ATSB report on very low flying Thai Airways B777 at Melbourne.

[Lookleft]

I think it will be many years before we see airliners using GPS RNAV approaches

There are some things that non-airline pilots shouldn't be making definitve statements about. Google RNP.

The truth is that we have under funded aviation infrastructure for years.

Couldn't agree more.

JR an ILS on 34 is like an Ipad in the cockpit- is it a need or a want?

All this discussion about the "dangers" of an NPA onto 34 and nothing said about the visual approach over sheed. There's your dangerous approach. 400' high with 6 miles to run and a howling quartering tailwind on base.

[Keg]

However, my 747 captain mate says it is not as simple in a widebody jet and even less simple in a glass cockpit wide body jet.

I disagree. Flying a ML 34 VOR/DME approach (or any NPA really) is relatively simple IF the crew understands the FMC, what it's got programmed and how it achieves what is programmed.

[Wally Mk2]

Am quite surprised the amount of interest this subject has sparked. It's good really as it sparks debate & keeps these potential dangerous situations in everyone's mind.
Humans learn form their mistakes, us Aussies included we are not immune here'
I look at it like this as the big question here now is do we need an ILS on this particular rwy. The answer is neither yes or no as it's much like a railway crossing where boom gates are installed. Do we leave the boom gates as they do the job if they are obeyed or do we install a bridge over the tracks to make it safer?
The whole idea of any inst App is to get the plane in the best position to land, end of story. The ILS improves that position doesn't guarantee you will get in but improves it much like the bridge over the tracks, improves yr chances of getting across the tracks but doesn't guarantee it (bridge might be blocked due car crash!)
ILS means it's safer, we don't need to be a rocket scientist to know that.
The 'boom-gates' (VOR) do the job, safety comes under the heading 'it's enuf 'till the horse has bolted'
As usual like all 'crossings' it's okay 'till someone dies!
The answer really is subjective.

Wmk2

[Derfred]

I'd say the question comes down to this:

We have identified a tendency of at least one foreign airline is to select an idle thrust descent mode to minima when conducting an NPA. That is downright dangerous.

Since we as a county do not want an airliner splattered on the ground, we have two choices - either restrict those airlines' operations to Australia until they can demonstrate suitable training for NPAs, or install ILS approaches on all runways those airlines will utilise.

For the relatively small cost of 1 ILS installation compared to banning airlines, I would go for the ILS.

[Old Akro]

We have identified a tendency of at least one foreign airline is to select an idle thrust descent mode to minima when conducting an NPA. That is downright dangerous.

I think a review of altitude infringements on NPA's to Melbourne reveals its more than one airline and includes Australian & US airlines.

[judge.oversteer]

Hi Everybody,
Interesting thread to say the least.
In my time an NDB approach (No such thing as an ADF Approach, an ADF is the piece of equipment in the aircraft, the NDB is the radio beacon on the ground!) in a F27 or a Viscount properly executed down to near minimums was an extremely satisfying thing to do accurately. And everyone knew how to do one, ie Wynyard, Tassie. Time and motion study.
I'm sure JL will agree with me.
I'm sorry if I'm showing my age but to give an NDB/VOR approach to students in the simulator without any aircraft emergencies is an extremely good handling exercise for all pilots, with, or without, RNAV, PRNAV or GNAV or whatever you want to call it and a good lesson in crew management.
In my 30 years on B747/B744 I think I only ever did the real thing at JFK 13L, Tabriz, and on RWY06 VOR, and sometimes RWY24, at Manila at some very interesting times! There was no ILS on RWY06 and always a few CB's! (LAVS on the B744).
In my opinion its perhaps not a bad idea to keep these approaches (VOR/RNAV) in the Sim. RNAV approach into Kansei to ILS/GS at 1200 feet was also good effort.
Boeing and Airbus are continually designing the flying pilot out of the flightdeck through automation but these procedures must be taught!
I know, it's very hard to teach students the loop these days, ie stick/control column, throttle/s, rudder/s and scan! (Winjeel and Vampire days, eh! No, not that one!).
They just want to play with the autopilot!
Oh well, back to the Port and Stilton...
Cheers.
JO.

