INSTALL HORIZONTAL HINGE PIN, PITCH-VARYING HOUSING, AND PIN
These are installation critical flight
safety parts. All aspects of their
assembly and installation must be
Ensure that specified installation tools
are used to preclude damage to lugs.
Ensure that lugs are heated to
specified temperature to ease
installation and minimize chances of
Ensure that the proper bearing is
installed in the appropriate lug. Lead
lug and lag lug take different bearings.
Ensure that pitch housing to be
installed is the same pitch housing
that was removed. Installation of
replacement pitch housings is not
permitted at this level.
Ensure that all rollers are in the cages
of the pitch bearings.
Ensure that the tie-bar pins are
installed and properly seated and
that the correct retention hardware is
installed and tightened to the proper
Procedure is similar to install any
horizontal hinge pin, pitch-varying
housing, and bearing assembly. There
are three horizontal hinge pins, six
pin bearings, and three pitch-varying
housings on a rotary-wing head.
Forward head is shown here.
When installing new lead and lag
horizontal hinge pin bearing, use the
preferred bearings 114RS225-1 (lead)
and 114RS226-1 (lag).
INSTALL HORIZONTAL HINGE PIN BEARINGS
Horizontal hinge pins with serial
numbers of UW2407 and prior that do
not have a suffix "A" vibro engraved
after the serial number and with total
time since new of 4800 flight hours
or more must be replaced.
Heat lugs (1 and 2) to 250 F (121 C). Use heat
gun. Monitor temperature. Use temperature
indicating strips (E413). Wear gloves (E187).