Section 2. SUA
Legal Descriptions
21-2-1. GENERAL
a. 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.
b. All bearings and radials used in SUA legal
descriptions are true from point of origin.
c. Mileage used in the description must be
expressed in nautical miles (NM).
d. Descriptions of approved SUA, except temporary
areas and CFA's, are compiled and published once a year
in FAAO JO 7400.8, Special Use Airspace. Updates to the
order are not published between editions and the
listings are considered current only as of the date
specified in the order. For this reason FAAO JO 7400.8
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 Airspace Regulations and ATC Procedures
Group or AIM.
21-2-2. LATERAL
BOUNDARIES
a. SUA lateral boundaries are normally defined by
geographic (latitude/longitude) coordinates. All
coordinates must be expressed in a “degrees, minutes,
and seconds" format. Do not round off, or convert
seconds to tenths of minutes (enter 00' and 00" to
specifically reflect the “zero" minutes and “zero"
seconds places respectively). See
TBL 21-2-1 for examples.
b. 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.
When a NAVAID is used as a reference point, include its
geographic location in degrees, minutes, and seconds.
c. 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.
d. Except for temporary SUA areas, boundaries
must not be described as “along the boundary" of another
designated airspace area.
e. Where feasible, consider subdividing large SUA
areas to enhance joint use of the airspace.
21-2-3. VERTICAL
LIMITS
a. For areas that contain aircraft operations
exclusively, altitudes at or above 18,000 feet MSL must
be expressed as flight levels (FL).
b. For areas that contain other than aircraft
operations, altitudes above 18,000 feet MSL must be
expressed in feet above MSL.
c. 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).
d. 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.
e. 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."
f. 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.
g. Where feasible consider
stratification of SUA areas to enhance joint-use of the
airspace.
21-2-4. TIMES
OF USE
a. The times of use indicate the period during
which the using agency is authorized to schedule and use
a SUA area. 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.
NOTE-
The times of use should be based on the intended typical
use of the area. These times are depicted on
aeronautical charts to assist other airspace users in
determining the most likely periods of area activation.
b. 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.
EXAMPLE-
1. “0700 - 2200, Monday - Friday."
2. “Sep - Apr, 0800 - 1700, Monday - Friday;
an May - Aug, 0600 - 2400 Monday - Friday."
3. “0800 - 0930 and 1300 - 1600, Monday -
Friday."
4. “0700 - 1600, daily."
NOTE-
1. As used in SUA legal descriptions, the
term “daily" means 7 days per week.
2. If the SUA area overlaps more than one
local time zone, state the predominant time zone in the
description, for example: “0700 - 1800 central time;
Monday - Friday."
2. 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."
3. 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:
(a) “Other times by NOTAM." Used along with
specific times to provide for activation of the area
outside the specified times of use that were established
according to b.1.,
above.
EXAMPLE-
“0700-1900 local time, Monday - Friday - other times by
NOTAM."
(b) “By NOTAM," along with specific times from
b.1.,
above: Used when issuance of a NOTAM is required prior
to activating the area during the specified hours.
EXAMPLE-
1. “By NOTAM 0700-1800 local time, Monday
- Friday."
2. “0700-1800 local time, Monday - Friday, by
NOTAM 4 hours in advance."
(c) “By NOTAM" without specific times: Used when
anticipated usage times cannot be specifically
determined, or when the nature of the user's mission
requires infrequent or erratic use.
(d) The NOTAM provision must apply to the entire
area and not only a portion thereof. If times of use
will vary from one portion of the area to another, the
dissimilar portions should be subdivided or redesignated
as separate areas.
(e) NOTAMs should be issued as far in advance as
feasible to ensure widest dissemination of the
information to airspace users. Normally, the minimum
advance notice should be at least 4 hours prior to the
activation time.
NOTE-
Under no circumstances may SUA be activated by a NOTAM
unless the words “By NOTAM" or “other times by NOTAM"
are stated in the area's legal description.
4. Sunrise to sunset. This option should be
reserved for cases where seasonal sunrise/sunset time
variations make publication of specific clock times
impractical.
5. Intermittent. Must include
an associated time-period or “by NOTAM" provision. In
any case, intermittent must not be used for restricted
areas without a “by NOTAM" provision.
EXAMPLE-
1. “Intermittent, 0700 - 2200, Monday -
Friday."
2. “Intermittent by NOTAM at least 4 hours in
advance."
21-2-5. CONTROLLING AGENCY
The ATC facility designated as the controlling agency
(see paragraph
21-1-10).
NOTE-
A controlling agency is not designated for prohibited
areas, alert areas, or controlled firing areas.
21-2-6. USING AGENCY
The agency, organization, or military command designated
as the using agency (see paragraph 21-1-11).
21-2-7. 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 times of use.
TBL 21-2-1
EXAMPLES OF SPECIAL USE AIRSPACE LEGAL
DESCRIPTIONS
REGULATORY SUA DESCRIPTION:
R-2305 Gila Bend, AZ
Boundaries - Beginning at lat. 32°50'25"N., long.
112°49'03"W.;
to lat. 32°50'52"N., long. 112°42'56"W.;
to lat. 32°49'00"N., long. 112°39'03"W.;
to lat. 32°29'00"N., long. 112°43'03"W.;
to lat. 32°29'00"N., long. 112°53'33"W.;
to the point of beginning.
Designated altitudes Surface to FL 240.
Time of designation 0700-2300 local time daily,
other times by NOTAM.
Controlling agency FAA, Albuquerque ARTCC.
Using agency U.S. Air Force, 58th Fighter Wing,
Luke AFB, AZ.
NONREGULATORY SUA DESCRIPTION:
Taiban MOA, NM
Boundaries - Beginning at lat. 34°34'36"N., long.
104°07'00"W.;
to lat. 34°33'00"N., long. 103°55'02"W.;
to lat. 34°10'00"N., long. 103°55'02"W.;
to lat. 34°10'00"N., long. 104°07'00"W.;
to the point of beginning.
Altitudes 500 feet AGL to but not including FL
180.
Times of use 0800-2400 Monday-Friday; other times
by NOTAM.
Controlling agency FAA, Albuquerque ARTCC.
Using agency U.S. Air Force, Commander, 27th
Fighter Wing,
Cannon AFB, NM.
COORDINATE FORMAT - Do not round off latitude and
longitude coordinates. Always use the full format
consisting of degrees, minutes, and seconds, as follows:
Correct Incorrect
40°06'00"N. 40°06'N.
104°35'30"W. 104°35.5'W.
39°00'00"N. 39°N.
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