Chapter 4. Air Traffic Control | Section 7. Operational Policy/Procedures for the Gulf of Mexico 50 NM Lateral Separation Initiative
4-7-1. Introduction and Background
a. Introduction. On 20 October 2011 at 0900 UTC, the Federal Aviation Administration (FAA), Serviciós a la Navegacion en el Espacio Aéreo Mexicano (SENEAM) and the Direccion General de Aeronautica Civil (DGAC) Mexico implemented 50 Nautical Mile (NM) lateral separation between aircraft authorized Required Navigation Performance 10 (RNP 10) or RNP 4 operating in the Gulf of Mexico (GoMex) Oceanic Control Areas (CTA). Existing Air Traffic Services (ATS) routes and route operating policies did not change for this implementation.
b. RNP 10 Versus RNAV 10 Terminology. “RNP 10” has the same meaning and application as “RNAV 10”. The ICAO Performancebased Navigation (PBN) Manual (ICAO Doc 9613), Volume II, Part B, Chapter 1 (Implementing RNAV 10, Designated and Authorized as RNP 10) explains that the term “RNP 10” was in use before the publication of the ICAO PBN Manual and the manual has “grandfathered in” its continued use when implementing an “RNAV 10” navigation specification.
c. Background. 50 NM lateral separation was first applied between aircraft authorized for RNP 10 operations on the North Pacific Route System in April 1998. Since that time, 50 NM lateral separation has been expanded throughout the Pacific Flight Information Regions (FIRs) and is currently applied in other airspaces, including, starting in June 2008, the West Atlantic Route System. GoMex 50 NM lateral separation implementation will apply the experience gained in those operations.
d. Project Objectives. The project objectives were to:
1. Reduce lateral separation to 50 NM between aircraft authorized RNP 10 or RNP 4.
2. Leave existing ATS routes and operating policies in place.
3. Have approximately 90% of flights conducted by operators/aircraft over the Gulf of Mexico authorized for RNP 10 or RNP 4 operations by the appropriate State authority.
4. Accommodate the operation of the small percentage of flights not authorized RNP 10.
5. Establish a policy that aircraft equipped with a Single LongRange Navigation System (SLRNS) can qualify for RNP 10 operations in the Gulf of Mexico in accordance with the ICAO PBN Manual and the appropriate FAA and DGAC documents. (See paragraph 4-7-7e.)
e. Control Areas (CTA) Affected. 50 NM lateral separation is implemented in the following CTAs/FIRs/Upper Control Areas (UTA).
1 The Houston Oceanic CTA/FIR and the Gulf of Mexico portion of the Miami Oceanic CTA/FIR.
(a) The Monterrey CTA and Merida High CTA within the Mexico FIR/UTA
f. Policy and Procedures Coordination with SENEAM and the DGAC. The policies and procedures were coordinated with SENEAM and the Mexico DGAC. They are applied in the GoMex CTA's where the FAA and SENEAM provide Air Traffic Control.
4-7-2. Gulf of Mexico 50 NM Lateral Separation Initiative Web Page: Policy, Procedures and Guidance for Operators and Regulators
Information on plans, policies and procedures for 50 NM lateral separation is posted on the “Gulf of Mexico 50 NM Lateral Separation Web Page”:
The web page contains detailed guidance on operator and aircraft authorization for RNP 10 or RNP 4 and includes Job Aids with FAA and ICAO document references.
4-7-3. Lateral Separation Minima Applied
a. 50 NM lateral separation is applied in the GoMex CTA's between aircraft authorized RNP 10 or RNP 4 at all altitudes above the floor of controlled airspace.
b. The current lateral separation minima of 100 NM in the Houston, Monterrey and Merida CTAs, and 90 NM in the Miami Oceanic CTA will continues to be applied between aircraft not authorized RNP 10 or RNP 4.
4-7-4. Operation on Routes on the periphery of the Gulf of Mexico CTAs
Operations on certain routes that fall within the boundaries of affected CTAs are not affected by the introduction of 50 NM lateral separation. Operation on the following routes is not affected:
a. Routes that are flown by reference to ICAO standard groundbased navigation aids (VOR, VOR/DME, NDB).
b. Special Area Navigation (RNAV) routes Q100, Q102 and Q105 in the Houston, Jacksonville and Miami CTAs.
