Eagle ICA-D212-725, Instructions Manual

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ICA-D212-725 (63)
Page 120 of 144
CHAPTER 63 – MAIN ROTOR DRIVE SYSTEM (63-00-00)

COPYRIGHT

2007 BY DART AEROSPACE LTD.

THIS DOCUMENT IS PRIVATE AND CONFIDENTIAL AND IS SUPPLIED ON THE EXPRESS CONDITION THAT IT IS NOT TO BE USED FOR ANY PURPOSE OR COPIED OR COMMUNICATED TO ANY
OTHER PERSON WITHOUT WRITTEN PERMISSION FROM DART AEROSPACE LTD.
Revision:
6
Date: 13.08.26
63.9 TRANSMISSION MOUNTS
63.9.1 Pylon
Mounts
Five vibration isolating mounts located on the
support structure of the fuselage (Figure 63-53)
are provided to mount the transmission. A special
bolt is used to secure transmission to mounts.
63.9.2 Maintenance
63.9.2.1 Removal
63.9.2.1.1
Remove transmission assembly
(paragraph 63.4.5.1). Components need not be
removed from transmission mast if only pylon
mounts are going to be removed.
63.9.2.1.2
Detach each of four main mounts
from pylon support by removing four bolts and
washers from mount flange. On each of two rear
mounts: Either disconnect friction damper (11,
Figure 63-53), lower end fork from fitting (14) in
pylon support to allow damper to be removed with
mount assembly; or disconnect upper end of
damper from lower end of mount bolt to allow
damper to remain in pylon support.
63.9.2.1.3
Lift each main mount assembly
from pylon support, including mount bolt (with
dampers on rear mounts, if left attached). Tag
filler plates (10 and 16) for forward or rear
locations. Separate upper and lower bushings (17
and 20), boots (19), and bolts (15) from mounts
(18).
63.9.2.1.4
Detach fifth mount (5) from fifth
mount support (1) by cutting Iockwire and
removing four bolts and washers from mount
flange. Lift out mount assembly. Tag laminated
filler plates (6) for location.
63.9.2.1.5
Remove cotter pin and nut from
fifth mount eyebolt (2). Separate retaining washer,
mount (5), boot (4), and upper washer (3) from
eye bolt (2).
63.9.2.1.6
Detach fifth mount support (1)
from pylon support by removing four bolts and
washers at each end. Leave fillers bonded to
pylon support.
63.9.2.2 Inspection
63.9.2.2.1 Replace
pylon mounts, (5, 9, and
18, Figure 63-53) under following conditions.
63.9.2.2.1.1
When excessive vibrations in flight
operation are believed to indicate mounts no
longer have correct spring rate to isolate normal
pylon vibrations.
63.9.2.2.1.2
When rubber-to-metal bond has
separated deeper than raised rubber fillets at inner
and outer metal sleeves.
63.9.2.2.2
Replace any damaged boots.
63.9.2.2.3
Replace mount bolts (2 or 15),
bushings (17 and 20), or washer (3) for any
indication of cracks, or when unserviceable due to
wear, scoring, or other surface damage.
63.9.2.2.4
Replace friction dampers (11) for
any evidence of malfunction. After a hard landing,
perform Conditional Inspection as required
(Chapter 5).
63.9.2.2.5 Perform
spring rate check as
follows:
63.9.2.2.5.1 Fabricate
a steel support sleeve,
and pressing button workaids, Figure 63-54. Top
and bottom of the sleeve must be square in
relation to sides so mount will be deflected in
vertical plane only.
63.9.2.2.5.2
Place mount, long end down, into
support sleeve workaid.
63.9.2.2.5.3
Place support and mount into a
suitable arbor press (pressure gage of arbor press
should be marked in five pound graduations and
have a range of 0 to 1500 lbs. (0 to 4448 N).
63.9.2.2.5.4
Center pressing button workaid
over inner sleeve of mount.
63.9.2.2.5.5 Apply pressure to bottom and