Tag: NAT (page 1 of 3)

New NAT Contingency Procedures for 2019

Starting 28th March 2019, there will be some changes to the contingency and weather deviation procedures on the NAT. ICAO has published a new NAT Ops Bulletin with all the details.

Before, there was a lot of confusion around the wording of these two procedures – but ICAO has now made this much clearer, and they have even included a little graphic to help us understand how it will work.

Thing is, it’s still a little clunky. So we decided to make our own version!

Click on the image to open larger version.

What’s new?

The simple answer is this: contingency offsets that previously were 15 NM with actions at 10 NM are basically now all 5 NM offsets with a turn of at least 30 degrees (not 45 degrees).

Rarely do we see ICAO oceanic contingency procedures undergo a formal revision. The last time a major revision occurred was in 2006 when ICAO standardized a 15 NM offset executed with a turn of at least 45 degrees. Prior to that, the North Atlantic and the Pacific had used different offset distances and a 90 degree turn.

Where and when?

A trial implementation is scheduled to begin in the North Atlantic High Level Airspace (NAT HLA) and New York Oceanic West (WATRS) starting 28th March 2019. ICAO is expected to formally publish the Standard in an update to PANS-ATM (ICAO Doc 4444) on 5 November 2020.

Why?

To support reduced separation being implemented in conjunction with Advanced Surveillance Enhanced Separation (ASEPS), Space Based ADS-B surveillance. The details for the ASEP trial can be found in NAT OPS Bulletin 2018-006 Trial Implementation of ASEPS using ADS-B.

Old version vs New version – full wording

Here’s the old version, as per the latest version of the NAT Doc 007, paragraph 13.3. (Note – this will be valid UNTIL 27 March 2019):

The aircraft should leave its assigned route or track by initially turning at least 45° to the right or left whenever this is feasible.

An aircraft that is able to maintain its assigned flight level, after deviating 10 NM from its original cleared track centreline and therefore laterally clear of any potentially conflicting traffic above or below following the same track, should: 
a) climb or descend 1000 ft if above FL410 
b) climb or descend 500 ft when below FL410 
c) climb 1000 ft or descend 500 ft if at FL410

An aircraft that is unable to maintain its assigned flight level (e.g due to power loss, pressurization problems, freezing fuel, etc.) should, whenever possible, initially minimise its rate of descent when leaving its original track centreline and then when expected to be clear of any possible traffic following the same track at lower levels and while subsequently maintaining a same direction 15 NM offset track, descend to an operationally feasible flight level, which differs from those normally used by 500 ft if below (or by 1000 ft if above FL410).

Before commencing any diversion across the flow of adjacent traffic or before initiating any turn-back (180°), aircraft should, while subsequently maintaining a same direction 15 NM offset track, expedite climb above or descent below the vast majority of NAT traffic (i.e. to a level above FL410 or below FL290), and then maintain a flight level which differs from those normally used: by 1000 ft if above FL410, or by 500 ft if below FL410. However, if the flight crew is unable or unwilling to carry out a major climb or descent, then any diversion or turn-back manoeuvre should be carried out at a level 500 ft different from those in use within the NAT HLA, until a new ATC clearance is obtained.

And here’s the new version, as per the NAT OPS Bulletin 2018-005 Special Procedures for In-flight Contingencies in Oceanic Airspace (Note – this will be valid FROM 28 March 2019):

If prior clearance cannot be obtained, the following contingency procedures should be employed until a revised clearance is received:

Leave the cleared route or track by initially turning at least 30 degrees to the right or to the left, in order to intercept and maintain a parallel, direction track or route offset 9.3 km (5.0 NM).

Once established on a parallel, same direction track or route offset by 9.3 km (5.0 NM), either: 
a) descend below FL 290, and establish a 150 m (500 ft) vertical offset from those flight levels normally used, and proceed as required by the operational situation or if an ATC clearance has been obtained, proceed in accordance with the clearance; or 
b) establish a 150 m (500 ft) vertical offset (or 300 m (1000 ft) vertical offset if above FL 410) from those flight levels normally used, and proceed as required by the operational situation, or if an ATC clearance has been obtained, proceed in accordance with the clearance.

Note. — Descent below FL 290 is considered particularly applicable to operations where there is a predominant traffic flow (e.g. east-west) or parallel track system where the aircraft’s diversion path will likely cross adjacent tracks or routes. A descent below FL 290 can decrease the likelihood of: conflict with other aircraft, ACAS RA events and delays in obtaining a revised ATC clearance.

So to reiterate, the important change is that contingency offsets that previously were 15 NM with actions at 10 NM are basically now all 5 NM offsets with a turn of at least 30 degrees (not 45 degrees).

Weather deviations

If you have to deviate from your assigned track due to anything weather-related, there’s a whole different procedure to follow. Again, the NAT Ops Bulletin has all the details for this, but the bottom line seems to be:

For deviations of less than 5 NM, remain at the flight level assigned by ATC.

For deviations of 5 NM or more, when you are at the 5 NM point initiate a change as follows:

If flying EAST, descend left by 300ft, or climb right by 300ft.

