A320 NEO PW green dot speeds
Only half a speed-brake
Somewhat unrelated observation: what about the holding speeds? Surprise
No mention of PW at all 
DSC-22_20-30-10-18 "G" (FMS2 Thales)
Originally Posted by FCOM 320-271N
When no specific speed limit applies, the default hold speed is approximately equal to:
‐ Green Dot speed on the A318, A319, A320 (CFM) and A321
‐ Green Dot +20 kt on the A320 (IAE).
‐ Green Dot speed on the A318, A319, A320 (CFM) and A321
‐ Green Dot +20 kt on the A320 (IAE).
DSC-22_20-30-10-18 "G" (FMS2 Thales)
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I also don't understand why on IAE the holdig speed is higher then GD but tried it on real airplane. Holding cca. 1.5 hrs at FL80 with green dot it was burning about 150 KGs more fuel then it was predicted.
Only half a speed-brake
I like the suggestion that it might be tuned to ISA 1500 AMSL altitude, if that's what you are saying. Should not be the FMS able to handle that with an optimum speed in all of the holding patterns? Okay, maybe with anti-ice...
My experience in 6-9000 altitude band was same as Lotetu's: sticking to GD +3 resulted in FF lower by around 60 kg on each side.
My experience in 6-9000 altitude band was same as Lotetu's: sticking to GD +3 resulted in FF lower by around 60 kg on each side.
Last edited by FlightDetent; 13th Apr 2019 at 07:46.
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Well it explains why neo Vref is less than CEO but it doesn't explain why neo Conf 3 Vls is higher(Vref+10) than CEO which is Vref +3 or +4kt.
Another query! Guys flying both Neos and CEOs what is your experience of landing a neo? I am told neo tends to sink and if not careful hard landing is possible. Request your inputs. Thanks
Another query! Guys flying both Neos and CEOs what is your experience of landing a neo? I am told neo tends to sink and if not careful hard landing is possible. Request your inputs. Thanks
It's more to do with the engine type, IAE and CFM respond slightly differently when you chop the power. IIRC with CFM engines the thrust comes off quicker so allow for this.
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We will receive our first Neo end of this month so for now I can’t comment about it but the IAE engines idle power is higher compare to the CFM ones. At least ground Idle, not sure about Approach idle. I don’t fly CFM. You never need to add power to move forward on flat smooth surface on with IAE engines. That can explain part of it. And also since the engines are much smaller so less drag during flare maybe? That’s my guess.
Approach idle is also higher. I flew A320ies mixed, IAE and CfM, and the characteristics in flare could hardly be more different.
The IAE has lots of idle power, and is smaller; while the CfM has very little idle thrust, but is larger and hence it's drag becomes more apparent when thrust is flared.
You can chop the thrust completely on an IAE powered A320 in like 60 ft above the runway, and still won't lose much speed, and can easily obtain a smooth touchdown.
Whereas in a CfM powered one even if you cut the thrust quickly in as low as 20 ft the bus will still fall out of the sky and bump onto the runway.
Even more pronounced if the IAE one has sharklets, and the CfM one doesn't.
I found this to be the reason why CfM Airbusses tend to land a little firm, especially when flying with auto thrust on it is almost impossible to flare the thrust slowly (because you would have to bring the thrust levers back from the climb detent to an angle where it does limit the thrust quickly, and then retard further slowly, fairly difficult to do 20 ft above the runway).
Once you cut the power, it bumps onto the runway. Without auto thrust, if you start reducing thrust slowly from 30 ft down just to reach the idle stop at touchdown even a CfM bus lands very smoothly (but will call you a retard all the way down).
The IAE has lots of idle power, and is smaller; while the CfM has very little idle thrust, but is larger and hence it's drag becomes more apparent when thrust is flared.
You can chop the thrust completely on an IAE powered A320 in like 60 ft above the runway, and still won't lose much speed, and can easily obtain a smooth touchdown.
Whereas in a CfM powered one even if you cut the thrust quickly in as low as 20 ft the bus will still fall out of the sky and bump onto the runway.
Even more pronounced if the IAE one has sharklets, and the CfM one doesn't.
I found this to be the reason why CfM Airbusses tend to land a little firm, especially when flying with auto thrust on it is almost impossible to flare the thrust slowly (because you would have to bring the thrust levers back from the climb detent to an angle where it does limit the thrust quickly, and then retard further slowly, fairly difficult to do 20 ft above the runway).
Once you cut the power, it bumps onto the runway. Without auto thrust, if you start reducing thrust slowly from 30 ft down just to reach the idle stop at touchdown even a CfM bus lands very smoothly (but will call you a retard all the way down).
