747-400 vs NAT requirements

[jon b 2,041]

I’m not sure how realistic you guys do your flight planning, but I suspect you put a lot into to it so this maybe of interest to you.

You may be familiar with the Rlat trial tracks on the NAT system, these for those who aren’t familiar these Rlat (reduced latitude) tracks separated by half degree of latitude, rather than full degrees of latitude separation.

Certain levels of performance based navigation and CPDLC were a requirement to use these tracks.

As of 29th March these tracks have now been replaced by PBCS tracks-performance based communication and surveillance using FL350-390 inclusive.

As well as RNP4 which the 744 is more than capable of there is also now a requirement for RCP240- required communication performance 240 seconds. This is basically a time restriction for a message to be sent from ATC to the aircraft and for the aircraft to respond back within 240 seconds. This is broken down into various components for example the controller has 30 secs to enter a message and the crew have 60 to enter their response. The aircraft system-the FMC (and the ATC system)itself is only allocated 15 seconds to transmit a response.

This 15 seconds processing it seems is asking a little too much of the 744’s ancient FMC CDU processors and so it can’t use these PBCS tracks between FL350-390.

It gets worse.... as of 29th March 2019 the whole of the NAT will become PBCS! 

So as of next year, as incomprehensible as this seems , to me at least, the 744 won’t be able to fly the NATs.

There are, I believe 2 ways around this : 

1) a dispensation is issued from the regulators to allow the 744 to continue operations in NAT airspace 

2)The 747-8 FMC can be retrofitted to the 744, which is a lot faster and even has a colour screen, ooh😍

For what I can gather option 2 was the plan, however I now believe option one has reared its head.

Ineresting times, could I therefore ask PMDG if they would consider as part of their upcoming 747-8 expansion giving users the option of retrofitting the 747-8 FMC to their 747-400 ? Failing that,Issue a letter from Capt Randazzo Authorising all PMDG 747-400s to continue to operate in simulated NAT airspace😉

 

Cheers

 

Jon Bunting 

 

[scandinavian13 5,192]

MOD Note: Changed up the title to better reflect the actuality of the situation.

In aviation, you're compliant, or you're non-compliant. "Banning" isn't really a thing. Equip and participate, or don't.

[jon b 2,041]

Ta, yes , that’s a better way of putting it.

That’s what I was trying to say, but wasn’t as articulate enough to get the words right !

Cheers 

Jon Bunting 

[scandinavian13 5,192]

9 minutes ago, jon b said:

Ta, yes , that’s a better way of putting it.

That’s what I was trying to say, but wasn’t as articulate enough to get the words right !

Welcome. I used to work on the FAA side of these projects (and tracked all of the oceanic events and errors in the NAT and PAC regions - pilot and ATC), so I got to deal with all kinds of subtle ways of putting things, so as to not irritate the operators in those areas.

Compliant v non-compliant; equipped v not equipped; participant v non-participant...

Pertinent to the communication issue, though, we had an issue where many compliant, and equipped aircraft on RLatSM failed to maintain the comm requirement due to equipment errors and therefore immediately became non-compliant (and therefore in conflict with all surrounding, compliant RLatSM aircraft).

----------

As a final note, a lot of ATC is coordination and tactical decision-making. Even a non-compliant aircraft/operator can be tactically permitted in the areas, provided they do not actually join the track itself, traffic permitting. We had several aircraft fail out of RLatSM because of CPDLC logon/heartbeat failures, yet remain on the track because - tactically - the leading/trailing/paralleling traffic were far enough away that the increased sep requirement didn't cause conflicts. No sense in having a plane cross a bunch of tracks, or descend through levels - reducing actual separation in the process - to satisfy theoretical separation requirements.

[Samany69 41]

@scandinavian13 dear Kyle.

do you mind if I ask a related question regarding this matter ? I need your help .... even if you ask me another way for conversation Since I know you are far more knowledgeable than many people around, I will be honored.

 

Cheers.

 

-S.

[jon b 2,041]

6 hours ago, scandinavian13 said:

 

Pertinent to the communication issue, though, we had an issue where many compliant, and equipped aircraft on RLatSM failed to maintain the comm requirement due to equipment errors and therefore immediately became non-compliant (and therefore in conflict with all surrounding, compliant RLatSM aircraft).

----------

As a final note, a lot of ATC is coordination and tactical decision-making. Even a non-compliant aircraft/operator can be tactically permitted in the areas, provided they do not actually join the track itself, traffic permitting. We had several aircraft fail out of RLatSM because of CPDLC logon/heartbeat failures, yet remain on the track because - tactically - the leading/trailing/paralleling traffic were far enough away that the increased sep requirement didn't cause conflicts. No sense in having a plane cross a bunch of tracks, or descend through levels - reducing actual separation in the process - to satisfy theoretical separation requirements.

Interesting that, sacrificing actual separation for theoretical separation.

i had this issue the other night for the first time, where we were planned on an Rlat or PBCS as it is now and had to drop from FL370 down to F330 to enter the track. Our notes stated that traffic and workload permitting we could pass through the airspace but not remain in it,as you mentioned.

We made a request with both Gander and later Shanwick to make a continuous climb up to FL400 but were “ unable due traffic “ .It was always a big ask though.

I must admit to being a little saddened, it’s the first time that I’ve ever experienced,that the “queen’ of the skies” hasn’t been considered up to the task. I guess it’s a sign that she, and me are starting to get old.

