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If you don't like the service we are providing at Class 'D' airfields then we can offer you a re route. Keeps you away from us, and perhaps will stop you commenting on things that are outwith our control. We do our best within the rules, as said before if you don't want to fly on the QFE then stay away from the airspace.
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WWW
In the UK there is no such block of airspace which extends from the surface up to 45,000 ft. Everything above FL245 is Controlled Airspace. Also if you were flying at 24,500 ft on the regional pressure then there is a danger that you could be above FL245 and entered CAS illegally. |
ILS 119.5, you're absolutely wrong. There are blocks (very big ones at that), which go from 5000ft to 55000ft (promulgated in the AIP) with class G below. If one is cleared into these blocks, there is nothing that would necessarily stop you goinng from 55 grand down to sea level. that
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I think that maybe the time has come for a review of the altimeter setting procedures used by military ATC in the UK. This thread already highlights some areas where the current procedures do not seem to be best practice or are liable to cause confusion.
As an example (and by know means wishing to cause embarrassment to stillin1) he mentions on page 1 of the thread that transit traffic in IMC will be told the Sector Safety Altitude based on the QFE. Surely this should be refered to as the Sector Safety Height? Whilst I think I know what he was getting at, it shows that confussion can easily arise (especially for simple minded pilots like myself). A statement by whowhenwhy saying that traffic outside the pattern should be on an RPS when below TA is also illuminating. My dusty old MATS part 1 says that RPS should be used "at, or below 3000' amsl when outside controlled airspace and not in the vicinity of an aerodrome". Now, it seems to me that you have to be in the vicinity of an aerodrome in order to receive a LARS, otherwise there would be no radio/radar contact or the pilot would be outside of the operational area of the unit and hence the sevice would have been refused. Furthermore, if you have just transitted a zone (under QFE) I do not see how the next pressure setting given can be the RPS. How can you transit a zone and then not be in the vicinity of an aerodrome? I fly in the South East of England where a lot of the airspace above me has its lower level defined as an altitude. The last setting I want to use is RPS which is the lowest FORECAST QNH and hence could put me closer to my work colleagues above me than I want to be on a day off! As a parting thought, the controllers at Seaton TWR use QFE for circuit/landing traffic and QNH for transit traffic as do many other units around the country, so this type of operation is not without precendent and help and advice should be readily available. As always, just my view. G W-H |
The more I think about this subject, the more I discover that the UK altimeter setting procedures are absolute rubbish. Some examples;
The general transition altitude is well below the highest terrain. Looking at Brize as an example - The Transition Altitude is 3000ft but the top of the CTR is defined as an altitude of 3500ft. The top of a MATZ is 3000ft above the appropriate airfield which in all cases puts it more than 3000ft AMSL thus aircraft passing over the MATS are required (for safety sake) if IFR to fly at a Flight level that keeps them above the fast moving jets that are using QFE. Does the pilot use RPS to assess separation (NO TMA, CTR or other CAS) or does he call the mill ATC unit for QNH only to be given the QFE?............The biggest danger in aviation is not knowing what is going to happen to the flight! I am amazed that there are not more incidents relating to altimeter setting..........however I could safely say that there are several each day that go unreported or even unnoticed!! ILS119.5..............have a look at a danger area of the big variety - all have an upper height AMSL. As far as I am aware the ACC use the RPS to separate flights crossing above i.e. use the RPS to determine a minimum FL..........however aircraft operating within the danger area could be using the QFE of an aerodrome within it!!!!! --- KPax, Perhaps you should review the separation provided in Class D between a VFR flight (transit or otherwise) and any other flight - none. Thus QNH or QFE for a VFR transit aircraft makes little difference because all you do is give traffic info and the pilot does the manoeuvering as required to avoid traffic and maintain VMC............I have received a clearance from