the learning never stops!

North Atlantic High Level Airspace (NAT HLA)

Airspace

By the time you read this, it will probably be out of date . . .

But perhaps up-to-date enough to make a difference. All of us who fly the North Atlantic for a living are in a continuing battle to keep up with the changing requirements. I think I have a handle on it. (At least at this snapshot in time.)


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Photo: NAT HLA, NAT Doc 007, figure 1.

Click photo for a larger image

Summary of Requirements

How do you know where you can fly? It all depends on your Performance Based Communications, Navigation, Surveillance capabilities. The Navigation we know about: that's PBN, after all. The rest is now being called PBCS, at least tentatively.

If you have the following equipment: You can fly:
Communications Navigation Surveillance
VHF VOR, DME, ADF Mode C Limited parts of the NAT HLA
HF (in Shanwick OCA) 1 LRNS VHF / HF Position Reports Special Routes

Note that we are talking about equipment for these parts of the airspace. Click on the links in the right column to learn about just how limited this can be. If you want greater access, you will need communications, navigation, and surveillance capabilities and those require authorizations.

If you have the following authorizations: You can fly:
Communications Navigation Surveillance
HF RNP 10 and 2 LRNS HF Position Reports NAT Tracks, NAT HLA
(Except FL350-390)
CPDLC RNP 10 and 2 LRNS ADS-C NAT Tracks, NAT HLA
(All Flight Levels)
*
and
RLongSM
CPDLC / RCP 240 RNP 4 and 2 LRNS ADS-C / RSP 180 NAT Tracks, NAT HLA
(All Flight Levels)

and
RLongSM and RLatSM

* The NAT Tracks between FL350 - 390 will require RCP 240 and RSP 180 starting March 29, 2018.

A Summary of Changes

  • March 29, 2018 — PBCS required to fly NAT Tracks between FL350 - 390, you need RCP 240 and RSP 180
  • January 4, 2018 — The number of RLatSM tracks expanded to include most tracks between FL350 - 390.
  • January 1, 2017 — TCAS 7.1 required in entire NAT region.
  • December 7, 2017 — Data Link required FL 350 - 390, except for Tango routes, the airspace north of 80N, Surveillance airspace, Blue Spruce routes, and New York OCA.
  • December 2015 — RLatSM instituted for 3 Core tracks.

A Summary of Authorizations

  • A056 — Data Link Communications (you will need this for ADS-C and CPDLC)
  • B036 — Required Navigation Performance Airspace (you will need this for RNP-4 or RNP-10)
  • B039 — North Atlantic High Level Airspace (NAT HLA), formerly North Atlantic Minimum Navigation Performance Specifications (NAT/MNPS) Airspace
  • B046 — Reduced Vertical Separation Minimum (RVSM) Airspace

Limited parts of the NAT HLA

There is more to this than shown in this short paragraph from NAT Doc 007. You will probably be transiting the airspace of several countries (Canada, Greenland, Iceland, Scotland, Ireland, to name a few) and will need to get smart about their individual requirements.

[NAT Doc 007, p. vi] Aircraft without NAT HLA or RVSM Approvals may, of course, also fly across the North Atlantic below FL285. However, due consideration must be given to the particular operating environment. Especially by pilots/operators of single and twin engine aircraft. Weather conditions can be harsh; there are limited VHF radio communications and ground-based navigation aids; and the terrain can be rugged and sparsely populated. International General Aviation (IGA) flights at these lower levels constitute a very small percentage of the overall NAT traffic but they account for the vast majority of Search and Rescue operations.

Flights Planning to Operate Without Using HF Communications

[NAT Doc 007, ¶4.2.18 The carriage of functioning HF communications is mandatory for flight in the Shanwick OCA, even if the pilot intends using alternative media for regular ATS air-ground contacts. Aircraft with only functioning VHF communications equipment should plan their route outside the Shanwick OCA and ensure that they remain within VHF coverage of appropriate ground stations throughout the flight. Theoretical VHF coverage charts are shown in Attachment 5. Such strict routing restriction may not apply in all NAT Oceanic Control Areas. Some may permit the use of SATCOM Voice to substitute for or supplement HF communications. Details of communication requirements by individual NAT ATS Providers are published in State AIPs. However, it must also be recognised that the Safety Regulator of the operator may impose its own operational limitations on SATCOM Voice usage. Any operator intending to fly through the NAT HLA without fully functional HF communications or wishing to use an alternative medium should ensure that it will meet the requirements of its State of Registry and those of all the relevant ATS Providers throughout the proposed route.

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Photo: VHF Coverage at FL300, NAT Doc 007, Attachment 5.

Note: There are also charts for FL100 and FL200.