If flying WEST, climb left by 300ft, or descend right by 300ft.

In other words – SAND! (South of track = Ascend, North of track = Descend; Up/Down by 300ft)

But remember, going right is probably better – it gets you out of the way of all the SLOP offset traffic that might be coming at you from the opposite direction!

Turnback procedure

In both the NAT Ops Bulletin and the new NAT Doc 007 which will take effect from 28 Mar 2019, ICAO has left out any specific reference to how to divert across the flow of traffic or turn-back procedure, and instead simplified it to just “proceed as required by the operational situation”. Turning back would assume you either employ the 5NM offset as per the new contingency procedure, or else get a new revised clearance.

Bottom line

If you operate in the NAT HLA, we recommend you read and review the NAT Ops Bulletin in its entirety. It’s relatively short but, beginning 28 March 2019, the procedures are expected to be implemented. You might want to prepare changes for your Ops Manuals and checklists too.

Make sure you stay tuned to OPSGROUP for changes that may occur as we approach 28 March 2019!

Mitch Launius is an International Procedures Instructor Pilot with 30 West IP and can be contacted through his website, www.30westip.com

Further reading:

  • On Nov 1st we had a call with 140 OPSGROUP members about upcoming changes on the NAT in 2019, and how we can effect change. OPSGROUP members can find the PDF notes of this in your Dashboard.
  • A big thing driving the ASEPS trial is the rollout of Space-based ADS-B, which is scheduled to complete its deployment by 30 Dec 2018, giving us worldwide, pole-to-pole surveillance of aircraft. For more on that, and how it will affect operations on the NAT specifically, read the article by Mitch Launius here.
  • Use our quick guide to figure out where you are welcome on the NAT, depending on what equipment and training you have.

First look at NAT changes for 2019

Starting 28th March 2019, a new trial will be implemented on the NAT called ASEPS (Advanced Surveillance Enhanced Procedural Separation) using ADS-B in the Shanwick, Gander and Santa Maria FIRs.

Compliant aircraft will see a reduction in longitudinal separation to as close as 14 NM. This is not restricted to particular tracks or altitudes, just between properly equipped aircraft – you’ll need RVSM/HLA approval, ADS-B, and to be fully PBCS compliant (that means meeting the specifications of RNP4, RCP240 and RSP180). Read this ICAO Bulletin for all the details.

When the ASEPS trial starts, there will also be some changes to the contingency and weather deviation procedures. Before, there was a lot of confusion around the wording of these two procedures – this has now been made much clearer, and they have even included a nice little graphic to help us understand what to do. Read this ICAO Bulletin for all the details.

ICAO have published all these changes in their updated NAT 007 Doc valid for 28th March 2019.

Further reading:

  • On Nov 1st we had a call with 140 Opsgroup members about upcoming changes on the NAT in 2019, and how we can effect change. Opsgroup members can find the PDF notes of this in your Dashboard.
  • A big thing driving the ASEPS trial is the rollout of Space-based ADS-B, which is scheduled to complete its deployment by 30 Dec 2018, giving us worldwide, pole-to-pole surveillance of aircraft. For more on that, and how it will affect operations on the NAT specifically, read the article by Mitch Launius here.
  • Use our quick guide to figure out where you are welcome on the NAT, depending on what equipment and training you have.
  • All the big changes on the NAT in 2018 are covered on our page here.

Why, How and Where should you SLOP?

In Short: Strategic Lateral Offset Procedures (SLOP) costs nothing and increases flight safety. If the airspace permits it, you should be “randomly” offsetting, especially across the North Atlantic. Left is for losers – don’t SLOP left of track.

We had a discussion in OpsGroup recently about SLOP (Strategic Lateral Offset Procedures) and it elicited some interesting responses, as well as some confusion.

So – Why, How and Where should you SLOP?

Why?

GPS technology allows modern jets to fly very accurately, too accurately it turns out sometimes! Aircraft can now essentially fly EXACTLY over an airway/track laterally (think less than 0.05NM), separated only by 1000FT vertically. A risk mitigation strategy was proposed over non-radar airspace to allow pilots to fly 1-2 nautical miles laterally offset from their track, randomly, to increase flight safety in case of any vertical separation breakdown.

How did we get here?

Navigation paradox

What we just described is known as the navigation paradox. The research shows that “increases in navigational precision” actually increases the collision risk – huh?

Here are some interesting stats to consider:

  • In a simulation, aircraft cruising at random altitudes have five times fewer collisions.
  • During a 2000 study, it was shown that hemispherical cruising altitude rules resulted in six times more mid-air collisions than random cruising altitude non compliance.
  • If more randomness was applied to the hemispherical cruising level model, the navigational paradox risk could have been largely reduced and up to 30 midair collisions avoided (up to 2006). Including the tragic GOL 2006 accident.

So we get it; the rules of the air, sometimes inject risk to flight safety due to their lack of randomness.

A way to reduce risk and inject randomness?

It was 2004 when SLOP was adopted in the most congested non-radar airspace in the world, namely the North Atlantic.

