Road construction and airfield construction have much in common, such as construction methods, equipment used, and sequence of operations. Each road or airfield requires a subgrade, base course, and surface course. The methods of cutting and falling, grading and compacting, and surfacing are all similar. As with roads, the responsibility for designing and laying out lies with the same person-the engineering officer. Again, as previously said for roads, you can expect involvement when airfield projects occur. In this section, you will be introduced to airfields and airfield terminology. More information on airfields will be discussed in a later chapter of this TRAMAN.

Figure 3-14 is a plan view of a small advanced-base airfield. Afield of this type is constructed for operational use in a combat area. It contains a minimum of servicing facilities and is not intended for permanent occupancy. Some of the terms shown in the figure are defined as follows:

APPROACH ZONE. A trapezoidal area established at each end of a runway. The approach zone must be free of obstructions on the plane of a specific glide angle. (See fig. 3-15.)

APRON. A stabilized, paved or metal-plank surface area, designed for the temporary parking of aircraft

Figure 3-16.Typical flexible pavement and terminology.

other than at hardstands. Aprons are classified as service, warm-up, and parking.

END ZONE. A cleared and graded area that extends beyond each end of the runway. The dimensions of the end zone depend upon the safety clearances specified by the design criteria for advanced-base airfields. (See fig. 3-15.)

GLIDE ANGLE. The angle between the flight path of an airplane during a glide for landing or takeoff and a horizontal plane fixed relative to the runway. The glide angle is measured from the outer edge of the end zone. (See fig. 3-15.)

HARDSTAND. A stabilized, paved, or metal-plank- surfaced parking area of sufficient size and strenght tp accomodate a limited number of aircraft. Handstands are usually dispersed over the ground area beyond the safety clearance zones of a landing strip. They provide protection for aircraft on the field by dispersal, concealment, and revetment

LANDING AREA. The paved portion, or runaway, of the landing field. The landing area should have unobstructed approaches and should be suitable for the safe landing and takeoff of aircraft under ordinary weather conditions.

LANDING STRIP. Includes the landing area, end zones, shoulders, and cleared areas.

REVETMENT. A protective pen usually made by excavating into the side of a hill or by constructing earth, timber, sandbag, or masonry traverse around the hardstands. Such pens provide protection against bomb fragments from high-altitude bombing but provide little protection against ground strafing. They may actually draw this type of fire if they are not well concealed.

RUNWAY. That portion of the landing strip, usually paved, that is used for the landing and takeoff of aircraft.

SHOULDER. The graded and stabilized area adjacent to the runway or taxiway. Although it is made capable of supporting aircraft and auxiliary equipment (such as crash trucks) in emergencies, its principal function is to facilitate surface drainage.

TAXIWAY. A specially prepared area over which aircraft may taxi to and from the landing area.

TRANSITION SURFACE. A sloping plane surface (about 1 foot rise to 7 feet run) at the edge of a landing strip. Its function is to provide lateral safety clearances for planes that accidental] y run off the strip. (See fig. 3-15.)