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This chapter provides information on the characteristics of common military aircraft, the design of military airfields, and the interrelation of the two. The design criteria for each military airfield must be formulated individually to satisfy its specific set of operational requirements. The final airfield design must meet the design requirements for the given aircraft and airfield type, allow safe aircraft operations, and be approved by the user. Local conditions and future operations may limit the dimensions of runways and taxiways, their orientation concerning wind, and the treatment of their surfaces. Also exercise practical judgment in the provision for protection and maintenance facilities, the installation of aids to navigation, and the construction of parking areas and storage facilities for fuel and ammunition.


The airfield design criteria and layouts in this chapter are based on usage by specific aircraft in relative location on the battlefield. The most demanding characteristics of the using aircraft establish the controlling aircraft. Less critical category types of aircraft also may use these facilities. More critical category types may use these facilities only under special limitations. Tables 11-1 and 11-2 show the important characteristics of selected Air Force and Army aircraft.


The primary air field complex has three specific types of airfields. As Indicated by its name and anticipated life, each airfield is included in the complex for a specific purpose, and their design criteria are based on requirements for the aircraft shown in Table 11-3. Note that each type airfield has a controlling aircraft that will ultimately determine the length of the runway (described in this chapter) and the thickness of pavements, subbase, and subgrade (discussed in Chapter 12).

Besides the three primary air fields, there are several special airfields (including DZs, EZs, blocked-out airfields, special operations forces (SOF) airfields, and unmanned aerial vehicle (UAV) airfields) described in detail later in this chapter. Table 11-3 details the requirement for the three primary airfields.

The Army airfield classification system for TO construction is the same as the Air Force airfield classification system. As described in Chapter 10, airfields are constructed to one of two standards showing the expected life of the airfield. Initial construction airfields are for short-term use (zero to six months) and include close battle area and rear area airfields. Temporary construction airfields are for long-term use (6 to 24 months) and include COMMZ airfields. Permanent airfield construction is discussed in detail in TM 5-800 series publications.


Army and Air Force staff engineers acting for the Joint Force Commander determine base airfield criteria for a specific TO, and they base criteria on local conditions.

Table 11-3 shows the controlling characteristics and geometric and minimum area requirements for each airfield. The key to a proper airfield design is the thoroughness and accuracy of a topographic survey with minimum 5-foot contour intervals. (See Appendix C, FM 5-430-00-1/AFPAM 32-8013, Vol 1, for information on subgrade strength requirements.)


Figures 11-1, 11-2, 11-3, and 11-4 show typical layouts and section views applicable to TO airfields. Figure 11-1 shows the basic airfield layout. For example, to find the geometric requirements for a support area airfield, enter Table 11-3 at the applicable airfield type in column 1, then read horizontally across the table under the various column headings to obtain the required dimensions (geometric requirements).

The circled numbers referring to the various elements of the airfield shown in Figures 11-1 through 11-4 identify the column numbers in Table 11-3, which give the geometric requirements for each element. Use of these figures with the table determines the specific airfield geometric requirements for each critical aircraft in each military area (close battle, support, and rear), as applicable.


The elements that make up the airfield include runways, taxiways, aprons, and hardstands. These elements usually consist of pavement placed on a stabilized or compacted subgrade, shoulders and clear zones (normally composed of constructed in-place materials), and approach and lateral safety zones (which require only clearing and removing obstructions that project above the prescribed glide and safety angles). The nomenclature for these elements is defined below and shown in Figures 11-1 through 11-4.


Runway location, length, and alignment are the foremost design criteria in any airfield plan. The major factors that influence these three criteria are--

  • Type of using aircraft.
  • Local climate.
  • Prevailing winds.
  • Topography (drainage, earthwork, and clearing).


Select the site using the runway as the feature foremost in mind. Also consider topography, prevailing wind, type of soil, drainage characteristics. and the amount of clearing and earthwork necessary when selecting the site. (See Chapter 2, FM 5-430-00-1/AFPAM 32-8013, Vol 1, for airfield location criteria.)


The following is a procedural guide to complete a comprehensive airfield design. The concepts and required information are discussed later in this chapter.

1. Select the runway location.

2. Determine the runway length and width.

3. Calculate the approach zones.

4. Determine the runway orientation based on the wind rose.

5. Plot the centerline on graph paper, design the vertical alignment, and plot the newly designed airfield on the plan and profile.

6. Design transverse slopes.

7. Design taxiways and aprons.

8. Design required drainage structures.

9. Select visual and nonvisual aids to navigation.

10. Design logistical support facilities.

11. Design aircraft protection facilities.


When determining the runway length required for any aircraft, include the surface required for landing rolls or takeoff runs and a reasonable allowance for variations in pilot technique; psychological factors; wind, snow, or other surface conditions; and unforeseen mechanical failure. Determine runway length by applying several correction factors and a factor of safety to the takeoff ground run (TGR) established for the geographic and climatic conditions at the installation. Air density, which is governed by temperature and pressure at the site, greatly affects the ground run required for any type aircraft. Increases in either temperature or altitude reduce the density of air and increase the required ground run. Therefore, the length of runway required for a specific type of aircraft varies with the geographic location. The length of every airfield must be computed based on the average maximum temperature and the pressure altitude of the site.

The pressure altitude is a measure of the atmospheric pressure at the site. The pressure altitude is zero under standard day conditions of 59° Fahrenheit (F) and barometric pressure of 29.92 inches. However, pressure altitude varies with atmospheric pressure and is usually greater than the geographic altitude. Compute pressure altitude by adding the pressure altitude (dH) value (height or elevation differential) shown in Figure 11-5 to the geographic altitude of the site.

The average maximum temperature is the average of the highest daily values occurring during the hottest month of the year. Figure 11-6 shows worldwide temperature values to be used. In using these charts, obtain temperature and pressure altitude values for a specific site by interpolation.

Determining Takeoff Ground Run

Table 11-3 shows the TGR at mean sea level, 59°F, with a runway effective gradient of 2 percent for most aircraft based on the location within the TO. Use data in Figures 11-1 and 11-2 if aircraft is not found in Table 11-3. This standard TGR must be increased for different local conditions. The steps used to determine the adjusted TGR follow:

1. Determine the standard TGR for an aircraft shown in Column 6, Table 11-3.

2. Correct for pressure altitude. Add the dH value of the site (from Figure 11-5) to the geographic altitude. Increase the TGR by 10 percent for each 1,000-foot increase in altitude above 1,000 feet. No reduction in TGR is permitted if the pressure altitude is less than 1,000 feet.

3. Correct for temperature. If the pressure-corrected TGR is equal to or greater than 5,000 feet, increase the pressure-corrected TGR by 7 percent for each 10°F increase in temperature above 59°F (from Figure 11-6). If the pressure-corrected TGR is less than 5,000 feet, increase the pressure-corrected TGR by 4 percent for each 10°F increase above 59°F. Never decrease the runway length if the temperature is less than 59°F.

4. Adjust for safety. Multiply the temperature-corrected TGR by 1.5 for rear area airfields and by 1.25 for support and close battle area airfields.

5. Correct for effective gradient. Increase the safety-corrected TGR by 8 percent for each 1 percent increase of effective gradient over 2 percent. No reduction in TGR is permitted if the effective gradient is flatter than 2 percent.

NOTE: The term effective gradient, as used here, is the percentage expression of the maximum difference in elevation along the runway, divided by the length of the runway. Table 11-3, column 7, shows the maximum allowable longitudinal gradients for runways. If the proposed design exceeds Table 11-3, column 7, earthwork must be performed to reduce the gradient. The maximum allowable longitudinal gradient is the steepest slope into which an aircraft can safely land.

6. Round off the gradient-corrected TGR to the next higher 100 feet.

7. Compare the computed value of the TGR with the minimum runway length required (see Table 11-3, column 5). Use the higher of the two values.

The final runway length is the TGR as corrected (if required) for conditions of pressure altitude, temperature, safety factor, and effective gradient and rounded to the next larger 100 feet. Never apply negative corrections to the TGR. For example, do not shorten the runway for operating temperatures below 59°F. Also, the final length of the runway is never less than the minimum length shown in Table 11-3, column 5.

Takeoff Ground Run Determination Example

Assume that a close battle area is to be built for C-17 aircraft and you have the following information: geographic altitude of the proposed site is 1,600 feet, dH value is 100, average maximum temperature is 79°F, and effective gradient is 3 percent.

1. Takeoff ground run.

3,000 feet (ft) (from Column 6, Table 11-3)

2. Pressure altitude correction.

NOTE: 1,700 feet is the only variable in the equation.

3. Temperature correction.

Correction factor (%) =

Therefore, increase the corrected runway length by 8%.

108% of 3,210 = 1.08 X 3,210 ft = 3,467 ft

NOTE: The only variable in the equation is 79°F. If the pressure-corrected TGR was greater than 500 feet, the equation would read {(79°F -59°F)/10°F} x 70%.

4. Safety factor.

1.25 X 3,467 ft = 4,334 ft

5. Effective gradient correction.

Correction factor (%) =

108% of 4,334 ft = 1.08 x 4,334 ft = 4,681 ft

NOTE: The effective gradient of 3 percent must be less than or equal to Table 11-3, column 8 = (3 percent). Also, 3 percent is the only variable in the equation.