Although the Navigation Paradox is the reason SLOP was introduced and continues to be implemented, there are some nice risk mitigation side-effects too: wake turbulence reduction (at times), contingency buffers if you experience severe turbulence and can’t maintain altitude (“level busts”), etc.

SLOP therefore reduces the risk between traffic which is not operating in accordance with the correct air traffic control clearance or where an error has been made in the issue of an air traffic control clearance.

Still, there is a large number (>40%) of aircraft not adopting these procedures even though they are now mandatory on the NAT.

If >40% of pilots are using SLOP 0 (meaning no offset at all), what does that matter? That means half the flights are operating over the same lateral paths and all it takes is one minor vertical deviation for there to be a significant loss of separation.

The daily NAT track message always reminds pilots to employ SLOP procedures:

FOR STRATEGIC LATERAL OFFSET AND CONTINGENCY PROCEDURES FOR OPS IN NAT FLOW REFER TO NAT PROGRAMME COORDINATION WEBSITE WWW.PARIS.ICAO.INT.
SLOP SHOULD BE STANDARD PROCEDURE, NOT JUST FOR AVOIDING WX/TURB.
How should you SLOP?

Consider some best practice advice:

  • LEFT IS FOR LOSERSnever offset LEFT. On bi-directional routes a LEFT offset will INCREASE collision risk rather than decrease it. There are areas in the NAT Region where bi-directional traffic flows are routinely used. And there are times when opposite direction traffic may be encountered in any part of the Region. Once upon a time (between introduction of RVSM and pre-SLOP, it was ok to go LEFT, not anymore!)The only exception would be in certain airspace where ATC request you to SLOP LEFT (e.g. China).
  • The system works best when every 2 out of 3 crossings you fly, you apply an offset. Shanwick says this generally means at least 1 out of 3 aircraft are slopping.
  • You don’t need to ask ATC for approval; you can SLOP from the NAT entry point to the NAT exit point.
  • Only offset if your FMC has the function to do so – do not do it manually.
  • Good airmanship applies here. What’s happening around you? Who is above, below and near you on the same track. Co-ordinate on 123.45 if needed.
  • 2nm RIGHT is the maximum approved SLOP.
  • Flip a coin to decide like some do! Captain is PF? 1R going west; First Officer 2R going east etc. Studies show that on the NAT, 40% do 1R and only 20% go 2R. Don’t be afraid to go the full 2R!
  • If you are overtaking someone, the ICAO guidance in NAT DOC 007 is to apply SLOP so as to create the “least amount of wake turbulence for the aircraft being overtaken”.

Where though?

Our friend Eddie at Code 7700 gave a great comprehensive list so here it is verbatim.

  • Africa, almost all remote locations employ SLOP. Check the Jeppesen Airways Manual / Air Traffic Control / State Rules and Procedures – Africa) to be sure. Rule of thumb: if you are in radar contact, you probably should not SLOP.
    • One notable exception where they don’t want you to SLOP is in the HKNA/Nairobi FIR. The AIP states: “SLOP is not applicable in the Nairobi FIR due to efficient surveillance and communication systems.” (We do remind you however that recently in the Nairobi FIR, a 767 and 737, both at FL370 came a little too close for comfort).
  • Australia is another special case. You may only offset in the OCA, and, if you’re still on radar, then you need to tell ATC, both when starting the offset, or changing it. Within domestic CTA airspace, you must fly centerline. (According to Australian guidance in Jeppesen Pages).
  • China, on routes A1, L642, M771, and N892 (according to China guidance in Jeppesen Pages). In some areas they employ their unique SLOP offsets, but do allow the standard 1 nm and 2 nm offsets.
  • New York, Oakland and Anchorage Oceanic FIRs (according to U.S. FAA guidance).
  • Oceanic airspace in the San Juan FIR (according to U.S. FAA guidance).
  • North Atlantic Track Region: SLOP is mandatory (according to the North Atlantic Operations and Airspace Manual).
  • The Pacific (including the NOPAC, Central East Pacific (CEP) and Pacific Organized Track System (PACOTS) (according to U.S. FAA guidance).
  • South Pacific airspaces (according to U.S. FAA guidance).
FAQ:
  • Should I SLOP crossing the Atlantic even if I’m on a random route or above the published NAT FL’s?

Yes! You should especially do it then. There is a higher chance of opposite direction traffic. That extra mile or two (randomly selected of course) could be a life saver!

  • What about micro-slop?

That is lateral offsets between 0 and 1 nm (0.1 etc). ICAO mentions “LOP provisions as specified in ICAO PANS-ATM Doc.4444 were amended 13 November 2014 to include the use of “micro-offsets” of 0.1 Nms for those aircraft with this FMS capability. Appropriate guidance for the use of this amended procedure in the North Atlantic is under study and hence pending.”

We have been advised that the USAF is doing this trial over the NAT in the coming months but at this stage it is NOT APPROVED. Most FMC systems can’t micro-offset yet anyway.


We might have missed something or maybe we didn’t cover your specific question?

Drop us a line and will do our best to answer.

Bottom line, SLOP costs nothing but increases flight safety.