Click photo for a larger image

Flights Planning to Operate with a Single Functioning LRNS

[NAT Doc 007, ¶4.2.19] Within the NAT HLA only those routes identified with an asterisk in sub paragraphs (1), (2), (3) and (4) of paragraph 3.2.1. may be flight planned and flown by aircraft equipped with normal short-range navigation equipment (VOR, DME, ADF) and at least one approved fully operational LRNS. Specific State Approval for such NAT HLA operations must, however, be obtained from the State of the Operator or the State of Registry of the aircraft.

[NAT Doc 007, ¶3.2.1] Other routes within the NAT HLA (illustrated in Fig 4) are as follows:

  1. * ‘Blue Spruce’ Routes, established as special routes for aircraft equipped with only one serviceable LRNS. (Chapter 1 refers.) State approval for NAT HLA operations is required in order to fly along these routes. (See Chapter 12 for full route definitions);
  2. routes between Northern Europe and Spain/Canaries/Lisbon FIR. (T9*, T13 and T16);
  3. * routings between the Azores and the Portuguese mainland and between the Azores and the Madeira Archipelago;
  4. * routes between Iceland and Constable Pynt on the east coast of Greenland and between Kook Islands on the west coast of Greenland and Canada
  5. Note: *routes/routings identified with an asterisk in sub paragraphs (1), (2), (3) and (4) above may be flight planned and flown by approved aircraft equipped with normal short-range navigation equipment (VOR, DME, ADF) and at least one approved fully operational LRNS.

Flights Planning to Operate with Normal Short-Range Navigation Equipment Only.

[NAT Doc 007, ¶4.2.20] Two routes providing links between Iceland and the ICAO EUR Region (G3 and G11) (see Chapter 3) are designated as special routes of short stage lengths where it is deemed that aircraft equipped with normal short-range navigation equipment can meet the NAT HLA track-keeping criteria. Nevertheless, State Approval for NAT HLA operations is still required in order to fly along these routes.

Special Routes

If you don't have two LRNS, you will be restricted to one of several special routes, often called "Blue Spruce" or "Tango 9" routes. More about this: Blue Spruce Routes.

First off, what is an LRNS? See Technology, below.

[NAT Doc 007, ¶1.4]

Routes for Aircraft with Only One LRNS

1.4.1 A number of special routes have been developed for aircraft equipped with only one LRNS and carrying normal short-range navigation equipment (VOR, DME, ADF), which require to cross the North Atlantic between Europe and North America (or vice versa). It should be recognised that these routes are within the NAT HLA, and that State approval must be obtained prior to flying along them. These routes are also available for interim use by aircraft normally approved for unrestricted NAT HLA operations that have suffered a partial loss of navigation capability and have only a single remaining functional LRNS. Detailed descriptions of the special routes known as ‘Blue Spruce Routes’ are included in paragraph 12.2.2 of this Document. Other routes also exist within the NAT HLA that may be flown by aircraft equipped with only a single functioning LRNS. These include routings between the Azores and the Portuguese mainland and/or the Madeira Archipelago and also routes between Northern Europe and Spain/Canaries/Lisbon FIR to the east of longitude 009° 01' W (viz.T9). Other routes available for single LRNS use are also established in the NAT HLA, including a route between Iceland and the east coast of Greenland and two routes between Kook Islands on the west coast of Greenland and Canada.

Note: if this single LRNS is a GPS it must be approved in accordance with FAA TSO-C129 or later standard as Class A1, A2, B1, B2, C1 or C2, or with equivalent EASA documentation ETSO- C129a. Some States may have additional requirements regarding the carriage and use of GPS (e.g. a requirement for FDE RAIM) and pilots should check with their own State of Registry to ascertain what, if any, they are. These above mentioned documents can be found at:

www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgWebcomponents.nsf

and

www.easa.europa.eu/ws_prod/g/doc/Agency_Mesures/Certification Spec/CS-ETSO.pdf

Routes for Aircraft with Short-Range Navigation Equipment Only

1.4.2 Aircraft that are equipped only with short-range navigation equipment (VOR, DME, ADF) may operate through the NAT HLA but only along routes G3 or G11. However, once again formal State Approval must be obtained. (See paragraph 12.2.2 for details of these routes.)

1.4.3 The filed ATS Flight Plan does not convey information to the controller on any such NAT HLA Approval limitation. Hence, it is the responsibility of those pilots with “less than unrestricted” (i.e. with limited) Approval to reject any ATC clearances that would otherwise divert them from officially permitted routes.