4-7-5. Provisions for Accommodation of NonRNP10 Aircraft (Aircraft Not Authorized RNP 10 or RNP 4)
a. Operators of NonRNP10 aircraft must annotate ICAO flight plan Item 18 as follows:
“STS/NONRNP10” (no space between letters and numbers).
b. Pilots of NonRNP10 aircraft that operate in GoMex CTA's must report the lack of authorization by stating “Negative RNP 10”:
1. On initial call to ATC in a GoMex CTA:
c. Operators of NonRNP10 aircraft must not annotate ICAO flight plan Item 18 (Other Information) with “NAV/RNP10” or “NAV/RNP4”, as shown in paragraph 7, if they have not obtained RNP 10 or RNP 4 authorization.
d. NonRNP10 operators/aircraft may file any route at any altitude in a GoMex CTA. They will be cleared to operate on their preferred routes and altitudes as traffic permits. 50 NM lateral separation will not be applied to NonRNP10 aircraft.
e. NonRNP10 aircraft are encouraged to operate at altitudes above those where traffic is most dense (i.e., at/above FL 380), if possible. NonRNP10 aircraft should plan on completing their climb to or descent from higher FLs within radar coverage, if possible.
4-7-6. Operator Action
In order to maximize operational flexibility provided by 50 NM lateral separation, operators capable of meeting RNP 10 or RNP 4 that operate on oceanic routes or areas in the GoMex CTA's should obtain authorization for RNP 10 or RNP 4 and annotate the ICAO flight plan accordingly.
1. RNP 10 is the minimum “Navigation Specification (NavSpec)” required for the application of 50 NM lateral separation. RNP 4 is an operator option. Operators/aircraft authorized RNP 4 are not required to also obtain RNP 10 authorization.
2. “RNP navigation specification” (e.g., RNP 10) is the term adopted in the ICAO Performancebased Navigation (PBN) Manual (Doc 9613). It replaces the term “RNP type”.
4-7-7. RNP 10 or RNP 4 Authorization: Policy and Procedures for Aircraft and Operators
a. RNP NavSpecs Applicable To Oceanic Operations. In accordance with ICAO guidance, RNP 10 and RNP 4 are the only NavSpecs applicable to oceanic and remote area operations. Other RNAV and RNP NavSpecs are applicable to continental en route, terminal area and approach operations.
b. FAA Documents. The guidance and direction of FAA Order 8400.12 (as amended) (RNP 10 Operational Authorization) is used to grant RNP 10 authorization to operators and aircraft for which the FAA is responsible. FAA Order 8400.33 (as amended) (Procedures for Obtaining Authorization for RNP 4 Oceanic/Remote Area Operations) is used to authorize RNP 4. The FAA RNP 10 and RNP 4 orders are consistent with the ICAO PBN Manual guidance discussed below. FAA and ICAO documents are posted on the FAA Gulf of Mexico 50 NM Lateral Separation Initiative Web Page.
c. ICAO Performancebased Navigation (PBN) Manual (ICAO Doc 9613). Guidance for authorization of RNP 10 and RNP 4 is provided in ICAO Doc 9613. RNP 10 is addressed in Volume II, Part B; Chapter 1. RNP 4 is addressed in Volume II, Part C; Chapter 1.
d. RNP 10 and RNP 4 Job Aids. Operators and authorities are encouraged to use the RNP 10 or RNP 4 Job Aids posted on the FAA Gulf of Mexico 50 NM Lateral Separation Initiative Web Page. For U.S. operators, one set of RNP 10 and RNP 4 Job Aids provides references to FAA documents. For international operators, a second set of Job Aids provide references to the ICAO PBN Manual. These Job Aids address the operational and airworthiness elements of aircraft and operator authorization and provide references to appropriate document paragraphs. The Job Aids provide a method for operators to develop and authorities to track the operator/aircraft program elements required for RNP 10 or RNP 4 authorization.
e. Qualification of Aircraft Equipped With a Single LongRange Navigation System (SLRNS) For RNP 10 Operations In GoMex CTA's.
1. Background. SLRNS operations in the Gulf of Mexico, the Caribbean Sea and the other designated areas have been conducted for at least 25 years. Provisions allowing aircraft equipage with a SLRNS for operations in specified oceanic and offshore areas are contained in the following sections of 14 Code Of Federal Regulations (CFR): 91.511, 121.351, 125.203 and 135.165.
2. ICAO PBN Manual Reference. In reference to RNP 10 authorization, the ICAO PBN Manual, Volume II, Part B, Chapter 1, paragraph 188.8.131.52 states that: “A State authority may approve the use of a single LRNS in specific circumstances (e.g., North Atlantic MNPS and 14 CFR 121.351 (c) refer). An RNP 10 approval is still required.”