The Impact of Space-Based ADS-B on International Operations

I can distinctly remember the build up to and roll out of GPS navigations systems. Like so many of us, I was excited to see this new technology integrated into my cockpit. The idea that I would have the capability to accurately determine my position anywhere in the world was exciting!

It’s hard to overstate the significance of GPS navigation on the international operation of aircraft, particularly when operating in oceanic airspace. Today we are about to reach a similar milestone that could be even more significant – the introduction of a Space-Based Automatic Dependent Surveillance Broadcast (SB ADS-B) monitoring system.

When SB ADS-B completes its deployment (scheduled 30 December 2018), we will achieve worldwide, pole-to-pole surveillance of aircraft. This goes beyond a pilot knowing his or her own location. This opens up the ability for ATC to locate any ADS-B equipped aircraft anywhere in the world. With the US and EU ADS-B requirements approaching in 2020, aircraft that operate internationally will almost certainly be ADS-B equipped.

A brief history of Space-Based ADS-B

SB ADS-B technology has been placed into service by a commercial company, Aireon, and not a governmental entity, which has enabled it to be brought to operational status in a much shorter timeline than most other government implementations.

Although Aireon was initially established in 2012 to provide civilian surveillance services, the disappearance of Malaysia Flight 370 changed the industry. The inability to locate the aircraft forced industry regulators to consider how improved aircraft tracking might have helped to resolve the location of the aircraft in distress and prevent a future disaster. In response to this concern, ICAO created a standard for aircraft tracking designated as the Global Aeronautical Distress Safety System (GADSS). Aireon responded by creating a low-cost tracking solution based on aircraft ADS-B equipage utilizing the SB ADS-B network to meet that tracking requirement faster and cheaper than many of the alternatives.

This implementation takes advantage of the same ADS-B 1090ES systems already installed in most aircraft, not requiring any additional investment or modification from operators who currently comply with ICAO ADS-B approved 1090ES systems. Compare this to the evolving and evasive FANS 1/A+ requirements that have placed many operators in the position of having to upgrade aircraft (at great expense) only to find they are not PBCS and/or U.S. domestic compliant. Quite a contrast.

What are the benefits?

The primary advantage of the introduction of surveillance into oceanic operations will be a reduction in separation. Initially, this will be applied to in-trail spacing (longitudinal separation) and potentially reduce that separation to as close as 14 Nautical Miles (NM). The current longitudinal standard for data link approved aircraft is 5 minutes or approximately 50NM. The introduction would significantly increase the capacity of the most fuel-efficient routes and altitudes. The trial implementation is not expected to be restricted to specified tracks or altitudes, just between properly equipped aircraft.

Another key advantage of SB ADS-B is that the system is based on an active constellation of 66 low earth orbit satellites with geo-synchronous orbits that provide worldwide coverage. The system will also have 9 backup satellites available in orbit as well. The information on worldwide aircraft location will be in the system, it’s just a matter of having it sent to ATC control panels that are properly equipped to display the information. The SB ADS-B system operates independently from the ADS-B ground stations and can provide a direct data feed to air navigation service providers (ANSPs).

The primary targets for Aireon SB ADS-B services are ANSPs such as the FAA, EASA, Africa’s ASECNA, South Africa, New Zealand, Singapore, etc. This brings tremendous value to areas like Africa and Southeast Asia where ANSP’s face unique challenges involving infrastructure. Placing a network of ground-based ADS-B receivers in remote areas can expose them to vandalism or theft. As an example, a recently installed ILS system in Benin, Nigeria was stolen!

What does my aircraft need to be compliant?

In order for SB ADS-B separation reduction to be applied, aircraft will be required to be ADS-B and fully PBCS compliant. The controlling agency will determine eligibility based on the flight plan filing codes for ADS-B and PBCS. Let’s recall that the PBCS requires FANS 1/A+ approval with RCP240, RSP180, and RNP 4 capabilities. Just add ADS-B, NAT HLA, and RVSM equipage and approval and you’re ready! That is a lot of approvals, plus let’s not forget, TCAS Version 7.1 and Enhanced Mode S Transponder equipage is required as well.

Where will it be implemented?

Initial trial use of SB ADS-B for surveillance and separation will begin in Canada’s Edmonton Flight Information Region (FIR) in the first quarter of 2019. This will be followed by a planned trial launch in the North Atlantic (NAT) on 29 March 2019. The NAT oceanic surveillance trial program will be employed in both in Gander and Shanwick’s oceanic FIRs. Santa Maria will also introduce ADS-B separation standards, but that program will initially be limited to ground-based ADS-B operations.

We anticipate a mid-December 2018 release of a North Atlantic Ops Bulletin detailing the trial implementation which will be referred to as “Advanced Surveillance-Enhanced Procedural Separation” (ASEPS). This is to be followed by ICAO publishing the associated standards for ASEPS in a 5 November 2019 update to Procedures for Air Navigation Services – Air Traffic Management (PANS-ATM) Document 4444. This would move the ASEPS program beyond trial use and allow implementation of ASEPS based operations worldwide.