6. Round up to the next higher 100 feet.

Length of runway = 4,700 ft

7. Check minimum required (Table 11-3, column 5) = 3,500 ft.

Select 4,700 feet as the appropriate length.


The primary factors that determine runway width are (1) the safety of operation under reduced visibility conditions and (2) the degree of lateral stability and control of the aircraft in the final approach and landing. The minimum widths given in the design-criteria tables increase with increased aircraft weight and size because maneuverability decreases as size increases. Where safety requirements permit, the theater Air Force component commander may reduce the widths. Table 11-3 shows required widths of clear areas and dimensional criteria of clear zones.

Approach Zones

Approach zones are at both ends of the flight strip. The end of the approach zone nearest the runway should be as wide as the clear zone that adjoins it. From this width, the approach zone funnels out trapezoidally to the wider dimension at its outer end. (See the design criteria in Table 11-3 for widths to be used for each type of airfield and stage of construction.) Table 11-3 shows the required length of the approach zone. The following dimensions are required to describe the size of an approach zone:

  • Width at the runway end.
  • Width at the outer end.
  • Length.
  • Slope of the plane determined by the glide angle that defines the upper limit of permissible obstructions.

Glide Angle

No obstruction should extend above the glide angle within an approach zone. The upper limit of the glide angle is a sloping plane, extending from the ground surface at the end of the approach zone nearest the runway to a higher elevation at the zone's outer edge. The slope of this plane depends on the glide-angle characteristics of the using aircraft.

The glide angle of an aircraft is a ratio that expresses its angle of ascent or descent, whichever is the most restrictive, as measured at the end of its ground run or at its point of touchdown. Glide-angle ratios, as they are given for various aircraft, include a safety adjustment.

The denominator of the ratio is usually 1 (vertical foot of ascent or descent), and the numerator is a number expressing how many horizontal feet of distance (increased by 10 as a safety quantity) the aircraft must travel to climb or descend that single foot. Glide angles range from 35:1 to 50:1, depending on the location of the airfield.

Approach Zone Dimensions Example

Assume that a design is being prepared for a support area airfield. From Table 11-3, the required width at the runway end of the approach zone (column 22) is 600 feet, the required length (column 21) is 32,000 feet, the required width at the outer end (column 23) is 8,073 feet, and the glide ratio (column 24) is 50:1. Also note that the widths increase when this same type airfield is located in the rear area.


The design-criteria table (Table 11-3) contains requirements pertaining to maximum longitudinal grades for runways. For support area airfields, the maximum longitudinal grade (column 8) for the runway and overrun is 2 percent. The corresponding figure for close battle area airfields is 3 percent.

Use ditches at the shoulder edges, parallel to the centerline (longitudinally), to provide adequate drainage. Also, lateral ditches might be required to provide flow of water away from the longitudinal ditches which parallel the runway. Neither longitudinal nor lateral ditches can have side slopes greater than 7:1. This ensures the ditches meet the design drainage requirement but do not present a safety hazard to aircraft running off the runway.

Where there is more than one change in longitudinal grade, the distance between successive points of grade intersection must not be less than the minimum distance given in the appropriate design criteria table. The maximum rate of change of longitudinal grade is 1.5 percent per 200 feet for all TO airfields. These figures pertain to centerline measurements, but higher rates of grade change to permit transverse sloping of the runway may be allowed along the edges of the runway. These requirements will be satisfied by following the vertical curve design procedure discussed later.

When jet aircraft are involved, hold longitudinal grade changes to an absolute minimum. Make any necessary grade transitions as long as possible to keep grade change rates very low.

Crowns or transverse slope sections should have a transverse gradient ranging between 1 and 2 percent. Transverse grades more than 2 percent are a hazard in wet weather because aircraft may slip on wet surfaces.

Grade shoulders to a transverse slope of 1.5 to 5 percent. Permissible transverse overrun grades are the same as those for the runway.

Surface Type and Pavement Thickness

The design-criteria tables contain recommendations on the type of surfaces and thickness of pavement to be used for each type of airfield. Chapter 12 discusses the design thicknesses for unsurfaced, aggregate, and bituminous surfaces.


Shoulders are required for all runways. Shoulders range in width from 10 feet to 50 feet, depending on the airfield's location and the using aircraft. Normally, airfield pavement shoulders are thoroughly compacted and constructed with soils having all-weather stability. Use vegetative cover, anchored mulch, coarse-graded aggregate, or liquid palliative other than asphalt or tars to provide dust and erosion control. When using coarse-graded aggregates, thoroughly blend and compact them with in-place materials to ensure proper binding and to avoid damage to aircraft from foreign objects.

Signal Cables

Communications personnel plan and install telephone and radio facilities, but coordination with the engineers is essential. Lay signal cables that cross the runway before starting the surfacing operation. Place conduits or raceways under the runway every 1,000 feet during construction so that flight operations may continue during future expansions of communication facilities.


Runways usually are oriented in accordance with (IAW) the prevailing winds in the area. Pay particular attention to gusty winds of high velocity in determining the runway location.

The established runway direction should ensure 80 percent wind coverage, based on a maximum allowable beam wind (perpendicular to the runway) of 13 miles per hour (mph). This requirement, however, should not cause rejection of a site that is otherwise favorable. Where dust is a problem on the runway or shoulders, locate the runway at an angle of about 10 degrees to the prevailing wind so that dust clouds produced by takeoffs will blow diagonally off the runway.

Gathering Wind Data

Wind data is usually based on the longest period for which information is available. A minimum of 10 years' data showing wind directions, velocity, and frequency of occurrence is necessary for conclusive analysis. Military and civilian maps for all populated areas of the world usually have this information, especially those prepared by marine or aeronautical agencies. If no observations are available for a site, adjust the nearest recorded observations for changes that will result from local topography or other influencing factors. Table 11-4 shows the form in which wind data may be obtained from AWS.

Wind Rose

A wind rose graphically depicts wind velocities, directions, and their probability of occurrence in a format resembling a compass (see Figure 11-7). The radii of the concentric circles arc scaled to represent wind velocities of 4, 13, 25, 32, and 47 mph. The radial lines are arranged on the diagram in a manner similar to a compass card to show directions such as north, north northeast, northeast, cast northeast, and east. Each direction subtends an angle of 22.5 degrees.

The probabilities of occurrence for the wind velocities and directions are recorded in the appropriate spaces on the diagram. The example below uses the wind data to be analyzed from Table 11-4.


Record 9 percent (the sum of 2 percent calms plus 7 percent winds under 4 mph) within the innermost concentric circle, the radius of which represents 4 mph. Record the percentages 3.3, 1.4, 0.1, 0.0, and 0.0 (shown for the north direction in columns (b), (c), (d), (c), and (f) of Table 11-4) on the diagram (Figure 11-7) between the radial lines showing north and between the concentric circles showing wind velocities of 4-13, 13-25, 25-32, 32-47, and more than 47 mph, respectively. Record the remainder of the data in Table 11-4 on the diagram in the same manner.

Wind Vectors

Figure 11-8 outlines a graphical method showing wind speed and direction. Line Do represents the direction of the prevailing wind, and line A-B represents the direction of the runway. The velocity of the prevailing wind is scaled off on line D-o and is shown as line c-o. If the scale used is 0.1 inch equals 1 mph (the scale generally used) and the prevailing wind has a velocity of 18 mph, the length of line c-o is 1.8 inches. Determine the wind velocity perpendicular to the direction of the runway by drawing line c-b at a right angle to line AB. This line measures 0.9 inch and at the same scale represents 9 mph, the crosswind velocity. Line b-o measures 1.56 inches and represents 15.6 mph, the wind velocity parallel to the runway. The designer may use simple trigonometric functions of a right triangle instead of this method. The results can be verified using the Pythagorean theorem. (Example: (9 mph)2 + (15.6 mph)2 = (18 mph)2)

Graphic Analysis of Wind Rose

Use a thin, transparent, rectangular indicator (Figure 11-9) to analyze a wind rose. This indicator is constructed to the same scale as the wind rose on which it is used. The width of the indicator is based on the acceptable crosswind velocity. With an acceptable crosswind velocity of 13 mph and a wind rose scale of 0. 1 inch equals 1 mph, the rectangle is 1.3 inches from its center to its edge and has an overall width of 2.6 inches. The rectangle is slightly longer than 6 inches, the diameter of the windrose diagram. The long axis (the centerline) of the rectangle is marked with a fine, opaque line that shows the direction of a runway. A small hole at the midpoint of this line is used for a pivot to rotate the rectangle.

The indicator is securely pivoted at the center of the wind rose (Figure 11-10). Because the edges of the indicator define the limits of the acceptable crosswind velocity components, the spaces and portions of spaces covered by the indicator represent acceptable surface wind velocities and directions. Rotate the rectangular indicator about its center and orient it so that the total percentages (of occurrence for each wind velocity) is maximized. Total the percentages under the indicator. This total is the percentage of time that crosswind velocities will be within the specified limit for a runway oriented in the direction shown by the rectangular indicator.

Determine the percentage coverage totals with the indicator oriented in several directions. Compare these totals to determine the best runway orientation, as based solely upon surface wind data. If the percentage coverage for one runway is inadequate, make a wind-rose analysis for combinations of runway directions to determine the most suitable combination that will provide the necessary coverage.

