altmeter setting crossing FIR's

[genius-747]

Consider a flight from somewhere in Ireland say.. Dublin, to a destination in the UK.

If you plan to fly VFR and cruise at 3500', when you are flying within the Shannon FIR there is no probs because you are on the QNH all the time because Ireland Trans alt is 5000'.

But when you cross the FIR boundary to say Scottish or London FIR's and where the trans alt is 3000' are you immediatly expected to set 1013 on the subscale and then use FL as oppose to alt when giving height over the radio?

I hope some ATC chaps can help me out here!

[Chilli Monster]

1013 is only mandatory for IFR flights above Transition Altitude.

You can fly on local or regional QNH if you wish, It'll help give better awareness for terrain avoidance (though you'll be VFR and fully visual of course). The thing to remember is not to enter CAS if the base is defined as a flight level and you, being on the QNH, and the pressure is low (see your previous thread) puts you into the base of CAS

Take those simple factors into account and you can use whatever you wish and report your level in whatever way you wish. An ATC unit however may change you in order to give them better situational awareness of your level in relation to other traffic but in the expanse of airspace you're going to be crossing it's not a situation that's likely to come up.

[genius-747]

So are you saying if its a really clear day and I manage to get my cessna up to 10,000' and fly from A to B in the UK no matter where I may be, just because I am VFR, I can have QNH or QNE set in the sub scale?

I'd like to see that on CAA printed paper!:confused:

[DFC]

747,

It is on paper......in the AIP!

The quadrantal cruising levels are only "recomended" for VFR flights.

The reason why it is only recomended is because VFR flights must remain in VMC. Remaining VMC is the priority.

When flying from Dublin to Ronaldsway for example, once you cross the FIR boundary, you can if you wish set your altimeter to 1013 and fly at an appropriate quadrantal level.....30/50 etc....provided that the flight level is terrain safe and available for use (above the transition altitude).

On the return flight, you would fly at 40/60 etc again subject to the level being available for use and terrain safe.

Prior to entering the Dublin CTA, you must obtain a clearance and adjust your level to cross the boundary in accordance with the clearance.

When there is no controlled airspace, what you do at the boundary is adjust your level so that you are flying in acordance with the AIP requirements for the new FIR.

Regards,

DFC

[Chilli Monster]

It's also in the UK Rules of the Air - the legal document of anything aeronautical (Readable at CAP393 (http://www.caa.co.uk/docs/33/CAP393.PDF) ) You want to read Rules 24 - 28 (Visual Flight Rules) and then compare that with Rule 30 of the Instrument Flight Rules.

Another thing that needs correcting. You keep referring to 1013 as QNE - it's not:

1013 is the Standard Altimeter Setting

QNE is the level indicated on an altimeter when 1013 is set, used mainly at mountain airfields in low pressure areas so as to give some form of easily identifiable landing datum. It would be transmitted as "QNE is 5000ft" (for example).

[ratt]

In VFR flight you can fly on whatever pressure you wish. Flight level quadrantals, as DFC says, are only recomended. An ATC unit may ask you to fly at a quadrantal level if they deem it to be suitable for the area or unless you request a specific height for a reason.

To aid the ATC you may be asked for your altitude on a certain pressure, or when transiting a zone or subject to co-ordination you may be asked to fly on a pressure at a height/altitude/flight level.

It aids ATC no end when they have multiple aircraft using the same pressure setting. It can save precious seconds in co-ordination of different height/altitude/flight levels.

Remember, the more efficient we are, the more you get out of your flying!

[Chilli Monster]

That'll be the military overcontrolling again ;)

When are they going to learn that you don't instruct VFR aircraft in class 'G' to fly at any level (Standard military phraseology to an aircraft when it checks in reporting it's level - "Fly at **** ft, on xyz pressure" - which sounds pretty much like an instruction to me).

VFR is VFR end of story, and as such they have to fly at a level which keeps them VMC - which is why you can't stipulate a non-deviating level as that may make them IMC at some time. By all means request they fly 'not above' a level if you want to cross IFR traffic over the top or even 'not below' if you want to route beneath (and it's pretty sure they can stay within the privileges of their licence on that one) but that's as far as it goes guys.

