PS Magazine - TB 43-PS-687
PS, The Preventative Maintenance Monthly
ISSUE 687
FEBRUARY 2010
39
PS 687
When troubleshooting a fault that includes
a message of “computer good,” don’t be too
quick to remove the AFCC. Most likely, the AFCC
is
not
the problem.
Too many mechanics are confused by the
fault tree of TM 11-1520-237-23 as they try to
isolate the actual fault.
The problem is, when the fault tree identi±es
the AFCC as the problem, mechanics then have
reduced con±dence in the “computer good”
message. So they treat the “computer good”
message as a computer fault.
Most people then remove the AFCC, and ship
it to depot for repair. When the depot tests it,
they ±nd the AFCC is fully operational as the
“computer good” message indicated. It should
never have been removed from the aircraft.
Many mechanics call this a false pull. False
pulls degrade Black Hawk performance and put
a strain on the supply system. If false pulls go
unchecked in the supply system, replacement
AFCCs become hard to get.
Mechanics, if the AFCC displays
“computer good” along with a
fault code, you must investigate
the fault and not
assume
the
AFCC is faulty. The only time
you remove the AFCC without
performing TM troubleshooting
is when the BIT test displays a
fault with a message that states
“replace computer”.
When there is a problem
with the AFCC, don’t turn in
one AFCC for another until you
have identi±ed the actual fault.
Rushing to replace an AFCC as
the quick ±x can actually increase
aircraft downtime.
UH-60 Series…
Haste
Makes
Waste
AH-64A/D…
Don’t Rush Gearbox Servicing
mechanics, the black hawk
automatic flight control
computers (afccs) are a
lot better than you think.
eliminate
all afcc
fault code
possibilities
when
trouble-
shooting.
if the
computer
says it’s
good, it’s
usually
good.
as a twist on an ole’ saying goes,
if it ain’t broke, don’t replace it!
don’t rush the after operation
servicing of your ah-64’s tail rotor,
intermediate and nose gearboxes!
time to
check your
gearboxes.
slow it down,
kemosabe!
you
need to wait until
they
cool off!
this AFCC
is going to
the depot.
not
so
fast!
if it doesn’t say
“replace computer”,
it’s usually a
false pull!
687.38-39.indd
1-2
12/28/09
10:08:07 AM
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