Calculating Percentage Covered

Either of two procedures may be followed to evaluate the total percentage covered by the rectangular indicator on a wind rose. One procedure is to calculate the total of the representative percentages covered by the indicator. The other is to calculate the total of the representative percentages not covered by the indicator and subtract this total from 100. Tables 11-5 and 11-6 show examples of each procedure. The wind data in Table 11-7, the resultant wind rose, and the indicator in the position shown by Figure 11-10, are used to compile the examples.

Determining the percentage value for a partially covered space requires special consideration. To calculate the representative percentages covered by the rectangular indicator, assume uniform distribution of the percentage of time within each space on the wind rose. For example, if an entire space represents 2.8 percent of the time, one-half of that space represents 1.4 percent of the time. The basic assumption of uniform distribution leads to inaccuracies. A high degree of accuracy in the determination of the proportions of space partially covered by the indicator may be determined by calculation, estimation, or measurement; or it may be determined by using a nomograph (Figure 11-11).

As an example of how the nomograph is used, assume that Figure 11-10 is the wind rose to be evaluated when the runway is in the direction indicated by the rectangular indicator. Also assume that the windrose space from which a proportionate percentage is to be determined represents southeast winds ranging from 13 to 25 mph. Because this space is only partially covered by the indicator, the percentage of time (represented by the portion covered by the indicator) must be determined.

In this example, the azimuth of the wind direction (southeast) is 135 degrees. The azimuth of the centerline of the indicator is roughly 181 degrees. Their angular difference is roughly 46 degrees. Figure 11-11 shows that for this angular difference, the rectangular indicator covers approximately 0.3 percent of the space representing winds from 13 to 25 mph. Because the entire space represents 2.9 percent of the time, the 0.3 portion of the space represents 0.9 percent (0.3 x 2.9) of the time. Accuracy to the closest 0.1 percent is the same as that of the basic wind data.

Follow a similar procedure for the rest of the spaces and portions of spaces covered by the indicator. Enter the percentages determined into a table similar to Table 11-5. The total of the percentages is the indicated wind coverage of a runway.

Follow a similar procedure when the calculation is based on spaces not covered. The calculation based on spaces not covered substantially reduces the work required. The results of a not-covered calculation for the wind-rose analysis in Figure 11-10 are recorded in Table 11-6.

True and Magnetic North Directions

Wind data directions are based on the true geographic north, whereas airfield runway directional numbers are based on the magnetic north. Magnetic declination adjustments must be made in the results of windrose runway orientation determinations to show runway directions based on magnetic headings.


Airfield construction specifies a minimum length of each grade line or a minimum distance between the grade line intersection points. Although this specification is based on the type of aircraft involved and the standard of construction desired, a minimum of 400 feet between points of vertical intersection is used.


The same vertical-curve design procedures used for roads in Chapter 9, FM 5-430-00-1/AFPAM 32-8013, Vol 1, are used for airfields. However, the curve length may be longer. In many cases, the runway is a segment of a curve, and both the point of vertical curvature (PVC) and point of vertical tangency (PVT) are off the airfield. Confusion of stationing must be avoided. Table 11-7 shows equations to determine the length of airfield vertical curves. For overt curves, use either sight distance or maximum change of grade to determine the curve length. Use whichever length is longest.


A close battle area airfield is to be built to accommodate C-17 and C-130 aircraft. The runway length is determined to be 3,000 feet (after adjustments made to TGR). Figure 11-12 shows the profile and plan views of the selected site with final trial grade lines. To meet the criteria for an unobstructed glide angle of 35:1, the overrun must start at station 0 + 00. Complete the design of the vertical curve to include PVC and PVT, calculate the offsets every 100 feet, and prepare the equation in tabular form.


10. Determine final elevations.

The cross section of a runway may be of two general types-a crowned cross section or a transverse slope cross section as shown in Figure 11-13. Transverse slope cross sections may slope to either side of the runway. The terms right and left, when used in connection with a runway, refer to the right and left sides of the runway as the observer stands on the centerline and faces the higher numbered stations on that centerline.

Transverse slopes are applied to sections at appropriate stations to make the finished runway surface fit close to the original topography of the site. A sloped runway follows the transverse and the longitudinal shape of the original ground as closely as possible while staying within acceptable grade limitations. Using transverse slopes on a runway reduces the amount of earthwork and drainage construction. The changes in shape and grade of a properly sloped runway are small compared with the runway length.

Runway transverse slopes do not cause a hazard to flight operations. Records show no increase in operational accidents as a result of using transverse slopes. Changes in the transverse slope on airfields used by jet aircraft must be kept to a minimum. Transverse slopes are not needed for roads or taxiways. They usually are located to conform to the existing ground surface.


In applying transverse slopes to a runway, it may be economical to change from a left-hand to a right-hand transverse-slope cross section or to change from a transverse-slope cross section to a crowned cross section. These changes may occur often, provided two limitations are observed:

  • The longitudinal distance from the center of one transition to the center of the next transition must not be less than 400 feet.
  • The length of the transition connecting typical cross sections must be such that the maximum grade limitations in Table 11-3 are not exceeded.

Designing Transverse-Slope Cross Sections

Transverse sloping of a runway is primarily a computing and drafting job. The two main tasks in a sloping problem are--

  • Selecting the proper cross sections for various lengths of the runway.
  • Designing proper transitions to connect the lengths of different cross-sectional shapes.

These steps are illustrated in Figures 11-14 and 11-15.

Selecting cross sections. Use the following procedure to select proper runway cross sections:

1. Plot the ground profiles at the centerline, left edge, and right edge of the runway as shown in Figure 11-14. Plot each profile with a different color pencil.

2. Determine the relative positions of three profiles at each cross section. When both edges arc below the centerline, use a crowned cross section (does not need to be symmetrical). Use a transverse-slope cross section when one edge is above and the other is below the centerline.

3. Design proper cross-sectional shapes for each distinct length of runway. Observe the two limitations explained earlier. The cross-sectional shapes, as designed, should fit as closely as possible to the undisturbed ground shape within the allowable limitations for changes of grade.

Figure 11-14 shows how cross sections may vary along a runway and how cross sections are selected by comparing the center, left-edge, and right-edge ground profiles. Note that between stations 0 + 00 and 10 + 00, 28 + 00 and 48 + 00, and 60 + 00 and 70 + 00, the right edge of the runway is above the centerline profile while the left edge is below the centerline profile. This suggests using a left-hand, transverse-slope cross section. The three profiles show that a crowned cross section is most suitable between stations 10 + 00 and 28 + 00. Between stations 48 + 00 and 60 + 00 and between stations 70 + 00 and 80 + 00, a right-hand, transverse-slope cross section is best because the left edge is above the centerline and the right edge is below the centerline.

Designing transitions. The upper part of Figure 11-15 shows a transition suitable for changing from a left-hand, transverse-slope cross section to a right-hand, transverse-slope cross section, In Figure 11-15, the dotted line on the plan connects high points of the successive cross sections. A similar situation occurs when the change involves a crowned section. The lower part of Figure 11-15 shows a crowned section, high points, and typical cross sections in a similar fashion. Note that all the cross sections, between and including C-C and D-D, are alike.

When staking out a transition on the ground, use at least five lines of grade stakes. Locate the grade stakes along the centerline. quarter points, and edges of the runway. These are enough stakes for construction, but additional stakes may be required for close grade control.


Taxiways are pavements provided for the ground movement of aircraft, They connect the parking anti the maintenance areas of the airfield with the runway. The location of these facilities determines the location of taxiways.

Locate taxiways to provide direct access to the ends of the runway for takeoffs. Avoid designs with long taxiways and designs that require excessive crossing and turning on the runway. Such designs reduce the operational capacity of the runway and cause needless hazards.

Provide cutoff taxiways or exit paths that permit landing aircraft to clear the runway promptly. Excessive cutoffs can complicate the traffic control problem.

Construct taxiways on a loop system. This provides an alternate route in case a disabled plane or maintenance operations block the taxiway. Make the taxiway parallel with the runway and tie onto it at both ends, thus forming a closed loop.

Straight taxiways are preferred for modern, high-performance aircraft that consume large amounts of fuel. Straight taxiways permit movement from one point to another in the shortest possible time with the greatest fuel savings.


In a TO airfield, three types of aprons are used: warm-up, operational, and cargo.

Warm-Up Apron

The warm-up apron, sometimes called a warm-up/holding-pad apron, is a paved area adjacent to the taxiway near the runway end. The warm-up apron permits--

  • The final portion of warm-up and engine and instrument checks to be done before takeoff without interrupting normal traffic.
  • The flow of traffic from the taxiway to the runway to be uninterrupted in case of breakdowns or malfunctions.
  • Jet engine aircraft with high minimum fuel consumption to bypass slower reciprocating engine aircraft between the taxiway and the runaway.
  • Aircraft to wait for takeoff clearance without blocking the runway or taxiway.

A satisfactory warm-up apron should--

  • Provide a paved area at each end of each operational runway.
  • Be large enough to accommodate two of the largest aircraft assigned to the air base simultaneously.
  • Be configured to allow 20-foot wingtip clearance between aircraft on the pad and 50-foot clearance between parked aircraft and aircraft passing on the adjoining taxiway.
  • Be positioned so the pilot of an aircraft on the holding pad has a clear view of the active taxiway, the control tower, and the runway end where he must move for takeoff.
  • Allow parked aircraft to face both the runway end and the taxiway while headed into the wind.