Heck I still remember the old days crossing the Atlantic pre GPS where we’d get a couple of  hundred miles off the coast and she’s start DME/DME updating and hang a right turn as the FMC realised we were 2 miles off course!

cheers

Jon Bunting 

Edited May 1, 2018 by jon b

[jon b 2,041]

9 minutes ago, jon b said:

Interesting that, sacrificing actual separation for theoretical separation.

i had this issue the other night for the first time, where we were planned on an Rlat or PBCS as it is now and had to drop from FL370 down to F330 to enter the track. Our notes stated that traffic and workload permitting we could pass through the airspace but not remain in it,as you mentioned.

We made a request with both Gander and later Shanwick to make a continuous climb up to FL400 but were “ unable due traffic “ .It was always a big ask though.

I must admit to being a little saddened, it’s the first time that I’ve ever experienced,that the “queen’ of the skies” hasn’t been considered up to the task. I guess it’s a sign that she, and me are starting to get old.

Heck I still remember the old days crossing the Atlantic pre GPS where we’d get a couple of  hundred miles off the coast and she’s start DME/DME updating and hang a right turn as the FMC realised we were 2 miles off course!

cheers

Jon Bunting 

 

[Samany69 41]

22 minutes ago, jon b said:

I must admit to being a little saddened, it’s the first time that I’ve ever experienced,that the “queen’ of the skies” hasn’t been considered up to the task. I guess it’s a sign that she, and me are starting to get old.

 when I read this ... I felt so sad to be honest.... The queen is my only beloved bird ..... 

[thibodba57 462]

9 hours ago, jon b said:

2. The 747-8 FMC can be retrofitted to the 744, which is a lot faster and even has a colour screen, ooh

😍

 

Maybe it's just us here at Atlas. But we have been retrofitting our -400 aircraft with the NG FMC.  Same CDU new software.

I asked PMDG a long time ago about allowing the NG FMC and never replied to it.  Just thought I'd throw that out there.

[Captain Kevin 586]

51 minutes ago, thibodba57 said:

Maybe it's just us here at Atlas. But we have been retrofitting our -400 aircraft with the NG FMC.  Same CDU new software.

I asked PMDG a long time ago about allowing the NG FMC and never replied to it.  Just thought I'd throw that out there.

Did you submit a support ticket with references that they were doing this. I would imagine that's probably what they want to see.

[PopsBellNC 21]

4 hours ago, jon b said:

Heck I still remember the old days crossing the Atlantic pre GPS where we’d get a couple of  hundred miles off the coast and she’s start DME/DME updating and hang a right turn as the FMC realised we were 2 miles off course!

cheers

Jon Bunting 

On the contrary! In the -200B, I was amazed how often we'd be bang-on course after 2,000nm! Yes, occasionally we'd drift maybe 1 to 2 nm (2 nm was, honestly, the most I'd personally seen and even then, at any reasonable attitude you'd could point just off the nose and say "Oh, we need to be a skosh over there" Lol😎) but I remain impressed by the 70's-80's engineering that enabled onboard INS to perform at such levels.

[berts 97]

On 5/1/2018 at 11:24 AM, jon b said:

I’m not sure how realistic you guys do your flight planning, but I suspect you put a lot into to it so this maybe of interest to you.

As of 29th March these tracks have now been replaced by PBCS tracks-performance based communication and surveillance using FL350-390 inclusive.

As well as RNP4 which the 744 is more than capable of there is also now a requirement for RCP240- required communication performance 240 seconds. This is basically a time restriction for a message to be sent from ATC to the aircraft and for the aircraft to respond back within 240 seconds. This is broken down into various components for example the controller has 30 secs to enter a message and the crew have 60 to enter their response. The aircraft system-the FMC (and the ATC system)itself is only allocated 15 seconds to transmit a response.

This 15 seconds processing it seems is asking a little too much of the 744’s ancient FMC CDU processors and so it can’t use these PBCS tracks between FL350-390.

It gets worse.... as of 29th March 2019 the whole of the NAT will become PBCS! 

So as of next year, as incomprehensible as this seems , to me at least, the 744 won’t be able to fly the NATs.

Jon, This begs the question "Whatever next?" 

How long will it be before ATC take over complete navigation control of the aircraft, leaving the pilots to get the aircaft airborne and put the autopilot in as soon as the Gear is up?  Then all they will have to do is disconnect it after the landing roll, so that they can taxy to the gate.  Then what's next?!!

I will be interested to see how the likes of Vatsim handle this change.

Bertie G 

[BlueStar 323]

20 hours ago, PopsBellNC said:

On the contrary! In the -200B, I was amazed how often we'd be bang-on course after 2,000nm!

Our "320s" would do that. I remember coming out of PHNL on the way Kwajalein or Kadena and there would be .1NM difference between the two units.  Close enough for me.  We could see all those little atolls on the radar, interesting times. 🙂

A side note one afternoon I was about 200 NM from Kwajalein when ATC gave me a Cruise clearance. ROFL

[BlueStar 323]

27 minutes ago, berts said:

How long will it be before ATC take over complete navigation control of the aircraft,

Not going to happen. ATC can only suggest.  

[downscc 1,327]

I just finished UA20 KIAH-EHAM in B77L N890UA (I routinely substitute the B77L for B772) and noticed the remarks section of the tracks messaged included this:

PBCS OTS LEVELS 350-390. PBCS TRACKS AS FOLLOWS: NO ASSIGNED PBCS TRACKS.

I noticed this yesterday and it is still PBCS OTS today TMI 123 both directions.

The visual 18R approach at EHAM was stunning with the new Orbx TrueEarth Netherlands... all I can say is wow wow wow.