Help with altimeter question for air law exam

[rossrobertson]

Hi,

I was not sure where i should post this question. I am just about to do my air law exam. I have been working through some example questions and i am not sure how to work out the following and need a bit of help:


A pilot setting off on a cross country route in a cruise climb over a part of the country where the transition altitude is 3000 feet, has just been given a regional pressure setting of 970mb(hPa), from a local ATSU. His magnetic track is 260deg. What will be the transition level and what will be the lowest availabe flight level that the pilot can use, in accordance with the quadrantal rule? (assume that pressure falls with increasing height by 1mb every 30 feet).

a. FL45 FL60
b. FL40 FL55
c. FL30 FL30
d. FL45 FL55


Thanks for any help.

Regards,

Ross

[Slopey]

His magnetic track is 260, so an appropriate level for the quadrantal rule would be an Even flight level (0-90 Odd, 90-180 Odd +500, 180-270 Even, 270-000 Even +500).

(just from the above, you already know the answer is (a) as it's the only even FL)

So we can try FL40. FL40 is with 1013 set on the altimeter. But we have 970. That's 43 hPa below 1013, so FL40 is really 4000 - (43 * 30) = 4000 - 1290 = 2710 ft.

2710ft is below 3000ft, so we can't use that.

As it has to be an Even FL, the next available FL is FL60. As a sanity check, 6000 - 1290 = 4710ft. So that one is fine.

So it's (a).

(I hope!)

[Miken100]

Hello Ross,

I'm not 'having a go' but just wanted to get you to reflect on something... You've posted a question from the air law exam on PPruNe and someone has told you the answer... have you learned anything from this process I wonder?

It isn't clear from the general nature of your question exactly what it is you don't understand.. are you not clear on Transition Altitudes, Quadrantal Rule, how pressure settings work, basic maths etc. etc... it's hard to tell.

One day you could be flying solo, near high ground and on a regional setting, you'll have to work out 'live' in the cockpit your actual altitude and terrain clearance (this may be very necessary if you are, say, flying towards a low pressure system in deteriorating weather)... at this moment you can't put a question on PPruNe.. you are going to have to know what to do to ensure that you don't fly into 'Cumulus Granitus'

As I said at the start.. I'd just like to create some thoughtfulness about a trend I'm noticing on PPruNe...

Your flying school/FI should be the 'go to' place for this kind of thing... they can coach you through the answer rather than simply tell you the answer.. you are much more likely to learn the underlying principles and as a consequence be a safer pilot.

Good luck with the exams, not many of us really like doing them but they do have their place in flying training - I'm glad I had to go through the pain of doing them and from time to time colleagues at Liverpool still throw questions like this at me in the cockpit.. keeps us all sharp!

Regards, Mike

[peterh337]

Yes, the UK quad rule is bonkers (nobody else in Europe uses it) and the regional altimeter setting is also bonkers (nobody else in the world uses it).

Also almost nobody flies the quad altitudes/levels in UK Class G. Flying them would merely increase the chance of hitting somebody because all traffic would be concentrated into altitude bands as potentially narrow as one's altimeter errors.

Consequently, the ability to work out that answer is of no relevance to flying for real.

[TractorBoy]

It did occur that the OP might be a troll, but if not I can sure understand the frustration

There are some odd posts on this forum. This person posted on 5th Dec 2009 that he was off to complete his PPL in California the next year, and then posted end Nov 2011 that he'd just started his PPL.

[Jan Olieslagers]

the regional altimeter setting is also bonkers (nobody else in the world uses it)

Whenever I call Brussels Information they are quick to give me the regional QNH.
I must admit I have questioned the usefulness of this parameter: more than once, upon returning from nav, I have found myself a hundred or more feet separated from people working t&g's in the circuit, still relying on local qnh as set before take-off.

[Slopey]

Likely a troll, but I needed the practice - just off to do the IMC exam, and it loves those kind of things [:)]

[ShyTorque]

I must admit I have questioned the usefulness of this parameter: more than once, upon returning from nav, I have found myself a hundred or more feet separated from people working t&g's in the circuit, still relying on local qnh as set before take-off.