Operational Apron

The paved areas required for aircraft parking, loading, unloading, maneuvering, and servicing are called operational-parking aprons. Aircraft should normally be able to move in and out of parking spaces under their own power.

Consider the following factors when determining the size of the operational apron:

  • Aircraft size.
  • Aircraft maneuverability.
  • Jet engine blast.
  • Distance between fueling outlets.
  • Fire and explosion hazards.

The minimum wingtip clearance for aircraft taxiing or parked on the operational apron is 10 or 20 feet, depending on aircraft use categories.

The air base commander determines the smallest operational apron required to fit the expected number of aircraft at any particular time. The operational apron provides access to hydrant fueling outlets, maintenance areas, the runway access taxiway, and other facilities to which tactical and support aircraft must taxi from the apron.

Jet aircraft must operate within a designated parking area so the blast velocity and temperature will not injure personnel or damage other aircraft or facilities. Safe clearance to the rear of a jet engine is that area in which the blast velocity does not exceed 35 mph and the temperature does not exceed 100°F. The apron configuration at each base depends on the number and type of aircraft to be parked and the local apron and terrain features.

The operational apron is usually designed to accommodate 100 percent of assigned aircraft, with reductions (based on experience) for aircraft that can be parked in maintenance areas. Also consider the concept of maintaining unit integrity in an operational apron.

Cargo Apron

Besides the normal tactical mission, some air bases have a supplementary cargo or transport mission. Such a mission affects airfield layout and criteria in two ways--the pavement may have to be strengthened, and additional operational (loading and unloading) aprons must be provided. These additional requirements are determined by frequency of operation, total number of cargo aircraft involved, air-traffic-control rate, runway saturation rate, and station workload capabilities.

Experience from within the TO or a specific assessment by the troop transport commander should determine apron requirements. Use an estimate of 10 percent of the total number of cargo aircraft in the operation, or estimate the additional apron areas required by multiplying the number of aircraft to be accommodated at anytime by the factors shown in Table 11-8.


Modern tactical aircraft contains navigational, bombing, and gunnery equipment that must be maintained within a given accuracy to produce the desired precision. To ensure these results, the equipment must be properly calibrated at fixed intervals after each engine change or anytime a major modification is made to the aircraft. Failure to perform this calibration periodically reduces the ability of the aircraft to complete its assigned mission.

A calibration facility normally consists of a calibration hardstand and a firing-in butt. This facility provides a suitable means for aligning an aircraft or the precise calibration of all types of navigation, bombing, and gunnery equipment in the aircraft. The calibration hardstand was formerly called a compass swinging base. For nontactical missions, this facility is limited to the hardstand required for calibration.

The hardstand is a level, surfaced area marked with precision alignment indications accurate to within 0.25 of 1 degree. Because of the calibration operation involved, locate the paved hardstand in an area where the local magnetic influence is at a minimum.


Aircraft must always be kept clean. Dirt, grime, oil, and grease on aircraft increase airflow drag, promote corrosion, change balance, slow the dissipation of heat from the engines, and prevent effective aircraft inspection for airframe and mechanical failures.

Aircraft corrosion control facilities, called washing areas, are specifically designed with the necessary tools for washing and cleaning aircraft quickly and efficiently. The design must provide adequate drainage facilities to dispose of large quantities of water, oil, and other substances.


Aircraft revetments may be needed for protection against small-arms fire, mortars, strafing attacks, and near misses with conventional bombs and to prevent sympathetic detonation of explosives on nearby aircraft. Any of the various types of open revetments or soft shelters may be used. Chapter 14 discusses revetment details.


The maintenance mission and facilities of air bases depend on the number and type of aircraft assigned and the degree of maintenance desired. The theater commander specifies the maintenance mission. Therefore, it is impossible to forecast the exact type of facilities required at any TO base. In general, the following guidelines may be used:

Initial Construction

On air bases provided with initial facilities, no area is specifically laid out as a maintenance site. Aircraft maintenance is done at the parking aprons. Portable nose hangars or improvised portable shelters that fit over the engine may be used to protect personnel from advance weather. Mobile shops containing tools and necessary power equipment are transferred from aircraft to aircraft as needed. Aircraft requiring major repairs or overhaul are sent to rear area maintenance facilities if possible.

Temporary Construction

An air base provided with temporary facilities usually has a maintenance site that has facilities needed for the proper and efficient maintenance and repair of aircraft. Keep the area free of all structures and other facilities except those directly concerned with technical functions. The maintenance site should contain the required hangars, shops, and covered and open storage. Covered floor space requirements can be met with tentage, prefab or portable structures, frame TO fixed structures, or converted existing structures. The choice of facilities depends on locale, tactical situation, weather conditions, duration of operational usage, and related factors.

In a moving tactical situation or under temporary static conditions, tentage or converted existing structures are normally used. Prefab, portable, or frame TO fixed structures are used under more stable conditions. For information on portable structures and frame TO fixed construction, see FM 5-430-00-1/AFPAM 32-8013, Vol 1, and TM 5-302-series. An important factor in the relative locations of maintenance facilities, particularly hangars, is the functioning of the control tower.


Aids to navigation are both visual and nonvisual. Nonvisual aids are required to guide and control flying activities, particularly with instrument flight rules (IFR), when weather or other conditions demand instrument flying. Visual aids are necessary with visual flight rules (VFR) when flight operations are conducted at night or under conditions of reduced visibility. For a detailed discussion of aids to navigation, see Air Force Instruction (AFI) 32-1044 for Air Force airfields and TM 5-823-4 for Army airfields. Principal aids to navigation are airfield markings, airfield lighting, and NAVAID. Control towers are grouped with NAVAIDs.

Airfield marking and lighting aids to air navigation are considered as elements of the airfield. They are related to construction stages discussed in Chapter 10 as follows:

  • Stage I construction is authorized under construction combinations A and B.
  • Stage II construction is authorized under construction combinations C and D.
  • Stage III construction is authorized under construction combinations E and F.

NAVAID facilities are related to construction types as follows:

  • Initial construction of NAVAID facilities is authorized under combinations A and B (Table 10-1).
  • Temporary construction of NAVAID facilities is authorized under combinations C, D, E, and F (Table 10-1).
  • At no time will temporary NAVAID facilities be emplaced on a temporary runway.



The airfield marking system is a visual aid in landing aircraft. It requires illumination from either an aircraft lighting system or daylight. Standards for airfield marking have been adopted by the Army and Air Force. Determination of an airfield marking system is a TO responsibility and is a prerogative of the theater commander. The methods and configurations described here are those most commonly applicable to TO use. For a more detailed discussion of airfield marking, see TM 5-823-4, TM 5-302-series, AFCS facility drawings, and AFI 32-1044.

Runway Markings

The following four elements of markings apply to runways in general. Figure 11-16 shows the proper use of these markings.

  • Centerline marking. The centerline marking is a broken line with 100-foot dashes and 60-foot blank spaces. The minimum width for the basic runway centerline marking is 18 inches. For precision and nonprecision instrument runways, the minimum width is 3 feet.
  • Runway designation numbers. Runway designation numbers are required on all runways (basic, precision, and nonprecision instrument). They are not required on a minimum operating strip or short-field assault strip. The numbers designate the direction of the runway and accent the end limits of the landing and takeoff area. Figure 11-16 shows the dimensions and forms of standard direction numbers. The number assigned to the runway is the whole number closest to one-tenth the magnetic azimuth of the centerline of the runway, measured clockwise from magnetic north. Single digits are preceded by a zero.
  • Threshold marking. Threshold marking is required on all precision--and nonprecision--instrument runways. Threshold markings for runways at least 150 feet wide are shown in Figure 11-16. On runways less than 150 feet wide, start the threshold markings 10 feet from each edge of the runway. Reduce all other widths in proportion to the reduction in the overall width of the threshold marking.
  • Touchdown-zone markings and edge stripes. Keep their use in the TO to a minimum because of the time and effort required to obliterate them if the tactical situation requires it. Touchdown zone markings and edge strips are required on runways served by a precision instrument approach.
  • Fixed-distance markings. Fixed-distance markings are rectangular painted blocks 30 feet wide by 150 feet long beginning 1,000 feet from the threshold. They are placed equidistance from the centerline, 72 feet apart at the inner edges. They are required on all runways that are 150 feet wide or wider, 4,000 feet long or longer, and used by jet aircraft.

Expedient Runway Marking

For expedient construction, surfacing is normally soil-stabilized pavement, membrane, or air-field landing mat. Do not provide runway direction numbers on landing mat surfaces. Put an inverted T at the end of the runway, combined with a centerline stripe, and edge markings, combined with a transverse stripe mark at the threshold, at 500 feet and at the midpoint of the runway.

Taxiway Marking

Mark taxiways to conform with the following requirements shown in Figure 11-16.

  • Centerline stripes. Mark each taxiway with a single, continuous stripe along the centerline, These stripes should have a minimum width of 6 inches. At taxiway intersections with runway ends, taxiway stripes should end in line with the nearest edge of the runway. At taxiway intersections, the taxiway centerline markings should intersect.
  • Holding line marking. Place a taxiway holding line marking not less than 100 feet and not more than 200 feet from the nearest edge of the runway or taxiway that the taxiway intersects (see Figure 11-16). Measure this distance on a line perpendicular to the centerline of the runway or taxiway that is intersected. Increase the distance from the minimum 100 feet to whatever distance is necessary to provide adequate clearance between large aircraft operating on the runway or taxiway and the holding aircraft.