[ratt]

That'll be the ex-mil civvy atco ppl holder not reading the thread before he answers again ;)

Not above/not below won't work in many cases when flying near alot of other a/c who may be IMC or RAS due to company rules (it happens).

You are always right Chilli but what you seem to take is a "whats best for me" attitude to flying, which surprises me for someone with your background. One of these young impressionable readers may take you to your word one day and I'd hate to see the concequences.

What was stated in this thread so far was advice on when and why ATC would want someone on a certain pressure. If ever I am talking to ATC and they ask me to comply I will gladly do so, but if I cannot comply I will advise them so and they can re-plan.

As for instructing an aircraft, I think you are the only one in this thread to mention that.

As for the phraseology we use, then why don't you petition ATCEB if it means that much to you. Seems to work fine for 99.9% of our happy customers.

[spekesoftly]

Chilli Monster wrote:
QNE is the level indicated on an altimeter when 1013 is set,

Correct, but only: 'when the aircraft is at aerodrome or touchdown elevation'

[Chilli Monster]

Not above/not below won't work in many cases when flying near alot of other a/c who may be IMC or RAS due to company rules (it happens)Sorry - don't see it. Ask the VFR if he'll fly not above 'x' ft, stop the descent of the IFR/RAS to x+1000ft until 3nm separation (if allowed, or 5nm if not). It's worked for me (and others) plenty of times. If the VFR won't accept then take 5 but hey - thems the breaks :D.
One of these young impressionable readers may take you to your word one day and I'd hate to see the concequences I would say worse would be one of these impressionable readers flying along one day and taking the above mentioned phraseology as an instruction, ending up in IMC and losing control - a slightly more dangerous consequence, I would venture.If ever I am talking to ATC and they ask me to comply I will gladly do so, but if I cannot comply I will advise them so and they can re-plan. You would do that, I would do that, but the inexperienced student pilot or newly qualified PPL holder doesn't have that mindset - and as we don't know the qualifications of all the people who talk to us then you have to start at the lowest common denominator and work upwards.

As for the "what's best for me" attitude - interesting concept. You'd be surprised how many several thousand hour pilots I know often share my views in discussions. Does that not change it to a consensus?

[ratt]

To be honest, I've never experienced a pilot that has been afraid to tell me that he cannot fly at a certain level due to IMC.

The message I get from pilots is that the foremost thing on their mind is to stay VMC. As you well know that can sometimes cause a huge amount of 'fun' when someone elects to take a screaming jesus turn towards your RAS traffic so they can avoid a cloud. That's the job though.

As I stated before, the phraseology seems to work for 99.9% of the flyers out there who understand their rights and limitations. But then we are reminding piots not to fly into the ground currently so maybe you're on to something ;)

If someone is a little cautious crossing a Matz or Zone then good, it may be Class G but it can also be a busy place.

I'll leave it at that for this thread.

[genius-747]

Thanks for all the replies, but could someone please tell me what is the commom practice for VFR aircraft do do (ie: altmeter sub scale setting) when flying from one FIR to another that has a trans alt of 3000' and the other a trans alt of 5000' and they are flying at 3500'?



thanks:O

[Chilli Monster]

If flying in the UK, as we've stated before, it doesn't really matter. It's up to you on what you're happiest with subject to the provisos above. Make your own decision subject to airspace requirements. It doesn't hurt to go to 1013 if you want - just remember that it doesn't automatically give you terrain avoidance if the pressure is low (Your other thread on Private Flying had this very point made on it).

Different countries have different rules, and it pays to find out before you go. If you're flying across to France (for example) then the French want you on 1013, as they fly a system of semi-circular for IFR and semi-circular + 500ft for VFR.

It all depends on the countries own rulings.

[VFE]

Let me get something right in my head here:

When I'm flying VFR at say, 3000ft on a regional QNH and want to upgrade to radar information service and go IMC, I climb to my MSA which is say, 4000ft, do I then select 1013 on the altimeter and fly the correct quandrantal rule FL? Or do I stick on the regional QNH but still fly on the correct quandrantal rule?

Altimetry in this country is far too complicated for it's own good I say and defeats the object.

VFE.

[Chilli Monster]

VFE

Rules 29 & 30 Air Navigation, the Order and the Regulations (http://www.caa.co.uk/docs/33/CAP393.PDF)