Data Link Exceptions

[NAT Doc 007, ¶1.10.5] Some airspace will be excluded from the mandates, including ATS surveillance airspace; airspace north of 80° North; and New York Oceanic FIR. Aircraft not DLM equipped may be permitted to operate on the TANGO Routes and other specified routings during Phase 2B. Any such exemptions will be promulgated via ANSP State AIS. Also certain categories of flights may be allowed to plan and operate through the mandated airspace with non-equipped aircraft. Details will be promulgated in future via State AIS.

Phase 2B refers to the data link requirements for the NAT HLA in effect 7 December 2017, pertaining to the airspace between FL350 and FL390, inclusive.

The NAT HLA (Except FL350-390)

Flying anywhere within the NAT HLA means you will need some kind of authorization (an LOA or OpsSpecs) and will need to be RVSM compliant. If you are not RVSM approved, however, there are special provision to allow you to climb and descend through RVSM levels, detailed in NAT Doc 007, ¶1.6

What about navigation accuracy? Well that depends on when you got your current authorization and which parts of the NAT HLA you want to use.

Location

[NAT Doc 007, p. v]

  • A large portion of the airspace of the North Atlantic Region, through which the majority of these North Atlantic crossings route between FLs 285 and 420 inclusive, is designated as the NAT High Level Airspace (NAT HLA). Within this airspace a formal Approval Process by the State of Registry of the aircraft or the State of the Operator ensures that aircraft meet defined NAT HLA Standards and that appropriate crew procedures and training have been adopted.
  • The lateral dimensions of the NAT HLA include the following Control Areas (CTAs): REYKJAVIK, SHANWICK (excluding SOTA & BOTA), GANDER, SANTA MARIA OCEANIC, BODO OCEANIC and the portion of NEW YORK OCEANIC EAST which is north of 27°N.

Authorization

[NAT Doc 007, ¶1.1]

  • Aircraft operating within the NAT HLA are required to meet specified navigation performance in the horizontal plane through the carriage and proper use of navigation equipment that meets identified standards and has been approved as such by the State of Registry or State of the Operator for the purpose. Such approvals encompass all aspects affecting the expected navigation performance of the aircraft, including the designation of appropriate cockpit/flight deck operating procedures.
  • Since January 2002 when the final phase implementation of RVSM at all levels in NAT MNPS Airspace took place, all aircraft intending to operate within the NAT MNPSA/HLA have had to be equipped with altimetry and height-keeping systems which meet RVSM Minimum Aircraft System Performance Specifications (MASPS). RVSM MASPS are contained in ICAO Doc 9574 and detailed in designated FAA document, AC91-85A, and in equivalent Joint Aviation Authority (JAA) documentation.

[NAT Doc 007, ¶1.2]

  • All flights within the NAT HLA must have the approval of either the State of Registry of the aircraft, or the State of the Operator. Aircraft operating in RVSM Airspace are required to be compliant with the altimetry Minimum Aircraft System Performance Specifications (MASPS) and hold an issued approval. Approval for NAT HLA operations will require the checking by the State of Registry or State of the Operator, of various aspects affecting navigation performance. These aspects include: the navigation equipment used, together with its installation and maintenance procedures; plus the crew navigation procedures employed and the crew training requirements.
  • Since the NAT HLA is now designated as RVSM airspace at all levels (i.e. FL290-410 inclusive) specific State RVSM Approval is also required to operate within the NAT HLA. RVSM Approvals prescribe both airworthiness requirements to ensure aircraft height-keeping performance in accordance with the RVSM MASPS, and also crew operating procedures. In general, RVSM Approvals granted by most States are not regionally specific but are valid for world-wide operations. However, some crew operating procedures, particularly those to be followed in contingency situations, are specific to the airspace environment. Such procedures for use in the NAT HLA vary from those adopted in a domestic airspace environment in which radar surveillance and DCPC are available (see Chapter 9 & Chapter 12). States provide approval of these procedures specific to NAT HLA or Oceanic airspace operations in different ways. It may be explicitly addressed in the general RVSM Approval. It may be included as an element of the NAT HLA Approval or it may be a stated item of the Operations Specifications. Nevertheless, however provided, all NAT crews/operators must be State approved specifically for NAT RVSM operations and each aircraft intended to be flown in the NAT HLA must have State RVSM Airworthiness Approval.

Longitudinal Navigation

[NAT Doc 007, ¶1.3.1]

  • Time-based longitudinal separations between subsequent aircraft following the same track (in-trail) and between aircraft on intersecting tracks in the NAT HLA are assessed in terms of differences in ATAs/ETAs at common points. The time-based longitudinal separation minima currently used in the NAT HLA are thus expressed in clock minutes. The maintenance of in-trail separations is aided by the application of the Mach Number Technique.
  • Mach Number Technique has been required in the North Atlantic for quite a while. About the only thing that has changed since its inception is the tolerance went from 0.002 Mach to zero. But there is more to longitudinal separation than just speed control.