Marking Materials and Methods

The materials and methods used in airfield marking must provide visual contrast with the airfield surface, They vary primarily with the type of surface and less directly with the construction type or stage. Fewer permanent materials require constant maintenance. Use the following guides to select marking materials:

  • Paint is used only on permanent surfaces.
  • Lime is used primarily for marking unsurfaced areas such as earth, membranes, or similar surfaces.
  • Oil or similar liquids are used for marking unsurfaced areas.
  • Panels made of materials such as cloth or canvas, properly fastened to the pavement, may be used for many marking requirements.

Use yellow flags to show temporary obstructions caused by flying accidents or enemy action. As temporary expedients, sandwich-board markers or stake-mounted signs may be used to define the runway width. These markers, 2 feet by 2 feet in size, have black-and-white triangles on each side. They are spaced 200 feet apart longitudinally on the outer edge of the runway shoulder.

For taxiways, sandwich-board markers or flat pieces of wood or metal painted with black-and-white triangles may serve as expedient markers. Fasten these 12- by 12-inch markers to stakes and place them 100 feet apart along the outer edge of the taxiway shoulder.

All expedient markers should be lightweight and constructed to break readily if struck by an aircraft. They should never be hazardous to aircraft. Figure 11-17 shows several types of expedient markers. Markers for snow-covered runways should be conspicuous. Upright spruce trees, about 5 feet high, or light, wooden tripods may be used. Place the markers along the sides of the snow-covered runway. Space them not more than 330 feet apart and locate them symmetrically about the axis of the runway. Place enough markings across the end of the runway to show the threshold. Aluminum powder and dyes can effectively mark snow in the runway area.


Airfield lighting includes the systems of illuminated visual signals that help pilots in the safe, efficient, and timely operation of aircraft at night and during periods of restricted visibility (IFR conditions). In general, airfield lighting is comprised of runway lighting, approach lighting, taxiway lighting, obstruction and hazard lighting, beacons, lighted wind direction indicators, and special signal lights. Not all these items are included in TO airfields. Normally, all lighting (except certain obstruction lighting) is controlled from the control tower. The lighting system includes all control devices, circuit protective devices, regulators, transformers, mounting devices, and accessories needed to produce a working facility.

The configuration, colors, and spacing of runway, approach, and taxiway lighting systems are uniform regardless of the anticipated length of service of the installation, the mission of the tenant organization, or the method of installation.

The colors and configuration used in airfield lighting generally are standardized on an international scale, and there is no difference between permanent and TO installations. The basic color code follows:

  • Blue-taxiway lighting.
  • Clear (white)-sides of a usable landing area.
  • Green-ends of a usable landing area (threshold lights). When used with a beacon, green indicates a lighted and attended airfield.
  • Red-hazard, obstruction, or area unsuitable for landing.
  • Yellow-caution. When used with a beacon, yellow indicates a water airport.

Airfield lighting requirements are detailed in AFI 32-1044.

Runway Lighting

Runway lighting, the principal element of airfield lighting, provides the standard pattern of lights to outline the runway and to show side and end limits. Side limits are marked by two parallel rows of white lights, one row on each side of and equidistant from the runway centerline. Lights within the rows are uniformly spaced, and the rows extend the entire length of the runway. End limits are outlined by green runway threshold lights, which are visible from all sides and vertical angles.

Space runway threshold lights along the threshold line, which is 0 to 10 feet from the end of the runway and perpendicular to the centerline extended off the runway. Runway lighting is divided into two classes--high intensity to support aircraft operations under IFR conditions and medium intensity to support aircraft operations under VFR conditions.

Approach Lighting

This system of lights is used to guide aircraft safely to the runway on airfields intended for instrument flying and all-weather operations. The system is installed in the primary approach to the Stage II runway. Its use is generally confined to installations that are or will be provided with precision, electronic, low-approach facilities. Never use approach lighting with a medium-intensity runway lighting system.

Taxiway Lighting

When an airfield becomes fully operational, lights and reflectors are used to increase safety in ground movements of aircraft. Taxiway lighting is standardized. In general, blue taxiway lights mark the lateral limits, turns, and terminals of taxiway sections.

Reflectors are also used to delineate taxiways. Standard taxiway reflectors are panels approximately 12 inches high by 9 inches wide. Both sides of the panels consist of a retroreflective material that reflects incident light back to the light source (aircraft landing or taxiing lights). Mounting wickets can be manufactured locally from galvanized steel wire, size Number 6 or larger. The wire, cut into 42-inch pieces, is bent into a U-shape so parallel sides are 7 1/2 inches apart.

Install reflectors along straight sections and long-radius curves at 100-foot intervals. At intersections and on short-radius curves, set the reflectors 20 feet apart and perpendicular to one another. Embed wickets 12 to 15 inches in the ground and set them firmly. When reflectors are set where grass or other vegetation grows 2 inches or more in height, treat the ground surface with engine oil or salt to prevent this growth.


Airport-type beacons are not commonly used in a combat zone. They may be used in rear areas of the TO. Mobile beacons are sometimes employed to transmit orders of the day, Beacons are considered organizational equipment and are not part of the construction program.

Lighted Wind-Direction Indicators

These indicators provide pilots with visual information about wind directions. Under conditions of radio silence, they are the only means available to the pilot to determine direction of landing and takeoff.

Special Signal Lights

Signal lights may be used to convey operating information to pilots during periods of radio silence. Such signals may be used to transmit orders of the day and to aid in air and ground traffic control. No standards for TO construction of signal lights are presently available. The theater commander determines the criteria necessary for construction.

Expedient Lighting

Expedients may be used for lighting if issue equipment is not available, Lanterns, smudge pots, vehicle headlights or reflectors may be used to distinguish runway edges. Reflectors are also useful when placed along taxiways and at handstands to guide pilots in the dark. An electrical circuit may be laid around the runway with light globes spaced at regular intervals and covered by improvised hoods made from cans. A searchlight, pointed straight in the air, is sometimes used as a substitute for beacon lights. The searchlight is placed beyond the downwind end of the runway. When the pilot is oriented, the searchlight is lowered so its beam shines down the runway to light it.

Portable airfield lighting is available for use. It is normally used when permanent lighting has been damaged or is not available. Tables 11-9 through 11-11 and Figures 11-18 through 11-20 show portable marking standards. Table 11-9 indicates portable markings for fixed-wing landing zones.

Lighting and Communication Cables

Place cables for lighting and communication in ducts when passing under taxiways, runways, ditches, and streams or where it is difficult to reach the cable for repairs. At a minimum, place three ducts transversely under the runway at its midpoint, one duct under the runway at each end, ducts under the taxiway approaches on both sides and both ends of the runway, one duct under the perimeter taxiway directly opposite the three ducts under the midpoint of the runway, and ducts under all taxiways at all junctions with the runway or other taxiway. Locations may be modified or ducts may be added if required by field conditions.

The cable duct should be 4 to 8 inches in diameter or an equivalent rectangle. It may be made with lumber, drain tile, building tile, water pipe, or corrugated metal pipe. To facilitate drainage, the duct may be placed roughly parallel to the runway surface. For convenience in stringing the communications circuits through the duct, leave a pull wire (approximately 9 gauge) in place during construction. Enclose each end securely in a conduit box with a heavy plank cover to keep earth out and to eliminate hazards to aircraft wheels. (See Figure 11-21.)

Obstruction Marking and Lighting

This type marking and lighting must be kept to a minimum in a TO, particularly in a combat zone. Specific criteria and details follow. Additional criteria can be found in TM 5-823-4.



Obstructions are marked either by color, markers, or flags. Mark objects by color according to the following requirements:

  • Solid. An object whose projection on any vertical plane in a clear zone is less than 5 feet in both dimensions and is colored aviation-surface orange.
  • Bands. An object with unbroken surfaces whose projection on any vertical plane is 5 feet or more in one dimension and less than 15 feet in the other dimension. It is colored to show alternate bands of aviation-surface orange and white. Any skeleton (broken surface) structure or smokestack-type structure having both dimensions greater than 5 feet and is colored in alternate bands of aviation-surface orange and white.

The widths of the aviation-surface orange and white bands should be equal and should be approximately one-seventh the length of the major axis of the object if the band has a width of not more than 40 feet nor less than 1 1/2 feet. The bands are placed perpendicular to the major axis of the construction. The bands at the extremities of the object should be aviation-surface orange. Figures 11-22 and 11-23 show the color requirements.

Checkerboard pattern. Objects with unbroken surfaces whose projection on any vertical plan is 15 feet or more in both dimensions. They are colored to show a checkerboard pattern of alternate rectangles of aviation-surface orange and white (Figure 11-23). The rectangles are not less than 5 feet and not more than 20 feet on a side, and the corner rectangles are aviation-surface orange. If part of or all the objects with spherical shapes do not permit the exact application of the checkerboard pattern, modify the shape of the alternate aviation-surface orange and white rectangles, covering the spherical shape to fit the structural surface. Ensure the dimensions of the modified rectangles remain within the specified limits.

Marking by Markers

Use markers when it is impractical to mark the surface of objects with color. Markers are used in addition to color to provide protection for air navigation.

