fasten the other end to the hole at the bottom back area of
b. Remove the two screws (also not shown in figure 5-1)
the helmet, using the screw, washer, and nut removed in
at the pilot holes on the helmet. Each screw secures a head
c. Drill out strap-tab holes with a number 12 drill bit.
d. Remove the two visor guides from the helmet by
removing the screw from the center of each guide.
Be sure not to overtighten the holding device.
Turn the clamp only enough to insure that the
rubber pieces in the back of the helmet are snug
against the helmet and the helmet sight
assembly is firmly in place.
In step e below, be extremely careful not to
m. Adjust the holding device to pull the back of the
change the existing centerline of any of the
helmet sight assembly firmly into place.
four holes. Be sure to use a hand drill, not an
n. Repeat step j. This measurement must still be 1/4
inch or less.
e. Install a number 12 bit in a tap handle or hand chuck
and use this tool to hand-drill out the top and bottom holes
o. Place the helmet on an operator's head and fasten the
in each of the two visor guides.
chin strap. Insure that the internal webbing is adjusted so
that the earpieces are comfortable.
f. Using the screws removed in d above, reinstall the
visor guides on the helmet.
p. Perform the boresighting procedures in Chapter 2,
Section HI, or paragraph 4-16c and subsequent to verify
g. Turn the visor 90 degrees to the helmet sight
that the new helmet and the new helmet sight assembly are
assembly and slide the visor over the visor nut. Turn the
visor back to the original position (horizontal), and secure
the visor to the helmet sight assembly with the visor-lock
q. After successfully completing the boresighting
spacer, visor-lock washer, visor lock, and visor-lock screw.
procedures, remove the helmet from the operator's head.
h. Secure the front of the helmet sight assembly and the
r. Hold the helmet-sight-assembly strap tabs snugly
nylon gaskets to the helmet with four threaded pins, using
against the helmet and mark the location of the helmet
the two longest threaded pins (6, fig. B-2) in the two
pilot holes on the tabs. (Mark from the inside of the
bottom holes and the two next-to-longest threaded pins (7)
in the two top holes. Using your fingers only, install the flat
washers and pin collars on the threaded pins. (Pin collars
s. Adjust the holding device to the near maximum
should be only tight enough to hold the pins at this time.)
length. Then remove the holding device by removing the
screw, washer, and nut; replace the screw, washer, and nut
i. Loosen the visor lock and check for free up and down
that secured the holding device in the helmet.
movement of the visor.
t. Leaving the threaded pins in place, remove the pin
j. Measure vertically from the front center edge of the
collars installed in h above and remove the helmet sight
helmet sight assembly to the lower edge of the helmet. This
distance must not be more than 1/4 inch.
u. Center-punch the holes marked in r. Then, with a
k. From the rear center of the helmet, remove the
number 12 hand drill, drill holes through the pilot holes
screw, washer, and nut that will be used to secure the
and through the heimet-sight-assembly strap tabs. Hold the
back straps firmly.
v. Reinstall the helmet sight assembly with the pin
l. Adjust the holding device to near maximum length.
collars removed in t above.
Place the loop over the magnetic linkage receptacle and