QNH

Drecula

Drecula

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Drecula
8635FC0C-D0AC-494C-9E22-55A895FBEA11.jpeg Can someone explain this to me :)
 
luvflyin said:
It's the high to low watch out below thang. QNH I'm pretty sure is what we know as "altimeter 3002," the local altimeter setting. There are other "Q's." Some big iron dudes who fly internationally will explain
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Correct! Everyone in Europe flies on QNH (except US military and some US leased military aircraft). We don't know "alimeter settings" here.

So aerodome A is 800 ft AMSL and aerodrome B is 500 ft AMSL.

They assume 1 MB = 30 ft (That is one like QNH 1001, 1002) in ISA conditions.
Difference between 1020 and 999 is 21 MB. 21 * 30ft (1mb=30ft) = 630 ft difference between the altimeter setting of 1020 and 999.
Add the elevation (because of higher setting then local QNH) of the airport to it, so 630 ft + 500 ft Aerodrome B elevation makes 1130ft. Answer C.

Correct me if I am wrong !
 
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dennisc172 said:
Correct! Everyone in Europe flies on QNH (except US military and some US leased military aircraft). We don't know "alimeter settings" here.

So aerodome A is 800 ft AMSL and aerodrome B is 500 ft AMSL.

They assume 1 MB = 30 ft (That is one like QNH 1001, 1002) in ISA conditions.
Difference between 1020 and 999 is 21 MB. 21 * 30ft (1mb=30ft) = 630 ft difference between the altimeter setting of 1020 and 999.
Add the elevation (because of higher setting then local QNH) of the airport to it, so 630 ft + 500 ft Aerodrome B elevation makes 1130ft. Answer C.

Correct me if I am wrong !
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You are right. Thanks for the help. I really Appreciate it.
 
There are three "Q" altimeter settings, QNH, QNE, and QFE. The first two are commonly used in the United States while other countries use all three. QNH is our local altimeter setting giving you an altitude on the altimeter above MSL. QNE is 29.92, used above the transition level (18000' MSL in the States but varies in other countries down to as low as 3000' MSL). QFE is a local altimeter setting that indicates 0' on the altimeter on the ground at the reporting point (used at airfields).
 
What test is this question from?
 
This is the Pilots of AMERICA Forum, right?

Bob
 
From the blog of Brian Foster, who built an RV-10 in Port Alfred, South Africa, and flew it westbound around the world last year:

Can anyone tell me why the North Americans have to do everything differently to the rest of us. We know they drive on the wrong side of the road, use miles, feet and inches, write the date the wrong way round and use their forks in a very strange way but why why why do they use local pressure settings for the altimeter on any IF flight up to 18k? I only found out when ATC kept telling me to check my altitude. Having retorted that I had everything right, flight level 100 on 29.92 (at least I had the inches bit) I was told very politely that I should be at 10000 feet on the local pressure. Oh well!

[...]

The following day we flew to Lexington, Kentucky, the capital of the horse world. Once again we had the new flight plan before departure, expert ATC, and another FBO at Lexington for whom nothing was too much trouble. I’m getting used to the “system” now and you know what…the USA can do what it wants. Why should they give up their ways when it all operates so well!!! ​
 
The way I'd look at it, to simplify the problem, is to forget the field elevation in MSL of aerodrome "A" and only worry about "B."

The airplane is sitting at 500 ft. MSL, and the altimeter setting there is 999mb. At that moment in time the field elevation in MSL and the altimeter indication should match.

You change the altimeter setting to 1020mb.

That's increasing it by 21mb. Easy to remember that the indicated altitude goes up, because whether it's mb or in. Hg, when you increase the baro setting in the Kollsman window the indicated altitude always increases, and vice versa for going down.

21 * 30 feet = 630 feet.

So add 630 feet to the 500 feet MSL field elevation and you get 1130 feet.
 
Pilawt said:
From the blog of Brian Foster, who built an RV-10 in Port Alfred, South Africa, and flew it westbound around the world last year:

Can anyone tell me why the North Americans have to do everything differently to the rest of us. We know they drive on the wrong side of the road, use miles, feet and inches, write the date the wrong way round and use their forks in a very strange way but why why why do they use local pressure settings for the altimeter on any IF flight up to 18k? I only found out when ATC kept telling me to check my altitude. Having retorted that I had everything right, flight level 100 on 29.92 (at least I had the inches bit) I was told very politely that I should be at 10000 feet on the local pressure. Oh well!
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Well, he's only partly right about that. For one thing the majority (about 65%) of the world drives on the right side of the road.

The differences between countries (not just the U.S. and "everyone else") are quite numerous. Altimetry in the Russian Federation is dramatically different than almost anywhere else. The Schengen countries largely subscribe to common ICAO SARPs as individual member states, but not pilot certification/medical requirements. Country AIPs throughout Europe and Asia are riddled with differences which must be studied before flying in the airspace. LOAs are occasionally required by countries which aren't even available by the member state's civil aviation authority for the operator.

Further, the United States' ATC and NAS is superior to anything else in the world - it's not even close. For whatever other differences there may be, you will not find better service or capability anywhere. That's not patriotism, that's just bottom line truth. I'll hang my hat on that statement quite comfortably.
 
Ryan F. said:
Well, he's only partly right about that. For one thing the majority (about 65%) of the world drives on the right side of the road.

The differences between countries (not just the U.S. and "everyone else") are quite numerous. Altimetry in the Russian Federation is dramatically different than almost anywhere else. The Schengen countries largely subscribe to common ICAO SARPs as individual member states, but not pilot certification/medical requirements. Country AIPs throughout Europe and Asia are riddled with differences which must be studied before flying in the airspace. LOAs are occasionally required by countries which aren't even available by the member state's civil aviation authority for the operator.

Further, the United States' ATC and NAS is superior to anything else in the world - it's not even close. For whatever other differences there may be, you will not find better service or capability anywhere. That's not patriotism, that's just bottom line truth. I'll hang my hat on that statement quite comfortably.
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Totally Agree!!
 
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