Sample air search problem: Quarter Grid (in Central Minnesota) 1 NM track spacing 90 Knots Airspeed. 45 30’ N. 46 00’ N. - PowerPoint PPT Presentation
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Search EffortSearch Effort
The Balancing ActThe Balancing Act
Limited ResourcesLimited Resources Planning Time in Search Area – how much Planning Time in Search Area – how much
time does it take to complete a search time does it take to complete a search assignment?assignment?
Time in Search AreaTime in Search Area
Sample air search problem:Sample air search problem:– Quarter Grid (in Central Minnesota)Quarter Grid (in Central Minnesota)– 1 NM track spacing1 NM track spacing– 90 Knots Airspeed90 Knots Airspeed
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
30’ x 30’
93 45’ o
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
45 45’ o
15’ x 15’ 15’ x 15’
15’ x 15’ 15’ x 15’
93 45’ o
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
45 45’ o
413 414
445 446
TwinCities
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
93 45’ o
45 45’ o
414
445 446
7.5’ 7.5’
7.5’ 7.5’TwinCities
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
93 45’ o
45 45’ o
414
445 446
MSP413
A B
C D
94 00’ W o 93 30’ W o
45 30’ No
46 00’ No
93 45’ o
45 45’ o
414
445 446
MSP413 A
B
C D
A
Computing Time in Search AreaComputing Time in Search Area
1 “square” degree in 1 “square” degree in Central Minnesota is Central Minnesota is about 60x42 NM, so about 60x42 NM, so a quarter grid is about a quarter grid is about 7.5 x 5.25 NM.7.5 x 5.25 NM.
Quarter Grid:
MSP 413A
5.25 NM
7.5 NM
Computing Time in Search AreaComputing Time in Search Area
We have 8 sweeps We have 8 sweeps 4.25 NM long each 4.25 NM long each plus 7 NM distance plus 7 NM distance covered moving covered moving between sweeps.between sweeps.
That’s 8*4.25+7, or That’s 8*4.25+7, or about 41 NM. about 41 NM.
At 90 Kts, that is At 90 Kts, that is about a half hour.about a half hour.
Quarter Grid:
MSP 413A
1/2 NM
1 NM
1 NM
1 NM
1 NM
1 NM
1 NM
1 NM
7.0 NM
4.25 NM
Time in Search AreaTime in Search Area
Typical sortie assignment is a half grid (two Typical sortie assignment is a half grid (two quarter grids)quarter grids)
Additional time is needed to travel to and Additional time is needed to travel to and from the search areafrom the search area
For missions, we restrict our flight time in For missions, we restrict our flight time in C-172s (with standard tanks) to three hoursC-172s (with standard tanks) to three hours
Search Time EquationSearch Time Equation
A = V*S*T*NA = V*S*T*N– A, AreaA, Area– V, VelocityV, Velocity– S, SpacingS, Spacing– T, TimeT, Time– N, Number of ResourcesN, Number of Resources
This equation works for ground search tooThis equation works for ground search too(think search lines)(think search lines)
Search Time Equation: Search Time Equation: Velocity, VVelocity, V
Search Speed of SRUSearch Speed of SRU– Not cruise speedNot cruise speed
For Aircraft, 60-90 KtsFor Aircraft, 60-90 Kts For Ground Teams, 0.25-0.30 MPHFor Ground Teams, 0.25-0.30 MPH
– 0.29 MPH typical0.29 MPH typical» Based on studies of trained searchers in moderately Based on studies of trained searchers in moderately
dense trees and underbrush in the Pacific Northwestdense trees and underbrush in the Pacific Northwest
» works out to about 3.5 hours per mileworks out to about 3.5 hours per mile
Search Time Equation: Time, TSearch Time Equation: Time, T
Time spent actively advancing the patternTime spent actively advancing the pattern Time Enroute to and from search area not includedTime Enroute to and from search area not included Must discount time spent maneuvering and Must discount time spent maneuvering and
investigating sightingsinvestigating sightings Rule of thumb for aircraft:Rule of thumb for aircraft:
– T is 85% of time in search areaT is 85% of time in search area
– Less if complicated by lots of junk that needs to be Less if complicated by lots of junk that needs to be investigatedinvestigated
May be bound by available daylight hoursMay be bound by available daylight hours
Search Time Equation:Search Time Equation:Number of Resources, N Number of Resources, N
Number of identical resources usedNumber of identical resources used Examples:Examples:
– Number of searchers in a ground teamNumber of searchers in a ground team– Number of aircraft searching at the same Number of aircraft searching at the same
airspeed for the same length of timeairspeed for the same length of time
Search Time Equation: Search Time Equation: Track Spacing, STrack Spacing, S
The distance between searchers or legs of The distance between searchers or legs of the search patternthe search pattern
Search Time Equation:Search Time Equation:Solving for Other VariablesSolving for Other Variables
Spacing Required Spacing Required S=A/(V*T*N)S=A/(V*T*N)
Resources RequiredResources RequiredN=A/(V*S*T)N=A/(V*S*T)
Time RequiredTime RequiredT=A/(V*S*N)T=A/(V*S*N)
(We don’t generally try to solve for V)(We don’t generally try to solve for V)
Search Time Equation RecapSearch Time Equation Recap
Our Example One Last Time: A Quarter Grid in Central MN Our Example One Last Time: A Quarter Grid in Central MN is 7.5 x 5.25 is 7.5 x 5.25 NM NM or about 40 or about 40 NMNM22
– T = A / ( V * S * N ) [from previous slide]T = A / ( V * S * N ) [from previous slide]
– T = 40 T = 40 NMNM22 / ( 90 / ( 90 NMNM/hr * 1/hr * 1NMNM * 1) * 1)
– T = 4/9 hr T = 4/9 hr 0.44 hr 0.44 hr
– But this doesn’t account for maneuvering (turning onto But this doesn’t account for maneuvering (turning onto new legs of search pattern)new legs of search pattern)
» So, divide by 0.85, the rule of thumb, and we get 0.52 hrSo, divide by 0.85, the rule of thumb, and we get 0.52 hr
» This estimate assumes little time spent investigating sightingsThis estimate assumes little time spent investigating sightings
The Balancing Act Revisited:The Balancing Act Revisited:The POA – POD Trade-OffThe POA – POD Trade-Off
Requirements for Successful Search:Requirements for Successful Search:– You must be searching where the person isYou must be searching where the person is
» POA is the likelihood you are in the right placePOA is the likelihood you are in the right place
– You must be able to detect the personYou must be able to detect the person» POD is the likelihood you can detect the personPOD is the likelihood you can detect the person
Your goal: search an area large enough to likely Your goal: search an area large enough to likely contain the person but small enough so that your contain the person but small enough so that your searchers will be closely enough spaced to likely searchers will be closely enough spaced to likely detect the persondetect the person
An obvious conflict…An obvious conflict…