What are different search patterns as per IAMSAR ?

TRACK LINE SEARCH (TS)

• Normally used when an aircraft or vessel has disappeared without a trace along a known route.
• Often used as initial search effort due to ease of planning and implementation.
• Consists of a rapid and reasonably thorough search along intended route of the distressed craft.
• Search may be along one side of the track line and return in the opposite direction on the other side (TSR).
• Search may be along the intended track and once on each side, then search facility continues on its way and does not return (TSN).
• Aircraft are frequently used for TS due to their high speed.

Aircraft search height usually 300 m to 600 m (1,000 ft to 3,000 ft) during daylight or 600 m to 900 m (2,000 ft to 3,000 ft) at night.