JP 3-50 National Search and Rescue Manual Vol I - US Navy

TABLE 5-5. Recommended Visual Search Altitudes
Search Target Terrain Recommended Altitudes (ft)
Person, cars, light Moderate 200 to 500
aircraft crashes terrain
Trucks, large aircraft Moderate 400 to 1000
terrain
Persons, one-person Water or flat 200 to 500
rafts, surfboards, terrain
light aircraft crashes
Small to medium- Water or flat 1000 to 3000
sized boats, liferafts, terrain
trucks, aircraft
Distress signals Night-all 1500 to 2000
terrain
6. Search Speed. At low altitudes, higher speed causes blurring
of targets at close ranges and decreases exposure time to the
scanner. At altitudes above 500 feet, search speed of
traditional SRUs has no significant influence on overwater
sweep widths. The increase in area searched more than
compensates for the small reduction in sweep width at higher
search speeds.
7. 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 5-6, 5-6a, 5-7, 5-7a or 5-7b, whichever
is smaller.
a. Daylight Detection Aids. Effectiveness of daylight
aids is marginal due to the difficulty in achieving target
contrast in a sunlit environment. Estimated sweep widths for
various daylight detection aids are given in Tables 5-6 and
5-6a. Hand held orange smoke detectability varies by type of
SRU, and also by time on task for surface SRUs. Estimated
sweep widths for hand held orange smoke are given in Table
5-6a for winds 10 knots or less. For winds over 10 knots the
smoke tends to dissipate and sweep width degrades to less than
2 nautical miles.
b. Night Detection Aids. If it is known, or suspected,
that survivors can make a night signal, night visual searches
should be conducted.
5-20