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 shall 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 and Rules or AIM.
21-2-2. LATERAL BOUNDARIES
a. SUA lateral boundaries are normally defined by
geographic (latitude/longitude) coordinates. All
coordinates shall 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
shall 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
shall be expressed as flight levels (FL).
b. For areas that contain other than aircraft
operations, altitudes above 18,000 feet MSL shall 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 shall 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 shall 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 shall 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 shall 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 shall 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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