Unfortunately the TRUCE (Training In Unusual Circumstances and Emergencies) season at Swanwick is coming to an end.

Get in contact and come next year to a TC one and...

...instead of rambling on here we'll show you the radar replays.

Thank you, Roffa, I'd love to come to see your TC TRUCE radar replays ... but wouldn't they just be proving that the current system we are debating doesn't prevent altitude busts ... ? :confused:


JD
:)

Now there I do have to agree with you. It was a constant battle throughout my career.

Jumbo Driver,

From the MATS Part 1 Section 3 Chapter 1 Page 10 para 11.5

'In the case of a departure ATIS, controllers must obtain a readback of all relevant
altimeter settings contained in the broadcast, unless the setting will also be passed
in association with start up or taxi clearance.'

So you DO have to orally confirm that you have the correct QNH - there is no 'implicit' at all.

DD

Well spotted, DD - at last we're getting somewhere - I (grudgingly :O) accept that as the justification for the readback procedure from your point of view.

Now we still need to deal with whether this "double-speak" is actually effective at reducing altitude busts, as claimed - or is it simply part of the general a*se-covering mentality that is everywhere today ...


JD
:)

we got somewhere all the way back at post #14 where CAP413 was quoted.


I'm still not sure of your point JD, do you have an issue reading back the QNH whilst acknowledging ATIS because you get asked to read it back again before departure? Is this the double-speak you talk of?
Because Gonzo stated


Or are you only asked to readback the QNH once at EGLL (on receipt of ATIS) and you have an issue with that?

JD,

You get the runway in use on the atis, yet you still get given it again with the taxi instruction, the line-up instruction, the take-off clearance, or the runway crossing don't you? No complaints there?

You write down your V speeds, yet you still bug them and call them. Or you cross check levels, or you double check you're shutting down the correct engine after a fire warning etc.

The point is, most of the items that are checked in this way are done so because the lessons of not doing so have already been learnt the hard way.

My point, DP, is summed up in my post #32, when I said:

That is the double-speak I am referring to.

I fully accept DD's reference to MATS Part 1 as explaining why you do it ... I just remain unconvinced that it enhances safety (where is the evidence?) and suggest that all it does is to unnecessarily clutter the R/T. Any duplication of readback or clearance should be avoided, should it not?


JD
:)

According to Gonzo, if you give QNH with ATIS letter you won't be asked to acknowledge QNH again.
Are you suggesting you should be able to depart EGLL without ever (specifically) having readback the QNH?

I completely understand that, DP.

Yes, why not? Because (as I keep saying :bored:) acknowledging the ATIS should imply acknowledgement of all its contents, including the QNH. There is no logical reason that I can see for singling this item out for a specific readback.


JD
:)

Blimey, no wonder this thread is 4 pages long.

because not all pilots get it right when listening to the ATIS, the ATIS is not always right and not all pilots are as dilligent as you checking the elevation against altimeter when lining up on the runway.

There have been countless incidents caused by aircraft departing EGLL on the wrong pressure setting and I've corrected QNH readbacks more times than I care to remember.

Actually, no they wouldn't. They'd be proving the fact that some crew are still stupid enough to get airborne on the wrong QNH, despite reading back the correct one.

Reading back the QNH instead of just acknowledging the ATIS letter is a way of cross checking that the crew have copied the QNH correctly as it is a safety critical piece of info in a very congested TMA.

I don't think Heathrow have ever done a scratchpad survey to show how many times they have had occasion to correct crews who have written down the wrong QNH by mistake but the fact of the matter is they do so on a fairly regular basis.

The fact that some crews still manage to get airborne on the wrong setting despite correction, or even despite reading back the correct QNH in the first instance is the only proof that you need that this check, far from being redundant, is actually a good thing.

Because mistakes do happen; how many more instances of climbing out on the wrong QNH would happen if this readback was not required?

That's why it gets done, there is no logical argument against the above facts!

JD,

I was doing Delivery today and our departure ATIS had 27R reduced TODA due ice on the threshold. About 70-80% gave me the ATIS letter on first contact, and yet some of those were surprised when I asked them if they could accept the reduced take off distance.........Any explanations for that? They gave me the ATIS letter, so I should have assumed that they had received and understood every part of it, surely? ;)

So you say, DP - as does Roffa - but if there have been that many incidents in which safety has been prejudiced, where is the documentary evidence ... ? So many of you are saying this ... but so far there has not been any substantiation ... Anyway, I now see it is enshrined in CAP493, so I guess we'll have to live with it.

Gonzo, yes, I too despair of some of my colleagues - I suppose there are just many levels of "professionalism" that we have to deal with.

OK, chaps, I'll lie down ;) ... I rather think this discussion has run its course ...


JD
:)

JD,

You could start by looking here...

Where you'll note altimeter setting errors are amongst the prime causal factors for level busts.

Thank you, Roffa - I would be surprised if altimeter-related errors were not a significant causal factor in level busts - however, I see the notes say that
Unfortunately I can see no breakdown of the remaining 20%, and therefore it is difficult to see any clear relevance to our particular discussion.


JD
:)

If you get the ATIS digitally - does it include any additional messages that are tagged on to the broadcast ATIS?

AFAIK the digital ATIS still has the letter as well as QNH, surface wind, and so on, but I'm not convinced it has supplementary info like the TODA change?

Quote:

---

80% of the errors occur when the aircraft is in the climb, is above the transition altitude/level and the standard pressure setting isn’t set

---

So some pilots are incapable of setting 1013 at the correct time (in a multi-crew environment remember), yet you are still arguing the toss about the wisdom of ATC requiring a check that you have copied the QNH correctly?

A check that takes all of oh, 3 seconds? :ugh:

It's one thing to copy and acknowledge the QNH, quite another to set the altimeter(s) correctly. If errors occur this implies that the pilots concerned are not checking the altitude is correct against apron elevation having set the subscale. Even if you do set the QNH correctly it could be the indicated altitude that's incorrect if the altimeter/adc etc is giving the wrong information.

You can pass and readback the QNH as many times as you like but the pilot still has to set the subscale correctly.

fireflybob - you are indeed correct, but it isn't exactly a difficult thing to do... and surely ensuring you have copied the QNH correctly in the first place is an addition to safety?