you guys to fly VFR at 1500ft QFE when your actual was Overcast 1000ft.....because your circuit was active............not what we would call a good idea :) As for IFR - If your field elevation is 500ft and the circuit is 1000ft then you simply want the IFR flights to be not lower than 2500ft on your QNH without giving traffic info! All very simple for someone to put into local procedures which is always safer than making it up on the fly! --- Giles, The definition of "In the vicinity of an Aerodrome" is; Within, entering or leaving the aerodrome traffic circuit. In other words - the ATZ! The limits to LARS coverage is based on radar performance, airspace issues, adjacent units, local requirements and last but not least - the CAA limit on the distance at which controllers can provide a radar service without holding an Area Radar rating. Regards, DFC |
Hi Giles,
Drifting off topic a bit, but in response to your... "I fly in the South East of England where a lot of the airspace above me has its lower level defined as an altitude. The last setting I want to use is RPS which is the lowest FORECAST QNH and hence could put me closer to my work colleagues above me than I want to be on a day off!" I routinely provide a service to traffic transiting under airspace with lower limits defined as an altitude. I won't pass this traffic the RPS, I'll pass the pressure datum the airspace is based on. I would be surprised if you were given any other pressure if operating close to the limits of said airspace. Best Regards, LXGB |
The Vis cct is 1000' QFE, SPC 1500' QFE, RTC 2000' QFE, Procedure Pattern height (NDB, TAC) 2500' QFE. We try our best using the premise that if you are VFR and you are not visual with IFR traffic then we will separate you. We very rarely have problems and our procedures appear to work very well receiving not many complaints at all. As stated before if you don't feel comfortable with what we are doing then go west with Bristol or east with Brize.
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Wow what a hot topic! At my RAF civil manned unit we still have QGHs and Spiral Descents!! All Mil IAPs are flown on QFE, which seems to make sense to me as under a high workload, the man in the hot seat in the sky (who is after all our raison d'etre) doesn't have to think about whether he's about to hit the floor or not. Correct me if I'm wrong, but I believe both civil and mil IAPs give both altitudes and heights on approach plates, so the pilot can in fact please himself. The ATCO, I think, should, and generally does, carry out any correction required for separation, as he/she already does on low pressure days between highest Alt and lowest FL.
As for separation, we can only apply 500' between mil flights. Civ vs civ or civ vs mil get MATS1 standard separation. And I also believe I'm correct in saying that MATS1 states that all a/c are to be given QFE before commencing Final Apch, unless the pilot has stated, or it is known that the pilot/operator lands QNH. Hope I haven't left myself open to a broadside....... :D |
KPax,
Bit hard for a VFR flight to be visual with an IFR flight that is in cloud. However, provided the VFR flight remains outside cloud then the IFR flight who is inside that cloud is separated (segregated) from the VFR flight........if they are both in VMC then see and avoid applies in Class D with traffic info from ATC to help. If you are using radar of course the info provided to you via SSR is always referenced to 1013.2 Thus provided that you decide to put QFE or QNH into the processor, you will get the appropriate readout to judge separation by regardless of what we set on our altimeter!!! If we have an uncomfortable experience (safety) in any airspace we report the matter and then next time expect a more comfortable experience! ;) --- Lord Seven, Please advise QTH as I would love to come and do a speechless, compass and gyro U/S flameout descent.....haven't done one in decades!!! :D In class D separation is only provided between IFR-IFR-Special VFR. VFR flights are not separated from anything and nothing is separated from VFR!!!.........Basically, the only thing that the mil gain from having class D is that it removes the option from the VFR flight to corss without bothering to call which can happen in a MATZ. Regards, DFC |
And how on earth you do inter-unit coordination |
'If the VFR ac is VMC and the IFR is IMC then as long as the VFR is clear of cloud then hthey are separate' not sure what the ATCEB would say to that. 1000' QFE is our separation standard for Mil against Civ, only in exceptional circumstances and if the Civ pilot is happy do we reduce to 500'. The bottom line is if the VFR is not visual with the IFR then he must avoid.
