PS Magazine - TB 43-PS-580
PS, The Preventative Maintenance Monthly
ISSUE 580
MARCH 2001
PS 580
53
PS 580
MAR 01
52
10 Percent Variance
The Scoop on the
Dear Half-Mast,
There’s a lot of confusion in
Army maintenance shops these days
about the 10 percent maintenance
variance window. Some units use it
as the standard rather than the
exception it is intended to be.
Everybody seems to have their
own way to calculate and apply it.
Then it’s Confusion City when you
try to figure out how to use it
when you piggyback services to
save time and manpower.
Finally, many units don’t know
how to report equipment when
services go into an overdue status.
Can you shed some light for me
on the variance rule for completing
scheduled maintenance?
CW2 R. D.
Calculating the Variance
Calculate the variance by multiplying
the scheduled service time by 10 per-
cent. For a semiannual service (180
days), multiply 180 days by 10 percent.
The variance equals 18 days. Some
scheduled services use rounds, miles or
hours instead of days. No problem. Just
substitute rounds, miles or hours for
days and multiply by 10 percent.
The variance is authorized by Para
3-3b(1)(h)1 of DA Pam 738-750. Its
purpose is to give you time before and
after a service is scheduled so that you
have time to accomplish the mission
and still get the service done on time.
Of course, you should always try to
do scheduled services on time and use
the variance as an
exception
when
missions get in the way. And, always
check out your TM before you use the
variance. Some services can’t use the
variance because time is too critical.
For example, Item 19 of Table 2-1 in
TM 9-1425-646-20, states “Interval:
Annual. MLRS system is Not Mission
Capable if: Safety load test date has
expired.”
FREQUENCY:
IN DAYS:
(TIMES)
10% VARIANCE
MULTIPLIER
AUTHORIZED
VARIANCE (IN DAYS)
Quarterly
90
X
.10
9
Semiannual
180
X
.10
18
Annual
360
X
.10
36
SCHEDULED SERVICE
When you know the variance, get out
your calendar and do the following:
1. Determine the scheduled service
date. Let’s say the scheduled service
date is 12 Feb 01.
2. Apply the variance (18 days for
our semiannual service) as follows:
* Back off the scheduled service
date (12 Feb 01) by 18 days. The vari-
ance start date, then, is 25 Jan 01.
* Add 18 days to the scheduled
service date (12 Feb 01). The variance
close date is 2 Mar 01.
The 10 percent variance window for
this semiannual service is 25 Jan 01
through 2 Mar 01. Services done with-
in this window are considered done on
time.
Applying the Variance
Applying variance window
for a semiannual service:
scheduled for 12 Feb
The top Army maintenance experts knew that missions would sometimes get
in the way of pulling all scheduled PM on time. So they approved a 10 percent
variance to help you out.
The Variance Is Authorized!
Maintenance Management …
580. 52-55 (C)
1/29/01
10:33 PM
Page 1
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