QNH Ponderings #1: When should ATC identify the site?
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QNH Ponderings #1: When should ATC identify the site?
Posed the following questions through internal processes and have never recieved a result, do pilots (or other ATC) have an opinion on this?
When should ATC identify the site the QNH setting is sourced from?
"When it is not Melbourne, coz we are Melbourne Center? When it is not for the aerodrome for which the aircraft is bound, (if allowed, see below)?
If a controller calling himself "Blurbville Centre" has one aircraft inbound to Blurbville and one to Storytown just down the road one would usually be told, "Descend to 9000, Storytown QNH 1013," the other "Descend to 9000, QNH 1014." In the US, enroute sectors always indicate the QNH site, which would be transmitted as, "descend to 9000 feet, the Blurbville QNH 29.92," and, "descend to 9000 feet, the Storytown QNH 29.94." Here MATS is silent on the subject and the actual practice seems to vary.
If ATC give you a QNH do you assume it is for the aerodrome you are flying into?
Is it all bollocks because you ignore what we say and use the current ATIS/AWIS?
When should ATC identify the site the QNH setting is sourced from?
"When it is not Melbourne, coz we are Melbourne Center? When it is not for the aerodrome for which the aircraft is bound, (if allowed, see below)?
If a controller calling himself "Blurbville Centre" has one aircraft inbound to Blurbville and one to Storytown just down the road one would usually be told, "Descend to 9000, Storytown QNH 1013," the other "Descend to 9000, QNH 1014." In the US, enroute sectors always indicate the QNH site, which would be transmitted as, "descend to 9000 feet, the Blurbville QNH 29.92," and, "descend to 9000 feet, the Storytown QNH 29.94." Here MATS is silent on the subject and the actual practice seems to vary.
If ATC give you a QNH do you assume it is for the aerodrome you are flying into?
Is it all bollocks because you ignore what we say and use the current ATIS/AWIS?
Sprucegoose
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Is it all bollocks because you ignore what we say and use the current ATIS/AWIS?
I've actually often wondered why ATC (approach mainly) will tell me after first contact " (when ready) descend xxxx QNH blah blah" - I just told them I've "received ATIS rah rah" which invariably has a QNH and was set (or will be) at transition.
On the same note, after reporting ready for descent OCTA, centre will give Area QNH after traffic (or "no traffic"). I'm not going to set area QNH on transition, I'm going to set TAF (or better, AWIB etc.) QNH for arrival. This assumes you have a TAF of course, if not you have an Arfor complete with area QNH, and an alternate (with a TAF).
I can't really see what they need to give me QNH for, except to save me looking it up on the forecast...
What am I missing?
CR.
On the same note, after reporting ready for descent OCTA, centre will give Area QNH after traffic (or "no traffic"). I'm not going to set area QNH on transition, I'm going to set TAF (or better, AWIB etc.) QNH for arrival. This assumes you have a TAF of course, if not you have an Arfor complete with area QNH, and an alternate (with a TAF).
I can't really see what they need to give me QNH for, except to save me looking it up on the forecast...
What am I missing?
CR.
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CR, see exactly what you are saying, but at the mo, it's not optional it's required for us to say it. If you are transitioning the we must give you a valid option to use; normally A/QNH OCTA or aerodrome specific, or nearby one at least.
