Section 2. SUA Legal Descriptions

1. GENERAL

1. The legal description is the official airspace definition used for NAS database and charting purposes. This section provides guidelines and formats for preparing SUA legal descriptions. See TBL 21-2-1 for examples of regulatory and nonregulatory SUA legal descriptions.
2. All bearings and radials used in SUA legal descriptions are true from point of origin.
3. Mileages used in SUA legal descriptions must be expressed in nautical miles (NM).
4. Descriptions of approved SUA, except temporary areas and CFAs, are compiled and published once a year in FAA Order JO 7400.10, Special Use Airspace. Updates to the order are not published between editions and the descriptions are considered current only as of the date specified in the order. For this reason, FAA Order JO 7400.10 should be used as a general reference only and should not be relied upon as a sole source when accurate positional data are needed (e.g., video maps, letters of agreement, etc.). For up-to-date descriptions of SUA areas, contact the Rules and Regulations Group, AJV-P2 or AIS.

1. BOUNDARIES

1. SUA boundaries are normally defined by geographic (latitude/longitude) coordinates. All coordinates must be expressed in a “degrees, minutes, and seconds" format using whole numbers. Do not convert seconds to tenths of minutes. To reflect “zero" minutes or “zero" seconds, enter 00' or 00" respectively. See TBL 21-2-1 for examples.
2. Other methods may be used to define boundaries, if necessary, to simplify the description, such as defining the boundaries by reference to a NAVAID radial/DME or NAVAID arc.
3. To aid pilots in area identification, boundaries may be aligned along a prominent terrain feature, such as rivers, highways, railroad tracks, etc., provided the feature is clearly discernable from the air.
4. Except for temporary SUA areas, boundaries must not be described as “along the boundary" of another designated airspace area.
5. Consider subdividing SUA areas laterally to enhance joint-use of the airspace.

1. ALTITUDES

1. For SUA areas that contain aircraft operations exclusively, altitudes at or above 18,000 feet MSL must be expressed as flight levels (FL).
2. For SUA areas that contain other than aircraft operations, or a combination of aircraft and other than aircraft operations, altitudes at or above 18,000 feet MSL must be expressed in feet above MSL.
3. Where terrain considerations or other factors would make the use of an MSL altitude impractical, the floor of the area may be described in feet above ground level (AGL).
4. In describing SUA ceilings, unless otherwise specified in the description, the word “to" an altitude or flight level means “to and including" that altitude or flight level. If the upper vertical limit does not include the altitude or flight level, the ceiling must be stated as “to but not including" the altitude or flight level.

1. Do not designate variable altitudes to describe the floor or the ceiling of an SUA area. When there is a requirement for the altitude of the floor or ceiling to change based on time of use, or geographic position within the SUA area, etc., the differing sections must be established as separate subdivisions.
   EXCEPTION-
   The floor of an area may be described using a combination of MSL and AGL altitudes if necessary due to terrain or operational considerations. For example, “5,000 feet MSL or 3,000 feet AGL, whichever is higher."
2. In limited situations, and provided a specific operational requirement exists, the same altitude may be used to describe both the ceiling of one SUA subdivision and the floor of an overlying subdivision. In this case, the same ATC facility must be designated as the controlling agency for both subdivisions.
3. Consider subdividing SUA areas vertically to enhance joint-use of the airspace.

1. TIME OF DESIGNATION (RULEMAKING SUA) / TIMES OF USE (NON-RULEMAKING SUA)

1. The time of designation/times of use indicate the period during which the using agency is authorized to schedule and use a SUA area. The time of designation applies to SUA rulemaking and times of use applies to SUA non-rulemaking. These times should reflect when normal operations are expected to occur. In determining the times of use, the proponent should select the minimum period needed to meet the using agency's requirements. The goal is to capture the majority of the day-to-day activities. When the using agency has a requirement for intermittent, less frequent use of the airspace (outside the specific published time period), a provision to activate the airspace by NOTAM may be stated in the SUA legal description.

1. Times of use are stated using the options, or combination of options, shown below:

1. Specific hours/days. Local time using the 24-hour clock, and days of the week. If the time of use will change significantly on a seasonal basis, or mission requirements call for specific time blocks, variable times of use may be designated. NOTAMs will not be issued when the time of designation/times of use for a SUA area reflect specific hours/days only.

1. Continuous. Use only when justification exists for utilization 24 hours a day, 365 days a year.
   EXCEPTION-
   “Continuous" may also be used when the area will be utilized 24 hours per day over a specific period, such as “Continuous, Monday - Friday;" or “Continuous, April - June."
2. NOTAM activation. Use “By NOTAM" or “Other Times by NOTAM" to indicate when a NOTAM must be issued in order to activate the area. NOTAM options are:

1. “Other times by NOTAM." Used along with specific times to provide for activation of the SUA area outside the specified times of use that were established according to b.1., above.

1. “By NOTAM," with specific times from b.1., above. Used when issuance of a NOTAM is required prior to activating the area during the specified hours.

1. “By NOTAM" without specific times. Used when anticipated usage times cannot be specifically determined, or when the user's mission requires infrequent or erratic use.
2. The NOTAM provision must apply to the entire area and not only a portion thereof. If the time of designation or times of use will vary from one portion of the area to another, the dissimilar portions should be subdivided as separate areas.
3. NOTAMs should be issued as far in advance as feasible to ensure widest dissemination of the information to airspace users.

1. Sunrise to sunset. This option should be reserved for cases where seasonal sunrise/sunset time variations make publication of specific clock times impractical.
2. Intermittent. Must include an associated time-period or “by NOTAM" provision. In any case, intermittent for restricted areas must include a “by NOTAM" provision even if an associated time-period is identified.

1. CONTROLLING AGENCY

The ATC facility designated as the controlling agency (see paragraph 21-1-10).

1. USING AGENCY

The using agency, is the organization, or military command/unit whose activity established the requirement for the SUA. For military using agencies, specify the military service, command/unit, and location. For non-military using agencies, specify the organization name and location.

1. SUA LEGAL DESCRIPTION AMENDMENTS

All changes to a published SUA legal description must be made through the appropriate regulatory or non-regulatory procedures described in this order. This includes minor changes, editorial corrections, internal subdivisions of an existing area, changes of the controlling or using agency, or reducing the area's dimensions or time of designation/times of use.