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<<However, provided the VFR flight remains outside cloud then the IFR flight who is inside that cloud is separated (segregated) from the VFR flight>>
I don't recall seeing this in any manual. Please quote the reference DFC.. |
DFC
I am not sure about your definition of "in the vicinity". Heathrow have been using "reduced separation in the vicinity of an aerodrome" for years and since their ATZ would not extend much past the ends of the runways, does this mean that their operation has been illegal?????!! LXGB I have been passed the RPS on a number of occasions by a unit not a million miles away from Middle Wallop as I was heading in the direction of the TMA, but I always ask for the QNH instead anyway. Back to QFE for a second. It is worth bearing in mind that the EGPWS must be over-ridden for QFE operations on the Boeings that I fly. Just one of those little things that add to the workload when we conduct QFE operations. Regards G W-H |
As a Mil Type currently operating in a Cold part of the world (near a Lake) where QNH reigns, I can say that I prefer it to QFE ops, all this hoop about what the altimeter reads when you hit the runway, IT DOESNT MATTER!!!!! who the hell looks at the altimeter below 200 either on a precision/non precision approach (assuming you are visual) or an a VFR approach?? After all, the height you fly circuits/radar patterns at is just a number, it doesnt matter what that number is. QFE is outdated and unnecessary and having seen and operated under both regimes I would like to see it got rid of. The rest of the civvy world operate on QNH and there is no reason why the RAF/mil guys need to operate on QFE.
I know the counter to this argument is that it isnt difficult to add/subtract before the blunties beat me to it, but if we dont need to do mental gymnastics in the radar pattern then why bother. I would much prefer to just look out the window and remind myself how cool my job is. (assuming it is not IMC) Get rid of it I say, although I know that for most in the Military it would be like the HM the Queen saying that she wants to be referred to as 'Lil. Did someone say "Jehova";) DS |
One final observation - UK military controllers use QFE 'cos that's what the pilots say they want. Maybe this thread should continue on the mil pilots forum?
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ILS 119.5. WB's SATCO is alluding to other airspace users who use a regional pressure setting to maneouvre up to say 45 000'. In this instance, when coordinating with said users, finding that the 30' per millibar assumption is wrong has come as quite a shock and no-one is quite sure exactly what to do about it. We presumably agree that if you have an aircraft at 1,000 ft on an altimeter setting of 1013, it will be about 300 ft below an aircraft 1,000 ft on an altimeter setting of 1003. If you have an aircraft at 45,000 ft on an altimeter setting of 1013, it will still be about 300 ft below an aircraft 45,000 ft on an altimeter setting of 1003. The first aircraft is 45,000 ft above the 1013 mbar surface, the second is 45,000 ft above the 1003 mbar surface. The difference between the 1013 and 1003 mbar surfaces is about 300 ft. |
Some eastern countries, like Ukraine, had their procedures quite a long time based on QFE.
They are adopting to QNH nowadays. Will the british military adopt, too? I doubt it. Why? Because it has always been like this! During my military time we just accepted the QFE for landing in Britain. British military jockeys came on the radio in old Germany: "Request all infos for QFE" The empire?;) |
Agree with WB's SATCO. Good idea to cross-link this thread to the Mil Aircrew forum if possible. See what the
"customers" think! LXGB |
Can't say too mich but I am argueing with my fleet manager at the moment and will be first thing in the morning as to whether we fly over the pond tomorrow on regional qnh or 1013.25!!