  • However, aircraft clock errors resulting in waypoint ATA errors in position reports can lead to an erosion of actual longitudinal separations between aircraft. It is thus vitally important that the time-keeping device intended to be used to indicate waypoint passing times is accurate, and is synchronised to an acceptable UTC time signal before commencing flight in the NAT HLA. In many modern aircraft, the Master Clock can only be reset while the aircraft is on the ground. Thus the pre-flight procedures for any NAT HLA operation must include a UTC time check and resynchronisation of the aircraft Master Clock (typically the FMS).
  • To take advantage of Reduced Longitudinal Separation, you will need something more than just good Mach Number technique and a clock. See Reduced Longitudinal Separation, for more.

Lateral Navigation Accuracy Requirements

If you have an existing MNPS approval issued before January 2013, this applies to you:

[NAT Doc 007, ¶1.3.3] In terms of accuracy, an aircraft which is approved for operations within NAT MNPSA/HLA prior to January 2015 shall have a navigation performance capability such that:

  1. the standard deviation of lateral track errors shall be less than 6.3 NM (11.7 km);
  2. the proportion of total flight time spent by the aircraft 30 NM (56 km) or more off the cleared track shall be less than 5.3 x 10-4;
  3. the proportion of total flight time spent by the aircraft between 50 and 70 NM (93 and 130 km) off the cleared track shall be less than 13 x 10-5.

If you have an existing MNPS approval issued after January 2013 but before January 2015, you have a choice of the previous standard and the following one. After January 2015, you hands are tied:

[NAT Doc 007, ¶1.3.4]

  • For (MNPS) Approvals issued before January 2013, the State of Registry or the State of the Operator, as appropriate, should have verified that the lateral navigation capability of approved aircraft meets the above specified requirements. For Approvals issued between January 2013 and January 2015 Approvals can have been based on these foregoing navigational performance capabilities or based on the PBN specifications, RNP 10 (PBN application of RNAV 10) or RNP 4. For Approvals issued after January 2015 the navigation system accuracy requirements for NAT MNPSA/HLA operation should only be based on the PBN specifications, RNP 10 (PBN application of RNAV 10) or RNP 4. Although when granting consequent approval for operations in MNPSA/NAT HLA, States should take account of the RNP 10 time limits for aircraft equipped with dual INS or inertial reference unit (IRU) systems. All Approvals issued after 04 February 2016 must be designated as “NAT HLA” approvals.
  • Additionally, in order for the 50 Nms lateral separation minimum to be utilized in the New York Oceanic East the following navigation performance criteria must also be met by aircraft with RNAV 10 (RNP 10) Approvals: -
    1. the proportion of the total flight time spent by aircraft 46 km (25 NM) or more off the cleared track shall be less than 9.11 × 10-5; and
    2. the proportion of the total flight time spent by aircraft between 74 and 111 km (40 and 60 NM) off the cleared track shall be less than 1.68 × 10-5.
    3. And similarly the additional criteria which must be met by aircraft approved as RNP 4 are as follows : -

    4. the proportion of the total flight time spent by aircraft 28 km (15 NM) or more off the cleared track shall be less than 5.44 × 10-5; and
    5. the proportion of the total flight time spent by aircraft between 44 and 67 km (24 and 36 NM) off the cleared track shall be less than 1.01 × 10-5.
  • Furthermore, when granting approval for operations in the NAT HLA on the basis of PBN navigational standards, States of Registry should also ensure that in-flight operating drills are approved which include mandatory navigation cross-checking procedures aimed at identifying navigation errors in sufficient time to prevent the aircraft inadvertently deviating from the ATC-cleared route.

Technology

[NAT Doc 007, ¶1.3.6] In most cases, Operators will be able to select equipment for which performance capability has already been established to the satisfaction of a State of Registry. However, where a completely new navigation system is proposed for use, or where major changes have been made in the technology of an existing system, an evaluation will be necessary, to establish its quality of performance, before authorisation for use as a primary means system can follow. Currently, it has been demonstrated that the requisite accuracies may be achieved using Long Range Navigation Systems, namely INS, IRS or GNSS. Consequently, State approval of unrestricted operation in the NAT HLA may presently be granted to an aircraft equipped as follows:

  1. with at least two fully serviceable Long Range Navigation Systems (LRNSs). A LRNS may be one of the following:
    • one Inertial Navigation System (INS);
    • one Global Navigation Satellite System (GNSS); or
    • one navigation system using the inputs from one or more Inertial Reference System (IRS) or any other sensor system complying with the NAT HLA requirement.
    • Note 1: Currently the only GNSS system fully operational and for which approval material is available, is GPS.

