Altimeter Settings

[Axel-Flo]

Ladies and Gents,
a question of trivia I know but,
during a descent from FL whatever, when cleared to 4000ft for example, we set the QNH (Mil QFE) depending where, when or what your'e descending for.
During a climb however, I thought I had read that once cleared to a FL setting standard was ok (regardless of your height/altitude in relation to transition level). I do remember reading this somewhere and also remember reading in days gone by that within 2000ft or so of transition you could do the same, I now believe that to have been superseeded by the "when cleared to a flight level set standard..."
In the big scheme of things I fully appreciate that its trivia but the're is always someone trying to prove you're wrong and there right...so ultimately the question is does anyone know the facts legal or otherwise and where it is written down...Thanks

:confused:

[boeing_bananas]

Hi,

This is the way we operate where I work:

After departure, when cleared to a flight level, we set standard on both of the main altimeters straight away, leaving QNH set on the standby altimeter until we have climbed above both MSA and transition altitude.

During the descent, while still operating to flight levels, we set QNH on the standby altimeter in order to monitor our position with respect to the MSA. When we get cleared to an altitude, we set QNH on the main altimeters.

Hope that answers your question.

BB.

[Scott Voigt]

For those of you who fly on the other side of the pond <G>...

In the US, you reset the altimeter when you go through FL 180 both going up and going down...

regards

Scott

[Axel-Flo]

Thanks for the answers, setting standard when cleared to a Flight Level and leaving the standby on QNH makes ultimate sense to me. As for the US procedure of resetting it as you pass through transition Alt that was the jist of my question...anyone know where the actual requirement or procedure is written down. On departing New York, cleared to FL 330 from well below the transition I was critisised for setting standard as other aircraft below the transition and descending would be on QNH.:cool:

[Seba]

If you immediately set the altimeter to standard when being cleared to a FL (and still well below TA), and suddenly you're told to maintain an altitude because of a serious cause, you'd have to request QNH again etc...you get the point. So in my view, it's better only to switch when you actually reach the TA/TL

[Ausatco]

I agree with Seba. In Australia, TA is 10,000ft, TL is FL110. Set standard climbing through TA and descending through TL.

AA

[Scott Voigt]

Axel-flow;

One reason is that if we have traffic and we need to get an actual altitude leaving from you, we can't get it as you already have 29.92 set in. It has already been brought up too that if we have to stop your climb you aren't set up for it...

regards

PS. Don't have the FAR cite in front of me, but I do know that it is a requirement.

[refplus20]

In the USA, setting the altimeter passing 18,000ft is fine as it's well into the enroute climb phase of the flight or fairly early in the descent phase. But when in the UK or even Europe, we have a mix of TAs ranging from 3000ft, 4000ft, 5000ft , 6000ft etc. This is puts the altimeter setting into a busy part of the flight. Is there any reason that the European airspace couldn't harmonise on a common TA of say 10,000ft which would coincide with the 10,000ft checks that our company uses and removes any possible confusion as to what the TA is at a particular airport during a high workload part of the flight?

[fireflybob]

This sounds like a rerun of another thread!

Altimeters Again! (http://www.pprune.org/forums/showthread.php?s=&threadid=92604)

Have a Nice Day!

[keithl]

Axel-Flo, I think what you originally wanted to know was where it was written down. Fascinating subsequent posts but very little to the point.
My company also had a "within 2000 ft" SOP until a few years ago when, like yours it changed to "when cleared". I can't find exactly what you're after, but offer a couple of thoughts.

ENR 1-7-2, 5.1.4 uses the term "when cleared" to FL to say that from then on "vertical posn will be expressed in terms of FL", in other words when cleared...set 1013.

Also, such procedures are set by Ops Manuals, which usually evolve from liaison meetings between operators and the CAA (among other things) and this one has the stamp of that kind of process about it.