Obstruction markers should be distinctive so they are not mistaken for markers employed to convey other information. Color them as specified earlier. Markers should be recognizable in clear air from a distance of at least 1,000 feet in all directions from which an aircraft is likely to approach.

Position markers so the hazard presented by the object they mark is not increased. Locate markers displayed on or adjacent to obstructions in conspicuous positions to retain the general definition of the obstructions. Markers displayed on overhead wires are usually placed not more than 150 feet apart, with the top of each marker not below the level of the highest wire at the point marked. However, when overhead wires are more than 15,000 feet from the center of the landing area, the distance between markers may be increased to not more than 600 feet.

Marking by Flags

Use flags to mark temporary obstructions or obstructions that are impractical to mark by coloring or by markers. The flags should be rectangular and have stiffeners to keep them from drooping in calm or light wind. Use one of the following patterns on flags marking obstructions:

  • Solid color, aviation-surface orange, not less than 2 feet on a side.
  • Two triangular sections--one aviation-surface orange and one aviation-surface white--combined to form a rectangle not less than 2 feet on a side.
  • A checkerboard of aviation-surface orange and aviation-surface white squares, each 1 foot plus or minus 10 percent on a side, combined to form a rectangle not less than 3 feet on a side.

Position the flags in such a way that the hazard they mark is not increased. Display flags on top of or around the perimeter of the highest edge of the object. Flags used to mark extensive objects or groups of closely spaced objects should be displayed at approximately 50-foot intervals.


Obstruction lights show the existence of obstructions. These lights are aviation red, with an intensity of not less than 10 candlepower. The number and arrangement of lights at each level should be such that the obstruction is visible from every angle. Figures 11-24 through 11-26 illustrate methods of obstruction lighting.

Vertical Arrangement

Locate at least two lamps at the top of the obstruction, either operating simultaneously or circuited so that if one fails the other operates. An exception is made for chimneys of similar structures. The top lights on such structures are placed between 5 and 10 feet below the top. Where the top of the obstruction is more than 150 feet above ground level, provide an intermediate light or lights for each additional 150 feet or fraction thereof. Space the intermediate lights equally between the top light (or lights) and the ground level.

Horizontal Arrangement

Built-up and tree-covered areas have extensive obstructions. Where an extensive obstruction or a group of closely spaced obstructions is marked with obstruction lights, display the top lights on the point or edge of the highest obstruction. Space the lights at intervals of not more than 150 feet so they show the general definition and extent of the obstruction. If two or more edges of an obstruction located near an airfield are at the same height, light the edge nearest the airfield.

Lighting of Overhead Wires

When obstruction lighting of overhead wires is needed, place the lights not more than 150 feet apart at a level not below that of the highest wire at each point lighted. When the overhead wires are more than 15,000 feet from the center of the landing area, the distance between the lights may be increased to no more than 600 feet.


Three methods are used for lighting construction areas:

  • Method A is normally confined to emergency airfields and to emergency repairs at more permanent installations. Precision methods of layout are not used, cables are laid on the ground, and lights are stake-mounted. The wind indicator is pipe-mounted instead of being placed on the tower.
  • Method B is an upgrade of Method A, when emergency repairs might take a longer time to accomplish. Precision methods of locating fixtures are also not used. Cables are buried at least 6 inches. Remote control features, which are not usually provided with Method A installations, are used in Method B.
  • Method C is used when installing airfield lighting. Construction should approach the standards outlined in AFI 32-1044 and TM 5-823-4. Cables are buried 24 inches below the finished grade. Lighting fixtures are precisely located and mounted in concrete bases. The wind indicator is tower-mounted.


Navigational aids refer to the ground equipment and supporting facilities that provide electronic (radio and radar) assistance in the navigation of aircraft. NAVAIDs consist of components of equipment, housing, and utilities. Each component serves a specific mission in directing or assisting the direction of airborne aircraft.

The NAVAIDs used in a TO include--

  • Mobile and air-transportable search and precision approach radar ground-controlled approach (GCA).
  • Radio homing beacons.
  • Ultrahigh frequency direction finders (UHFDFs) and omnibearing distance equipment--tactical air navigation (TACAN).
  • Radar beacons (RACONs).
  • Remote receiver and transmitter buildings for temporary construction (used with control tower).
  • Control tower.

Criteria and Requirements

Not all systems listed are required at any one base. Requirements are determined by factors such as base mission, type of aircraft, geographic location, terrain, and meteorological conditions. Final selection of the facilities required is made by the theater commander and requires technical determination by the AFCS or United States Army Aeronautical Services Office (USAASO).

When facilities selection is made, consider survivability by hardening (if use permits), tone down, camouflage, concealment, and other measures designed to complement any base vulnerability reduction program. The following NAVAIDs are the minimum desirable for planning and obstruction design purposes:

  • Priority 1--Mobile GCA and homing beacon on TACAN.
  • Priority 2--UHFDF.
  • Priority 3--RACON.

Most NAVAID equipment is portable and has self-contained housing that is adequate for short-time use. In more deliberate construction and for supporting hardstands or cable line, additional construction must be performed and building materials provided. The AFCS personnel provide, install, and erect all equipment, cables, and antennas. The USAASO personnel provide technical assistance only.

The construction force provides and constructs prefab housing, access roads, hardstands, and foundations (bases) for antennas. The construction force also cuts ditches or trenches for laying cable, although the actual cable laying and antenna erection are done by AFCS personnel supported by construction forces. The final siting of all facilities is done by AFCS and USAASO personnel. In this section, only approximate siting is given. Thus, NAVAIDs are considered in planning the layout of other facilities on a base. (See Figure 11-27.)

Adoption of standard NAVAID buildings (types T-0, T-1, T-2, and T-3) has been made by using fractions of the basic 20- by 48-foot prefab building. The type of building used depends on the power supply generators required. In all field-and intermediate-type facilities requiring a shed for a power unit, cable is laid on the ground between the power shed and the equipment. For temporary-type construction, direct burial power cable is used. Remoting cable is buried only in temporary-type constriction.

The selection of cable size depends on the distance over which the cable must carry power. Cable is not listed in BOMs, but it must be considered in planning and logistics.

Equipment and Power

The following is a summary of commonly used NAVAID equipment and the power requirements for each group of related equipment:

Precision Approach Radar (GCA). The AN/CPN-4, AN/MPN-11, and AN/TSQ-71 apply to all types of construction because these units are housed in mobile shelters. An access road, turnaround loop, and level hardstand for an approximate wheel load of 9,000 pounds should be provided. In temporary-type construction, an underground transformer vault with 120/208-volt (v), 3-phase, 4-wire, 60-hertz (Hz), 45-kilo-voltamp (KVA) transformer secondary service; a 100-ampere disconnect switch; and a 26-pair telephone cable to base main frame are required. The access road and hardstand normally are paved. Power requirements for GCA equipment are--

  • AN/CPN-4. 16-kilowatt (kw), 120/208-v, 3-phase, 4-wire, 60-Hz.
  • AN/MPN-11. 20-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.
  • AN/TSQ-71. 10-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.

Radio homing beacon. Either an AN/MRT-7 (1/2-ton trailer), an AN/MRN-13 (1/2-ton trailer), or an AN/GRN-6 (3/4-ton truck) is applicable to field and intermediate construction. The AN/URN-5 or BC-446 is applicable to temporary construction. Power requirements for radio homing beacons are--

  • AN/MRT-7. 5-kw, 120-v, 1-phase, 60-Hz.
  • AN/MRN-13. 5-kw, 120-v, 1-phase, 60-Hz.
  • AN/GRN-6. 5-kw, 120-v, 1-phase, 60-Hz.
  • AN/URN-5. 6.9-kw, plus 10 kw for heaters, 120/240-v, 1-phase, 60-Hz, 3-wire.
  • BC/446. 5.5-kw, plus 10 kw for heaters, 120/240-v, 1-phase, 60-Hz, 3-wire.

In initial construction, trailer-mounted units without additional housing are sufficient. Keep access roads and hardstands to a minimum. In temporary construction, use one of the appropriate NAVAID buildings.

UHFDF. The AN/MRD-12 and AN/MRD-13 are used in initial construction, or an AN/MRD-12 can be used with the AN/MRN13 control tower. In temporary construction, use either AN/CRD-6, AN/FRD-2, or AN/URD-4. Power requirements for UHFDF equipment are--

  • AN/MRD-12. 5-kw, 120/240-v, 1-phase, 60-Hz.
  • AN/MRD-13. 5-kw, 120/240-v, 1-phase, 60-Hz.
  • AN/CRD-6. 4.3-kw, plus 10 kw for electric heater, 120/240-v, 1-phase, 60-Hz.
  • AN/FRD-2. 4.3-kw, plus 10 kw for electric heater, 120/240-v, 1-phase, 60-Hz.
  • AN/URD-4. 5-kw, 120/240-v, 1-phase, 60-Hz.

In initial construction, the trailer-mounted equipment only requires access roads and hardstands. In temporary construction, the equipment is housed in a prefab shelter or in one of the NAVAID buildings.

TACAN. Use the AN/TRN-6 or the AN/TRN-17 in all types of construction. Both pieces of equipment are air-transportable and are housed in prefab shelters. Power requirements for these systems are--

  • AN/TRN-6. 20.5-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.
  • AN/TRN-17. 10-kw, 120-v, 1-phase, 60-Hz.