3. Policy Development. The FAA worked with the ICAO NACC Office (North American, Central American and Caribbean), State regulators and ATS providers in the GoMex and Caribbean areas to implement a policy for SLRNS equipped aircraft to qualify for RNP 10 for GoMex operations. Allowing SLRNS equipped aircraft to qualify for RNP 10 enables more operator aircraft to be authorized RNP 10, thereby creating a more uniform operating environment for the application of 50 NM lateral separation. The factors considered were: the shortness of the legs outside the range of ground navigation aids, the availability of radar and VHF coverage in a large portion of GoMex airspace and the absence of events attributed to SLRNS in GoMex operations.
4. Document Revision. The following documents were revised or created to enable implementation of the SLRNS/RNP 10 qualification policy:
(a) FAA Order (FAAO) 8400.12
(b) FAA Order 8900.1 (Flight Standards Information Management System (FSIMS))
(c) Paragraph B054 of FAA Operations Specifications and Management Specifications (Class II Navigation Using Single LongRange Navigation System)
(d) LOA B054 (Class II Navigation Using Single LongRange Navigation System (SLRNS) Equipped Airplane Authorized RNP 10) (LOA's are applicable to International General Aviation operators.)
(e) FAA RNP 10 Job Aid with FAAO 8400.12 references
(f) RNP 10 Job Aid with ICAO PBN Manual references
5. SLRNS/RNP 10 Authorization Limited To GoMex. At this time, SLRNS qualification for RNP 10 only applies to GoMex operations. Any expansion of this provision will require assessment and agreement by the appropriate State authorities.
f. RNP 10 Time Limit for INS or IRU Only Equipped Aircraft. Operators should review their Airplane Flight Manual (AFM), AFM Supplement or other appropriate documents and/or contact the airplane or avionics manufacturer to determine the RNP 10 time limit applicable to their aircraft. They will then need to determine its effect, if any, on their operation. Unless otherwise approved, the basic RNP 10 time limit is 6.2 hours between position updates for aircraft on which Inertial Navigation Systems (INS) or Inertial Reference Units (IRU) provide the only source of long range navigation. Extended RNP 10 time limits of 10 hours and greater are already approved for many IRU systems. FAA Order 8400.12 contains provisions for extending RNP 10 time limits.
4-7-8. Flight Planning Requirements
Operators must make ICAO flight plan annotations in accordance with this paragraph and, if applicable, paragraph 4-7-5, Provisions for Accommodation of NonRNP10 Aircraft (Aircraft Not Authorized RNP 10 or RNP 4).
a. ICAO Flight Plan Requirement. ICAO flight plans must be filed for operation on oceanic routes and areas in the Houston Oceanic CTA/FIR, the Gulf of Mexico portion of the Miami CTA/FIR, the Monterrey CTA and Merida High CTA.
b. To inform ATC that they have obtained RNP 10 or RNP 4 authorization and are eligible for 50 NM lateral separation, operators must:
1. Annotate ICAO Flight Plan Item 10 (Equipment) with the letters “R” and “Z”, and
2. Annotate Item 18 (Other Information) with, as appropriate, “NAV/RNP10” or “NAV/RNP4” (no space between letters and numbers).
2. On the ICAO Flight Plan, the letter “R” in Item 10 indicates that the aircraft will maintain the appropriate RNP navigation specification for the entire flight through airspace where RNP is prescribed. Letter “Z” in Item 10 indicates that information explaining aircraft navigation and/or communication capability is found in Item 18.
d. Operators that have not obtained RNP 10 or RNP 4 authorization must not annotate ICAO flight plan Item 18 (Other information) with “NAV/RNP10” or “NAV/RNP4”, but must follow the practices detailed in paragraph 4-7-5.
e. Recommendation for Filing to Show Domestic U.S. RNAV and Oceanic RNP Capabilities.
1. Explanation. The FAA program to enhance operators' capability to communicate their domestic U.S. RNAV capabilities to ATC has been in place for over three years. It requires an entry following the NAV/ indicator in Item 18 of the ICAO flight plan. The initiative has provisions for including RNAV capabilities for departure (“D”), enroute (“E”) and arrival (“A”) with RNAV accuracy values. Detailed instructions are available on the following web page: http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/
An example Item 18 entry is: NAV/RNVD1E2A1. The characters in the example indicate RNAV 1 and RNAV 2 accuracy.
