Gulf RNP Lateral Separation

AIM ¶ 4-7-1 Gulf RNP Lateral Separation

AIM 4-7-1 explains 50 NM lateral separation in the Gulf of America for RNP 10/RNP 4 aircraft. Key facts for pilot oral exams and checkrides.

In Plain English

AIM 4-7-1 describes how ATC applies 50 NM lateral separation between aircraft authorized for RNP 10 or RNP 4 when operating over the Gulf of America. This reduced spacing lets more airplanes fly optimum routes and altitudes in oceanic airspace where radar coverage is limited.

The 50 NM lateral separation may be used in:

  • Houston Oceanic CTA/FIR
  • Gulf of America portion of the Miami Oceanic CTA/FIR
  • Monterrey CTA
  • Merida High CTA within the Mexico CTA/FIR

To qualify, your flight plan must indicate PBN approval along with RNP 10 or RNP 4. Aircraft without RNP 10/4 capability are spaced farther apart:

  • At least 90 NM in Miami Oceanic CTA/FIR
  • At least 100 NM in Houston, Monterrey, and Merida CTA/FIRs

The 50 NM standard does not apply on routes defined by ground navaids or on Gulf RNAV Routes Q100, Q102, or Q105. Operators can find planning details and RNP authorization guidance in the FAA's West Atlantic, Gulf of America, and Caribbean Resource Guide. This is a recommended/operational policy, not a regulatory mandate on pilots.

AIM Source Text
FAA AIM ¶ 4-7-1
4-7-1. 4-7-1. Introduction and General Policies Air traffic control (ATC) may apply 50 nautical mile (NM) lateral separation (i.e., lateral spacing) between airplanes authorized for Required Navigation Performance (RNP) 10 or RNP 4 operating in the Gulf of America. 50 NM lateral separation may be applied in the following airspace: Houston Oceanic Control Area (CTA)/Flight Information Region (FIR). Gulf of America portion of the Miami Oceanic CTA/FIR. Monterrey CTA. Merida High CTA within the Mexico CTA/FIR. Within the Gulf of America 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/FIR, and at least 100 NM separation is maintained in the Houston, Monterrey, and Merida CTA/FIRs. The reduced lateral separation allows more airplanes to fly on optimum routes/altitudes over the Gulf of America. 50 NM lateral separation is not applied on routes defined by ground navigation aids or on Gulf RNAV Routes Q100, Q102, or Q105. Useful information for flight planning and operations over the Gulf of America, 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, Gulf of America, and Caribbean Resource Guide for U.S. Operators located at: https://www.faa.gov/headquartersoffices/avs/wat-gulf-and-caribbean-resource-guide .
Oral Exam Questions a DPE Might Ask
Q1What lateral separation does ATC apply between RNP 10 or RNP 4 authorized aircraft in the Gulf of America?
Per AIM 4-7-1, ATC may apply 50 NM lateral separation between airplanes authorized for RNP 10 or RNP 4 operating in the Gulf of America airspace.
Q2If your aircraft is not RNP 10 or RNP 4 authorized, what lateral separation will ATC apply in Gulf of America airspace?
Per AIM 4-7-1, ATC will maintain at least 90 NM lateral separation in the Miami Oceanic CTA/FIR and at least 100 NM in the Houston, Monterrey, and Merida CTA/FIRs.
Q3Where does the 50 NM lateral separation standard NOT apply?
Per AIM 4-7-1, 50 NM lateral separation is not applied on routes defined by ground navigation aids or on Gulf RNAV Routes Q100, Q102, or Q105.
Related Paragraphs in AIM Chapter 4
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AIM 4-7-1 — Gulf of America 50 NM Lateral Separation