RNAV Approaches

[sbclark 55]

Hi,

Is 747-400 capable of performing RNAV approaches like the 737-NGX?

What I mean, is can I use the APP button on the 747 MCP to assist in generating the artificial GPS glide-slope?

Bill Clark

 

[Budbud 227]

Hi,

The term you are looking for is IAN (Integrated Approach Navigation) and the answer is no afaik.

 

 

[iwebber 207]

But, of course, it will still do RNAV approaches (at least, the real one does), using VNAV and LNAV.

It's clunky, clumsy and fraught with traps for the unwary, tired, busy and/or distracted but... it will do them.

Hope this helps,

Ian Webber

[vadriver 248]

4 hours ago, iwebber said:

But, of course, it will still do RNAV approaches (at least, the real one does), using VNAV and LNAV.

but to higher minimums etc. depending on procedures authorised for the aircraft & crew !!

[busdriver 258]

May not be helpful, but my 2 cents.... IAN was actually introduced on the 737 first. The airline I fly for also flies the 787 and IAN is indeed on the 787. We also fly the 744, and as iwebber suggested, no IAN. The 748 does.

Cheers,

Greg Boyington

Edited May 16, 2017 by busdriver
Typo

[busdriver 258]

Folks, FYI, the above post is from my co-worker, who hijacked the reply. He thinks he's special, because he flies the 78. Seriously though, we are in training together right now, so if you have questions, fire away, he likes to show all of us how smart he is. :)

Bill Davis

 

 

[Budbud 227]

7 minutes ago, busdriver said:

Greg Boyington

Like Greg "Pappy" Boyington? 

[busdriver 258]

He was born Steven Gregory, but dropped the Steven because he thought being like "Pappy" was cool. True story. Now he flies the 787, while I slum it on the electric jet.

Anyway, sorry to hijack the thread, back to regular programming.

-Bill Davis

[iwebber 207]

3 hours ago, vadriver said:

but to higher minimums etc. depending on procedures authorised for the aircraft & crew !!

Absolutely, but depending on procedures authorised, that's true for every aircraft !!

The OP's question could have led to a misunderstanding though and I was trying to clear that up.

9 hours ago, sbclark said:

Is 747-400 capable of performing RNAV approaches like the 737-NGX?

No, but it is capable of performing RNAV approaches, it just doesn't do it like the NG.

9 hours ago, sbclark said:

What I mean, is can I use the APP button on the 747 MCP to assist in generating the artificial GPS glide-slope?

No, but that's not the only way to fly a RNAV approach.

If his intent is to fly RNAV approaches in the 744 then I don't want him to think he can't; but to let him know he can, just not using IAN like the NG does. If his intent is to fly the RNAV approaches in the 744 like the NG; then no, he can't.

Hope this helps,

Ian Webber

[downscc 1,327]

I assume on most days, the clearance for a visual approach is flown with the ILS set up as an additional reference rather than the RNAV approach.  When IMC, I assume most destinations are using the ILS as the active approach.  I suspect there are a minority of cases where ATC is using the RNAV approaches to avoid the increased separation requirements for ILS and conditions or light IMC or marginal VMC and in these cases the B744 will fit right in.

[Yoda967 23]

This has actually come up for me, too, since KSAN's RWY 27 has LOC or RNAV only. Kind of amazing to watch the BAW 747/777s operate in and out of KSAN's 9,000 foot runway. VNAV really doesn't work on this approach.

[scandinavian13 5,192]

20 minutes ago, downscc said:

I assume on most days, the clearance for a visual approach is flown with the ILS set up as an additional reference rather than the RNAV approach.  When IMC, I assume most destinations are using the ILS as the active approach.  I suspect there are a minority of cases where ATC is using the RNAV approaches to avoid the increased separation requirements for ILS and conditions or light IMC or marginal VMC and in these cases the B744 will fit right in.

Here in the States, it's a rarity or a traffic management decision for RNAV at the airports you're going to find 744s. RNAV's main advantage is curved paths, and/or ease/cost of implementation (think, small airports that don't want to pay for the infrastructure of a LOC or ILS). You may find a mix of ILS and RNAV approaches to a single airport, but again, this is usually for TM decisions to increase throughput, and these cases are specific to the airfield. SFO comes to mind, in this case, where 28L will use the ILS, and 28R will use an offset RNAV to get you below the clouds, call the traffic on the 28L approach, and proceed visually (negating the requirement of radar sep, at least in FAA-land).

With all that in mind, I'd say it's pretty reasonable to assume most approaches will either be vis with ILS backing (something I even do in little planes), or ILS. Again, at the airports you're going to find them, you're going to preferentially fly the ILSs for the advantage of the lower mins anyway (even if you had IAN).

[kevinh 409]

Some years ago, I was working on a simulator project for a 744 cargo operator. They were very keen to have RNAV approach capability in the sim for training purposes. I had no reason to ask why at the time, but looking back I guess it was because some of the out of the way places they had to fly to didn't have ILS.

[skelsey 765]

23 minutes ago, scandinavian13 said:

RNAV's main advantage is curved paths, and/or ease/cost of implementation (think, small airports that don't want to pay for the infrastructure of a LOC or ILS). You may find a mix of ILS and RNAV approaches to a single airport, but again, this is usually for TM decisions to increase throughput, and these cases are specific to the airfield. SFO comes to mind, in this case, where 28L will use the ILS, and 28R will use an offset RNAV to get you below the clouds, call the traffic on the 28L approach, and proceed visually (negating the requirement of radar sep, at least in FAA-land).

With all that in mind, I'd say it's pretty reasonable to assume most approaches will either be vis with ILS backing (something I even do in little planes), or ILS. Again, at the airports you're going to find them, you're going to preferentially fly the ILSs for the advantage of the lower mins anyway (even if you had IAN).

However, this is unlikely to be the case for ever (as I have no doubt you will know far better than I, Kyle!). Over here in the UK, ILS is still king, but the RNAVs are used whenever the ILS is off or, as Dan inferred, at Heathrow and Gatwick traffic following an A380 will be put on the RNAV in order to close up the spacing.

However, in Europe and the rest of the world there are increasing numbers of RNAVs out there in common use at major airfields (not necessarily RNP with lots of curvy RF legs, which the 747 can't do anyway, at least not with the legacy FMC).

As well as curved paths, the other advantage is the ability to customise the vertical path: Heathrow has been experimenting with a "slightly steeper" 3.2 degree RNAV over the last year or so and the trial is restarting in a week or so.

[scandinavian13 5,192]

39 minutes ago, skelsey said:

However, this is unlikely to be the case for ever (as I have no doubt you will know far better than I, Kyle!). Over here in the UK, ILS is still king, but the RNAVs are used whenever the ILS is off or, as Dan inferred, at Heathrow and Gatwick traffic following an A380 will be put on the RNAV in order to close up the spacing.

However, in Europe and the rest of the world there are increasing numbers of RNAVs out there in common use at major airfields (not necessarily RNP with lots of curvy RF legs, which the 747 can't do anyway, at least not with the legacy FMC).

As well as curved paths, the other advantage is the ability to customise the vertical path: Heathrow has been experimenting with a "slightly steeper" 3.2 degree RNAV over the last year or so and the trial is restarting in a week or so.

Definitely, but in the context of the 744, with so many of them making their way out to the deserts, it's basic RNAV (LNAV/VNAV) or ILS, essentially, for as long as the remaining few continue flying. The 748 has IAN, so it's not really much of an issue going forward in that case.

You are right, though. There is a big push for a number of reasons to use RNAV, and my bet is that it will eventually take over ILS as the most commonly assigned approach (or vis app aid) in the years to come.