RACON. Either the AN/CPN-6 or AN/FPN-13 is used in all types of construction. In initial construction, the equipment is housed in 16- by 32-foot tents. In temporary construction, one of the NAVAID buildings is used. The RACON power requirements are--

  • AN/CPN-6. 16.5-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.
  • AN/FPN-13. 26.9-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.

Remote receiver and transmitter building. In initial construction, use separate buildings to house the receiver and transmitter. Power requirements for the receiver and the transmitter are--

  • Receiver. 5-kw, 120-v, 1-phase, 60-Hz.
  • Transmitter. 15-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.

Control tower. In initial construction, use the AN/MRN-15 control tower mounted on a 1/4-ton trailer, the AN/TSQ-70 mounted on a 3/4-ton truck, or the AN/MRN-12 mounted on a 1 1/2-ton trailer with associated receiver and transmitter equipment. In temporary construction, construct a control tower with a 16- by 20-foot room at its base and use an AN/FSQ-75. The power required is 12-kw, 120/208-v, 3-phase, 4-wire, 60-Hz.


As previously stated, special airfields include DZs, EZs, and SOF airfields; blacked-out airfields; and airfields for UAVs.


DZs are used for delivering supplies by various methods of low-level parachute drop. The DZ should be as level as possible and clear of objects that could damage material and personnel being dropped. While the following paragraphs prescribe the normal minimum DZ sizes, for other than Air Force unilateral airdrops, the ground commander may waiver these minimums on a by-exception basis. Specific details on DZ operations are contained in Air Mobility Command (AMC) Regulation (Reg) 55-60.

Tactical Airlift Drop Zone

Tactical DZs (DZs that have not been formally surveyed) are sometimes selected to support highly mobile ground forces. These DZs are evaluated and approved using tactical survey procedures (see paragraph 1-27, AMC Reg 55-60). The DZ size should be determined by mode of delivery, load dispersal statistics, discussion with the receiving unit, and professional judgment.

Recoverability of air items and survivability or recoverability of the load should be considered. For example, small trees covering the entire DZ might limit the recovery of air items but allow complete recovery of the loads. Table 11-12 shows the minimum DZ sizes.

High-Altitude Airdrop Resupply System

Table 11-13 shows the minimum DZ sizes for the High-Altitude Airdrop Resupply System (HAARS) anti the High-Velocity Container Delivery System (HVCDS).

Special Operations Airdrops

During special operations airdrops, the minimum DZ sizes shown in Table 11-14 normally apply unless they are precluded by mission requirements.

Area Drop Zones

An area DZ (see Figure 11-28) consists of a start point (point A), an end point (point B), anti a prearranged flight path (line of flight) over a series of acceptable drop sites between these points. The distance between points A and B generally should not exceed 15 nautical miles (NM)/28 kilometers (km), and changes in ground elevation along the line of flight should not exceed 300 feet/90 meters. Drop sites along the line of flight should not be located more than 1/2 NM/km on either side. The reception committee is free to receive the drop at any location along the line of flight, and the drop is made once the prebriefed DZ visual signal or electronic NAVAID has been identified and located. DZ signals/NAVAIDs may be displayed or turned on during any portion of a 10-minute window. Ensure they are displayed/turned on 2 minutes before the aircraft is scheduled to arrive over that segment of the DZ.

Circular Drop Zones

A circular DZ is a round DZ with multiple run-in headings. The size of the DZ is governed by mission requirements and usable terrain. The radius of a circular DZ corresponds to the minimum required distance from the point of impact (POI) to one of the trailing edge corners of a rectangular DZ for the same type and number of loads being dropped (see Figure 11-29). In other words, the entire DZ box must fit inside the circle. The POI of a circular DZ is normally at the DZ center.

Drop-Zone Markings

DZs are normally marked with a raised angle marker (RAM) or VS-17 marker panels, omnidirectional visible lighting systems, and if required, rotating light beacons. Virtually any type overt lighting or visual marking system is acceptable if all participating units are briefed and concur in its use. Other day markings or visual acquisition devices include colored smoke, mirror, railroad fusees, or any reflective/contrasting marker panel (space blanket). In some cases, geographical points may be used. Night markings or acquisition aids may include a B-2 light gun, flares, fire/fire pots, railroad fusees, flashlights, or chemlights. Combat control units also may use specialized clandestine infrared (IR) lighting systems. Electronic markings may be used for either day or night operations.

Tactical Airlift Drop-Zone Markings

Timing points. Timing points are not normally required for tactical airlift airdrop operations. If they are needed to meet mission requirements and the terrain allows them, timing points should be equidistant from the extended DZ centerline--no more than 1,300 yards (1,183 meters) before the POI and 300 yards (273 meters) to 400 yards (364 meters) (350 yards (319 meters) minimum for C-141) on either side of the centerline (see Figure 11-30).

POI. See Table 11-15 for normal POI location. When mission requirements dictate, the random POI placement option may be used. In this option, the mission commander will notify the drop zone control (DZC) unit that random POI placement is to be used at least 24 hours in advance. When the DZ is set up, the DZC randomly selects a point on the DZ and establishes that point as the POI for the drop. The DZC ensures DZ minimum size requirements are met for the load being dropped and that the entire DZ falls within the surveyed boundaries. The mission commander or supported force commander also may request the DZ be set up with the POI at a specific point on the DZ. These requests also must be made at least 24 hours in advance. The requester either ensures the minimum DZ size requirements remain on the surveyed DZ or accepts responsibility for the drop if they do not. Both these procedures are used only during VFR operations. Aircrew schedulers ensure requests for these type operations are consolidated to prevent more than two POI location changes on one DZ during a mission or operation.

Unless otherwise coordinated with the aircrew, the POI is normally marked with a RAM (day operations) or a block letter (night operations).

  • The RAM is aligned into the aircraft line of flight with the base on the actual intended landing point. If required for additional identification or authentication colored panels (placed flat on the surface in a block letter or other prebriefed symbol) may be added.
  • Block letters are at least 35 feet by 35 feet. They consist of at least nine white/IR, omnidirectional lights for night (if the tactical environment permits). Letters authorized for POI markings are A, C, J, R, and S. The letters H and O may be used for circular DZs. If used for day operations, the letter will consist of at least nine marker panels.

If used, smoke is displayed next to and downwind of the POI for other than Container Delivery System (CDS) drops. For CDS, visual acquisition signals are normally displayed on the DZ centerline, 200 yards/180 meters short of the intended POI.

On small CDS (resupply) DZs where obstacles may prevent timely visual acquisition by the aircrew, visual signals may be displayed at the trailing edge of the DZ on the centerline or at another location on the DZ. If this option is exercised, the DZC must ensure all participating aircrews have been thoroughly briefed on the change in location.

Trailing edge. For night airdrops, the trailing edge marker (if used) will be an amber, rotating beacon (or other briefed light) placed at the trailing edge of the minimum size DZ (for the type airdrop being done) on the DZ centerline.

No-drop signals. A scrambled block letter, a block letter X, markings removed, red smoke, red flares, a red beam from a B-2 light gun, or any other precoordinated signal on the DZ indicates a no-drop condition. Temporary closing of the DZ or temporary delay of the airdrop is shown by forming the letter identifier into two parallel bars, placed perpendicular to the line of flight. These visual signals may be confirmed by radio communication to the aircraft if communications security permits.

Visual clearance. Unless radio communications are specifically required, any precoordinated marking (other than red smoke, flares, or lights) displayed on the DZ indicates clearance to drop.

Special-Use Drop-Zone Markings

Marked special operations drop zone. This is an authenticated drop zone, which has the POI or release point marked with a precoordinated signal. This marking may be either overt (block letter, flares, smoke, mirror, or RAM) or covert (IR strobe, RACON, or zone marker). No other markings are required. Unless radio communications are specifically required, any precoordinated marking (other than red smoke, flares, or lights) displayed on the DZ indicates clearance to drop. For personnel drops, the DZ will be visually marked to identify it as a hazard to parachutists.

RACONs. Tactical airlift airdrops using RACONs require the use of a collocated pair of tuned I-band (SST-181) beacons. MC130 aircraft can use a single I-band beacon or other type radar beacons. The TACAN is not normally placed on a DZ as an airdrop aid.

For special operation airdrops, NAVAIDs are placed as directed by the mission commander. They are normally located on the release point or on the POI.


EZs are areas used for delivering supplies and equipment by aircraft without actually landing. At an EZ, the load is removed from the aircraft by a deployed parachute. As the aircraft flies by, the parachute pulls the load from the aircraft. This is called a LAPES. Figure 11-31 shows a typical LAPES deployment from a C-130 aircraft. Specific details on EZs are contained in AMC Reg 55-60.

The LAPES, as described in the previous paragraph, is a low-altitude method of aerial delivery. This system employs a 15-foot drogue parachute deployed behind the aircraft and attached to a tow plate on the aircraft ramp. At the release point, the parachute forces are transferred from the tow plate to the ring slot or ribbon main extraction parachute(s) that then extract single or tandem platforms from the aircraft. Ground friction decelerates the load. Loads up to 42,000 pounds may be delivered into small areas using LAPES and tandem platforms. The total distance from release to stopping point of the load depends on ground speed, size, number of extraction parachutes, weight of the load(s), and type of terrain.

General EZ Criteria

Since proper site selection for the EZ depends on a variety of conditions, there are specific criteria that must be used to ensure a safe operation when physically locating the EZ. These criteria are shown in Figure 11-32.