      Note 2: A GPS installation must be approved as follows:

      • If the two required LRNSs are both GPS, they must be approved in accordance with the current version of FAA Advisory Circular AC-20-138D Appendix 1. AC- 20-138 requires that GPS systems used in Oceanic airspace must have a FDE function. States other than the USA may set their own standards for operational approval of GPS to provide Primary Means of Navigation in Oceanic and remote areas but in all cases these approvals will include the requirement to carry out Pre-Departure Satellite Navigation Prediction Programmes (See Chapter 8 - GNSS (GPS) Systems for further details).
      • If, however, GPS serves as only one of the two required LRNSs, then it must be approved in accordance with FAA TSO- C129 or later standard as Class A1, A2, B1, B2, C1 or C2, or with equivalent European Aviation Safety Programme (EASA) documentation ETSO-C129a. In this instance individual States vary in their insistence upon the need for the conduct of pre-departure satellite navigation prediction programmes (viz.FDE /RAIM).

      Note 3: Currently equivalent approval material for GLONASS is not under development but it will need to be available prior to approval of any GLONASS equipped aircraft for NAT HLA operations.

  2. each LRNS must be capable of providing to the flight crew a continuous indication of the aircraft position relative to desired track.
  3. it is also highly desirable that the navigation system employed for the provision of steering guidance is capable of being coupled to the autopilot.
  4. Note : Some aircraft may carry two independent LRNS but only one FMCS. Such an arrangement may meet track keeping parameters but does not provide the required redundancy (in terms of continuous indication of position relative to track or of automatic steering guidance) should the FMCS fail; therefore, in order to obtain NAT HLA certification, dual FMCS is required to be carried. For example: a single INS is considered to be one LRNS; and an FMCS with inputs from one or more IRS/ISS is also considered to be a single LRNS.

NAT Tracks

The Organized Track System (OTS) carries with it all the restrictions of flying in the NAT HLA plus a few more. You must also be careful in that there are several layers of authorizations involved. You could be permitted the lower altitudes and standard spacing, all altitudes with the chance of decreased longitudinal spacing, and all altitudes with the chance of decreased longitudinal and lateral spacing.

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Photo: Example of Daytime Westbound NAT Organized Track System, NAT Doc 007, Figure 2.

Click photo for a larger image

[NAT Doc 007, ¶2.1]

  • As a result of passenger demand, time zone differences and airport noise restrictions, much of the North Atlantic (NAT) air traffic contributes to two major alternating flows: a westbound flow departing Europe in the morning, and an eastbound flow departing North America in the evening. The effect of these flows is to concentrate most of the traffic uni-directionally, with peak westbound traffic crossing the 30W longitude between 1130 UTC and 1900 UTC and peak eastbound traffic crossing the 30W longitude between 0100 UTC and 0800 UTC.
  • Due to the constraints of large horizontal separation criteria and a limited economical height band (FL310–400) the airspace is congested at peak hours. In order to provide the best service to the bulk of the traffic, a system of organised tracks is constructed to accommodate as many flights as possible within the major flows on or close to their minimum time tracks and altitude profiles. Due to the energetic nature of the NAT weather patterns, including the presence of jet streams, consecutive eastbound and westbound minimum time tracks are seldom identical. The creation of a different organised track system is therefore necessary for each of the major flows. Separate organised track structures are published each day for eastbound and westbound flows. These track structures are referred to as the Organised Track System or OTS.
  • It should be appreciated, however, that use of OTS tracks is not mandatory. Currently about half of NAT flights utilise the OTS. Aircraft may fly on random routes which remain clear of the OTS or may fly on any route that joins or leaves an outer track of the OTS. There is also nothing to prevent an operator from planning a route which crosses the OTS. However, in this case, operators must be aware that whilst ATC will make every effort to clear random traffic across the OTS at published levels, re-routes or significant changes in flight level from those planned are very likely to be necessary during most of the OTS traffic periods.
  • Over the high seas, the NAT Region is primarily Class A airspace (at and above FL60) (See ICAO Doc. 7030 - NAT Regional Supplementary Procedures), in which Instrument Flight Rules (IFR) apply at all times. Throughout the NAT Region, below FL410, 1000 feet vertical separation is applied. However, airspace utilisation is under continual review, and within the HLA portion of NAT airspace, in addition to the strategic and tactical use of ‘opposite direction’ flight levels during peak flow periods the Mach Number Technique is applied.

