QNH on first contact

[twentypoint4]

Hi guys.

I'm an approach radar trainee and am regularly faced with a situation that I wouldn't mind getting a few opinions on.

Most of our inbound aircraft are transferred to us from the previous sector at/descending to an altitude based on our QNH. When the pilot establishes communication with us he/she will most of the time pass the QNH set along with their cleared altitude. I'm wondering whether I'm required as the approach function of the landing aerodrome to pass the QNH on first contact even though the pilot has demonstrated they have the correct QNH set?

I'm aware it's a mandatory read back item, but since the pilot "reads it back" without me prompting him/her can I be satisfied my obligation of making sure they have the correct setting for the approach is fulfilled? Conversely should I be worried that me providing the pilot with the QNH and him/her reading it back is never recorded on the tapes?

[Spitoon]

The practical answer is don't pass the QNH if the pilot has already reported the correct setting - but keep an eye on the mode C to make sure that it ties up. Remember that you have to give the QNH before the aircraft commences final approach so maybe you can get into the habit of saying "cleared X approach, QNH is" - some might argue that there is no need to do it a second time but I recall at least one occasion where the setting was queried at this point.

Another relevant point is how your wx info is transmitted - do you have ATIS? I'm not operational any more but back in the day I expected the QNH to be read back along with the ATIS letter.

[windypops]

In my experience as a pilot even when I state the QNH on first contact with an approach controller along with the ATIS code, I'm pretty sure they always pass me the QNH. I'm trying to remember a time when they haven't. I'll pay more attention this week to see.

When you as a controller pass me the QNH (even though I've already stated it), I still check it against my written ATIS and if I'm descending to an altitude check it again on my altimeter.

Some controllers pass us the QNH again on final intercept to the ILS, and again I always, always look at my pad AND my altimeter and of course read it back again.

It will be interesting to hear what the actual rules are.

Standing by.

Windy Pops

[radarman]

r&p,

Tried asking your OJTI? That's what he's there for.

[supraspinatus]

A pilot should read ATIS letter and QNH on contact even if he is not descending to an altitude. If I give further descend to altitude I could say: "AIRLINE123, descend 5,0ft, expect ILS RWY XX, Information A, QNH XXXX"
If no descend is given I confirm his level: "AIRLINE123 Continue to FL XXX (or maintain FL XXX when reaching), expect ILS RWY, Information A valid"

[twentypoint4]

Cheers for the reply. We do indeed have ATIS and pilots are required to communicate which ATIS report they are in receipt of.

You say remember to give it before final approach, is there a document laying out this instruction? I have looked in the MATS Pt1 and have found nothing directly applying to this situation. All I found was:

A pilot normally assesses the vertical position of his aircraft above obstacles by using an accurately set altimeter. It is imperative, therefore, that controllers always issue the correct pressure setting and that they check the read-back from the pilot.

And Radarman, the reason I'm curious to gain more opinions is because I've already had different opinions from my OJTI's which has lead me to believe there is some ambiguity to the rules.

[Spitoon]

You say remember to give it before final approach, is there a document laying out this instruction? MATS Part 1, Section 3, Chapter 2, Paragraph 6 - Aircraft are to be given the QNH before commencing final approach. Aerodrome and threshold elevations shall be available on request.

PS - My copy is a couple of years old so the reference may have changed but I think the words have been there for many years.

[HEATHROW DIRECTOR]

I guess that's a recent instruction about QNH on final approach? All the years I was operational, aircraft were given QNH in initial descent and never again, unless it changed. Donkeys years ago we used to pass QFE or airfield elevation, but that ceased. Some very keen trainees gave the QNH every time they descended an aircraft to a lower altitude.... which grinds a bit after the fourth time in 5 minutes!!!

[GAPSTER]

My take on it fwiw - not so much to do with the rules perhaps but common sense and these days a bit of self protection...if you pass the correct QNH even if the pilot has already stated it you are covered.Otherwise,as per the above, once given at initial descent to altitude not given again unless it changes,however I always reiterate it before final descent commences on an SRA.

[Dan Dare]

If on first contact the pilot reports descending to an altitude with QNH then he has acknowleged it and does not need it again. If you read the QNH to the pilot for the 3rd time and he doesn't read it back that time, you will be assessed as at fault because you did not get a readback of a compulsory readback item.

While you are a trainee logic and common sense should have lower priority than jumping though the hoops required to finish training successfully. If your instructors tell you to read the QNH to the poor (pseudo?) pilot 3 times, then you read it to them 3 times and get 3 readbacks. Thats part of the game.

