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

Pattern Name SRU required Remarks
TSR Trackline 1 For search of a trackline
single-unit or line of position when
return unit must break off search
at same end of track as
search originated.
TMR Trackline 2 or more Same AS TSR except that 2
multiunit return or more SRUs are used
cruising abeam of each other.
TSN Trackline 1 Same as TSR except that
single-unit search terminates at
nonreturn opposite end of track from
commence search point.
TMN Trackline 2 or more Same as TMR except that
multiunit search terminates at
nonreturn opposite end of track from
commence search point.
PS Parallel track 1 Search of a large area when
single-unit position of distress is
unknown.
PM Parallel track 2 or more Same as PS except two or
multiunit more SRUs search abeam of
each other a distance S apart.
PMR Parallel track 2 or more Used for search of long
multiunit return rectangular area where only
one track out and back is
possible.
PMN Parallel track 2 or more Only enroute SRUs or
multiunit nonreturn transient craft available
for one track through
search area.
PSL Parallel track 1 Same as PS except SRU uses
single-unit Loran lines for greater
Loran line navigational accuracy on tracks.
PMC Parallel multiunit 2 or more Underwater pattern only.
circle
PSS Parallel 1 Underwater pattern only.
single-unit spiral
Pd Parallel drift 1 or more Used when target motion
compensated requires drift
compensation.