[NAT Doc 007, ¶2.2 - 2.4]

  • The night-time OTS is produced by Gander OAC and the day-time OTS by Shanwick OAC (Prestwick), each incorporating any requirement for tracks within the New York, Reykjavik, Bodø and Santa Maria Oceanic Control Areas (OCAs).
  • Subsequently, following the initial construction of the NAT tracks by the publishing agencies (Gander OAC for Eastbound tracks and Shanwick OAC for Westbound tracks), the proposed tracks are published on an internet site for interested parties to view and discuss. One hour is allocated for each of the proposals during which any comments will be considered by the publishing agency and any changes which are agreed are then incorporated into the final track design. This internet site is currently operated by NAV CANADA. Access to this site is by password which any bona fide NAT operator may obtain on application to NAV CANADA - see Canada AIP for details.
  • The agreed OTS is promulgated by means of the NAT Track Message via the AFTN to all interested addressees. A typical time of publication of the day-time OTS is 2200 UTC and of the night-time OTS is 1400 UTC.
  • The hours of validity of the two Organised Track Systems (OTS) are normally as follows:
    • Day-time OTS 1130 UTC to 1900 UTC at 30°W
    • Night-time OTS 0100 UTC to 0800 UTC at 30°W
  • To ensure a smooth transition from night-time to day-time OTSs and vice-versa, a period of several hours is interposed between the termination of one system and the commencement of the next. These periods are from 0801 UTC to 1129 UTC: and from 1901 UTC to 0059 UTC.
  • During the changeover periods some restrictions to flight planned routes and levels are imposed. Eastbound and westbound aircraft operating during these periods should file flight level requests in accordance with the Flight Level Allocation Scheme (FLAS) as published in the UK and Canada AIPs.

The NAT HLA (All Flight Levels)

They have gradually moved from selected tracks to all the tracks: if you want to fly between FL350 and FL390, inclusive, you will need data link.

[NAT Doc 007, ¶1.8.1] Phase 2A of the ICAO NAT Region Data link Mandate was implemented on 05 February 2015 (See ICAO NAT Supplementary Procedures (SUPPS) (Doc 7030) Sections 3.3 - CPDLC and 5.4 - ADS-C). In this phase the CPDLC/ADS-C mandated airspace includes all OTS tracks at FLs 350 to 390, inclusive. To flight plan or fly in the altitude band FL350-390 inclusive on any OTS Track, aircraft must be equipped with and operating FANS 1/A or equivalent CPDLC and ADS-C.

[ICAO Doc 7030, Amendment 9, NAT ¶3.3]

Area of applicability

3.3.1 All aircraft intending to conduct flights in the airspace defined below shall be fitted with and shall operate controller-pilot data link communications (CPDLC) equipment:

a) from 7 February 2013, on specified tracks and flight levels within the NAT organized track system (OTS); and

b) from 5 February 2015, in specified portions of NAT minimum navigation specifications (MNPS) airspace.

Note 1.— The specified tracks and flight level band within the NAT OTS will be published by the States concerned in national AIPs and identified daily in the NAT track message.

Note 2.— The specified portions of NAT MNPS airspace and aircraft equipment performance requirements where applicable will be published by the States concerned in national AIPs.

Means of compliance

3.3.2 Operators intending to conduct flights within the airspace specified in 3.3.1 shall obtain CPDLC operational authorization, where applicable, either from the State of Registry or the State of the Operator. The State of Registry or the State of the Operator shall verify that the equipment has been certified in accordance with the requirements specified in RTCA DO-258/EUROCAE ED-100 or equivalent, capable of operating outside VHF data link coverage.

3.3.3 The services provided within the airspace specified in 3.3.1 shall comply with the Oceanic Safety and Performance Requirements as specified in RTCA DO-306/EUROCAE ED-122 or equivalent.

Note.— Additional guidance can be found in the ICAO Global Operational Data Link Document (GOLD).

[ICAO Doc 7030, Amendment 9, NAT ¶5.4]

Area of applicability

5.4.1 All aircraft intending to conduct flights in the airspace defined below shall be fitted with and shall operate automatic dependent surveillance – contract (ADS-C) equipment:

a) from 7 February 2013, on specified tracks and on specified flight levels within the NAT organized track system (OTS); and

b) from 5 February 2015, in specified portions of NAT minimum navigation specifications (MNPS) airspace.

Note 1.— The specified tracks and flight level band within the NAT OTS will be published by the States concerned in national AIPs and identified daily in the NAT track message.

Note 2.— The specified portions of NAT MNPS airspace and aircraft equipment performance requirements, where applicable, will be published by the States concerned in national AIPs.

Means of compliance

5.4.2 Operators intending to conduct flights within the airspace specified in 5.4.1 shall obtain an ADS-C operational authorization, where applicable, either from the State of Registry or the State of the Operator. The State of Registry or the State of the Operator shall verify that the equipment has been certified in accordance with the requirements specified in RTCA DO-258/EUROCAE ED-100 or equivalent, capable of operating outside VHF data link coverage.

