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A320neo Rotation

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A320neo Rotation

Old 4th Sep 2018, 03:13
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A320neo Rotation

Anyone noticed a tendency to over-rotate on the A320 NEO? Kind of as if the aircraft were tail-heavy and incorrectly pitch-trimmed.

Iíve noticed several pilots applying a sidestick deflection similar to that of the A320 CEO but resulting in a much higher rotation rate.

Apparently Airbus has modified the FBW rotation law because of engine related issues and flap/slat angles, but I have no particular details about what theyíve done to the rotation law.

Thanks for any feedback! Have a good week.
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Old 4th Sep 2018, 07:35
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Originally Posted by rbhojwani View Post
Anyone noticed a tendency to over-rotate on the A320 NEO? Kind of as if the aircraft were tail-heavy and incorrectly pitch-trimmed.

Iíve noticed several pilots applying a sidestick deflection similar to that of the A320 CEO but resulting in a much higher rotation rate.

Apparently Airbus has modified the FBW rotation law because of engine related issues and flap/slat angles, but I have no particular details about what theyíve done to the rotation law.

Thanks for any feedback! Have a good week.
Unlike the current A320, the sidestick commands pitch rate on the neo during rotation. So if you're used to adding that extra "pull" through the dead spot at about 10 degrees you'll command a high rate. The rotation is muscle memory so it takes a conscious effort to set a pitch rate and stick to it.
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Old 4th Sep 2018, 08:26
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Not so hard on the joystick, Harry...

You might enjoy this accident report about a tail strike on an Australian A320 on a cadet's first time as PF for the takeoff:
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Old 4th Sep 2018, 08:54
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Thanks bright teeth...

Love it when they do little whoopsies in reports!

First quote from the FCTM in the rotation technique section
Initiate the rotation with a smooth positive backward sidestick input (typically 1/3 to 1/2 backstick). Avoid aggressive and sharp inputs. The initial rotation rate is about 3 deg/sec. If the established pitch rate is not satisfactory, the pilot must make smooth corrections on the stick. He must avoid rapid and large corrections, which cause sharp reaction in pitch from the aircraft.
Then a quote from the safety analysis section
During rotation, the cadet pilot applied a larger than normal pitch input (3/4 backstick versus the recommended 1/2 to 2/3 of backstick travel) resulting in an excessive pitch rate during rotation (9 deg/sec versus a target of 3 deg/sec)
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Old 4th Sep 2018, 10:01
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Can any of you who fly the A320/321 NEO and also fly the CEO confirm how many line training ( LT) sectors, if any, you received when converting onto the NEO. There is currently a push not to provide any LT and just rely on a half day class room and a home study CBT to cover the differences.
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Old 4th Sep 2018, 10:03
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Absolutely none apart from a self study module (that wasnít mandatory)
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Old 4th Sep 2018, 12:09
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I prefer the slightly sportier and more crisp initial pitch characteristics on the NEO vs the CEO. The initial nose attitude is also higher as the Leap version fitted to my company's fleet develop more thrust than the CFM56 version.
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Old 7th Sep 2018, 10:07
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Been flying the CEO and Neo regularly and the neo has a tendency to go to high pitch .. need a councious mind not to pull back....just ease the pressure passing 10 degrees and it settles at 15.
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Old 8th Sep 2018, 20:14
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Reason

Originally Posted by Fursty Ferret View Post
Unlike the current A320, the sidestick commands pitch rate on the neo during rotation. So if you're used to adding that extra "pull" through the dead spot at about 10 degrees you'll command a high rate. The rotation is muscle memory so it takes a conscious effort to set a pitch rate and stick to it.
Thanks everyone for your replies! Any idea what are the technical reasons as to why would Airbus rewrite the rotation law in order to control pitch rate during rotation?
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Old 8th Sep 2018, 20:40
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you have a 68" turbine vs an 81" turbine, and you dont expect differences?
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Old 9th Sep 2018, 03:06
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Originally Posted by underfire View Post
you have a 68" turbine vs an 81" turbine, and you dont expect differences?
Well actually I do expect and have noticed several differences. Iím just trying to source a technical explanation for one point in particular.
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Old 9th Sep 2018, 06:07
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Unlike the current A320, the sidestick commands pitch rate on the neo during rotation.
That means during take off run the aircraft at least the pitch is normal law and not in direct law. Does this happen at particular speed? Any Airbus referrence on this?
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Old 9th Sep 2018, 13:58
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They added pitch damping for tail-strike control to take-off only, perhaps because Vnmu is only 80 kts.
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Old 9th Sep 2018, 19:39
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Originally Posted by vilas View Post
That means during take off run the aircraft at least the pitch is normal law and not in direct law. Does this happen at particular speed? Any Airbus referrence on this?
Normal law is a misnomer on an Airbus.

It's actually quite a complex blend of multiple different flight control algorithms which vary depending on phase of flight and speed (ie, Airbus will tell you that sidestick demands load factor in flight, but that's only true at high speeds. Below that it's actually direct elevator deflection with a load factor feedback loop, and below that it's AoA directly).

​​​​​​​Can't tell you any more about the new rotation law as I now fly the Airbus wannabe, also known as the 787, and no longer have access to the neo FCOM.
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Old 10th Sep 2018, 07:13
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Originally Posted by vilas View Post
That means during take off run the aircraft at least the pitch is normal law and not in direct law. Does this happen at particular speed? Any Airbus referrence on this?
Um, isn't the pitch usually in normal law for takeoff?
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Old 10th Sep 2018, 09:31
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Laws and modes! More appropriately ground mode of normal law, much like direct law. Not a gee command.
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Old 19th Sep 2018, 02:58
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We had some problems with over rotation in my current company when we started to use mix fleet.Our flight data and analysis group sent some numbers of letters regarding over rotation during take off on the NEO planes particularly with maximum TOW and high OAT.
Some times later our flight department sent a letter with recommendations to carry out all take offs on the NEO fleet with F-2 only!
Since EFB calculations offers F-2/3 only
Safe flights
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Old 19th Sep 2018, 23:28
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What is interesting is how different an A320ceo with sharklets is in comparison to an A320neo in the flare. The ceo is very twitchy but the neo is probably less responsive than a A320 with the original tip fences. I can only imagine the differences are down to software
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Old 25th May 2019, 13:59
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Rotation mode

Weíre just seeing some more detail from Toulouse on Rotation mode in the neo; itís active upto 3/4 back stick and damps pitch commands and deck angles. Slightly new Airbus philosophy in that it can be overridden with aggressive Sidestick... looking forward to reading more...
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Old 25th May 2019, 14:23
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See this thread as well.

A321 tail strike
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