**AFM 91-19 / TM 5-629 / NAVFAC MO-314**

**24 May 1989**

**45**

operator cost computed on line 3g is $12,290.98

round-trip distance of 6 miles, yielding a total of

(1,066 hours x $11.53 per hour) for the tractor

408 miles on line 4c. A cost of $0.35 per mile

mower and $5,099.70 for the riding mower.

for the truck, multiplied by the 408 miles, gives

Operator costs for the 21-inch power mower and

us a cost of $142.80, which is entered on line 4e.

the weedeater are computed similarly.

(c) The truck drivers will spend about an

hour driving over to pick up the riding mowers,

(c) The cost of providing a supervisor is

waiting as they are loaded, driving them to the

calculated on lines 3h, 3i, and 3j. In this case, it

site, and returning. This 1 hour figure is shown

is assumed that one supervisor will handle all

on line 4f. This figure is multiplied by the

four operations on a full-time basis and that the

number of round-trips (line 4a), and the result,

job will take 2 weeks to complete. The supervi-

68, is entered on line 4g. The truck drivers are

sor is a WS-6, and document A (figure 6-1)

WG-4s, with a composite pay rate of $11.53 per

indicates this wage to be $16.87 per hour. The

hour, as shown by document A (figure 6-1).

80-hour work period costs $1,349.60 for the

This figure is entered on line 4h. The total driver

supervisor, as shown on line 3j. The supervisor

cost of $784.04 (68 hours x $11.53 per hour) is

cost and operator costs are combined in the total

entered on line 4i. The transportation costs for

column to produce a total labor cost of

the 21-inch power mowers and the weedeaters

$28.943.00 on line 3k.

are computed similarly. There is no driver cost

(3) Transportation Costs:

for the tractor mowers since their time spent

(a) The tractor mower is driven to the

driving to and from the site was accounted for

site by its operator. Line 3d indicates that it

earlier in their nonproductive time. Transporta-

must be driven to the work site 133 times, and

tion costs are totaled on line 4j.

this is entered on line 4a. In 133 trips, it is

(4) Total Cost. The total mowing cost of

driven 798 miles, and at 10 miles an hour this

$53,928.91 is shown on line 5f.

takes 79.8 hours. Document B (figure 6-2)

d. The completed document C for applying a

shows that the tractor operating cost is $18.46

PGR in our example is shown in figure 6-4. The

per hour, so the 79.8 hours spent traveling to

calculations are made in the same way as for the

and from the site incurs a cost of $1,473.11,

other operations. The cost of the PGR (and

which is entered on line 4e.

herbicides, if needed) is calculated under line 2.

It is the dominant cost factor in the spraying

(b) The calculations for those operations

requiring trucks to transport workers and equip-

operation.

(1) The gallons per acre are, in our exam-

ment to the site are somewhat different. The

trucks are assumed to take them to the work site

ple, a combined PGR and herbicide. (The two

could be calculated separately, if they were

in the morning and to pick them up in the

applied that way.) In this case, a gallon covers 5

afternoon. Therefore, the trucks make two

round trips each day. The riding mowers need

acres, so only 0.2 gallons are required per acre

67 mower-days to do the job (line 3d) and thus

(line 2a). The cost of the combined agents is

require 34 truck-days since each truck transports

estimated at $78.00 per gallon (line 2b), and the

operation is to cover the total area of 2300 acres

2 riding mowers. At 2 round-trips per truck per

(line 2c). The total chemical cost on line 2d is

day, 68 total round-trips are required. This is

entered on line 4a. Line 4b shows an average

the product of lines 2a, 2b, and 2c.

**DOCUMENT C**

**Cost of Grounds Maintenance Operations**

Date: 08/03/84

Place: Air Base Somewhere

Location: Runways and Taxiways

Runway

Type of area:

Areas

**Figure 6-4. Cost of PGR Application for "Air Base Somewhere."**