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AIM

10/12/17

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−7−1

Operational Policy/Procedures for the Gulf of Mexico 50 NM Lateral Separation Initiative

Section 7. Operational Policy/Procedures for the Gulf of

Mexico 50 NM Lateral Separation Initiative

4

−7−1. Introduction and General Policies

a.

Air traffic control (ATC) may apply 50 nautical

mile (NM) lateral separation (i.e., lateral spacing)
between airplanes authorized for Required Naviga-
tion Performance (RNP) 10 or RNP 4 operating in the
Gulf of Mexico. 50 NM lateral separation may be
applied in the following airspace:

1.

Houston Oceanic Control Area (CTA)/Flight

Information Region (FIR).

2.

Gulf of Mexico portion of the Miami Oceanic

CTA/FIR.

3.

Monterrey CTA.

4.

Merida High CTA within  the Mexico

FIR/UTA.

b.

Within the Gulf of Mexico airspace described

above, pairs of airplanes whose flight plans indicate
approval for PBN and either RNP 10 or RNP 4 may
be spaced by ATC at lateral intervals of 50 NM. ATC
will space any airplane without RNP 10 or RNP 4
capability such that at least 90 NM lateral separation
is maintained with other airplanes in the Miami
Oceanic CTA, and at least 100 NM separation is
maintained in the Houston, Monterrey, and Merida
CTAs.

c.

The reduced lateral separation allows more

airplanes to fly on optimum routes/altitudes over the
Gulf of Mexico.

d.

50 NM lateral separation is not applied on

routes defined by ground navigation aids or on Gulf
RNAV Routes Q100, Q102, or Q105.

e.

Information useful for flight planning and

operations over the Gulf of Mexico under this 50 NM
lateral separation policy, as well as information on
how to obtain RNP 10 or RNP 4 authorization, can be
found in the West Atlantic Route System, Gulf of
Mexico, and Caribbean Resource Guide for U.S.
Operators located at:

www.faa.gov/about/office_org/headquarters_offices
/ a v s / o ff i c e s / a f x / a f s / a f s 4 0 0 / a f s 4 7 0 / m e d i a /
WATRS.pdf

f.

Pilots should use Strategic Lateral Offset

Procedures (SLOP) in the course of regular
operations within the Gulf of Mexico CTAs. SLOP
procedures and limitations are published in the U.S.
Aeronautical Information Publication (AIP), ENR
Section 7.1, General Procedures; Advisory Circular
(AC) 91

−70, Oceanic and Remote Continental

Airspace Operations; and ICAO Document 4444,
Procedures for Air Navigation Services – Air Traffic
Management.

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−7−2. Accommodating Non−RNP 10

Aircraft

a.

Operators not authorized for RNP 10 or RNP 4

may still file for any route and altitude within the Gulf
of Mexico CTAs. However, clearance on the
operator’s preferred route and/or altitude will be
provided as traffic allows for 90 or 100 NM lateral
separation between the non

−RNP 10 aircraft and any

others. Priority will be given to RNP 10 or RNP 4
aircraft.

b.

Operators of aircraft not authorized RNP 10 or

RNP 4 must include the annotation “RMK/NON-
RNP10” in Item 18 of their ATC flight plan.

c.

Pilots of non

−RNP 10 aircraft are to remind

ATC of their RNP status; i.e., report “negative
RNP 10” upon initial contact with ATC in each Gulf
CTA.

d.

Operators will likely benefit from the effort

they invest to obtain RNP 10 or RNP 4 authorization,
provided they are flying aircraft equipped to meet
RNP 10 or RNP 4 standards.

4

−7−3. Obtaining RNP 10 or RNP 4

Operational Authorization

a.

For U.S. operators, AC 90

−105, Approval

Guidance for RNP Operations and Barometric
Vertical Navigation in the U.S. National Airspace
System and in Oceanic and Remote Continental
Airspace, provides the aircraft and operator
qualification criteria for RNP 10 or RNP 4
authorizations. FAA personnel at flight standards
district offices (FSDO) and certificate management
offices (CMO) will use the guidance contained in

3/29/18

AIM