[Old Akro]

There are some things that non-airline pilots shouldn't be making definitive statements about. Google RNP.

Firstly, I didn't make a definitive statement, I expressed an opinion. You can tell because it started with " I think.." In this instance I may be wrong. Although, my reading so far indicates that RNP is a navigation tolerance standard which is technology agnostic - it can be achieved with VOR, INS, DME and possibly other systems. I understand RNP originated in Europe and uses angular clearance tolerances rather then height or vice versa. Either way it requires full procedure redesign.

Secondly, I think the Queenstown GPSS RNAV RNP approach (which is the poster girl for RNP approaches) has been around for maybe 10 years? Or more? I think it was originally developed using an Apollo CNS-80. It doesn't really seem to be catching on. Which is my point, that (especially with airline capital expenditure programmes) these things are long linked.

As I understand it, a precision RNP approach requires an additional altitude input. This can be from either WAAS (back to the WAAS debate) or a precision barometric input, which I assume has to be part of the Flight Management System. This barometric input can also turn a VOR NPA into a VOR RNP precision approach.

If I read the draft CASA CAAP correctly (AC-91U-II-C-5), it says that Australia will only develop RNP VNAV approaches (ie precision approaches) if we "acquire a GNSS augmentation system". In other words, we'll only get precision RNP approaches if we install WAAS beacons, which I understand is not on the agenda.

Which brings us full circle back to ILS.

How did I do for a non-airline guy?

[Keg]

It (RNP approaches)doesn't really seem to be catching on.

There are now RNP-AR approaches for BNE, CB, ML, CNS (I thinK). They're catching on in a huge way. RNAV approaches into CTAFs and procedural control aerodromes are the norm for QF 737s.

QF 767s can do RNP-AR into BNE. Small issues with the design (both procedural and FMC programming) of RNP-AR into CB and MEL but they should be up and running for the 767 within 6 months.

This is on top of the RNAV approaches that QF GE powered 767s CAN do in virtually every major aerodromes around Australia.

There is no reason why any 777 or 744 operator can't go through the appropriate motions and avail themselves of the RNAV straight in to 34 at MEL.

[Lookleft]

How did I do for a non-airline guy?

Proved my point.

Jetstar uses RNP down to .3 at OOL and it gets us down to 439'. .11 will get us to 367'. We also use it in BN.QF use RNP approaches in preference to ILS on most occasions but a QF pilot could give you more detail. GBAS ILS like approaches are already being trialled in Sydney. Reading stuff on RNP and using it on a regular basis are not the same thing. I'm not trying to be superior but I do get annoyed when people make statements about airline operations and procedures that they really do not know much about. The long term future for ILS will be to go the way of the NDB.

I don't disagree with the argument for having an ILS installed but someone has to agree to pay for it and I can't see too many hands going up.

[Capn Bloggs]

Perth had only a VOR on 03 for years. Much whinging, moaning and complaining by all and sundry made no difference, despite the relative difficulty of the VOR approach, especially in bad weather (yes, we do get bad weather from the north occasionally, like Melbourne, by the sound of it). Then an ILS was installed. All the problems with landing on 03 went away, instantly.

Old Akro, no disrespect intended, but you are a bit off-track. Even RNP AR approaches (the whizzbang ones like ILSs/Queenstown) do not need a WAAS (airlines are doing them all over Australia now, see the AIP SUPPs), but do need a lot of organisation, training (initial and ongoing) and equipment standards. Too hard/impossible for many operators, including, I suspect, Thai. Could they do even an RNAV-Z to 34 (higher MDA though)? The capabilities of the 777 may be the issue.

As at the Gold Coast, on balance, we should bite the bullet and just chuck in an ILS on 34. The safety improvement is marked, the cost amortised quickly. I agree with the government paying; it's national infrastructure. If that crew is also buzzing around domestic Thai with VORs then they should have done better. However, if they are international types, then it is reasonable that they expect an ILS at one of the major gateways to Australia.

Originally Posted by Lookleft

All this discussion about the "dangers" of an NPA onto 34 and nothing said about the visual approach over sheed. There's your dangerous approach. 400' high with 6 miles to run and a howling quartering tailwind on base.

Agree. Never done it, don't want to.