The final specifics involved in the trial program will be detailed in Canadian and United Kingdom Aeronautical Information Publications (AIPs), most likely involving a release of Aeronautical Information Circulars (AICs) to formally initiate the trial programs.

The NAT HLA does not anticipate requiring ADS-B for airspace entry but simply employing it as available. The impending U.S. and EU ADS-B requirements in 2020 will help ensure common equipage.

The introduction of ASEPS reduced separation standards in oceanic and remote regions will also impact contingency procedures for operators in the NAT HLA. To address this concern ICAO has created new contingency procedures for oceanic and remote operations which will also be identified in the November 2019 update to Procedures for Air Navigation Services – Air Traffic Management (PANS-ATM) Document 4444.

We expect the mid-December release of an additional North Atlantic Ops Bulletin detailing the trial implementation of these new contingency procedures in the NAT HLA airspace to be implemented with ASEPS. These new contingency procedures will initially only be used in the NAT HLA but, after the ICAO approval in November 2019, they may be implemented in other oceanic regions as well.

It would be important to note that the ASEPS target date for implementation, 29 March 2019, is also the target date for the expansion of the PBCS tracks in the North Atlantic Organized Track System. Add in the change in contingency procedures and that is a lot of moving parts, all happening at the same time, in the most congested oceanic airspace in the world.

One thing we don’t anticipate changing on March 2019 is strategic lateral offset procedures (SLOP). Changes may follow down the road but it’s not on the calendar now.

Let’s all get ready for a busy spring in the North Atlantic!

Mitch Launius is an International Procedures Instructor Pilot with 30West IP and can be contacted through his website: www.30westip.com

Your top three PBCS questions answered

PBCS has been an ongoing PITA for some time now. We wrote about it back in March. Here are the top three questions we’ve had on it since then – and now we finally have some answers!

Question 1: What happens if I still haven’t received my updated A056 LOA?

After the PBCS tracks were introduced in March 2018, the FAA published a Notice requiring all N-reg operators to update their A056 LOA authorization – regardless of whether or not they intended to fly these PBCS tracks. For private (Part 91) operators, the deadline to submit the application was 30th September 2018.

There was a barrage of applications, and the FAA still seem to have a bit of a backlog, as even now some operators have still not received their updated approvals.

The FAA’s unofficial policy is that as long as you have applied for a revised LOA, you can continue to use your old authorization after September 30th, while you wait for the new one to be issued.

Bottom line: This means you are allowed to keep flying in the North Atlantic, just not on the PBCS tracks.

Question 2: What about that problem with aircraft with Honeywell systems installed?

Back in March, a latency timer issue with certain Honeywell FMS systems meant that there were bunch of aircraft which weren’t able to get the PBCS approval.

In June, Honeywell issued a service bulletin fix for the issue, available at varying times for different aircraft. Since then, the FAA has been issuing the updated A056 LOA approvals to those aircraft with the Honeywell systems that reflect the new capabilities but the still don’t meet the PBCS requirement of RCP240 due to the latency timer issue.

Bottom line: Now those affected aircraft are able to receive the updated A056 LOA approvals, just with a PBCS restriction – meaning they can continue to operate in the North Atlantic, just not on the PBCS tracks.

Question 3: What the heck is PBCS anyway?

PBCS stands for ‘performance-based communication and surveillance’.

PBCS involves globally coordinated and accepted standards for Required Communication Performance (RCP) and Required Surveillance Performance (RSP), with the goal being to allow the application of reduced lateral and longitudinal separation to aircraft which meet the criteria.

To be PBCS compliant, you basically need CPDLC capable of RCP240 and ADS-C capable of RSP180; this effectively means having a 4 minute comms loop, and 3 minute position reporting.

PBCS has been implemented in various different chunks of airspace around the world, but most notably in the North Atlantic, where the three core daily NAT Tracks are assigned as PBCS tracks between FL350-390. To fly those, you will need to be PBCS compliant (read above) but also have RNP4 (the rest of the NAT only requires RNP10).

Feeling queasy? That’s okay, reading about PBCS makes us feel that way too. If you’re still hungry for more though, check out our recent article on all things PBCS!

More questions? Get in touch!

NAT Circle of Entry 2018

For the latest changes and updates on the North Atlantic, including our most recent Guides and Charts, use our NAT reference page at flightservicebureau.org/NAT.

Updated Oct 15, 2018: Updated RNP requirements for the PBCS Tracks, updated entry requirements for the NAT Tracks.

Confused and overwhelmed with the changes on the North Atlantic of late? Especially with PBCS, RCP240, RSP180, RLAT, RLong, and all that? Yep, us too.

So, we drew a circle. Tell us if this helps. Click on the circle to download the more detailed PDF.

Download the NAT Circle of Change 2018 PDF.

To help ease your NAT Headache further, these goodies will probably also be useful:

PBCS – What, Where and How

In Short: The performance-based communication and surveillance (PBCS) framework allows for higher safety standards and more efficient airspace use. If your aircraft already has the equipment and you cross the Atlantic or Pacific Oceans often, it’s worth looking into getting your regulatory approval.

