JOB SITE MANAGEMENT - CONTINUED
LAND PLANING OPERATIONS - CONTINUED
(2) On a hard, smooth surface, the cutting edge is lowered to the lowest possible setting: cutting edge is on the same
plane as the wheels of the tractor and scraper.
When land planing, the operator should only carry enough material to fill in the low spots.
Land Planing Operations.
The first pass should be in the longitudinal dimension of the work site: this is the direction of travel anticipated/
required by the machines that will be using the horizontal surface.
Lower cutting edge to level of wheels.
Travel in 1st gear.
Note that machine tires compact ground with each overlapping pass.
Overlap subsequent passes with a 50% overlap until planing in longitudinal direction is complete.
After longitudinal direction is complete, repeat operation at a 45-degree angle.
After land planing in 45-degree direction is com-
plete, repeat operation in a cross pattern as shown.
Ground planing operations may be conducted with a full scraper bowl to combine finishing and compaction.
A fully loaded 621B Scraper weighs almost 112,000 lb (50,802 kg) or 28,000 lb (12,700 kg) per tire. Due to its weight, it
may be used as an effective tool on any job site for deep compaction of up to 12 in. (30 cm) of the surface.
Compaction involves taking advantage of the machine's weight by distributing wheel loads over a large area.
Compacted soil has greater bearing strength and drains better. Compaction provides a suitable surface for follow-on
machines, landing zones, expedient airfields, etc.