[Old Akro]

ML RWY 34 has both GNSS & RNP approaches. They have the same MDA (330 ft) as the VOR approach. They have the same 3 deg approach path (naturally) and RNP approach seems to approximate the DME arc and transition of the VOR approach.

The RNP approach seems to remove the circle-to-land minimum altitude, which makes the Australian NVMC visual approach clearance requirement interesting.

As I understand it, the RNP requires CASA approval which is primarily about flight crew training and equipment certification. The RNP requires RF which is some sort of flight management system distance measuring function - I guessing DME based. I think this is an example of an RNP approach that could be flown with DME & VOR and doesn't require GPS

Correct me if I'm wrong, but I believe this is still a non-precision approach (which would require an additional height reference - typically a WAAS beacon).

The Thai incident was NVMC, so visibility & MDA were not an issue. The issue was the early & mid procedure altitude reference, which for the VOR approach is basically read the chart, read the DME and check the altimeter. For whatever the reason, the crew on the night (and a number of other crews by reference to ATSB reports) didn't do a very good job of this.

So, unless the RNP hardware feeds the flight director, then the Australian non-precision RNP approach isn't much of an improvement over either the VOR or the GNSS NPA. The main difference (I think) is that the FMS of a RNP aircraft will fly the curved transition.

As I understand it, the benefit of the ILS for all RWYS at ML is that the crew falls into a more practiced routine and gets vertical guidance. I don't think the Australian implementation of RNP achieves this.

I found a US FAA reference that says an ILS costs USD$3m to install and a US AOPA reference that suggests they cost USD$18,000 pa to maintain. If that is all it is - then why the fuss? Mildura is spending more than that on a new terminal building. If it costs significantly more in Australia, then we should hold the blowtorch to the belly of AsA and find out why they are so uncompetitive. - Or subcontract it to the FAA.

[Jack Ranga]

If the visual star onto 34 is dangerous why fly it? Emirates refuse it & good on them. If you all refused to do it maybe you'd get an ILS? Which international airlines are flying RNP approaches in Australia?

[Capn Bloggs]

Old Akro, sorry mate, but you're rapidly losing the plot.

ML RWY 34 has both GNSS & RNP approaches. They have the same MDA (330 ft) as the VOR approach.

Not they aren't. VOR 430 AGL, RNAV-Z 450 AGL, RNAV-P 381 AGL.

As I understand it, the RNP requires CASA approval which is primarily about flight crew training and equipment certification. The RNP requires RF which is some sort of flight management system distance measuring function - I guessing DME based. I think this is an example of an RNP approach that could be flown with DME & VOR and doesn't require GPS

Wrong. RF is short for Radius to Fix, meaning the FMS is capable of flying a constant radius turn to arrive over a fix/waypoint on a particular track (ie not simply a join-the-dots box). This is needed for "curved" RNP AR approaches. It's got nothing to do with DME and is all done in the box itself.

Correct me if I'm wrong, but I believe this is still a non-precision approach (which would require an additional height reference - typically a WAAS beacon).

No! I said before and I'll say it again, RNP AR does not require WAAS. As for being a precision approach, you could say it is (exact definition irrelevant) because vertical guidance is provided and, I suspect, MUST be followed by either the autopilot or manually via the FD.

I don't think the Australian implementation of RNP achieves this.

Nothing Australian about it; RNP ARs are the same world over as far as I am aware and they do provide vertical guidance (just as any half-decent FMS will provide vertical guidance for the VOR or RNAV-Z/GPS NPA).

I found a US FAA reference that says an ILS costs USD$3m to install and a US AOPA reference that suggests they cost USD$18,000 pa to maintain. If that is all it is - then why the fuss?

With that, I agree.

[Old Akro]

etstar uses RNP down to .3 at OOL and it gets us down to 439'. .11 will get us to 367'.

Jeppesen don't have this procedure. It looks like a CASA special for approved operators only. So far, I can only find Jepp RNP charts for YMML & YBBN.

[Old Akro]

Old Akro, sorry mate, but you're rapidly losing the plot.

Maybe, but not completely, I'm just trying to learn & getting some bits wrong.

I screwed the MDA's - you are correct.