PB… what? It’s a good question. We have so many acronyms in aviation, it’s easy to forget what this one stands for and what it really means. So, let’s try and get to the bottom of it.

What is PBCS?

Official answer:

The ICAO performance-based communication and surveillance (PBCS) framework ensures that emerging technologies for communication and surveillance fully support ATM operations and are implemented and operated safely.

In plain speak:

With the technology already available on many aircraft and in the Air Traffic Control facility, aircraft can now fly closer than ever before, especially over non-radar oceanic airspace.

There are two key buzz words, so let’s define them. They are interlinked with RNP – Required Navigation Performance.

  • RSP – Required Surveillance Officially known as “surveillance data delivery”, often stipulated in the Airplane Flight Manual. Basically, how often does the aircraft send its position to ATC/ground station. There are two specifications, RSP180 and RSP400. The numbers indicate the maximum number of seconds (180 or 400) for the transaction to occur.
  • RCP – Required Communication ICAO has two specifications, RCP240 and RCP400. Again, the numbers indicate the maximum number of seconds (240 or 400), or “transaction time” taken for the controller to issue an instruction to the crew and for them to receive a response. This could be via CPDLC, HFDL, VDL or SATCOM.

So, we have a loop here, C-N-S. Communication, Navigation and Surveillance. An aircraft sends surveillance information to ATC about where it is; the aircraft stays within confines of RNP navigation requirements and ATC communicates with the aircraft within the required transaction times.  Pretty easy!

But why do we need PBCS?

The take away? If all given aircraft in a certain airspace have a lower RSP value and a lower RCP value, we can start putting these aircraft closer together.

Essentially – performance-based separation minima. This allows aircraft to be separated safely according to technological capability rather than “one-size-fits-all” prescriptive distances.

What are the differences from PBN?

They are similar but there are notable differences. In a simple sense, the PBN (RNP/RNAV) only requires that the operator obtains approval because it focuses on how the equipment works. PBCS (RSP/RCP) however requires the involvement and approval of the air traffic service provider because it’s a two-way communication and surveillance effort. There are dependencies and complexity with the equipment standards on both ends.

In this graphic you can see a high-level summary of who is responsible for what:

Where is it in place?

Currently PBCS is in effect in one form or another in the following FIR’s

  • NZZC/Auckland Oceanic
  • NFFF/Nadi
  • KZAK/Oakland Oceanic
  • PAZN/Anchorage Oceanic
  • WSJC/Singapore
  • VCCF/Sri Lanka
  • NTTT/Tahiti
  • RJJJ/ Fukuoka
  • KZNY/New York Oceanic
  • CZQX/Gander
  • EGGX/Shanwick
  • BIRD/ Reykjavik
  • LPPO/Santa Maria Oceanic

The Air Traffic Service providers of China, Brazil and Indonesia have also shown interest to introduce PBCS in the future.

Specifically, PBCS is being used between FL350 and 390 on certain “half” NAT tracks as we have written about before.

What do I need to do?

Requirements vary from state-to-state on the exact procedure for obtaining approval. It’s important to note that not all aircraft are automatically PBCS ready (refer to your aircraft manufacturer and your airplane flight manual).

The FAA has outlined its approval process here and has a handy powerpoint document here.

An important element is to prove that you have signed the “PBCS Global Charter” which can be found at the FANS Central Reporting Agency (CRA) website.

When a PBCS authorization is obtained an operator is required to file both P2 (indicating RCP240) in item 10 and SUR/RSP180 in item 18 of the flight plan, in addition to the J codes for CPDLC and D1 or G1 for ADS-C in item 10.

The correct filing of these two codes will indicate to any ATM ground systems applying performance-based separation minima that the aircraft is eligible for these minima and that the crew have received the relevant training in order to safely operate using the reduced separations.

Will you notice that PBCS standards are being applied to your flight?

Ok this is the funny part of this story. The short answer, probably not.

While it may be easier for RCP240/RSP180 approved aircraft to obtain optimal flight profiles, especially during high traffic periods, and particularly for NAT flights using the OTS, the application of these standards is generally tactical in nature for ATC. An aircraft may not have performance-based separation applied at all on an individual flight, or possibly may never have had it applied to any of its flights. Even if a you have RCP240/RSP180 approvals, if the aircraft nearby does not also have the approvals, the separation standards cannot be applied!

What if I don’t have RCP240 and RSP180 approval?

If you do not have RCP240/RSP180 approvals you will always have the larger separations, e.g. 10-min, applied, and not be eligible for the lower standards in cases where it may be beneficial.

The only airspace that has implemented tracks that will require PBCS to file is in the NAT OTS. There are still non-PBCS tracks in the OTS for which PBCS approvals are not required.

All other airspace in which performance-based separation minima are currently applied will allow aircraft with and without RCP240 and RSP180 approvals to enter and use the airspace in a mixed-mode operation.

Will I be penalized if I don’t have it?

Probably not in the short term. In the future as more and more airspace corridors become PBCS only, then it is possible you may be subject to reroutes, delays or the requirement to fly outside of certain flight levels.

So, our conclusion?

