TM 55-6610-247-40
i. Replace third pointer (18) with a suitable pointer
2-12. Closing and Sealing.
replacing tool. Replace intermediate pointer (17) in the
Close and seal as follows:
same manner as described for small pointer. Press large
a. Replace gear assembly (31. figure 2-1) meshing it
pointer (16) on hand staff so it indicates same altitude as
with idler gear (46). Replace cluster spur gear (30)
master when barometric scale is set to indicate existing
further from adjustment pinion. Replace gear assembly
barometric pressure.
(29) that meshes with pinion (43).
j. With suitable adjustment knob, turn mechanism so
b. Replace gear (28). Replace dial assembly (27)
the large pointer indicates 0. Intermediate and small
aligning reading 29.92 with rivet hole at right of top plate.
pointers should also indicate exactly 0. With finger,
Replace shutter (26) locating lips of shutter in slots of
move large pointer 90 clockwise. This should put
setting mark gear.
c. Replace dial (23) aligning rivet holes with holes in
intermediate pointer in such a position that small pointer
top plate and hold it temporarily in place b. inserting a
is barely visible along outside edge. Repeat procedure by
moving large pointer 90 counterclockwise from 0 and
toothpick in each hole. with dial held in this position,
insure inner setting mark indicates 0 and barometric dial
note position of pointers. Position should be the same as
indicates 29.92 "reference mark on dial. If inner setting
above but on opposite side. If above conditions do not
marker barometric dial is not in its correct position. dial
exist. pointer which is out of position may be shifted with
(23) must be removed and mark or barometric dial
a toothpick to desired position. Turn mechanism back to
positioned correctly.
its original position.
d. Remote one toothpick at a time. And secure outer
k. Insure pointers do not interfere with each other
dial to top plate with pins (29).
and that large hand will clear glass.
e. Replace third hand hub and wheel assembly,
l. Replace gasket (15, figure 2-1) window dial (14),
meshing it with intermediate pinion.
and washer (13). Replace shim (12), spring (11), and
f. Place shim (25) on third hand hub and wheel
washer (10) on knob stern. Replace mounting flange (9)
assembly. Replace spacer (24) and dial (23), and secure
and secure it with lockwasher (8) and screws (5, 6, and
it with dial screws (21).
7).
g. Deleted.
NOTE
If the altimeter has not been previously
modified to a "D" configuration, install
Figure 2-11. Deleted
new pointers (16, 17, and 18), and dial
h. Replace ring assembly gasket (19).
(23) with part numbers as listed in the
I.P.B.
m. Replace nut (2) and adjust knob (1). Lightly tap
instrument glass to remove friction Check barometric
pressure and compare it with that read front a station
barometer If necessary to adjust barometric dial, pull
adjustment knob forward and while holding it in this
position turn it to reset barometric dial. When desired
barometric pressure is indicated, release knob.
n. Insert locking stud (4) into case so it ride in recess
of knob stem. Secure locking stud with screw (3).
2-13. Leak Check.
Check for leaks as follows:
a. Connect rubber tubing to static connection and
apply suction sufficient to produce a change in reading of
approximately 18,000 feet. At this point, clamp off tubing
and note any change in reading. Over a period of
minute, pointer should not move more than 100 feet.
b. If a leak is apparent , return altimeter to
Change 5 2-17
