What are different search patterns as per IAMSAR ?

CO-ORDINATED VESSEL-AIRCRAFT SEARCH PATTERN

• Normally used only if there is an OSC present to give direction to and provide communications with the participating craft.
• Creeping line search, co-ordinated (CSC) is often used.
• The aircraft does most of the searching, while the ship steams along a course at a speed as directed by the OSC so that the aircraft can use it as a navigational checkpoint.
• The aircraft, as it passes over the ship, can easily make corrections to stay on the track of its search pattern.
• Gives a higher probability of detection than can normally be attained by an aircraft searching alone.
• Ship speed varies according to the speed of the aircraft and the size of the pattern. The relationship among the speed of the surface facility, the aircraft’s speed, the track spacing and the length of the search legs is defined by the following equation:

Vs = (5 x Va)/ (L + 5)

Where,