PBCS is a great step forward in maximizing efficiency in a busier airspace environment thanks to the advent of better technology. If you fly the NATs often and have an aircraft capable of PBCS certification standards, then yes – do it! The approval process is not overly burdensome, and many modern transatlantic jets already meet most of the technical requirements.

Ultimately, reduced separation standards mean more great air-to-air views. So, pack your camera!

You were in a 4G inverted dive with a Mig 28? -Yes, ma’am. -At what range? -Um, about two meters. -Eh, lieutenant, what were you doing there? -Communicating. Keeping up foreign relations.

Did we miss something, or does something need more explaining? Let us know!

Extra Reading:

North Atlantic 2018 Operational Changes – Shanwick, Gander, Iceland, Santa Maria, New York – and the NAT HLA

We’ll use this page for NAT changes, including EGGX/Shanwick, CZQX/Gander, BIRD/Iceland, ENOB/Bodo, LPPO/Santa Maria, and KZWY/New York Oceanic East.

2018

Here are the latest important changes for the NAT. These are also published in the latest edition of NAT Doc 007, August 2018.

  • PBCS From March 29th 2018, PBCS is a requirement for the daily mandated PBCS NAT Tracks (right now, that the 3 core tracks each day) between FL350-390.  PBCS for the NAT means having both RCP240 (4 minute comms loop) and RSP180 (3 minute position reporting). If you’re missing approval for either, then you can fly anywhere other than along the core NAT tracks FL350-390. Read more about PBCS in our article, and check out the NAT Circle of Change for an easier graphical representation.
  • RLAT  From January 4th 2018, Shanwick and Gander increase the number of RLAT tracks – most tracks between FL350-390 will now be RLAT – 25nm separation between them.

And there will be more! Keep an eye on this page, we’ll keep it updated.


The NAT used to be simple. Fill your flask, fire up the HF, align the INS and away you went.

Now, it’s a little more complicated. Basic Instruments are not enough. Use this quick and dirty guide from FSB to figure out where you are welcome on the NAT, depending on what equipment and training you have. Valid January 31, 2018.

Free for OpsGroup, or you can purchase a copy here.

 


2017

Lots of important changes in 2017

  • SLOP – Offsetting is now mandatory. Choose 0, 1, or 2nm right of track. We think 1 or 2 is best. Consider the recent A380 story.
  • TCAS 7.1: From January 1st, 2017, TCAS 7.1 is required throughout the entire NAT region.
  • Cruising Level: Effective 2017, you no longer need to file an ICAO standard cruising level in NAT airspace.
  • Gross Nav Error:  is now defined as greater than 10nm (used to be 25nm)
  • Contingency Procedure: Published January 2017, a new turn-back (180) procedure is introduced – turn back to parallel previous track by 15nm.
  • Datalink Mandate Exemptions: Phase 2B of the Datalink mandate started on December 7, 2017 (FL350-390). Exempt: Radar airspace, Tango Routes, airspace north of 80N, and New York OCA.

2016

  • Confirm Assigned Route Introduced August 2016, you will see this message when you enter NAT airspace with datalink, and you should reply with the planned route in NAT airspace. Designed to catch errors.
  • NAT HLA The airspace formerly known as MNPS. Changed February 2016. NAT HLA = NAT High Level Airspace. Now includes Bodo Oceanic, and aircraft must be RNP 4 or RNP10. Previous MNPS approvals good through 2020.

2015

  • RLAT Started December 2015, spacing on the NAT Tracks reduced to “Half Track” (30nm) for 3 core tracks. RLAT=Reduced Lateral Separation Minima. Next phase (ie. all NAT Tracks 350-390) now planned for December 2017.
  • SLOP Offsetting right of track by 1nm or 2nm became Mandatory.

 


Feb 1st, 2018: FSB updated the full NAT Crossing Guide “My first North Atlantic Flight is tomorrow“.

– What’s different about the NAT, changes in 2018,2017, 2016, 2015, NAT Quick Map
– Routine Flight Example #1 – Brussels to JFK (up at 5.45am)
– Non Routine-Flights: No RVSM, No RNP4, No HF, 1 LRNS, No HLA, No ETOPS, No TCAS, No Datalink – what you can do and where you can go
Take a look.

 


New CPDLC procedure on the NAT

There’ll soon be a new CPDLC procedure on the NAT, designed to prevent pilots from acting on any old CPDLC messages that might have been delayed in the network.

ICAO have published a new Bulletin for all the NAT Air Navigation Service Providers (ANSP’s) to use as a basis for implementing this new procedure. They recommend that all aircraft should receive a message immediately after they enter each control area telling them to “SET MAX UPLINK DELAY VALUE” to a certain number of seconds. The idea is that this will prompt the pilot to enter the specified latency value into the aircraft avionics, so that it will ignore/reject any old CPDLC messages.

So far, only Iceland’s BIRD/Reykjavik FIR have implemented this procedure, effective May 24. All other sectors of NAT airspace (Gander, Shanwick, Bodo, Santa Maria, New York Oceanic) are busy writing their own AIC’s and will implement later in the year. 

