Ground Speeds
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Join Date: Jan 2004
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Ground Speeds
While on a famil visit to Perth the other day I noticed the flow controller favoured issuing ground speeds to inbound aircraft to achieve the desired spacing. How difficult is it to maintain a given ground speed while in the cruise? Are other methods (IAS or mach number) preferable? 
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Join Date: Oct 2000
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Yes this can be hard but Mach number is used where I am alot and an indicated airspeed, when on descent. Maintaining a ground speed on descent is a bit hard especially if the winds change, I find.
Sheep
Sheep
Bottums Up
Oz
Maintining a ground speed is as simple as adjusting power to achieve the appropriate readout on the GPS/LNAV.
Better than IAS or Mach getting close to the terminal as TAS will vary with either level or temp and therefore GS is affected.
Better than IAS or Mach getting close to the terminal as TAS will vary with either level or temp and therefore GS is affected.
Nunc est bibendum
For enroute stuff (IE, last couple of hundred miles of cruise), I can do groundspeed with no dramas. On descent, groundspeed is more work to maintain and an IAS is preferred. I can 'do' g/s if you want but the IAS is the preferred method for me once we start the descent.
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MAC on the early part of decent thence IAS is pretty much the normal and obviously much easier for the pilot to achieve.
G/S can change quite dramaticaly up high from initial decent due to enviromental changes.(jetstreams etc)
Maintaining a ground speed in the crz and intial descent i believe is a little urealistic to be a standard.
G/S can change quite dramaticaly up high from initial decent due to enviromental changes.(jetstreams etc)
Maintaining a ground speed in the crz and intial descent i believe is a little urealistic to be a standard.
