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Author Topic: Aircraft Altitude  (Read 3628 times)

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grasscutter

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Aircraft Altitude
« on: August 11, 2011, 09:04:40 PM »
Can someone please explain why aircraft that are on the runway or apron are showing an altitude eg. 625ft and 125ft. Surely they should be showing zero altitude.

Budgie

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Re: Aircraft Altitude
« Reply #1 on: August 11, 2011, 10:14:10 PM »
Could they be reporting height above sea level?

tarbat

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Re: Aircraft Altitude
« Reply #2 on: August 12, 2011, 07:53:22 AM »
Also check your Auto-QNH settings in SmartView, and set to your local airport.


grasscutter

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Re: Aircraft Altitude
« Reply #3 on: August 12, 2011, 10:07:42 AM »
Thanks for that Tarbat. I have set the QNH for Manchester Airport but it has not made any difference to the altitude showing on the aircraft on the apron.
Any other suggestions?

tarbat

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Re: Aircraft Altitude
« Reply #4 on: August 12, 2011, 10:46:47 AM »
With the correct QNH set, the altitudes shown by aircraft should be the same as the height of the airfield above sea level - 257 ft / 78 m.

grasscutter

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Re: Aircraft Altitude
« Reply #5 on: August 12, 2011, 11:03:20 AM »
I put in the correct code for Manchester Airport and the system showed a QNH of 1010 NOSIG however the altitudes are not showing zero. Is there anything further I need to do;

Budgie

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Re: Aircraft Altitude
« Reply #6 on: August 12, 2011, 11:57:15 AM »
I think what Tarbet is saying it that with the correct QNH set, it still won't show as zero when they are on the ground, it will show the height that the airport is above sea level.
So are aircraft on the ground showing something near to 257 ft or 78 m?

grasscutter

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Re: Aircraft Altitude
« Reply #7 on: August 13, 2011, 09:19:39 AM »
Thanks Budgie, understand now!

ATROPOS

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Re: Aircraft Altitude
« Reply #8 on: August 20, 2011, 08:30:43 PM »
If you want to see 0 in the altitude you have to set the correct QFE and not the QNH...for further details google it

QNE Height above sea level at standard setting 1013
QFE Height above airfield
QNH Height above sea level.

See also http://en.wikipedia.org/wiki/QNH

Budgie

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Re: Aircraft Altitude
« Reply #9 on: August 21, 2011, 12:11:32 AM »
Sadly there is only the option for QNH.
I assume that this is because QNH is the standard for reporting barometric pressure and is included in the airport METAR & TAF reports.

ACW367

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Re: Aircraft Altitude
« Reply #10 on: August 21, 2011, 01:11:22 PM »
Sadly there is only the option for QNH.
I assume that this is because QNH is the standard for reporting barometric pressure and is included in the airport METAR & TAF reports.

That is correct.  If you have a scanner and only want ground levels at a specific aerodrome.  Then you could listen to the ATIS service for that aerodrome which gives QFE, and then manually set that pressure setting in Radarbox. 

Obviously other airfields in the vicinity of the one you are interested in would be at differing heights above sea level.  So would have differing QFEs.