Sweep Width Correction (Weather, Speed, Fatigue)
The effective sweep width the searchers actually have.
Example
You enter
- Uncorrected sweep width (ft) 120
- Weather factor (0-1, 1 = clear) 0.5
- Speed factor (1 = reference pace) 1
- Fatigue factor (1 fresh, 0.9 fatigued) 0.9
You get
- Corrected sweep width 54 ft
- Combined factor 0.45
- Reduction (%) 55
Checked against published worked examples from: IAMSAR Manual Vol. II / US National SAR Supplement.
Details, formula, and sources
ScopeW = uncorrected width x weather factor x speed factor x fatigue factor (IAMSAR / US National SAR Supplement practice). A 120 ft raw detection width in rain with a tired crew (weather 0.5, fatigue 0.9) is a 54 ft effective width - a 55% haircut before the first track is walked. Produces the corrected W a track-spacing calculation expects, so the spacing gets planned against real conditions. A planning aid, not a promise of detection.
Formula or tabletotal_factor = weather_factor x speed_factor x fatigue_factor; corrected_width_ft = uncorrected_width_ft x total_factor; reduction_pct = (1 - total_factor) x 100.
Source and editionIAMSAR Manual Vol. II / US National SAR Supplement sweep-width correction (W = Wu x f_weather x f_speed x f_fatigue), by name.
Free accessSweep-width correction practice is public (IAMSAR / US National SAR Supplement references); the incident commander and search plan govern.
What governsEstimate. AHJ and licensed fire protection engineer govern.
API field namesuncorrected_width_ft, weather_factor, speed_factor, fatigue_factor, corrected_width_ft, total_factor, reduction_pct
- Multiplicative correction each published factor scales the width linearly and independently; weather and fatigue only degrade (factors at or below 1)IAMSAR Manual Vol. II / US National SAR Supplement