PS Magazine - TB 43-PS-636
PS, The Preventative Maintenance Monthly
ISSUE 636
NOVEMBER 2005
The term itself, variance, means this policy is for situations beyond usual prac-
tice. The Army doesn’t want scheduled services done too early—that would result in
waste because parts and lubricants would be disposed of before they have to be. But,
the Army doesn’t want scheduled services delayed too long. That increases wear on
equipment, exposes systems to costly, preventable breakdowns and soldiers to pos-
sible injury.
However, the Army recognizes that mission schedules may not always allow a
service to be done on the day it is scheduled. So DA Pam 750-8 allows units a 10-
percent variance when missions interfere with scheduled service dates. The variance
is an
exception
to normal unit maintenance. The service should be accomplished as
close to the scheduled service date as possible.
Some equipment is not authorized a variance because the service is considered
too critical. Check your TM PMCS table to find any restrictions.
Calculating the Variance
Scheduled services may be based upon days, rounds, miles or hours. The TMs
specify which interval to use. The method of figuring the variance is the same.
It’s important to note that the variance can be as much as 10-percent ahead of
schedule to as late as 10-percent after schedule.
For a semiannual service, multiply 180 days by 10 percent. The result allows 18
days variance from the scheduled date.
Applying the Variance
Mark the semiannual scheduled service date on a calendar. Let’s say the sched-
uled service date is 17 Apr 06.
1.
Count off 18 calendar days before 17 Apr, the scheduled semiannual date. The
variance begins on 30 Mar 06.
2.
Count off 18 calendar days after 17 Apr. The variance ends on 5 May 06.
DA Pam 750-8 allows the 10-percent variance before or after the scheduled serv-
ice date. Services done within this variance window are considered done on time.
Combining Scheduled Services
Sometimes quarterly, semiannual and annual services come due at nearly the
same time. To save time and manpower, some units decide to do these services at the
same time.
However, combining services does not affect the actual service due date for any
of the scheduled services.
Quarterly services have shorter variances than semiannuals, and semiannuals
have shorter variances than annuals. So when combining services, do the shorter
variance first, quarterly followed by semiannual and then annual.
That way if your mechanic is interrupted in doing the services more
of the most pressing service will be completed.
PS 636
NOV 05
58
don’t sweat
it! you’re still
in the
grace
period.
what
does
variance
mean,
anyway?
read
on!
all
shall be
revealed.
am I in
trouble?
you
can
put
all your eggs
into one basket
when it comes
to
scheduled
services!
do me
first!
my annual service
was due
last week
.
636.58-59(C).qxd
9/29/05
5:03 PM
Page 1
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