5.4.3 The data link services provided within the NAT airspace shall comply with the Oceanic Safety and Performance Requirements as specified in RTCA DO-306/EUROCAE ED-122 or equivalent. Conformance monitoring shall provide alerts to the controller when reports do not match the current flight plan, and the following ADS contracts shall be used:

a) ADS periodic contracts at an interval consistent with safety requirements and published by the States concerned in national AIPs; and

b) ADS event contracts that include the following event types:

1) lateral deviation event (LDE) with a lateral deviation threshold of 9.3 km (5 NM) or less;

2) level range deviation event (LRDE) with a vertical deviation threshold of 90 m (300 ft) or less; and

3) waypoint change event (WCE) at compulsory reporting points.

Note.— Additional guidance can be found in the ICAO Global Operational Data Link Document (GOLD).

RLongSM

If you have data link you could be given reduced longitudinal spacing and not know it. So you need to make sure your timing and speed control are good.

[NAT Doc 007, ¶1.10.9] Towards these goals various trials will be undertaken and suitably equipped operators will be offered the opportunity to participate in these trials. Information on current trials of reductions in longitudinal separations is available as NAT OPS Bulletins (available at www.icao.int/EURNAT/, following “EUR & NAT Documents”, then “NAT Documents”, in folder “NAT OPS Bulletins”). One such trial is currently running in the Gander and Shanwick OCAs. In this trial a 5 minutes longitudinal separation minima is being applied between pairs of aircraft equipped with and operating ADS-C and CPDLC. NAT OPS Bulletin 2012-030 provides fuller details. Also NAT OPS Bulletin 2010-007 provides details of a separate initiative “Flight Crew Guidance re 5 minutes Separation between GNSS Aircraft”.

[NAT OPS Bulletin 2012-030]

  • To be eligible to participate, aircraft must have a flight plan, use Automatic Dependent Surveillance-Contract (ADS-C) and Direct Controller Pilot Communications (DCPD) provided via data link communications (CPDLC). In addition, the flights must have reported passing a common point from which they follow the same or continuously diverging routes. The current turbo jet, constant Mach, same track longitudinal separation minimum on the NAT minimum navigation performance specifications (MNPS) airspace is 10 minutes. The five-minute longitudinal separation minimum used in the trial becomes available once eligible aircraft have entered the Gander or Shanwick OCA and the aircraft is equipped with FANS1/A (ADS-C and CPDLC) and a data link connection is established with air traffic control (ATC).
  • Operators do not need to apply to be part of the trial. Pilots simply have to request a change in altitude, be properly equipped, and have MNPS approval. Eligible aircraft benefit by having a greater opportunity to climb to more fuel-efficient levels, climb through or follow another eligible aircraft at the same level and, change Mach or altitude due to turbulence or bad weather.
  • Application of this specific procedure by ATC will be transparent to flights that have received an altitude change clearance. As always, flightcrews must adhere to the ATC cleared Mach number and report any failure or malfunction of their global positioning system (GPS), ADS-C, or CPDLC equipment to ATC as soon as it becomes apparent as the separation standard is dependent on aircraft equipment performance. Strategic Lateral Offset Procedure (SLOP) is unaffected

RLatSM

They don't seem to be using Reduced Lateral Separation often, but they do when the volume of traffic dictates. I've not heard of any times where all tracks were affected.

[NAT Doc 007, ¶1.10.10] In December 2015 the first phase of North Atlantic trials of reducing the lateral separation minimum to 25 NM was commenced. In this “RLatSM” Phase 1, 25 NM lateral separation is implemented by establishing ½ degree spacing between two specified core OTS tracks and a central track, within the vertical limits applicable to the airspace associated with the NAT Region Data Link Mandate (FL350 – 390). Only aircraft with the appropriate Required Navigation Performance (RNP4) approval and operating Automatic Dependent Surveillance-Contract (ADS-C) and Controller Pilot Data Link Communications (CPDLC), are permitted to operate on these ½ degree spaced tracks. Special procedures in respect of planning and operating on these tracks have been developed and promulgated via the AIS of the participating States i.e. Canada, Iceland and the United Kingdom. Operators intending to participate in these trials will need to ensure that advanced appropriate pilot and dispatcher training is undertaken. The second Phase of this RLatSM implementation is expected to commence in 2017. In this Phase ½ degree spacing will be established between all OTS tracks, within the vertical limits of the NAT Data Link Mandate (FL350 -390). At least two months advanced notification of the commencement of this Phase of RLatSM will be provided through the NAT States’ AIS.

Training

You will have to update your old MNPS LOA or OpsSpec (B039) for NAT HLA by 2020 and part of that process will be a cross examination by your local FAA about how well prepared you are for these changing standards. Part of that examination will include your training program.

