Tower Q's?
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QNH (field elevation) is most often used when parked at ramp start.
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QFE is the “poor man’s radar altimeter” showing 0 at the airfield surface but you really want to use QNH.
http://en.wikipedia.org/wiki/Q_code#Aviation -
QNH (field elevation) is most often used when parked at ramp start.
Depends on nation and/or SOP regulations, I suppose. There are some countries that still use QFE by default.
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They don’t stand for anything
Incorrect. The Q stands for ‘question’ and so the whole abreviation is a request. Indeed in morse followed by a question mark it means a request for whatever follows. Without, it will be follow by the value.
QFE = Field Elevation
QNH = Nautical Height
QNE = Nautical ElevationSince the radios its hard to hear the difference wether someone is asking so you add ‘request’ before the abbreviation.
Thus where ‘QNH?’ Woul be in morse we say ‘request QNH’. The reply would be the same as in morse. ‘QNH 1030’ for example and so we also reply by radio. -
Incorrect only the Q stands for nothing.
QFE = Field Elevation
QNH = Nautical Height
QNE = Nautical ElevationThat’s also how I remembered what each Q meant, even though it’s technically wrong. QNH is used to know your ALTITUDE above sea level, whereas QNE and QFE are used to know your HEIGHT above sea/ground level. Might be a bit confusing to have the only Q using height in its “name” not refer to height at all.
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I think you missed part of my message eagle. I was editing it that will explain the Q.
What you say about the abreviations is incorrect aswell. They infact ARE correct. They just dont refer to the aircraft’s vertical position (as most people mistakenly assume) but referes to the vertical position of the pressure level you are referencing with your altimeter.
With QFE you dail in the pressure which is dominating at the local ground level. Thus the pressure level you reference is the one of the field ELEVATION. Hence the name…
You now read the ‘height’ of the aircraft.
Not used in practice in aviation. Although I assume this is the setting of choice for a carrier landing.With QNH you dail your altimeter to the height of the mean sealevel. Which could be a certain value above or below the standard. You now read the ‘altitude’ of the aircraft.
The QNE is pure pressure LEVEL referencing. Standard atmosphere barometric pressure is 1013 hpa. So you tune in that. Now…when you fly at sealevel you know the EVEVATION of the sea compared to standard atmopheric conditions Again its pure pressure LEVEL referencing so we now see ‘flight level’ on our altimeter.
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Not official, but from word of mouth / tradition I was told the “Q” is some maybe greek “word” for pressure.
In the 737, theres an artificial feel unit that provides feel to the elevator controls based on pitot pressure, the unit which senses this pressure is know as the “q-pot”.
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Negative. Read my 2nd post above….
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so if i wanted to do a fully heads down instrumental landing qfe would be most effetive so i dont hit the runway before expected by the altimeter, and i should also request this again upon approach or during arc because this may change from take off to landing time? thanks for all the great info.
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Charts usually have both altitude (QNH) and height AGL (QFE) on them, so you could use both. Only thing you can’t use is QNE.
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so if i wanted to do a fully heads down instrumental landing qfe would be most effetive so i dont hit the runway before expected by the altimeter, and i should also request this again upon approach or during arc because this may change from take off to landing time? thanks for all the great info.
Theoretically…yes. and what eagle eye says is true aswell.
However IRL QNH is used at all times, taking the field elevation into account. -
thanks guy i think i got it now … i actually jus started another thread…probably see you guys there too… thanks again everyone!!!
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I believe Q stands for question or more likely query but I believe the meaning of the following two letters has been retroactively assigned to aid memory. If you look at the other Q codes the suffix isn’t tied to the meaning of the content. People assign memory aids to the suffix and until I see the 1929 telegraph handbook explaining the suffix letters that’s what I’m going to believe.
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I was told that QFE is still in use in the UK, is that correct?
And also usually at airshows… ???
Was also mistaken about usage of QFE in my country, which have already confirmation that’s not the case… -
I was told that QFE is still in use in the UK, is that correct?
And also usually at airshows… ???
Was also mistaken about usage of QFE in my country, which have already confirmation that’s not the case…Last time I looked, RAF procedures always include setting QFE before rejoining the circuit.
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I believe Q stands for question or more likely query but I believe the meaning of the following two letters has been retroactively assigned to aid memory. If you look at the other Q codes the suffix isn’t tied to the meaning of the content. People assign memory aids to the suffix and until I see the 1929 telegraph handbook explaining the suffix letters that’s what I’m going to believe.
Read my posts. There is the explanation. (Which is basically what you are saying)
Someone lock the thread.
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Depends on nation and/or SOP regulations, I suppose.
In Belgium, civil (GAT) generally uses QNH, while military (OAT) uses QFE. GAT will also switch to QNE when climbing through TA (set at 4,500ft) or to QNH when descending through TRL (varies between FL040 and FL075, iirc), while OAT always switches when passing 10,000ft/FL100.
GAT and Military use the same. Only the french military still fly in QFE.
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GAT and Military use the same. Only the french military still fly in QFE.
That’s not what I heard from a belgian mission planner thoug…
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GAT and Military use the same. Only the french military still fly in QFE.
That’s not what I heard from a belgian mission planner thoug…
Thanks Cheetah, Focal and I have the same source, and he initially told us BAF uses QFE. Yesterday, after checking, he told me he was wrong and BAF indeed uses QNH, so I stand corrected and will update my first post ASAP.:)
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Then i stand corrected also