Regardless, I will fly on a FL. |
Bookworm,
I have recently done a limited amount of research on the 30ft or not height difference per mb and I can confirm that WBS is correct. The 30ft per millibar difference is only valid up to (very approx) 20 - 23,000ish ft. At 35,000ft the difference can easily be 70ft per millibar! Ring your local Met man for confirmation. Regards, ADIS |
The 30ft per millibar difference is only valid up to (very approx) 20 - 23,000ish ft. At 35,000ft the difference can easily be 70ft per millibar! Try it out at FL350 some time. |
bookworm, let us take an example:
The calculations below show actual feet/mb for various altitudes assuming ISA: Zero ft 30 ft per mb 5000 ft 30 ft per mb 10000 ft 31.45 ft per mb 20000 ft 36.25 ft per mb 30000 ft 40.84 ft per mb 40000 ft 47.84 ft per mb 50000 ft 52.75 ft per mb 60000 ft 62.96 ft per mb If an aircraft is flying at 20000 ft on an RPS of 1033 (20 mbs x 36.25) the aircraft is 725ft lower than an aircraft at FL200. This differs from our traditional assumtion that, using 30ft/mb, the first aircraft would only be 600ft lower. If we then use this example in an ATC coordination scenario, we may find that ATC would agree for an aircraft not to be below 21600ft RPS to ensure standard separation against traffic at FL200. Under the 30ft/mb assumption this would be OK as 21600ft would equate to 21000ft 1013.2mbs. However, taking into account the 36.25ft/mb accurate equation, in this particular circumstance the aircraft on RPS would actually be at the equivalent of 20 875 ft 1013.2 mbs thus creating actual separation between the 2 aircraft of 875ft. This, in ATC separation parlance, is not enough. If we take the argument up to the 35000ft territory and are in airspace where the temperature bit of ISA is significantly different from the assumed, then the problem gets significantly more acute. |
....the CAA limit on the distance at which controllers can provide a radar service without holding an Area Radar rating. For at least two years now, the only restriction on the maximum range that a civil radar service can be provided using an Approach Radar ticket is radar coverage, adjacent airspace arrangements and the procedures written into the unit's MATS Part 2 ('Controllers' Order Book'). On the subject of QNH vs QFE, why would Brit mil aircrew 'want it' when US mil & Canadian mil appear to be able to function without??? Surely, if you fly an SRA you're given the threshold elevation and advisory altitudes i.e. QNH-based check altitudes, if you fly an ILS you simply follow the glidepath and the approach plate will give you check heights (altitudes) at the FAF and in tabulated form against ranges from touchdown, and if you fly a PAR you just do what the nice talkdown controller tells you to do over the earphones. As for publishing a CTR with an upper limit defined as an altitude of 3500' when the TA is 3000', or an AIAA with an upper limit of altitude 5000', (note: altitude and so based on QNH) this really is a load of complete and utter bo:mad:s; next time I'm near the Brize CTR I'll ask Zone for the QNE... :\ :\ |
The calculations below show actual feet/mb for various altitudes assuming ISA: Zero ft 30 ft per mb 5000 ft 30 ft per mb 10000 ft 31.45 ft per mb 20000 ft 36.25 ft per mb 30000 ft 40.84 ft per mb 40000 ft 47.84 ft per mb 50000 ft 52.75 ft per mb 60000 ft 62.96 ft per mb |
bookworm, I cannot put my hands on the source of the table, i will keep looking. In the meantime, the attached make interesting reading.
http://www.auf.asn.au/meteorology/section1a.html http://www.auf.asn.au/groundschool/umodule3.html |
WBS
I'm confused by your table of numbers. If you're attempting to work out the change in level corresponding to a change in pressure as a function of level in the ISA, then they're incorrect. The variation is much higher -- some approximate numbers are shown in the pressure gradient section of the reference you quoted. Even those are broad averages. I previously used 100 ft/mbar in the mid-300s, which comes from the knowledge that the 250 mbar level is conventionally FL340, and the 200 mbar level is conventionally FL390, so that's an average of 100 ft/mbar. Maybe you're using the average gradient between sea level and the level indicated? If that's what the numbers are meant to be, then I can only reiterate that it's not relevant, for the reasons that I've tried to set out. If I try to put it another way, you need to realise that changing the altimeter setting by 1 mbar is not the same as moving the aircraft up or down by one mbar of pressure in the atmosphere. When you change the altimeter setting, you shift the reference level, at which the altimeter would read zero. So in your example, your aircraft at 20,000 ft on the RPS of 1033 is 20,000 ft above the 1033 mbar level. Your aircraft at FL200 is 20,000 ft above the 1013 mbar level. The vertical distance between them is therefore the level difference between the 1033 mbar level and the 1013 mbar level, and that's about 20 mbar x 30 ft/mbar = 600 ft because the 1033 mbar level and the 1013 mbar level are both close to sea level. If you were to measure the actual pressure outside the FL200 aircraft, it would be about 435 mbar. If you were to measure the actual pressure outside the 20,000 ft on 1033 aircraft, it would be about 446 mbar. There would only be 11 mbar difference in pressure between them, even though their altimeter settings are 20 mbar apart. |
HD says <Now you can bet some loony will ask how military controllers can use 500 ft vertical inside a civil control zone!!!! Tee hee!!>
Looks like HD has shown a typical civil controllers lack of understanding of the military task. Shame, so I'll throw my tuppence worth in and say we use RVS in 'CTZs' because our limited airspace requires such controlling skills. Indeed, we are good enough to wheel and deal OAT/GA traffic in very limited space, we have too. We do seek the civil pilots permission to apply RVS and if they are happy they get a good view of a fast jet and the pleasure of flying on QFE too!! I will also go further and say that unlike HD's 'routine' job as a LHR Director, where evreything either comes off BOV,BPK,BIG or LAM and does the same thing day in day out. The Mil Controller has to cope with a far more dynamic, fast moving,unpredictable traffic flow from all points of the compass, with conflictors and the odd lack of SSR day. I would like HD to try recovering 13 Tornados (pattern speed of Concorde, remember?) with a number of emergencies, fuel priorities and the weather going downhill quickly in limited airspace. Throw a few transits in the way and 500' RVS is a luxury that Mil Controllers need to achieve their task. Hope this loon has answered the question. :O |
With arrogance like that prevalent thank god they don't get civil licences automatically!
