Reduced Lateral Separation RLATSM, Airline Briefing This guidance brief highlights the key aspects and details appropriate official publications supporting RLatSM implementation. NATS has also produced a video based training brief on RLatSM implementation specifically for airlines http://www.nats.aero/rlat/ Introduction On 12 November 2015 Reduced Lateral Separation Phase 1 will commence in the Gander and Shanwick oceanic control areas. Track spacing is currently one degree of latitude, which equates nominally to 60nm. The proposed change will reduce lateral separation for eligible aircraft to 25nm, which will be implemented by establishing tracks that are spaced by one-half degree of latitude. RLATSM will be implemented using phased approach between FL350 to FL390 inclusive (co-incident with NAT Region Datalink Mandate), the first of which will introduce one-half degree spacing between two core tracks of the NAT-Organised Track System (OTS). The second phase will be implemented approximately 1 year later, and will introduce one-half degree spacing between all tracks of the NAT- OTS from FL350 to FL390 inclusive. RLATSM tracks will be identified in the NAT Track Message in Note 3. Fig-1: Phase 1 RLatSM tracks. Note Track X will have one-half degree coordinates. Eligibility Operators will be eligible to flight plan and operate on RLATSM tracks provided flights are Required navigation performance (RNP) 4 approved Automated Dependent Surveillance-Contract (ADS-C) equipped and Controller-pilot data link communications (CPDLC) equipped The required Communications/Navigation/Surveillance (CNS) systems must be operational and flight crews must report any failure or malfunction of global position system (GPS), ADS-C, or CPDLC equipment to Air Traffic Control (ATC) as soon as it becomes apparent. Participation All aircraft operating on the three published tracks will be subject to the trial, other published OTS flight levels are not part of the RLATSM trial. There are no additional crew requirements associated with trial participation. Equipment and flight plans It is important that before entering the NAT, the flight crew should ensure that the aircraft is logged on for data link capability (J5, J7, D1) filed in the flight plan 30 minutes prior to entering the Shanwick, as per NAT Region Datalink Mandate. Failure to be logged on prior to entry is likely to result in a revised NATS RLatSm Briefing 1 August 2015
oceanic clearance being issued. Crews are not required to manually logon to next agency if they are already logged on to an adjacent ANSP, as the logon will be forwarded automatically by the ATC systems. See Global Operational Datalink Document (GOLD) which provides guidance to flight crews on datalink operations and service failures. Waypoints and navigation errors Track spacing for RLatSM may involve the use of waypoints consisting of half-degree coordinates. Existing cockpit map display limitations result in truncation of waypoints consisting of latitude/longitude to a maximum of seven characters; minutes of latitude are not displayed. To mitigate the possibility of gross navigation errors resulting from incorrect waypoint insertion, it is imperative that established cockpit procedures are followed whereby each pilot independently displays and verifies the degrees and minutes loaded into the FMC for each oceanic waypoint defining the cleared route of the flight. See UK AIC 059 & 062_2015. Flight crews are further advised that, should they be notified that ATC systems indicate the aircraft is not flying the cleared route, they should immediately display the full degrees and minutes loaded in to the FMC for the NEXT and NEXT+1 waypoints, and verify against the cleared route before responding. As a precaution against possible waypoint insertion errors, rerouting of flights onto RLatSM identified tracks containing one-half degree coordinates will only be permitted via CPDLC. ATC Notifications of possible track deviation Voice message example: SHANWICK CONFIRMS YORU POSITION REPORT INDICATES INCORRECT ROUTING. CHECK FULL DEGREES AND MINUTES LOADED INTO FMC. YOUR CLEARED ROUTE IS [route] CPDLC message example: YOUR POSITION REPORT INDICATES INCORRECT ROUTING. CHECK FULL DEGREES AND MINUTES LOADED INTO FMC. YOUR CLEARED ROUTE IS [route] ATC systems and procedures In support of RLatSM, ATC systems and procedures are being implemented such that flights entering from a domestic agency will be checked to ensure flight has logged on and established ADS-C contracts and CPDLC connection prior to entry. ATC will be alerted when flights fail to meet the criteria, which is likely to result in a revised clearance being issue to the crew prior to entry. Additional conformance monitoring will take place utilising both ADS-C and CPDLC. ATC will transmit confirm assigned route (UM137) CPDLC messages shortly after oceanic entry, this requires the crew to select the enabled response button, which will instruct the avionics to downlink the active route loaded into the FMC for the ATC