If the A-frame is not horizontal, the bridge modules will run at an angle making further
module connection difficult and will accelerate the wear of the bridge wear pads when the
bridge is boomed.
Check the level gauge on the lower A-frame cross member to confirm the A-frame is
level, check that the A-Frame pin height is set within the correct range of pin holes as
specified in Chapter 1 Section II Tables 1.8, 1.9 or 1.10.
Check the longitudinal slope of the slide frame to ensure that the slide frame is slightly
angled either positively or negatively. If the slide frame is horizontal raise or lower the
A-frame dependent on the ground slope to create a positive or negative slope on the
If the A-frame is not level or within the specified hole range, at the A-frame controls on
the centerline on the rear face of the A-frame cross member, extend the low side of
the A-frame until the spirit level on the lower A-frame transverse beam indicates the
A-frame is horizontal and within the required hole range.
Move the locking pin and the R clip to secure the stabilizer leg in position and retain
the A-frame horizontal. Make sure the slide frame remains clear of the launch vehicle
At the A-frame controls on the centerline on the rear face of the A-frame cross
member, lower the A-frame stabilizer leg until it sits on the locking pins.