Search Patterns

Initial track spacing < 15ft good conditions

0.5 nm

Initial track spacing for PIW

0.1 nm

Initial track spacing 15ft or > good conditions

1 nm

Orientation

Direction of first search leg

Track spacing

Distance between 2 parallel search patterns

Creep

General direction in which an move, same direction as cross legs

Minor axis

Short side of a rectangle

CSP

Location to start the search pattern

Expanding square search

Small area where some doubt exist, uniform coverage, start at datum, first leg usually into wind or current, use when confident the datum is within close limits, turns 90 to the right

Initial track spacing poor conditions

Winds 15 kts or greater Sea 3 ft or greater

Initial track spacing good conditions

Winds < 15 kts Seas < 3ft

Initial track spacing 15ft or greater poor conditions

0.5 nm

Major axis

Long side of a rectangle

When is a track line search used?

Used when the intended route of the search object is known

Initial track spacing < 15ft poor conditions

0.2 nm

Cross legs

Connection between 2 search legs

Search legs

Long leg along the track of any pattern

Datum

Most probable location of the search object corrected by movement over time

Parallel search

Used for large, fairly level area, where equal probability of object in search area, and uniform coverage, search legs along the major axis

Creeping line search

Used to cover one end of an area first, large area, uniform coverage

Barrier search

Search legs perpendicular

Victor sierra multiple units

Second SRU starts 90 to the left of the first leg of first SRU

Victor sierra search

Used when datum is established within close limits, very high coverage is desired, area to be searched is not extensive, first leg is in direction of drift, turn 120 to right, second pattern starts 30 to right of final course