New Transition Altitude UK & Ireland
 

Saw today this article: here at the CAA website. Consultation will begin, but why no mention of the proposed new level? They obviously have an idea of what will align them to neighbouring states...?

I've heard 18,000ft is on the cards.
How does this work in a TMA? Is there a 'regional QNH' type value for the TMA/CTA?

TMA QNH already exists, it's en-route QNH you need to worry about.
Anyway 18.000 ft sounds a bit high to me. It's OK in the USA where you have those things called mountains, but I would reckon either 9 or 10,000 (as there presently seem to be several 'divisions', such as floor of 8.33khz frequencies and top of LARS, at FL095 at present) or 6,000ft as it already is in some TMA.

The press release specifically states that they want to "significantly raise" the TA, so maybe something above 10k is what they are aiming for?

I had heard that it would be 18000ft and that there would be a push to make this the transition altitude throughout Europe. Which would certainly cut down on confusion.
I wonder if any US controllers would care to offer some opinions. It's 18,000ft there but the vast majority of the US doesn't have mountains anywhere near that. The highest peaks are all in Alaska and the highest in the continental US is Mt Whitney in California at 14500ft.

SoCal,
What did they impact with, the Rockies?
Surely though, your terrain is much higher than ours. We've only got a little pimple called Ben Nevis, (it's 4,400 and something-or-other), and your country is about 80 times as big as the UK.

Eurocontrol (I think) has made a paper discussing the impact of Transition Altitude (TA) and the consequences of various TAs.

I don't remember where it is though (and I can't find it on skybrary) but if I remember correctly the conclusion was something like this:

Low TA, easiest for enroute, least risk of having diffrent QNH for various aircrafts in the TMA (and if you have it they're generally going to airports very close so the diffrence is very small).

Downside is that during certain pressures the approach unit lose several available flight levels and it does complicate the work a fair bit.

High TA, removes the problem with losing altitudes in the TMA. The down side is that you need to start with regional QNH, since you can have enroute traffic going on QNH all the way (short hop propeller aircrafts etc) and you can have streams to airports quite far apart all being at an altitude.

There were also a medium TA option in this paper but if I remember correctly they concluded it was just in between, there are still lost levels in the TMA (just higher up where it might be easier to work with but can cause a ton of problem aswell) and there may still be aircraft needing a regional QNH rather than the airport pressure.


If anyone else has read this paper and remember the location feel free to link it, I will google a bit for it later (or tomorrow, I'm quite tired now :p).

I do by the way blame the terrible grammar and spelling on the fact that I've been travelling all day, it's not intentional :p

I thought they were already trying to roll out a TA of 6000ft across the UK? (I think Southampton/Bournemouth changed fairly recently & Birmingham is changing very shortly). Seems a bit pointless to spend all this time faffing about changing it now if they are going to make it even higher in the not so distant future...:confused:

The question is....do we want to lose the lower level in the stacks [occassionally] or do we want to screw the higher sectors in the most dense and complex airspace over London? Don't forget the massive increase in R/T loading......and that's even before SRG have written a complete chapter on transmission and readback protocol.
People's jobs depend on perceived work output....this is one result......but believe me when I say that the R/T loading alone should kill this off.

I found two documents by eurocontrol discussing and comparing diffrent TAs.

Flight deck perspective:
http://www.eurocontrol.int/airspace/...erspective.pdf
ATC pespective:
http://www.eurocontrol.int/airspace/...erspective.pdf

I and many others have advocated a TA of around 6000ft outside CAS.
It would make life so much easier for everyone and probably reduce the risk of quite a few airproxes which occur precisely because of the risk of confusion between flight levels and altitude.

I would venture to suggest 6000ft for all UK airspace would be most logical, but unfortunately those people in Brussels will probably dictate what we want.

Had a chat with the project manager today and 18k it is.

BD

Raising the TA won't be a bad thing but if it is 18k what QNH would that be based on and would approach units then have to change the aircraft to the airfield QNH later in the approach phase or would QFE make a comeback?. If so what level would that be done?

I Imagine it would be ok as the disparity between say a london TMA QNH and say the birmingham airfield measured QNH would not be as big as you sometimes get between QNE and QNH.

for non uk

QNE = altimeter setting for flight level
QNH= altitude (above sea level)
QFE = Height above aerodrome elevation

Will be interesting to see whether this major change is being tested and run through the enroute iFACTS kit.

How will it cope?

That should thoroughly confuse the uninitiated, particularly the QNE "definition", which, I note, Eurocontrol got wrong as well!

2 s

So what do the 'non uk' people use?

Apart from concise definitions.....

Australia uses Transition Alt 10,000ft, Transition Level FL110 (Min. available Level increases when area QNH is low).

New Zealand uses Transition Alt 13,000ft, Transition Level FL150 (Min. Level also increases).

Both countries use Area or Aerodrome QNH when operating at or below the Transition level, and QNE when above the transition level. I don't have a web link for the Australian Procedures, but the New Zealand procedures are here.

A point to note, New Zealand allows unpressurised operations without oxygen up to 13,000ft (for 30 mins max), whilst Australia only allows operations up to 10,000ft without oxygen.

The only real problem I can foresee in the UK are the extra words that will inevitably be bolted into every transmission "ABC623 Descent now altitude wun tree tousand QNH wun zero wun zero" instead of "ABC623 Descent now flight level wun tree zero. " Another four for both parties... unless of course we can get a bit smarter. Does Mode S pass an aircraft's current altimeter subscale setting?

PM

So about as much as the approach bods will save then?