The RPS is intended to safely separate you from the ground, not from other aircraft operating on a local, more accurate setting.

Obviously, it's a forecast lowest setting for a region, so it can hardly be expected to be accurate at any one airfield!

It dates back to a time when local altimeter settings were more difficult to obtain, especially for military aircraft flying at low level where radio contact was difficult or impossible.

I understand that in UK it will cease to be used in the fairly near future.

[mrmum]

I think that the ASR/RPS situation will be changing, rather than them disappearing all together, from the consultation document;
http://www.caa.co.uk/docs/2257/20120131HarmonisedTAConsultationDocument.pdf
49. It is accepted that the map of the UK Altimeter Setting Regions (ASRs) is likely to change as a consequence of the change to the TA. Extensive work has already been undertaken by the TAPT and the UK Met Office to determine the issues associated with revising the ASRs. This work will continue during the initial consultation period to ensure that the eventual shape of the new ASRs balances the needs of all airspace users to the greatest extent possible. Once complete, findings will be distributed to stakeholders for comment.

[mrmum]

Hi Slopey,

If you're about to take the IMCr theory exam, be careful where the quadrantals change.
They're actually;
000 - 089 ODD
090 - 179 ODD+500
180 - 269 EVEN
270 - 359 EVEN+500

Small difference I know, irrelevant in practice, but might make the difference in a theory exam, if whoever wrote the questions put the magnetic track right on the edge of the quadrant.

[ShyTorque]

I say again, the proposal is for the cessation of use of the term "Regional Pressure Setting (RPS)" ;)

As that document states, there are some disadvantages in doing away with RPS. Not surprisingly the same reasons why it was first introduced.

Time will tell once the consultation process is completed.

[BillieBob]

peter337 saidand the regional altimeter setting is also bonkers (nobody else in the world uses it).Jan Olieslagers saidWhenever I call Brussels Information they are quick to give me the regional QNH.Shome mishtake, shurely?

[Gertrude the Wombat]

if whoever wrote the questions put the magnetic track right on the edge of the quadrant
Do they ever not??

And for a bonus they try to do so such that if you erroneously use true track instead of magnetic you end up with the wrong level.

[Slopey]

@mrmum - yep, brushed up on that while waiting for the exam - sneaky quadrantal rule maker-uppers! Anyway 92%, very happy :ok:

[mad_jock]

I thought the quad rule was a thing of the past now with EASA?

[BillieBob]

Not yet, Jock, you'll have to wait for Part-SERA before you see the end of Quadrantals.

[BackPacker]

I understand that in UK it will cease to be used in the fairly near future.

I wonder what's going to replace it then, especially as they're going to raise the TA to some very high level, which would mean that more, not less, aircraft will need to fly on some sort of RPS.

The UK is NOT the only country using RPSs. It is, as far as I know, the only country that gave them funny names ("Skua QNH ..."), while other countries use names that have more meaning without detailed geographical knowledge ("North Sea North QNH ...").

Anyway, the way a FIR is divided up into RPS regions is listed in AIP ENR 1.7. The Netherlands has four (North Sea North, North Sea South, Amsterdam, Maastricht). Belgium has only one, which is called "The regional QNH". The UK has 20 regions, France has 5 FIRs with three to five QNH reporting stations in each, and so forth. So the concept of RPSs is universal.

[ShyTorque]

Backpacker, the document link given by mrmum gives details of the CAA proposals.

Looks like it will probably be brought in line with the system used in Europe....i.e. similar system to the present (or worse?), just given a name change to make us more European.

Obviously, the way to improve the service by making it more accurate would be to provide a better network of local, real time, met broadcasting stations but unfortunately that would cost money and is probably unlikely to happen.

[Heston]

Archaic indeed; but then I've never used them or known anyone that has.
:O
H

[UV]

Also almost nobody flies the quad altitudes/levels in UK Class G
Get up higher and you will find that lots do!

[kharmael]

RPS is used for low flying...