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Duplication of QNH on Clearance callup

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Duplication of QNH on Clearance callup

Old 12th Aug 2007, 20:53
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Duplication of QNH on Clearance callup

With the already congested status of all frequencies, in particular clearance del., might I ask why the need has emerged for the seemingly redundant callout of QNH in addition to the ATIS identifier most recently monitored. I thought that copying the ATIS, and confirming it on initial callup, conveyed that the requisite info, ie wx status - and QNH - had been received?

Seems that rather than making radio calls more succinct and clearing airspace for denser communications, we seem to be on a trend to make them more verbose and redundant.
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Old 12th Aug 2007, 21:17
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Exclamation are you expecting logic?

and can you imagine the havoc if you were to taxi and takeoff if the QNH has changed one millibar since you got the last ATIS?

also might be along the same lines that you hardly ever fly the assigned departure or arrival.
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Old 12th Aug 2007, 21:21
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From CAP 413. It's not terribly clear but might provide a clue:

1.3 Departure Information and Engine Starting Procedures
1.3.1 Where no ATIS is provided the pilot may ask for current aerodrome information before
requesting start up.
1.3.2 Requests to start engines are normally made to facilitate ATC planning and to avoid
excessive fuel wastage by aircraft delayed on the ground. At certain aerodromes,
along with the request, the pilot will state the location of the aircraft and acknowledge
receipt of the departure ATIS broadcast identifying letter together with the QNH.
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Old 12th Aug 2007, 21:27
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Sandman, unfortunately the correct readback of the QNH is something that we need to do, least not because pilots don't always have the latest ATIS and the QNH could have changed since. Also, it's the law! Besides, clearance delivery (or Ground Movement Planner as we are offficially titled) is usually the quieter/less complicated position, where aircraft are not moving/liable to hit each other, etc. and we can happily repeat instructions, requests etc over and over and over again if required.
At Heathrow, when the QNH changes, we broadcast it on all frequencies without the need for readback. It's only in delivery that we check you have recieved the QNH, when issuing clearances/start up, as you may not be monitoring the frequency at the time, whereas on the other 4 frequencies we expect you to be listening out. Indeed, there is a box on our "flight data entry" (electronic flight strip) which serves the purpose of recording the QNH you have reported to us.
I know 1mb is about 30 feet, but what if the QNH was copied wrongly (heaven forfend) from the ATIS? or there had been 2 changes (could happen) since you recieved the ATIS. And let's not forget how tightly packed aircraft are, especially in the skies above our fair capital city (and my house) - we don't really want less than 1000 feet vertical separation and TCAS etc going off (sorry for the tabloid style sensationlism)
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Old 12th Aug 2007, 21:29
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not to mention...

..."descend to altitude 4000 feet QNH 1012 millibars and turn right heading 340 degrees" on the busy london freqs?? And then you get cleared for an ILS approach but that doesn't necessarily mean you can descend with the G/P like it does in the rest of the world.. Of course like everything else in life it depends on the situation. If the frequency is not congested it doesn't bother me confirming and double confirming QNH's etc.
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Old 12th Aug 2007, 23:35
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."descend to altitude 4000 feet QNH 1012 millibars and turn right heading 340 degrees
"Altitude" is inserted between the "to" and the "4,000" to reinforce that you are being cleared to 4,000ft, not "two four thousand" (i.e. 24,000).
"Millibars" is so our Yankee friends don't set inches of mercury. I.e. QNH nine nine two (MB) is easily mistaken for 29.92 (inches).
"340 degrees reinforces that the 340 mentioned is not a FL.

There's method in the madness!
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Old 13th Aug 2007, 00:00
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And then you get cleared for an ILS approach but that doesn't necessarily mean you can descend with the G/P like it does in the rest of the world..
Yep, the UK definitely could use some work on R/T procedures. I usually seem to get a stealth implied clearance like "Report established on the localizer", followed by "Continue on the glide" The rest of the world seems to be more specific e.g. "Cleared to intercept the localizer, maintain 3000 feet" then "Cleared ILS Runway 09 Right approach."
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Old 13th Aug 2007, 02:23
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Oh, but it gets better, Airbubba.

A few years ago inbound to MAN, we're told to intercept the localizer, and then forgotten about, due to some other aircraft on the frequency.
Steaming ahead at 200 knots (the assigned speed), we of course pass the point where we should have descended on the glidepath, whereupon the approach controller then wants to know why we haven't.

When on the ground I called the TRACON chief and told 'em what I thought of their backwards way of doing things, as, well, lets face it, the UK is well behind in the ATC department, in many respects.

At FRA you don't have this problem, nor at AMS, as well as many other locations in Europe.

The UK is special alright...special behind.
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Old 13th Aug 2007, 04:07
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I my experience the UK controllers are not perfect but they are some of the best in the world, if you want controllers with attitude, rudeness, really fast speaking and non standard radio calls then look no further than the US of A. ( specifically JFK )

QNH is required to be given when you are cleared below TL. end of story
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Old 13th Aug 2007, 04:38
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Camel Hair you forgot to mention that the madness and the method have been paid for in blood. For those who do not believe research Flying Tigers, among others.

ACMS. and ORD and LAX and ATL and DFW to mention just a few.

Give me LHR/LGW any day.

