September-October - Air Defense Artillery

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AAA 1'\'0 ES No. 22,
GROU"lD ACTION AT RO(R RiVeR
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such d;at it was impossible for the guns to fire over anything
but relatively densely populated areas. England is a
small country with a large population. It has a negligible
amount of open country in the American sense of the term.
Naturally, during a raid the danger to the civilian population
from falling shell splinters was acceptable, but it was
quite another matter to fire trial rounds when no raid was
in progress and when, by virtue of the density of population,
lives might be endangered, whatever the line of fire.
The second contributory factor to the non adoption of Trial
Fire by th~ British, was their contention that the use of a
Rank spotting station to observe errors of trial rounds in
range would be impracticable under combat conditions.
Finally visibility is often very poor in the United Kingdom,
and this proved a further argument against !he adoption of
a system which relied on good weather conditions for
recording results.
e. During the flying bomb deployment on the south
coast of England, the British were firing their guns over
other than densely populated areas. This, coupled with the
alternative method of measuring range to burst which had
been developed wiped out the two main objections to Trial
Fire which the British had previously entertained. It was
natural, therefore, that the possibilities of its use should
be reinvestigated.
f. Today heavy Antiaircraft gunnery is an exact science.
Nothing must be left to chance, and least of all the preparations
made before "fire for effect" is opened. In future, trial
fire will have a place in the British as well as American procedurcs,
or, at least, the means of conducting it and correcting
as a result of it made available. This demands the
inclusion of "spot controls" in any future development of
fire control equipment.
B. Comments of Theater Antiaircraft Officer:
g. It has been observed that Trial Fire has not been
utilized to the maximum extent possible by U.S. AAA units
now engaged in operations. Unit commanders must be continually
alert to use the advantages afforded by Trial Fire.
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h. From National Defense Research Committee, Applied
Mathematics Panel Report 22-IR "Analysis of Trial
Fire Methods" dated November 1944, the following recommendations
as to a lower and an upper limit for the deviation
of the center of burst (CB) from the trial shot point
(TSP) within which Trial Fire might be expected to improve
accuracy is given for information:
(1) The premise is made that the lower limit is based on
the consideration that Trial Fire is not warranted if accidental
errors are likely to be large enough to overshadow
those caused by faulty ballistic data. The upper limit is an
estimate for the greatest deviation which could be reasonably
expected from faulty ballistic data, gun dispersion, etc.,
so that any larger error observed should probably be attributed
to faulty setting of the gun and orientation.
(2) The recommended limits based on firing four shots
at a single TSP are as follows:
(n) No trial fire corrections are warranted if the observed
CB differs from the TSP bv less than 60 yards. in
slant range, 2 mils in elevation, an~1 1 mil in azim~th.
(b) If the observed CB differs from the TSP by more
than 275 yards, in slant range, 7 mils in elevation, or 10
mils in azimuth, the set up of the gun and fire control
equipment should be checked for serious errors before attempting
to make Trial Fire corrections.
5. Subject: 90mm Batteries in a Dual Role
Source: Headquarters, Seventh Army Antiaircraft Artillery
a. Ninety millimeter batteries firing on ground targets
has become SOP in all battalions in forward areas, but sometimes
the nature of the action is such that it is of a peculiar
interest. Such was the case of the 62d AAA Gun Bn commanded
by Lt. Colonel Adam S. Buynoski, in the tactical
positions occupied along the Rhine River when the Germans
crossed the Rhine and established the Gambsheim
Bridgehead north of Strasbourg. The front along the Rhine
was very lightly held at the time and the prompt and
effective fire of the 90mm guns was largely instrumental
in the bridgehead being contained.
b. Following is the battalion commander's narrative report
of the action: "At about 1030A hours on 5 January
1945, Battalion Headquarters of this unit was advised by
the 59th Armored FA Battalion that a 40-man German
patrol had penetrated into the Gambsheim area and was
then somewhere on the road to \Veyersheim, where Battery
A of this battalion was sited. Later reports, however,
located the Germans as still in the vicinity of Gambsheim,
b!lt in considerably more strength than was originally reported.
"This unit, which had been maintaining wire communication
with the FA, notified the 33d FA Brigade that we
had two AA batteries so sited that the entire bridgehead
area was within their fire possibility area.
"'At about 1300A hours the FA notified this battalion
that a cub plane would be made available to us for adjustment
of fire on a woods N\V of Gambsheim where a considerable
number of Germans had been reported. The FA
requested that 100 rounds be placed in the woods.
"Battery B was assigned the mission. Range was about
13,000 yards. The battery was instructed to fire all rounds
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