system to interrogate. It is important that crews understand that the RLatSM separation relies on frequent position report updates provided by ADS-C contracts. Should there be any loss of datalink capability, the controller will be alerted and alternative clearances may be issued depending on the traffic situation at the time. References must be used as primary official publication of information UK AIC 062/2015 Provides detailed information on the trial of 25nm lateral separation minimum in the North Atlantic Region. NAT OPS BULLETIN 2015_003 Detailed information and references to existing procedures relevant to RLatSM operations. UK AIC 059/2015 Recommended Use of ARINC-424 Identifiers for Half-Degree Waypoints in the Shanwick Oceanic Control Area. Global Operational Datalink Document Provides detailed guidance on datalink operations, which can be found at www.icao.int/eurnat NATS RLatSm Briefing 1 August 2015
AERONAUTICAL INFORMATION CIRCULAR Y 065/2015 UNITED KINGDOM NATS Services UK Aeronautical Information Services Heathrow House Bath Road, Cranford Middlesex, TW5 9AT ais.supervisor@nats.co.uk http://www.ais.org.uk 01292-269 2490 (Content - NATS/Prestwick Centre Operaional Standards) 0191-203 2329 (Distribution - Communisis UK) Date Of Publication 1 October 2015 Subject Operational Cancellation Cancels AIC Y062/2015 TRIAL IMPLEMENTATION OF 25 NAUTICAL MILE LATERAL SEPARATION MINIMUM IN THE ICAO NORTH ATLANTIC REGION 1 Introduction 1.1 On or soon after 12 November 2015, Gander and Shanwick area control centers (ACCs) will commence participation in the trial of a 25 nm lateral separation minimum in portions of the Gander and Shanwick Oceanic Control Areas (OCA). This trial was notified by a State letter titled 'Implementation planning for RLatSM in the ICAO NAT Region', issued 30 January 2015 (EUR/NAT 15-0058.TEC) and Aeronautical Information Circular (AIC) 039/14, titled 'Trial Implementation of reduced lateral separation minimum in the ICAO North Atlantic region'. 2 Background 2.1 Advancements in aircraft avionics and air traffic management flight data processing systems have driven an initiative to analyse whether the lateral separation standard in the current North Atlantic (NAT) minimum navigation performance specification (MNPS) airspace can be reduced to increase the number of route options available and therefore increase capacity at optimum flight levels. 2.2 Track spacing for MNPS-approved aircraft is currently one degree of latitude, which equates nominally to 60 nm. The proposed change will reduce lateral separation for eligible aircraft to 25 nm, which can be practically achieved by establishing tracks that are spaced by one-half-degree of latitude. This track spacing initiative is referred to as Reduced Lateral Separation Minimum (RLatSM). 2.3 RLatSM will be implemented using a phased approach, the first of which will introduce one-half-degree spacing between the two core tracks of the NAT-Organized Track System (OTS) from flight level FL 350 to FL 390 inclusive. Phase 2 will expand the implementation throughout the entire NAT OTS. CIVIL AVIATION AUTHORITY AIC Y 065/2015-1
3 Operator Eligibility and Participation 3.1 Aircraft operating on the three published RLatSM tracks (W, X, or Y in the example diagram above), between FL 350 and FL 390 inclusive, will be subject to the RLatSM trial. Other published OTS flight levels are not part of the RLatSM trial. 3.2 The trial implementation of RLatSM will occur in NAT MNPS airspace; therefore MNPS approval remains a requirement. Only those operators/aircraft eligible for RLatSM operations will be allowed to operate on designated RLatSM tracks between FL 350- FL 390 (inclusive). All RLatSM tracks and FLs will be uniquely identified in note 3 of the OTS track message. 3.3 Operators will be eligible to flight plan RLatSM tracks provided the flights are: (a) required navigation performance (RNP) 4 approved; (b) Automated Dependent Surveillance Contract (ADS-C) equipped; and (c) controller-pilot data link communications (CPDLC) equipped. 3.4 The required Communications/Navigation/Surveillance (CNS) systems must be operational and flight crews must report any failure or malfunction of global positioning system (GPS), ADS-C, or CPDLC equipment to Air Traffic Control (ATC) as soon as it becomes apparent. 