Figure 11-18. - Placing typical keylocks in a matting field.

incoming aircraft from engaging or hooking onto the edge of the runway. (See fig. 11-19.)

The aprons are constructed in a brickwork type of pattern but may be entirely of half-length mat units and extend across the full width of the runway. The free end of the apron should fall a distance of 18 to 24 inches below the normal ground level. The ground surface beneath each mat should be shaped to provide full contact across the bottom of the mat. After installation of the ramp, the excavation should be backfilled (ramp covered to the normal ground level). The backfill should be tamped and compacted.

Installation of the ramp at the starting end of the runway can be readily accomplished although the installation procedure is slightly different. Place the side connector under the overhanging lip of the first row of mats and lift until contact is made. The mat is then rotated downward while keeping the two mats in contact. Locking bars are installed as described previously.

MAT END RAMPS are used at the ends of the runways, laid on a hard surface (concrete), to smooth the passage from one surface to the other. The edge connection between the ramp and mat sections is the same as between two rows of matting. The ramp is fabricated from aluminum extrusions and is provided with welded inserts and extension plates, drilled and tapped to allow the ramp sections to be joined and anchored. (See fig. 11-20,)

When installing mat end ramps, you should use the following procedure:

1. Install the first ramp at the right-hand corner, looking toward the opposite end of the runway. Place the next ramp adjacent to it, ensuring that holes in the overlapping plate on the ramp line up with threaded inserts on the matting ramp. Insert five flathead screws in each ramp, using the Allen wrench provided in the toolbox. Apply antiseize compound to the screw threads.

2. Next, use the locking baron the edge between the ramps and edges of the mats to assure the alignment is straight.

3. As the ramps are placed and screwed together, drill holes in the concrete for lag screw shields, using the holes in each ramp as a template. Drill holes to 5/8-inch diameter and 3 inches deep with the drill bit from the toolbox. Insert an expansion shield in each hole drilled in the concrete. Insert a lag bolt and washer in each counterbored hole. Tighten the lag bolts with the offset, square box-end wrench provided in the toolbox.

4. Complete the end ramp installation, as shown in figure 11-21.

Mat-Laying Procedure with a Guide Rail

The sequence for installing AM-2 mats and related components where a guide rail for a catapult system is required is shown in figure 11-22. The guide rail divides the runway into an 18-foot and a 78-foot