PS Magazine - TB 43-PS-679
PS, The Preventative Maintenance Monthly
ISSUE 679
JUNE 2009
38
PS 679
JUN 09
39
PS 679
JUN 09
The bracket can be used with both the old
and new high speed shafts and must be used
with the Black Hawk AVA script Fle
UH_60
75 version 7.5f
or higher.
The bracket holds the optical rpm sensor
for the high speed shaft balance procedure.
Engine high speed shaft balance procedures
must
be
completed
following
repair,
replacement, and or reinstallation of the high
speed shaft assembly. ±ollow the balancing
procedures in WP 0069 00 of TM 1-6625-724-
13&P.
Also, engine high speed shaft balance
must be done if the 120-hour vibration check
shows the No. 1 or No. 2 engine vibration
levels above the limit of 0.50 inches per
second (ips).
Engine high speed shaft balance procedures must be exact and the Fnal vibration
level must not be above 0.50 ips. If the aircraft is flown with vibration levels over the
limit, premature failure of the high speed drive shaft assembly can result.
The
four
antennas
should
be
inspected for paint, fuel, dirt and
damage to the radome. Look for broken
or missing mounting screws on the
antennas. Sometimes you remove them
to inspect the connections as a part of
your troubleshooting procedures.
If you torque the connector more
than 8 lb-in when installing it, you can
kiss it goodbye because it
will
break.
The extra torque on the connector ruins
the wire. Since 8 lb-in is not a lot, Fnger
tight is good enough.
Tight As
Can Be
UH-60
Series…
Drive Shaft Bracket
All Aircraft…
Tight As
Can Be
looks like we’ve
got to do a
shaft balance.
ok, I’ll get
that new
bracket.
New optical bracket MUST
be used with current UH-60
Script File Version 7.5f
mechanics, the connector
on the an/apr-39 radar
warning antennas on your
helicopters requires a
certain torque.
any more than
8 lb-in and
you’ve got
trouble.
so keep
the radar
warning
antennas
detecting
incoming
missiles by
not
over-
tightening.
Do not
over-tighten
connector nut
mechanics, there
is a new aviation
vibration analyzer
(ava) bracket, nsn
use it when balancing
your black hawk’s high
speed shafts.
679.38-39.indd
1-2
5/5/09
4:15:13 PM
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