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AIM

10/12/17

4−7−1

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

/avs/offices/afx/afs/afs400/afs470/media/

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.

4−7−2. 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