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Old 13th Aug 2007, 04:44
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UK ATC may not be the best in the world, but there are definately places with much worse. Like Tripoli (Libya) for example.
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Old 13th Aug 2007, 06:58
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Radio congestion for no purpose whatsoever!

I just wish ICAO/NAA would agree that a change of one millibar (or even two) is of no interest to anyone, with todays modern aircraft, Radalt, etc. It is all so pernickity(?) it makes me laugh.

Getting given a one millibar change during the take off roll, I wonder whether it is better airmanship to abort, because it must be too dangerous to get airborne with a major altimeter error!

No complaint with controllers! Just the rule makers!
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Old 13th Aug 2007, 07:04
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Come on, if we had to list places in the world with worse ATC than UK we'd be here all day! From what I've 'heard' UK sets the standard....ok set standard 1013.
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Old 13th Aug 2007, 07:43
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Its just as annoying for us to update every a/c on freq with the new QNH as it is for you to recieve it. If you say a change of 1 millibar doesn't matter then where do you draw the line? When does it matter? And is helps speed things along when pilots reply with a quick readback rather than a frustrated "yeh we got it" which just leads to more r/t asking for readback!
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Old 13th Aug 2007, 08:30
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if ever there was a thread to drive to drive a wedge of indiferrence between atc and pilots........................

standard RT.............if everyone did it we wouldn't be having this debate. Get past yourself people for heaven sake...........

BTW, to post 11, i was in HLLT last night................not bad at all
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Old 13th Aug 2007, 08:50
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Surely another purpose of confirming the QNH is that you or your oppo hasn't been a muppet and copied down QFE instead - then it can make a difference. Especially for performance penalties with QNH below 1013 in aheavy e/c with variable tailwindy conditions on a hot day.

As I see it most of UK ATC is there for a reason, the numpty who was questioning cleared to ALTITUDE xxx could do with a tiny bit of research on CFIT incidents, as for Localiser then ILS, well its what you are used to but doing it this way ensures that you are established inbound before commencing descent beyond a deignated safe area. Nothing a quick wilco call back followed by established doesn't sort out.

As someone said earlier its people who come back with flippant comments without understanding that it just adds to further RT as if given a QNH you need to read it back, simple as that so just do it and stop whinging.
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Old 13th Aug 2007, 09:28
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Well the numpty begs to differ.. I'm sure you'll make a great captain with that attitude

I think you may have missed the point: UK freqs being too busy causing other potential safety issues.

How about:

"Descend 4000 feet QNH 1012 millibars"

"Turn right heading 340"

...and do we need ATC to make sure we're established inbound before descending with the G/P? ..They never seem to call and ask if the cabin is secure for landing! But on the other hand they sometimes ask if the gear is down in Mother Russia

Nothing bad to be said about the UK ATCO's in general. I'm just expressing my personal opinion on the standard phraseology "over there".

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Old 13th Aug 2007, 09:40
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The UK does have some of the best ATC around but I do agree that it is (as with so many other things ) lagging behind with some of the RT procedures. If anyone could explain to me why we can't be cleared for an ILS approach like the rest of the world instead of using the "closing from left/right report established" phrase. I mean when you get the clearance "close from the left report estabslihed and descend further with the ILS once established" you really start to wonder... An update on the RT procedures would make the already good UK atc even better
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Old 13th Aug 2007, 10:16
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How about:

"Descend 4000 feet
The reason 'altitude' is inserted in RT relating to such clearances is not to distinguish from FLs (the THOUSAND bit ought to be a clue) but to avoid ambiguity, particularly for non-native speakers of english.

Example: aircraft flying at 6,000ft. Instructed to "Descend 4,000ft".

Does that mean descend TO ALTITUDE 4,000ft or could it mean descend BY 4,000ft (i.e.to 2,000ft)?

Yes of course WE all know the answer and of course WE wouldn't get it wrong...but as has been alluded to, these things are often learnt the hard way. Hence the inclusion in standard RT of all those things which so many object to (millibars, degrees, etc etc).
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Old 13th Aug 2007, 10:28
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There is actually agreed UK phraseology for this. Its just that " Turn left/ right heading xxx, closing localiser from the left/right, when established on the localiser descend on the ILS" is more of a mouthful than the alternative.
There are also some some areas for caution to be exercised.
1. Glide path signals are only protected to a range of 10 miles outside of this they may be corrupt.
2 VFR/SVFR or even IFR traffic may be transiting below, through the localiser.
3 Descending below the glidepath outside of the protected range may have terrain/ controlled airspace issues.
4 False localiser capture. Just the other week I saw a modern aircraft of a respected Western fleet, twice report established some distance from the actual localiser (over high ground in IMC). The ILS was taken out of service and checked but was found to be operating perfectly. The fault was in the onboard equipment.
All of these points can be avoided by good Radar monitoring. However to have immediate descent once established on the ILS in ever busier skies is not considered to be the fail safe procedure.
With regard to the initial question, our local instructions ask pilots to make first call with the information letter and QNH thereafter it is only mentioned again if there is a change.
411A You are right, our methods are pedantic but for a reason. If you feel strongly about it then you could always file a report. Might I suggest though that you file it over here just to make sure it doesnt get buried or hidden by the FAA over there.
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