NAVFAC P-300 Management of Transportation Equipment

42.5 Maintenance Program Evaluation
a. Maintenance Guidelines. An activity’s maintenance program should be
continually evaluated to ensure that it is effective. Guidelines and tools for program
evaluation that the Maintenance Supervisor may use are listed below.
(1)
Mechanic-to-Equipment Ratio. The ratio indicates the number of
mechanics assigned compared to the number of vehicles assigned to a location. In
addition to all the mechanics assigned to the shop, the title “mechanic” in this ratio
includes all administrative and supervisory maintenance personnel and any personnel
assigned to work with the mechanics, such as steelworkers, machinery repairmen, and
electricians. The ratios can be used as a general yardstick to determine if additional
mechanics may be required to maintain the unit’s equipment adequately. Obviously
many factors such as training, experience, environment, and equipment condition will
cause the optimum ratio to vary. However, experience shows that the ratio should
average approximately one mechanic to five pieces of equipment at each location. One
way to improve the on-site mechanic to equipment ratio is through the use of the live
storage program (see Appendix N).
(2)
PM-to-Repair Ratio. This ratio shows the number of scheduled
maintenance actions performed compared to unscheduled maintenance actions
(interim repairs). The ratio can be used as a primary indicator of the effectiveness of a
unit’s preventive maintenance program. The PM Clerk can compute the PM-to-repair
ratio from the ERO log. Ideally there should be many more PMs performed than interim
repairs. Experience indicates that a unit, operating on a 40-day PM schedule, should
average approximately three scheduled PM inspections to each interim repair: a ratio
of three to one. If the ratio drops below three to one, the preventive maintenance
program should be reviewed for the following problems: inadequate scheduling, not
adhering to the schedule, not performing the proper depth of PM, and inadequate shop
quality control. The closer the ratio comes to one to one, the more ineffective the PM
program becomes.
(3)
Equipment Availability. Equipment availability is the percentage
that shows the time the equipment is available to be dispatched as compared to
downtime. Equipment downtime is figured on a 24-hour, 7-day-week basis. Equipment
availability of a unit at 90 percent is considered excellent, 85 percent is good, 80
percent is fair, and 75 percent is poor. Equipment with a fair availability record should
be analyzed to determine the cause, such as overwork or abuse, inadequate COSAL
(Consolidated Seabee Allowance List) or supply support, or shortage of mechanics.
b. Maintenance Schedule. Ensure that all vehicles receive maintenance. If
the shop is on a 40-day PM schedule each vehicle should receive maintenance about
once every 8 weeks. Frequently check to ensure that all vehicles are on the PM
schedule and that the schedule is being followed.
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