[NAT Doc 007, ¶1.3.8] It is essential that crews obtain proper training for NAT HLA and RVSM operations. Current navigation systems, because of their precision and reliability, can induce a sense of complacency, which in turn tends to obscure the value of standard procedures, and in particular of cross-checks. Under these circumstances errors occur more easily. To prevent them, a special training programme for flight crews should be devised, which includes instructions on the efficient use of equipment, with emphasis on how to avoid mistakes. Crew members should be trained to develop a meticulous method of using Control Display Units (CDUs), with careful cross-checking at all operational stages, in line with procedures described in Chapter 8 of this Document.

[NAT Doc 007, ¶1.3.9] The Operator should thereafter seek to retain the interest and co-operation of flight crews by ensuring that a high standard of navigation performance be maintained. This may be achieved during ground refresher courses, routine checks, or/and by issuing periodic newsletters that include a focus on fleet navigation performance - hopefully indicating that standards are being maintained or are being improved upon. Newsletters might also include analyses of error reports volunteered by crews (i.e. covering instances of equipment being mishandled). However, periodic reminders should not be so frequent as to be selfdefeating.

[NAT Doc 007, ¶1.3.10] Crew training should stress the need for maintaining accuracy both along and across track (i.e. the careful application of Mach Number Technique, accurate reporting of positions and the use of accurate time in reporting positions).

[NAT Doc 007, ¶1.3.11] The following items should also be stressed in flight crew training programmes:

  1. knowledge and understanding of standard ATC phraseology used in each area of operations;
  2. importance of crew members cross-checking each other to ensure that ATC clearances are promptly and correctly complied with;
  3. use and limitations, in terms of accuracy, of standby altimeters during contingency situations. Where applicable, the pilot should review the application of Static Source Error Correction/Position Error Correction (SSEC/PEC) through the use of correction cards;
  4. characteristics of aircraft altitude capture systems which may lead to the occurrence of overshoots;
  5. relationships between the altimetry, automatic altitude control and transponder systems in normal and abnormal situations; and
  6. aircraft operating restrictions related to airworthiness approval.
  7. familiarity with the recommendations to reduce oceanic errors as contained in the current version of the “Oceanic Errors Safety Bulletin” (OESB) published by ICAO EUR/NAT Office as a NAT Oceanic Error Safety Bulletin and available at www.icao.int/EURNAT/, following “EUR & NAT Documents”, then “NAT Documents”, then “NAT OES Bulletins”.

[NAT Doc 007, ¶1.3.12] Finally, crew training should be extended to include instruction on what action should be considered in the event of systems failures. Chapter 11 of this Document provides assistance in establishing such action.

Keeping Up-to-Date

In case you were thinking I was joking about this page being out of date as soon as it was written, I was not. There are so many players out there, around the world, and no central mechanism to keep everyone else current. So you can just do your best. Here are my methods.

Good sources to monitor for changes:

  • NAT OPS Bulletins — available at www.icao.int/EURNAT/, following “EUR & NAT Documents”, then “NAT Documents”, in folder “NAT OPS Bulletins”.
  • NBAA Air Mail — https://www.nbaa.org/airmail/), several forums, including one for international operations. (Membership required.)
  • OpsGroup — opsgroup.com, a platform for pilots, controllers, dispatchers, and managers to ask questions, provide answers, and to learn from peers. (Membership required.)

See Also

Oceanic Clearance

Performance Based Communications and Surveillance (PBCS)

Regional: North Atlantic

Book Notes

Portions of this page can be found in the book International Operations Flight Manual, Part III, Chapter 7.

References

14 CFR 91, Title 14: Aeronautics and Space, General Operating and Flight Rules, Federal Aviation Administration, Department of Transportation

FAA Domestic/International NOTAMs.

FAA Orders 8400 and 8900

ICAO Doc 7030 - Regional Supplementary Procedures, International Civil Aviation Organization, 2008

ICAO Doc 7030, Amendment 1, International Civil Aviation Organization, 8 January 2009

ICAO Doc 7030, Amendment 9, International Civil Aviation Organization, 2 October 2017

Jeppesen Airway Manual

ICAO NAT Doc 007, North Atlantic Operations and Airspace Manual, v 2018-1

NAT OPS Bulletin 2010-026, Trial of a 5 Minute Along Track Longitudinal Separation in the Shanwick OCA, Issued 16 March 2012

NAT OPS Bulletin 2012-030, Reduced Longitudinal Separation (RLongSM) Trial, Effective 17 September 2012

NAT OPS Bulletin 2016_001, Re-naming of the Nat MNPSA to NAT HLA, Effective 4 February 2016

Transport Canada Aeronautical Information Manual

Revision: 20180210
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