Approach zones. The complete approach path for LAPES consists of the initial and final approach zones. These two zones overlap and use different glide slope ratios for obstacle clearance.

The initial approach zone is 10,500 feet long, and starts 11,000 feet and ends 500 feet (at the release panels) from the leading edge of the impact/slide-out zone. The recommended glide-slope ratio for obstacle clearance within this zone is 35:1.

For day operations, the final approach zone on the leading edge of the impact/slide-out zone should consist of two 400-foot zones (800 feet in total length). The inner 400-foot zone (nearest the impact/slide-out zone) may be a graduated slope with obstacles limited to a maximum of 1 foot at the leading edge of the impact/slide-out zone and 12 feet at the farthest edge from the impact/slide-out zone. The outer 400-foot zone may be a graduated slope with obstacles limited to a maximum of 12 feet at the inner edge and a maximum of 50 feet at the outer edge. The inner zone of the final approach zone must be sufficiently clear to make the impact panels clearly visible (because of the steep aircraft approach, the approach-zone slope must not exceed a 15:1 ratio).

For night operations, the final approach zone on the leading edge of the impact/slide-out zone should consist of two zones--one 600 feet long and the other 1,000 feet long (1,600 feet total length). The 600-foot zone nearest the impact/slide-out zone should be a level area with no obstacles over 1 foot high. The next 1,000-foot zone may be a graduated slope with obstacles limited to a maximum of 1 foot at the inner edge and a maximum of 12 feet at the outer edge. The entire portion of the final approach zone must be clear to make the approach zone and impact area lights clearly visible to the aircraft.

The impact/slide-out zone should be clear of obstructions and relatively flat. It may contain grass: dirt: sand: short, light brush; or snow.

The clear area may be a graduated slope with obstacles limited to a maximum of 1 foot high adjacent to the impact/slide-out zone and 2 feet at the outer edge.

The lateral safety zone may be a graduated slope with obstacles limited to a maximum of 2 feet at the inner edge and 12 feet at the outer edge.

The climb-out zone should contain no obstructions that would prevent a loaded aircraft from maintaining a normal obstacle clearance climb rate after an inadvertent touchdown, delivery abort, or extraction malfunction.

Multiple LAPES. Extraction lanes are designated in numerical sequence from left to right. The left lane in the direction of flight will be designated as lane one. The lead aircraft will extract on the downwind lane. Lane dimensions are the same as for single LAPES operations. When establishing two or more lanes, both sides of each lane are marked. If available, place radar reflectors at the trailing edge of the first and last lanes as shown in Figure 11-33. When possible, additional lanes are staggered 100 feet down from lane one. However, additional lanes are established side by side, beginning at the same parallel starting point. In all cases, there is 150 feet between lane centerlines. Minimum aircraft spacing is 10 seconds.

EZ marking equipment. EZs are normally marked with VS-17 marker panels, omnidirectional visible lighting systems, and if required, strobe lights, but virtually any type overt lighting or marking system is acceptable if all participating units are briefed.

EZ markings and identification. This information will be a special subject at the final briefing to ensure all required ground and aircrew members thoroughly understand the EZ recognition and identification procedures. EZ markings for day operations will be IAW Figure 11-34. EZ markings for night operations will be IAW Figure 11-35.

Control point. The control point for the EZ will be established at the direction of the extraction zone control (EZC). The EZC must take into account pertinent factors such as an unobstructed line of sight, winds, positive control of the EZ and surrounding airspace, and security requirements. The entire length of the extraction area(s) should be in full view of the EZC. It should, whenever possible, be upwind of the extraction area(s) so the dust and debris that rise from the EZ will not obscure the vision of the EZC.

Marking considerations. The EZ markings must be clearly visible to the pilot as early on the approach as possible. As a security precaution, night EZ markings should be visible only from the direction of the aircraft's approach. If flashlights are used, they may be equipped with simple hoods or shields and aimed toward the approaching aircraft. Fires or improvised flares may be screened on three sides or placed in pits with sides sloping toward the direction of approach. During daylight extractions, the marker panels should be slanted at a 45-degree angle from the surface toward the aircraft approach to increase the pilot's ability to see them.


Minimum airfield criteria for SOF are noted in Table 11-16. Runway marking patterns for SOF airfields are shown in Figures 11-36 and 11-37. Further detailed information on SOF airfields is contained in AMC Reg 55-60.


Airfields operating under blacked-out conditions are normally used by SOFs or special mission aircraft where aircrews use night vision goggles (NVG). For MC-130 aircraft used by SOFs, the minimum airfield criteria are noted in Table 11-16. Airfield marking patterns use no visual markings and are detailed in AMC Reg 55-60. For additional information on airfields where NVG are used, see Training Circular (TC) 1-204.


UAV airfields are used for UAV operations by military intelligence units for reconnaissance missions. Because of the limited geometric dimensions (1,800 feet long by 60 feet wide), a local asphalt or concrete road is normally used for the runway. However when a paved surface is not available, an airfield must be constructed. Because UAV operations must be mobile, the airfield is normally constructed of M-19 or AM-Z matting rather than asphalt or concrete.


The storage requirements for aviation fuels depend on the type and grade of fuel to be stored; the number and range of sorties to be flown; the type of aircraft used; the prestrike and poststrike refueling missions; and the support, transport, anti transient aircraft to be supported. The daily consumption of aviation fuels is a function of all these factors, and all factors should be considered when computing fuel consumption. The theater commander is responsible for establishing storage policy and requirements. Normally, facilities should provide storage for a 15-day operating supply. For planning storage facilities, lubricant requirements may be estimated as 1.304 percent of fuel requirements for reciprocating engines and 0.032 percent for jet engines.

The per-person/per-day method of estimating ground fuel and lubricant requirements described in FM 101-10-1 may be used to guide the early planning stages when definite information about the number and types of vehicles is not available. However, this method is not a substitute for more exacting computations. The theater commander is responsible for establishing the storage policy and requirements.

Types of Storage Facilities

Aviation and ground fuels are normally stored in drums; collapsible containers; or welded or bolted, above-ground storage tanks. Underground or revetted storage tanks may be required. This requirement is determined by the air or ground threat to the base and must be consistent with the overall vulnerability reduction program. Lubricants are only stored and distributed in drums. Recommended types of storage for different construction types follow:

  • Initial. Drums, collapsible containers, or fabric bags.
  • Temporary. Welded or bolted, steel tanks.

Construction Standards

The storage and distribution of aviation fuels and lubricants are direct-support operational functions, and construction is high priority. Initial construction is authorized under construction combinations A and B (Table 10-1). Temporary construction is authorized under combinations C, D, E, and F (Table 10-1).

Ground Fuels and Lubricants

The storage and distribution of ground fuels and lubricants is an indirect-support function, and construction is priority 2. Initial construction is authorized under construction combinations A, B, and C (Table 10-1). Temporary construction is authorized under combinations D, E, and F (Table 10-1).

Other Criteria

Information on fuel dispensing and distributing systems, TO pipeline systems, and tank-farm installations is given in FM 5-482 and TM 5-302-2. Petroleum handling operations are discussed in FM 10-69. Fuel storage requirements for Air Force airfields are discussed in Chapter 10.


Detailed computations of ammunition requirements and the consequent storage requirements depend on the mission, type and number of planes, number of sorties, takeoff load, and estimated ammunition expenditure rate. Calculate the requirements using information furnished by the theater commander. As a guide for temporary construction planning purposes, use the requirements in Table 11-17.

Temporary construction uses covered revetments, and initial construction uses unrevetted stacks. The layout of an explosive storage area is IAW TM 9-1300-206 and AFM 127-100.


Detailed information about space requirements and criteria for maintenance, supply, and administrative facilities is contained in Chapter 10. The AFCS, which is described in three manuals (TM 5-301, TM 5-302-series, and TM 5-304), allows the military planner and logistician to determine the Class IV materials required for engineer support of Army requirements.


Provide all-weather vehicle parks for squadron bomb trucks and fuel units, flight-control vehicles, engineer fire-fighting equipment, service-team vehicles, and squadron and group headquarter motor transport. Except for the area for fuel units and bomb trucks, locate vehicle parks away from the taxiway system.


At least one access road connecting the airfield site with the existing road net or adjacent railhead or port area is required. An installation containing operations and service facilities on both sides of a runway should have a perimeter road connected to the access road. Provide service roads with connections to hardstands, the control tower, service areas, fuel storage and dispensing areas, bomb and ammunition storage areas, and bivouac areas.


Where existing shelter is inadequate, provide tentage for initial construction. As construction progresses, portable, prefab housing or frame TO structures may be constructed. Do not locate bivouac areas in runway approach zones. Housing, administrative, and housekeeping facilities for officers and enlisted personnel may be dispersed or concentrated IAW the base dispersal policy.

The efficiency of an installation can be greatly increased by careful placement of bivouacs to minimize the distance traveled by personnel to and from duty stations, even though such facilities are not placed within the operational perimeter of the airfield.


Conduct air-base damage repair (ADR) operations, including emergency or rapid runway repair (RRR), as outlined in Chapter 8, FM 5-430-1/AFPAM 32-8013, Vol 1. Further detailed information can be found in Department of Defense (DOD) Directive 1315.6, TC 5-340, AFR 93-2, and AFP 93-12.

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