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Questions tagged [qnh]

QNH is a Q codes defined as the barometric pressure at an airport adjusted to sea level using the ICAO Standard Atmosphere. On the ground, an altimeter set to QNH reads the elevation of the airport.

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What’s the setting range altimeters can handle?

What’s the setting range altimeters can handle? Is there a standard requiring a certain range for aircraft to be certified? Are there many occasions where a QNH is so high or low that airplanes have ...
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Is it possible to get the QNH value in Austria using a web service?

I got a altimeter sensor which can be connected to a computer and can be adjusted by the QNH! I need the QNH for Austria, I figured out that the current QNH of the airports are streamed via radio. ...
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Why is there a provision of pressure setting in GPS?

Some of the GPS have a provision of setting barometric pressure (QNH/QFE). How does it work?
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How does changing the altimeter setting in the US and elsewhere compare?

I have been trying to track down an answer to this question and I stumbled upon this website. Apologies if this answer is already out there. I have seen the FAR regulation, 14 CFR 91.121 - Altimeter ...
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What is wrong about this interpretation of QFE and QNH?

I'm a little confused about the QFE and QNH definitions, and its application on aviation. I learnt that: $QFE$ = pressure measured by an altimeter which is adjusted to ground level (it gives a height ...
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How can I calculate QNH from QFE?

Can someone please explain in simple terms how to work out your QNH from QFE? For example, you take off at 0' but leave the circuit, what do you set the altimeter to? How do you know the QNH?
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What is the meaning of “altimeter three-zero-one-one”?

I've been listening to a lot of liveatc.net recently (mostly at CYVR). What does it mean when the ATC give an "altimeter" reading (usually around the 3000 area). Altimeter three-zero-one-one. I'm ...
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When is QFE used?

When is QFE, instead of QNH, used for the altimeter setting? QFE: If you set the subscale of your altimeter to read ... millibars, the instrument would indicate its height above aerodrome elevation ...
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How does ATC handle changing QNH/altimeter values?

Obviously for aircraft arriving to or departing from an airport/airspace (as relevant), they listen to the ATIS and/or are given the QNH. But what happens if that pressure changes? Even a fairly ...
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Do pressure altimeters take into account differences in temperature? [duplicate]

I work as ATC in Korea and recently, I have some question about winter altimeter setting. In my facility, we use winter altimeter adjustment because the aircraft's pressure altitude is lower than ...
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Why does the MH370 ATC transcript never mention QNH? When is QNH given to aircraft?

Looking at the ATC transcript from MH370, I noticed that nowhere is the QNH communicated to the aircraft. That seemed odd to me... it seems that every time I talk to a tower or airways they tell me ...