Holding speed A320 v2500
Thread Starter
Joined: Jul 2000
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From: My views - Not my employer!
Holding speed A320 v2500
G'day,
Other day entering the hold, actually in managed speed, Inoticed that the aircraft was holding at about green dot +20. Now my memory is crap, so I had to go looking in the doorstop of our library, FCOM 4.
Found that our 320's with v2500's held at gd +20, but all other aircraft in the fleet held at green dot.
Now, I have a theory why... GD has the best l/d ratio when straight and level, but in the hold when more than half the time is spent turning, it doesn't represent the most econ speed to hold at. Having slightly higher speed whilst in a banked turn would then be best for min fuel burn.
My question is, why did they do this only on the A320 and not 319/321?
Other day entering the hold, actually in managed speed, Inoticed that the aircraft was holding at about green dot +20. Now my memory is crap, so I had to go looking in the doorstop of our library, FCOM 4.
Found that our 320's with v2500's held at gd +20, but all other aircraft in the fleet held at green dot.
Now, I have a theory why... GD has the best l/d ratio when straight and level, but in the hold when more than half the time is spent turning, it doesn't represent the most econ speed to hold at. Having slightly higher speed whilst in a banked turn would then be best for min fuel burn.
My question is, why did they do this only on the A320 and not 319/321?
Joined: May 2004
Posts: 28
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From: INDIA
Holds and Speeds
hey there , well cant comment much on y is it that the v2500 series a320 hold speed is gd+20 and not so for 319/320 , but i have a therory too about wat you have to say..may be it can give us a clue about the diff in hold speeds...
well as i can recall hold speed is decided by the FMGS , its criteria is :
the hold speed is the lower of :
GD or ECON SPEED or ICAO Recommended Speed ( FAA/CAA/French CAA/ICAO) or A/c Best Endurance Speed. (Not to mention i havnt found ne explanation of wat is Best Enducance Speed) , now the A319/21 Fuel consumption may vary a bit diff from the a320 and as a result of which depending on fadec and engine interface standards the best hold speed seemed fit may be GD where as for the Older A320/v2500 series it may be gd+20 hence the diff...
open to ne correction if i might be wrong in thinkin...
I think it depends on the A/C configuration of Engine v/s FADEC stds and basic aerodynamics of each a/c design diff (ie diff bet the a319-321 family)..hope i shed some light on this topic ...
well as i can recall hold speed is decided by the FMGS , its criteria is :
the hold speed is the lower of :
GD or ECON SPEED or ICAO Recommended Speed ( FAA/CAA/French CAA/ICAO) or A/c Best Endurance Speed. (Not to mention i havnt found ne explanation of wat is Best Enducance Speed) , now the A319/21 Fuel consumption may vary a bit diff from the a320 and as a result of which depending on fadec and engine interface standards the best hold speed seemed fit may be GD where as for the Older A320/v2500 series it may be gd+20 hence the diff...
open to ne correction if i might be wrong in thinkin...
I think it depends on the A/C configuration of Engine v/s FADEC stds and basic aerodynamics of each a/c design diff (ie diff bet the a319-321 family)..hope i shed some light on this topic ...