4 Contingency and Strategic Lateral Offset Procedures 4.1 Contingency procedures applicable in the NAT Region are contained in Chapter 15 (15.2 Special Procedures for In-Flight Contingencies in Oceanic Airspace) of the Procedures for Air Navigation Services Air Traffic Management (Doc 4444), Chapter 9 (Special Procedures) of the NAT Regional Supplementary Procedures (SUPPS) (Doc 7030) and Chapter 13 (Special Procedures for In-Flight Contingencies) of the North Atlantic Operations and Airspace Manual (NAT Doc 007). Analysis conducted as part of the RLatSM safety assessment has confirmed these procedures remain appropriate for the application of the 25 NM lateral separation minimum. Therefore, no additions or changes to the existing procedures are required 4.2 The strategic lateral offset procedure (SLOP) which distributes aircraft along a route or track centreline with offsets of one or two miles to the right thereof has been implemented as a standard operating procedure in the NAT Region since 2004. Detailed guidance on SLOP application in the NAT Region is contained in Chapter 8 (8.5 Special In-Flight Procedures Strategic Lateral Offset Procedures (SLOP)) of the North Atlantic Operations and Airspace Manual (NAT Doc 007). Calculations used in the RLatSM safety assessment demonstrate sufficiency to allow provisions for the application of SLOP up to 2 NM right of track or route centerline where the 25 NM lateral separation minimum is being applied. 4.3 Operators may note that current procedures in the Procedures for Air Navigation Services Air Traffic Management (Doc 4444) indicates offsets up to 2 NM are only to be used where lateral separations of 30 NM or more are being applied. Based on similar calculations as those conducted for the RLatSM safety assessment, the Doc 4444 SLOP provisions are planned to be amended in 2016 to document that offsets up to 2 NM may be used where lateral separations of 23 NM or more are being applied. Therefore no additions or changes to the existing SLOP provisions in the NAT Region are required. AIC Y 065/2015-2 CIVIL AVIATION AUTHORITY
5 Flight Planning 5.1 Air Traffic Services (ATS) systems use Field 10 (Equipment) and Field 18 (Other Information) of the standard ICAO flight plan to identify an aircraft s data link and navigation capabilities. The operator should insert the following items into the ICAO flight plan for RNP 4 authorized and future air navigation systems (FANS) 1/A or equivalent aircraft: (a) Field 10a (Radio communication, navigation and approach aid equipment and capabilities); insert 'J5' to indicate CPDLC FANS1/A SATCOM (Inmarsat) and/or J7 to indicate CPDLC FANS1/A SATCOM (Iridium) data link equipment. (b) Field 10b (Surveillance equipment and capabilities); insert 'D1' to indicate ADS with FANS 1/A capabilities. (c) Field 18 (Other Information); insert the characters 'PBN/' followed by 'L1' for RNP 4. 6 Correct use of the CNS equipment that is indicated in the flight plan 6.1 Before entering the NAT, the flight crew should ensure that: (a) the aircraft is logged on for data link capability (J5, J7, D1) filed in the filed flight plan (FPL); and (b) RNP 4 is inserted into the flight management computer (FMC), when RNP 4 capability (L1) has been filed in the FPL. This is necessary to enable aircraft navigation system monitoring and alerting against the required RNP 4 navigation specification. 7 Verification of Waypoint Degrees and Minutes 7.1 Track spacing for RLatSM may involve the use of waypoints consisting of half-degree coordinates. Existing cockpit map display limitations result in truncation of waypoints consisting of latitude/longitude to a maximum of seven characters; minutes of latitude are not displayed. In the example below, the representation would be the same if the flight was operating along whole or halfdegree waypoints (e.g., the N50W020 label in the figure below could represent a whole degree (5000 North) or a half degree (5030 North) of latitude). 7.2 As shown below, full 13-character representations of latitude/longitude waypoints can be viewed via the FMC display. To mitigate the possibility for gross navigation errors resulting from incorrect waypoint insertion, it is imperative that established cockpit procedures are followed whereby each pilot independently displays and verifies the degrees and minutes loaded into the FMC for each oceanic waypoint defining the cleared route of flight. CIVIL AVIATION AUTHORITY AIC Y 065/2015-3
7.3 Flight crews are further advised that, should they be notified that ATC systems indicate the aircraft is not flying the cleared route, they should immediately display the full degrees and minutes loaded into the FMC for the NEXT and NEXT + 1 waypoints, and verify against the cleared route before responding. 7.4 As a precaution against possible waypoint insertion errors, rerouting of flights onto RLatSM identified tracks containing ½ degree coordinates will only be permitted via CPDLC using Uplink Message UM79, UM80 or UM83. Aircraft will therefore not be rerouted onto ½ degree OTS tracks if ARINC 623 data link or voice is used for the issuance of the oceanic clearance. 8 Current Version 8.1 The current and updated versions of the draft NAT RLatSM plan and associated documents are provided on the ICAO European and North Atlantic Office website. <www.paris.icao.int>, EUR & NAT Documents NAT Documents Planning documents supporting separation reductions and other initiatives. 9 Further Information 9.1 For further Information, please contact: Jamie Hutchison General Manager Operations NATS Prestwick Fresson Avenue Prestwick Ayrshire KA9 2GX Tel: +44-(0)1292 692011 Mobile: +44-(0)7826 531760 e-mail: Jamie.hutchison@nats.co.uk AIC Y 065/2015-4 CIVIL AVIATION AUTHORITY