In the real world I would suggest following the rules and if they don't follow logic (as they often don't) then make an effort to get them changed while still covering your rear by following them.

[GunkyTom]

I say 'QNH correct'

[Glamdring]

I've already had different opinions from my OJTI's

Ask your LCE for clarification.

[SLeo]

When an aircraft is cleared to descend below transition level you have to give the QNH. Also when you give the approach clearance you have to give the QNH. Simple as that.

[2 sheds]

It is not quite as simple as that.

PANS-ATM specifies:
"A QNH altimeter setting shall be included in the descent clearance when first cleared to an altitude below the transition level, in approach clearances or clearances to enter the traffic circuit, and in taxi clearances for departing aircraft, except when it is known that the aircraft has already received the information" (my italics).

2 s

[radarman]

r&p,

I was going to post earlier to say that a question such as your original one will elicit a number of replies from all over the world, from people working in quite different airspace environments and under different disciplines and regulatory regimes. The answers will obviously vary, depending on whether the poster is a pilot based in the Middle East, an ATCO from Glasgow, or a management type from some HQ, and at this early stage in your career you will probably end up getting more confused. As a trainee by all means use this forum to sound out ideas and ask for general advice, but beware of using a procedure in your day-to-day controlling just because someone on PPRuNe said they do it at their unit - it won't go down too well with the examiner on your validation board! My advice is to stick with your LCE's and UTO. I understand they may not agree amongst themselves, but put pressure on them to get a definitive answer from higher authority, and ensure that the procedure is then enshrined in unit procedures. It's called standardisation, and should be one of management's top priorities. (However, you will get to know more about management's idea of priorities as you progress through your career! :E )

[Right Way Up]

supraspinatus
*

A pilot should read ATIS letter and QNH on contact

Not on approach according to CAP413.

[proxus]

.....and sometimes ATC doesn't give you the QNH at all, like in Egypt (especially Marsa Alam). As a pilot you'd have to ask for it.

[Piltdown Man]

...and in the UK I'm sure we'll soon have to give our shoe sizes and the last three digits of our banks cards to every new contact, as well as everything else.

But back to the thread, radarman has hit the nail right on the head. The objective is to pass the test so don't worry about what others do or don't do. The examiner/s will assess you according to their standards - so until you pop out of the system, stick to their standard (even if it appears to be daft).

PM
(one of the enemy!)

[Married a Canadian]

While you are a trainee logic and common sense should have lower priority than jumping though the hoops required to finish training successfully. If your instructors tell you to read the QNH to the poor (pseudo?) pilot 3 times, then you read it to them 3 times and get 3 readbacks. Thats part of the game

"The game" should have some logic to it though. If the pilot has already read back a correct QNH setting..and it dosen't change thereafter why would you waste radio time with a number that is already set. Is the pilot going to change it just for fun??? An OJI should be able to answer "why?"..with a better answer than just.."because I told you to".
When ATCOs complain of frequency congestion then surely there are more important things you could be saying rather than reiterating an already confirmed figure.

PS Spoken by one who queried his OJI on this very topic (and still validated:))

[2 sheds]

The examiner/s will assess you according to their standards


Well, they should not be! They should be assessing according to the published objectives and procedures.

2 s

[HEATHROW DIRECTOR]

<<<Quote:
A pilot should read ATIS letter and QNH on contact

Not on approach according to CAP413.>>>

But if the local ATIS tells him to, then he should.

[WhiskeySierra]

In Germany, pilots doing the initial call on the approach freq, should report only the current ATIS letter. Even if the QNH is stated by the pilot, ATC will combine the first clearance to an altitude again with the QNH.

My question: When will the pilot switch the Altimeter from Standard to QNH?
With the first clearance to an Altitute, or when passing the Transition Level. I know it should be the last, but the first seems to be more practicable.

[Spitoon]

My question: When will the pilot switch the Altimeter from Standard to QNH?
With the first clearance to an Altitute, or when passing the Transition Level. I know it should be the last, but the first seems to be more practicable.

As ever, beware of assumptions.....

The UK AIP (ENR 1.7 para 5.3.1) says 'When an aircraft is descended from a Flight Level to an Altitude preparatory to commencing approach for landing, ATC will pass the appropriate aerodrome QNH. On vacating the Flight Level, the pilot will change to the aerodrome QNH unless further Flight Level vacating reports have been requested by ATC, in which case, the aerodrome QNH will be set following the final Flight Level vacating report'.

And, of course, individual aircraft operator SOPs differ too.