PS Magazine - TB 43-PS-705
PS, The Preventative Maintenance Monthly
ISSUE 705
AUGUST 2011
20
PS 705
AUG 11
21
PS 705
AUG 11
D
rivers, make sure your MRAP M-ATV’s battery disconnect switch is turned off
after the day’s run.
If the switch is left on, the
batteries can lose their charge in
just a week or two. No juice means
your M-ATV needs a slave start—or
you’ll be going nowhere!
Whatever you do, though, don’t
use the switch to turn off your
vehicle. That’s what the engine
ignition switch is for. If you do use
the battery disconnect switch to
shut down, you’ll fry your MRAP’s
electrical circuits!
And make sure you let the vehicle
idle at 800-1,000 rpms for 3 minutes
with the transmission in neutral
before shutdown. That allows the
turbocharger to slow down and cool
off. You’ll Fnd that info in WP 0021
of TM 9-2355-335-10 (Oct 09).
By the way, when the battery disconnect switch is turned off, battery power is
retained for about 30 seconds. That provides enough time for the vehicle’s electronics
to shut down properly.
± Always±use±a±work±stand,±a±work±platform±or±aircraft±step±areas±for±your±feet.±That±way,±
you±avoid±breaking±the±engine’s±temperature±bulb,±alternator±connector,±starter±speed±
sensor±wiring,±bleed±air±tube±and±the±hydromechanical±unit±(HMU).±If±you±step±on±the±HMU,±
you±can±break±the±shaft±that±goes±into±the±accessory±gearbox,±including±the±spline.±When±
your±feet±contact±the±engine,±that±puts±the±fuel±line±at±risk,±too.±
± You±may±not±notice±that±damage±
has±
occurred,±
but±
the±
internal±
connections±and±wiring±to±the±starter±
speed±sensor±will±let±you±know.±For±
example,± the± starter± will± not± sense±
the±engine±speed±and±won’t±shut±off±
after± the± engine± reaches± optimum±
speed.± So± the± pilot± has± to± shut± off±
the±starter±manually.
± The± only± thing± your± feet± can±
cause±when±stepping±on±an±engine±
is±defeat.±So±watch±your±step.
M-ATV±
MRAP…
Going Nowhere?
AH-64/UH-60±Series…
Don’t Be
Defeated
by the Feet
Use±driver’s±
side±door±
caution±
label±as±
reminder±of±
shutdown±
sequence
Engine±is±a
no step zone
Don’t±turn±battery±disconnect±switch±to±OFF±
until±after±turning±off±engine±ignition±switch
I’m
feeling
a bit run
down.
I forgot
to turn off
the battery
disconnect
switch again!
o
h, no
o
o
!
mechanics,
there comes
a time when
everyone
learns to
appreciate
his aircraft’s
step areas.
but it doesn’t
have to be
after
you
hear
snap,
crack
and
pop
from engine
components
that couldn’t
take your
weight.
705 20-21.indd
1-2
7/5/11
5:08 PM
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