SID/STAR charts with pressure-change prompt

[davidginola]

Is anybody out there aware of any SID/STAR charts which specifically prompt crews to change to QNH/1013 at a specific point?
I've seen an example of an Amsterdam arrival which states in the notes to change to QNH at NIRSI/NARIX, but am keen to find any other examples.
Many thanks.

[AdrienT06]

Hi!

You have to set QNH when the ATC clear you for an altitude (when you're coming from a level) or at the latest when you are passing transition level.
When you climb, you set altimeters to standard mode when you are cleared for a level or at the latest when you are passing transition altitude.
So, there isn't specific point to change your altimeter

[davidginola]

Thanks for your response...
I understand the concept of changing between pressures. I also understand that certain operators have different procedures, with some changing only on passing the TA and others changing as soon as they are cleared to a FL/altitude.
However, I'm interested to know if anyone is aware of any departures or arrivals which specifically state a point at which to change to QNH/1013?


In my mind, this would be particularly useful if a SID climbs to a FL but also contains altitude restrictions. Crews would remain on QNH (thus making the altitude restrictions accurately) and then switch to 1013 at the point quoted on the SID chart, ultimately climbing to the FL published on the SID.


Does anyone know of any examples where this is already the case?

[good egg]

Can't answer your last question but, in time, the TA should be increasing to somewhere around 16,000 - 18,000ft (and hopefully harmonised across Europe!) so it shouldn't be an issue for SIDs in the future.....

[de facto]

Hi Davidginola,

I will let you know if I come across one,so far i remember one airport in north west europe had such note but my memory is failing me

[zonoma]

Good egg wrote:

the TA should be increasing to somewhere around 16,000 - 18,000ft (and hopefully harmonised across Europe!)

and I laughed harder than I have for quite a long time.

It was a nice idea.

[ZOOKER]

6000' TA is high enough in the U.K.
Way back, we had SIDs that finished at Flight Levels, (our TA was 4000' then), but there was never any mention of when to change to 1013 on the charts.

[AdrienT06]

There isn't a specific point to change your altimeters setting indeed but only a level or altitude to change it because all aircraft don't have the same performance to climb or to descent... This is the reason why you'll never see a specific point to change from QNE to QNH or QNH to QNE. You set it at a specific altitude, not a specific point.