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teams (ASRT) which used the TPQ-10 radar system to control air strikes
in poor and marginal weather. Like the DASCs, each team was usually
collocated with the supported unit. At the beginning of 1968, there
were two ASRTs at Dong Ha with the 3d Division, one at Phu Bai, one
with the 1st Marine Division at Da Nang, and one at Chu Lai, which later
in the month moved to Khe Sanh and was operational there on 23 January.
From these locations, with the 50-mile range of the TPQ-10 radar, the
operators could cover most of I Corps. The Marine A-4s, A-6s, and F-4Bs
all came equipped with beacons that the TPQ-10 could track for the entire
50 miles.25*


In January, the MASS-2 DASCs controlled nearly 5,000 missions, about 3,000 fixed-wing and 2,000 helicopter. MASS-3 directed only slightly fewer, about 3,000 missions equally divided between helicopters and fixed-wing aircraft. The ASRTs belonging to the two squadrons ran about 3,400 radar-controlled missions between them.26


The Marine close and direct air support system called for an intimate relationship between the air and ground commands. With each Marine infantry battalion usually having its own forward air control (FAC) or air liaison party (ALP) attached to it, consisting usually of a Marine aviator and radio operators and equipment so as to be able to communicate with both aircraft and the DASC, ground commanders had their own aviation advisor on their staff. Although the ground FACs had the capability to control both fixed-wing and helicopter airstrikes, usually airborne controllers handled most of these missions because of limitations caused by terrain features and the elusiveness of the enemy. The ground FAC, nevertheless, contributed important assistance to the ground commander. He provided the infantry the ability to talk to the air and perhaps more important was able to advise the infantry commander just what type of air support and ordnance to use.**

Fixed-wing direct and close air support was of two kinds, preplanned
and immediate. In the preplanned strikes, the infantry battalion commanders,
usually with their air liaison officer, determined the day preceding
the mission what targets he wanted to hit. The battalion then sent the
list through channels to division headquarters where the collocated
DASC and FSCC consolidated the air requests. The division then forwarded
the complete package to III MAF which in turn relayed the information
to the wing TADC.At the TADC, the wing prepared the preliminary or fragmentary
order for the next day. In this order, usually called the "frag,"***
the TADC designated the number of missions, time on target, and the
type of ordnance. The "frag" then went out to the various aircraft groups
to carry out and to the Marine DASCs to control. Despite the complexity
of the system, the process allowed for flexibility. Ground commanders
could still call for modifications in the preplanned missions until
2000 of the night before. Normally, a battalion commander could expect
the air strike within 20 hours of the initial request.27****


Marine fixed-wing immediate support was even more responsive. In the event of need, battalion commanders could send in their request at any time. If necessary, the TADC or DASCs, in an emergency, could divert aircraft from preplanned missions and brief the pilots in mid-flight to the new targets. Lieutenant Colonel Twining, a commander of MACS-4, later


* Colonel Twining provided the following description of TPQ-10 operations:
"The TPQ-10 computer compared the aircraft radar track with the operator-entered
target location, taking into account bomb ballistics and winds. The
indicated aircraft track corrections and bomb release signal was relayed
by the operator to the pilot. For the A-4 aircraft this information
was designed to be sent automatically by data link to the aircraft autopilot
but equipment problems on both ends of the link resulted in the almost
exclusive use of the voice relay. The TPQ-10 operator and aircraft pilots
became so skillful that all-weather bomb miss distances were typically
less then 50 meters. The chief problem with TPQ-10 operations was the
occasional entry of gross errors in target location resulting in 'bad
drops' which in a number of instances caused casualties to friendly
forces and civilians." Twining Comments.


** Ground units used VHP radio nets while aircraft employed UHF radios. All FACs, both airborne and on the ground, could employ either system. Otherwise, the air could not talk to the ground.


*** Among both aviators and ground officers this process was called "fragging," not to be confused with the slang term later identified with the attempted killing or injuring of officers and senior noncommissioned officers by throwing fragmentation grenades at them.


**** Colonel Joel E. Bonner, the 1st MAW G-3, related that in Vietnam, the wing modified somewhat the formal procedure described above: "... due to improved communications both encrypted and unencrypted most of the required info[ormation] was in the hands of the G-3 action officers long before the formal info arrived. Much of this info came from the Divisions Air Officer and the Ops officers running specific operations. Also, at Da Nang the Wing G-3 and the TADC . . . were collocated in the same building and the G-3 produced the frag order." Bonner noted that the TADC worked for the G-3 as its control center: "The TADC was the instrument that was used not only to carry out those control functions dictated by the Frag Order, but also by the Commanding General to redirect Tactical Air for higher priority missions and emergencies as the tides of battle changed." Col Joel E. Bonner, Comments on draft, dtd 25Oct92 and 7Dec94 (Vietnam Comment File), hereafter Bonner Comments.







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