So when entering the BIRD/Reykjavik FIR, expect to receive a CPDLC message from ATC instructing you to “SET MAX UPLINK DELAY VALUE TO 300 SECONDS”. A copy of their AIC with more guidance can be found here.

The latency monitor function varies from one aircraft type to another: some just automatically reject old CPDLC messages, some will display a warning to the pilot that the message has been delayed, some have deficient equipment, and some do not have the message latency monitor function implemented at all.

Because of this, ICAO note that “it is impossible for ATC to tailor the uplink of the message… to different aircraft types. It has therefore been decided among the NAT Air Navigation Service Providers (ANSPs) to uplink this message to all CPDLC connected aircraft immediately after they enter each control area. An aircraft may therefore receive this message multiple times during a flight.”

So here’s the lowdown on what you need to do:

1. Work out in advance what kind of message latency monitor function your aircraft has, and what it is designed to do when it receives the CPDLC message “SET MAX UPLINK TIMER VALUE TO XXX SECONDS”.

2. When you receive this message, respond with the voice message “ACCEPT” or “ROGER”. If your aircraft has a functioning message latency monitor, punch in the specified number of seconds. If you don’t have functioning equipment, respond with the free text message “TIMER NOT AVAILABLE”.

3. If anything goes wrong, revert to voice comms.

Back in November 2017, we reported on an equipment issue with Iridium satcom that prompted a ban by a number of Oceanic ATC agencies. Some aircraft were receiving massively delayed clearances sent by ATC via CPDLC – and one took the instruction and climbed 1000 feet, even though the message was meant for the flight the aircraft operated previously.

Although the bans were dropped after Iridium fixed the problem at ground level (by ensuring the system no longer queued CPDLC uplinks for more than five minutes), this new CPDLC procedure on the NAT should ensure this kind of situation doesn’t happen again. It’s officially being brought in as one of the safety requirements for the roll-out of reduced lateral and longitudinal separation minima across the NAT, which is predicated on Performance Based Communication and Surveillance (PBCS) specifications – that means having CPDLC capable of RCP240 (4 minute comms loop), and ADS-C capable of RSP180 (3 minute position reporting).

Further reading:
ICAO NAT Bulletin 2018_002: CPDLC Uplink Message Latency Monitor
Iceland’s AIC on the new CPDLC procedure for the BIRD/Reykjavik FIR
– The latest PBCS rumours and facts
The latest NAT changes, including EGGX/Shanwick, CZQX/Gander, BIRD/Iceland, ENOB/Bodo, LPPO/Santa Maria, and KZWY/New York Oceanic East.
IRIDIUM satcom fault fixed

My first North Atlantic Flight is tomorrow – NAT Ops Guide (Updated 2018)

For the latest changes and updates on the North Atlantic, including our most recent Guides and Charts, use our NAT reference page at flightservicebureau.org/NAT.

Of all the hundreds of questions we see in OPSGROUP, one region stands out as the most asked about – the NAT/North Atlantic. So, we made one of our legendary guides, to get everything into one PDF.  It’s called “My first North Atlantic Flight is tomorrow” – and now we’ve updated it for 2018!

Contents:

  • 1. What’s different about the NAT?
  • 2. Changes in 2018, 2017, 2016, 2015
  • 3. NAT Quick Map – Gander boundary, Shanwick boundary
  • 4. Routine Flight Example #1 – Brussels to JFK (up at 5.45am)

  • 5. Non Routine-Flights: No RVSM, No RNP4, No HF, 1 LRNS, No HLA, No ETOPS, No TCAS, No Datalink – what you can do and where you can go
  • 6. Diversion Airports guide: Narsarsuaq, Sondy, Kef, Glasgow, Dublin, Shannon, Lajes, Fro Bay, Goose Bay, Gander, St. Johns
  • 7. Airport data
  • 8. Overflight permits – routine and special

  • 9. Special NAT procedures: Mach number technique, SLOP, Comms, Oceanic Transition Areas, A successful exit, Screwing it up, Departing from Close Airports
  • 10. North Atlantic ATC contacts for Shanwick, Gander, Iceland, Bodo, Santa Maria, New York – ATC Phone, Radio Station Phone, AFTN, Satcom, CPDLC Logon codes; and adjoining Domestic ATC units – US, Canada, Europe.
  • 11. NAT FPL Codes
  • 12. NAT Flight Levels
  • 13. Flight Plan Filing Addresses by FIR
  • 14. Links, Questions, Guidance

Excerpt from the Routine Flight #1:

 

Buy a copy ($20)   Get it free – join OPSGROUP

To get your copy – there are three options:

  1. OPSGROUP Members, login to the Dashboard and find it under “Publications > Guides”. All FSB content like this is included in your membership, or
  2. Join OPSGROUP with an individual, team, or department/airline plan, and get it free on joining (along with a whole bunch of other stuff), or
  3. Purchase a copy in the Flight Service Store!
Older posts
International Ops Bulletin
Get our weekly Ops Bulletin on changes and dangers: Airport closures, Security issues, ATC restrictions, Airspace changes, and New Charts
Sent to you every Wednesday
Thanks, I'm already a reader.