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Ah yes Northolt is absolutely awash with fast jets arriving unanounced from all directions with fuel emergencies! :D
As for using 500ft separation in places other than Heathrow Zone - simple - because JSP whatever says it can be done. However just because it says it can be done does not make it safe. If 500ft separation was safe in civil operations we would have double the capacity in the airways! Similarly one has to question the safety of the altimeter setting procedures in current use. Regards, DFC |
:{ Let's not allow a good bit of banter to cloud the issue. Mil pilots want to fly on QFE in the vicinity of the aerodrome. As mentioned earlier QNH was tried (posed no problems to ATC) but the aircrew didn't like it. If the primary customer is using QFE, it makes sense to me that all traffic likely to mix it should also use QFE. Procedures are very clear cut, well tried and tested and all Mil controllers are fantastic at sums! (I should know ;) )
Whilst A Good Headin might have gone a tad OTT, his/her sentiment is not a million miles wide of the mark - in very busy, constantly changing scenarios, the procedures really do work! :8 |
AGH says <where evreything either comes off BOV,BPK,BIG or LAM>
Looks like AGH has shown a typical military controllers lack of understanding of the civil task. Surely they all come off either BOV, OCK, BIG or LAM?!? Much harder i'm sure!!;) :ok: FB:ok: |
Having spent circa 2,000 hrs in the back of the simulator, training and checking, and having seen both QFE and QNH ops I know which I prefer - definitely QNH - as has been said by Chilli Monster the number of missed approaches I have seen where QFE is used and we get an alt bust due to not/late setting of QNH.
Stateside they dont even call it QNH - its THE altimeter setting. Lastly, reminds of going into Crete on a nice weather day and we were about number three in the visual approach "queue" to join right base RW 27. The Greek ATCO was working like a one armed paper hanger with arrival and departure tracks the same and much traffic - no radar, all separation based on DME. In the middle of all the RT chat Danair who had been cleared for a visual asks for the QFE - the controller replies in rather exasperated voice "Danair, the QFE is 3 millibars less than the QNH!" - I could hardly control my laughter - you had to be there to appreciate it! |
I do enjoy a bit of banter with civvy controllers and they usually get me back when they flash their pay chits at the end of the month. CB sums up the original question/answer nicely,thnks. Feel free to abuse me with your paychits as the end of the month is upon us! :ok:
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Lord Sven, Thank you for some sanity amongst all this blah. This country is not Canada or the Ukraine, or even Holland where you could land with a negative value on your QNH set altimeter. The Military choose to use QFE for recovery and the Civvies QNH. There is no need for a review, because we are all able to do maths or we wouldn't be in the jobs we are. Bookworm, you are quite correct. Move on!!!!!!:{ :{ :{ :{
Oh yeah, and lets not get onto the subject of Millibars, Inches, Metres and Feet!:\\ :uhoh: :{ :ugh: |
:hmm: Just a thought - of the replies posted from aircrew - how many are military?
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