View source for Example Manned Aircraft Search Patterns

==Track Line== 
AKA: Track Crawl, Route Search<br />
Suggested Altitudes: 1000-2000 AGL Daytime. 2000-3000 AGL Nighttime, depending on visibility and conditions.

Used for missing aircraft along their intended route.  Can also be used to search or monitor a corridor of airspace.  

Flown ½ S offset from the original course or track, then a return course that is offset ½ S in the other direction.  Expanding (subsequent) legs are offset a full S. 

==Parallel Track==
AKA: Grid Search, Parallel Sweep<br />
Suggested Altitudes: 1000-2000 AGL

Used when the search area is large and fairly level, and only an approximate LKP is known - i.e. the datum is not well defined.  

In this example, turns are made inside the assigned grid area. If possible, turns are made outside the area when there are no adjacent aircraft and coordination permits it. 

The initial leg is ½ S from the edge, and each leg thereafter is spaced at 1 S. Legs are run at cardinal headings when possible. 

==Creeping Line==
AKA: Narrow Grid Search<br />
Suggested Altitudes: 1000-2000 AGL

Used when the search area is long and narrow as well as fairly level and the probable target location is along a line or track (such a drift from LKP toward datum). This is appropriate when there is a weighted need for a search on one side (the entry side) of the search area - the entry side will be searched first.

Legs of the Creeping Line run parallel to the shorter side of the search area.

Upon completion, successive search patterns are conducted along the search line. 

==Expanding Square==
AKA: Squared Grid
Suggested Altitudes: 1000-2000 AGL

Appropriate when the search area is small (less than 20 square miles) and the LKP is well known.  The pattern begins at the datum and spirals outward in expanding square patterns. The pattern can be flown as an expanding rectangle, with the long axis following expected or possible movement of the subject. 

If the first search yields negative results, a second search can be conducted with the headings offset by 45 degrees. This results in a diagonally overlapping pattern to the first search.

Two legs of each length (1S, 2S, etc.) are flown. On the third leg, the distance is increased by 1S. This results in an evenly increasing pattern. 

==Sector Search==
AKA: Radial Search<br />
Suggested Altitudes: 1000-2000 AGL

The sector search is appropriate when a good LKP is known, and the terrain is flat and even. The radial approach provides increased search coverage near the center (datum) and is typically easier to fly than an expanding grid.  

This pattern also provides multiple views/angles of the center, helping to mitigate issues with terrain or lighting. It also reduces coverage outside the immediate central search area, so of the datum is incorrect, the POD drops sharply. 

==Contour Search==
[[File:search_ex_contour.png|thumb|150px|Courtesy Civil Air Patrol]
Suggested starting altitude: 500-1000 AGL

This pattern is appropriate in hilly or mountainous terrain. Its is dangerous, and only experienced and qualified aircrew should fly it.

The aircraft starts at an altitude 500 feet above the highest point and follows the contours of the mountain while maintaining altitude. Upon completion of the first circuit, the pilots steps down 500’ and repeats - descending on each pass.  In this manner, the aircraft will circle the mountain, following contours, as it descends in widening circuits.

==Shore Line Search==
Search conducted by either boat or aircraft scanning the shoreline in response to a marine incident.  This pattern is often implemented as part of an initial or hasty search, and can also be used if there is a possibility of someone entering the water from shore.

==Barrier Search==
A search asset is used to patrol a choke point where the subject cannot have passed. Typically used in river searches, where a search asset patrols an area downstream of the datum, preventing the subject from moving past.

Image from the New Zealand Coast Guard.