in. Return the ACQ TRK STOW switch to STOW.
Step n below is not necessary for HSS XM136
For HSS XM128 in an AH-1S(Mod) helicopter,
move the LOD 4 inches aft of the original position in
d and tighten the T-locks.
o. Slightly loosen the azimuth locking knob and the
elevation locking knob.
Do not lean or stand on the helicopter during
the operations below.
p. Rotate the LOD to approximately 90 degrees right
and insert the borescope.
q. View through the borescope and adjust the LOD in
azimuth and elevation until the intersection of the
crosshairs of the borescope reticle coincides with the
intersection of the crosshairs of the gunner's HSS target on
the right target.
r. Tighten the azimuth locking knob and the elevation
angle locking knob.
s. Being careful not to pull or push against the
borescope, in the LOD, recheck the alignment of step q.
Remove the borescope.
t. Hold the ACQ TRK STOW switch to ACQ.
u. The technician viewing through the TSU shall record
the elevation discrepancy between the TSU horizontal
Figure 4-7. Examples of pitch and roll
crosshair and the TSU optics target horizontal crosshair.
Return the ACQ TRK STOW switch to STOW.
v. Slightly loosen the azimuth locking knob and
z. If the total difference between the two TSU
elevation angle locking knob.
discrepancies exceeds 4 mils, readjust the helmet sight rails
as given in aa and ab.
w. Rotate the LOD approximately 180 degrees left and
aa. To eliminate the roll error (fig. 4-7), loosen the rol
insert the borescope.
adjustment locking screws (fig. 4-5) and readjust the rails
by turning both the fore and aft roll adjustment screws in
x. Repeat steps q through u for the gunner's HSS target
equal amounts in the proper direction, as-stated below:
on the left target.
(1) To raise the TSU LOS, sight through the
y. Review the two TSU elevation discrepancies to
orescope and, using the roll adjustment screws, lower t h e
determine if roll misalignment exists (see fig. 4-7, step A).