AirNav Radar
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
 


Author Topic: Aircraft On Ground  (Read 15003 times)

0 Members and 1 Guest are viewing this topic.

Allocator

  • RadarBox24.com Beta Testers
  • Hero Member
  • *
  • Posts: 3568
Re: Aircraft On Ground
« Reply #15 on: June 27, 2009, 03:34:46 PM »
OK Tony, here you go:

- find an aircraft on the ground, say the altitude readout is 300 ft - I think that you want it to read zero feet?

- First of all, click on the SmartView Tab to the right of MyFlight and Network.  Where it says 'Auto set QNH' make hure that the box is NOT ticked

- Goto the RadarBox File menu item at the top left of the screen

- Left click on File and then left click on Preferences and then on the RadarBox tab in the Preferences window

- Look down to the Transition Altitude section middle left of the window.

- Set the 'Above this value altitude etc' and set 6000 here

- Go to the box below where it says 'QNH (to display etc')

- Divide the height you are seeing the aircraft on the ground by 30 (in our example we said that the aircraft was showing 300 ft on the ground) so 300 divided by 30 = 10

- Whatever figure you have now in the QHN box, say 1016, subtract 10 from this = 1006

- Enter this figure in the QNH box and click Apply and OK to exit the Preferences menu

- The aircraft that was reading 300 ft on the ground SHOULD now read zero

You will have to do this every day an the pressure changes all the time.  You might even need to do this more than once a day if the pressure is changing rapidly.

Give it a go and see how you get on :-)

dudbaker

  • Full Member
  • ***
  • Posts: 166
Re: Aircraft On Ground
« Reply #16 on: June 27, 2009, 03:45:03 PM »
Allocator

I have just checked 737 ops manual.  Pre Take off Transponder ON.  Shutdown Transponder SBY/OFF.  I have been retired 4 years and things move fast in aviation.  I used to teach that there is a customer option.  Transponder on off can be operated by weight on ground switch.  A magazine recently suggested it can be landing position operated.  I have no knowledge of zero being sent on the ground but of course possible.

Dudley
« Last Edit: June 27, 2009, 03:55:09 PM by dudbaker »
Dudley Baker
Stansted
G8THH
[email protected]
Valiant, Victor, Shackelton, Canberra, VC10, Tornado Typhoon 737 747 A320 A300 Engineer.

Allocator

  • RadarBox24.com Beta Testers
  • Hero Member
  • *
  • Posts: 3568
Re: Aircraft On Ground
« Reply #17 on: June 27, 2009, 03:54:42 PM »
Thanks Dudbaker,

I read somewhere that there is a separate transponder message activated by 'weight on wheels' that can be decoded to show that the aircraft is on the ground.  I also read that RB doesn't decode this, so there is no 'on the ground' indication.  I'm sure somebody here will know the technical details, so I'll wait to be educated :-)

dudbaker

  • Full Member
  • ***
  • Posts: 166
Re: Aircraft On Ground
« Reply #18 on: June 27, 2009, 03:57:21 PM »
Allocator

This may be true but it will only apply during Taxi.  ATC get the right hump if the crew leave it on.  Joe Soap had to go out and find which one it was.

Dudley
Dudley Baker
Stansted
G8THH
[email protected]
Valiant, Victor, Shackelton, Canberra, VC10, Tornado Typhoon 737 747 A320 A300 Engineer.

aps

  • Jr. Member
  • **
  • Posts: 70
Re: Aircraft On Ground
« Reply #19 on: June 27, 2009, 04:13:44 PM »
Thanks Allocater , very helpful ....
Alas as usual with things its still confusing me !

Aircraft on the ground ... found .... altitude -1050 !! which goes against everything which im led to believe.

honestly , ive given up.

Tony



Allocator

  • RadarBox24.com Beta Testers
  • Hero Member
  • *
  • Posts: 3568
Re: Aircraft On Ground
« Reply #20 on: June 27, 2009, 04:26:12 PM »
Thanks Allocater , very helpful ....
Alas as usual with things its still confusing me !

Aircraft on the ground ... found .... altitude -1050 !! which goes against everything which im led to believe.

honestly , ive given up.

Tony




No problem just add 35 to the figure you have set in QNH.

1050 divided by 30 = 35

As I said before, you really are trying to complicate matters.  The correct option is to make sure that the auto set QHN is ticked in SmartView and that the airfield is entered in the 'Select Airports' box in Smartview - everything is then automatic and you will see what the controllers are seeing when the aircraft is airborne :-)

Remember, pressure changes all the time, as you will see if you watch a barometer - and an aircraft altimeter is really only a very expensive barometer.  Now imaging flying an aircraft using a barometer to show you how high you are and you will get an idea why air traffic controllers and pilots get so excited about having the correct pressure set!
« Last Edit: June 27, 2009, 04:29:40 PM by Allocator »

DaveReid

  • Hero Member
  • *****
  • Posts: 1815
    • Heathrow last 100 ADS-B arrivals
Re: Aircraft On Ground
« Reply #21 on: June 27, 2009, 08:37:27 PM »
I have no knowledge of zero being sent on the ground but of course possible.

There is no provision in the Mode S spec for sending QFE-based or QNH-based altitudes, so aircraft on the ground will still send altitude based on 1013.2mb, which is unlikely to be zero.

However the aircraft's response to any Mode S interrogation also contains a set of Flight Status bits, one of which can be used to indicate whether the aircraft is either airborne or on the ground.  Applications using this data can of course make use of this status bit to force display of a zero altitude.  Whether RadarBox or SBS/BaseStation actually do this, I don't know - not being close enough to an airport to pick up aircraft on the ground.

HTH
Dave
This post has been scanned for any traces of negativity, bias, sarcasm and general anti-social behaviour

ianmalc

  • New Member
  • *
  • Posts: 21
Re: Aircraft On Ground
« Reply #22 on: June 28, 2009, 08:15:22 AM »
Looking on the network right now , there are several aircraft at Heathrow showing ground at 0ft.

Ian