2. Recommendation. It is recommended that operators provide their RNAV capability for domestic U.S. and capabilities for oceanic operations (RNP 10 or RNP 4) by filing: “NAV/”, then the domestic U.S. alphanumeric sequence, then a mandatory space and then “RNP10” or “RNP4”, as appropriate.
3. Multiple NAV/ Entries. Operators should be aware that if they make multiple “NAV/” entries in a flight plan filed with EUROCONTROL, only the last “NAV/” entry will be forwarded to the next ATC facility. For example, if “NAV/RNVD1E2A1” and “NAV/RNP10” are entered, only “NAV/RNP10” will be forwarded. Multiple “NAV/” entries should, therefore, be consolidated following a single “NAV/” indicator.
4. Recommendation. Item 18 entries made in accordance with paragraph 478 e. 2. above will limit the number of characters needed to show domestic U.S. RNAV and oceanic RNP capabilities and mitigate the chance that one or the other will not be forwarded for use by FAA domestic and oceanic automation systems.
f. Implementation of ICAO Doc 4444, Revised Appendix 2 (Flight Plan). ICAO Doc 4444, Amendment 1 revises Appendix 2 (Flight Plan). Specifically, Amendment 1 revises the flight plan annotations in Item 10 (Equipment) and Item 18 (Other Information) that show aircraft communications, navigation and surveillance capabilities. The new Appendix 2 flight plan annotations will be required on 15 November 2012. The following Websites provide information on implementation planning:
1. FAA Website: http://www.faa.gov/go/fpl2012.
2. ICAO Flight Plan Implementation Tracking System (FITS): http://www2.icao.int/en/FITS/Pages/home.aspx.
4-7-9. Pilot and Dispatcher Procedures: Basic and Inflight Contingency Procedures
a. Basic Pilot Procedures. The RNP 10 and RNP 4 Job Aids contain references to pilot and, if applicable, dispatcher procedures contained in:
1. FAA Order 8400.12C (RNP 10), Appendix D (Training Programs and Operating Practices and Procedures)
2. FAA Order 8400.33 (RNP 4): paragraph 9 (Operational Requirements) and paragraph 10 (Training Programs, Operating Practices and Procedures)
3. ICAO PBN Manual, Volume II, Part B, Chapter 1 (RNP 10)
4. ICAO PBN Manual, Volume II, Part C, Chapter 1 (RNP 4)
b. ICAO Doc 4444, Chapter 15, Inflight Contingency Procedures. Doc 4444 Chapter 15 contains important guidance for pilot training programs. For ease of reference, significant Chapter 15 paragraphs are posted on the Gulf of Mexico 50 NM Lateral Separation Web Page. Chapter 15 paragraphs posted on the website include:
1. Paragraph 15.2 (Special Procedures for InFlight Contingencies in Oceanic Airspace). Paragraph 15.2.2 (General Procedures) provides guidance for inflight diversions, turnbacks and for loss of, or significant reduction in, required navigation capability when operating in an airspace where the navigation performance accuracy is a prerequisite to the safe conduct of flight operations.
2. Paragraph 15.2.3 (Weather Deviation Procedures). Paragraph 15.2.3 provides guidance for events where the pilot is able to obtain a clearance prior to deviating from track to avoid convective weather and for events where the pilot is unable to obtain clearance prior to deviating.
c. Strategic Lateral Offset Procedures (SLOP). Pilots should use SLOP procedures in the course of regular oceanic operations. SLOP procedures are published in ICAO Document 4444, 15th Edition, Amendment 2, paragraph 16.5 and FAA Notices. They are posted on the Gulf of Mexico 50 NM Lateral Separation Web Page and are addressed in the RNP 10 and RNP 4 Job Aids.
d. Pilot Report of NonRNP10 Status. The pilot must report the lack of RNP 10 or RNP 4 status in accordance with the following:
1. When the operator/aircraft is not authorized RNP 10 or RNP 4. See paragraph 4-7-5.
e. Pilot Statement of RNP 10 or RNP 4 Approval Status, If Requested. If requested by the controller, the pilot must communicate approval status using the following phraseology:
(Call sign) confirm RNP 10 or 4 approved
“Affirm RNP 10 approved” or “Affirm RNP 4 approved,” as appropriate, or
f. Pilot action when navigation system malfunctions. In addition to the actions suggested in ICAO Doc. 4444, Chapter 15, when pilots suspect a navigation system malfunction, the following actions should be taken:
1. Immediately inform ATC of navigation system malfunction or failure.
2. Accounting for wind drift, fly magnetic compass heading to maintain track.
3. Request radar vectors from ATC, when available