I pretty sure I'm correct about DME feeding the FMS - how else does it know the track miles to run? The INS needs updating. It can come from GNSS or DME. I'm guessing the FMS uses DME as default.

By definition, a precision approach requires an additional altitude reference. ILS does this with the radio based glideslope. GPSS does not have sufficient altitude accuracy, but it does when augmented with ground based reference (WAAS). The other alternative is a sensitive barometric input which I presume is something sophisticated that exists in FMS world only.

Without an additional altitude reference, I think we strictly speaking have RNP - LNAV approaches. This allows curved approaches and the fuel saving of shorter " Green" track approaches that AsA boasts about as well as reduced lateral obstacle clearances, but does not have the vertical accuracy of a precision ILS approach unless it has altitude augmentation.

My reading (mainly of FAA material) is that not all RNP approaches are alike. The CASA CAAP identifies 4 flavours of RNP approach. Only 2 of the four has ILS equivalent MDA's and accuracy - one using WAAS and one which requires localiser augmentation. See AC 91U-II-C-5. Its categorisation of sensitive barometric input differs from the design notes that I read on the Queenstown RNP design - it might just that the NZ stuff is old.

If you look at the YMML RWY 27 ILS & RWY 27 RNAV -M (RNP), the RNP approach has a DA(H) - being careful to get it right - for Cat D is 610ft & 931ft respectively. This reflects the greater altitude uncertainty of the (non WAAS) RNP NPA approach.

I am presuming (although I may be wrong) liability issues will mean that aircraft systems will not display vertical guidance ( a la ILS) for approaches with only C129a GNSS input. I contend it is the absence of this vertical guidance that contributed (or at least exacerbated) to the Thai incident.

But, this is off-topic, although its been interesting.

My fundamental thesis is that (whether through ability or not) the Thai crew joined a list of others who messed up an NPA approach to RWY 34. Rather than saying they are just not good enough and we are better, I'm saying there have been enough Australian, US & Thai crews to make similar mistakes that we should get on board with the rest of the world and put in more ILS approaches. If we can't do it for less than the cost of the carpark modifications at Melbourne, then we should be asking why we can't install them at International benchmark costs. If anyone mentions us being a small market, I'll scream. This level of equipment is an international market. A bunch of airfares & some airfreight from the US might add $100k, not $millions. The reference I found from the FAA was no less than Randy Babbitt about a year ago.

[UnderneathTheRadar]

Visual approaches

Just mulling over this, checked Jepps and I see under Departure, Approach and Landing Procedures:

....with the exception of Australian and New Zealand operators and aircraft conduction independent visual approaches at Sydney, Super or Heavy jet aircraft will only be assigned a visual approach when:
a. specifically requested by the pilot, and the pilot has reported the landing runway in sight; or
b. the straight-in approach aid is unservicable

Still curious as to why it's necessary to issue a visual approach clearance?

UTR

[Derfred]

I contend it is the absence of this vertical guidance that contributed (or at least exacerbated) to the Thai incident.

Mate, they had a perfectly serviceable VNAV path to follow. They just chose not to use it. It's in the report. They selected FLCH when the aircraft pitched up to intercept the correct approach path. Poor situational awareness or knowledge of systems or training or something.

[Jack Ranga]

I was kind of wondering if we'd get a point of view like angryrat's

Taking that & Keg's opinion, I've concluded an ILS is not required on R34

I've also concluded that you lot are like the People's Front of Judea, or is that the Judean People's Front?...............

[Capn Bloggs]

Originally Posted by Jack R

Taking that & Keg's opinion, I've concluded an ILS is not required on R34

It is an easy approach, especially with an FMS, and if it were Ozzies involved, an incident like this would embarrass the hell out of the operator and it would lift it's game pronto. But the reality is that we have no control over international operators and if one of their aircraft pranged in such a situation we'd be a laughing stock. Catering for the lowest denominator? I suppose. But that's what we are doing ourselves, introducing easier/safer approaches eg GPS NPA and RNP. It's all relative.

[Old Akro]

I've also concluded that you lot are like the People's Front of Judea, or is that the Judean People's Front?...............

I resent that, but standby while I draft a resolution......