fm 44-100 us army air and missile defense operations

FM44-100
5-149. Sectors of Fire and Primary Target Lines (PTL). PTLs are
established to assist in the distribution of ADA fires. Sectors of fire for
HIMAD are normally designated at battalion after review of radar coverage
diagrams. The battery commander or platoon leader normally designates
sectors of fire or PTLs for SHORAD. These limits must be clearly defined by
right and left azimuths. Those ADA units with automated tactical data
systems must know whether they are to assign and engage air targets within
or beyond the stated sector boundaries.
5-31