1) Most effective when the location of the search object is known within relatively close limit.
2) Used to search a circular area centered on a datum point.
3) The commence search point is always the datum position.
4) Accurately navigation is required, the first leg is usually oriented directly into the leeward

     to minimize navigation errors.
5) It is difficult for fixed-wing aircraft to fly legs close to datum if first leg is less than 2 NM.
6) Often appropriate for searching for persons in the water