A320neo Rotation

[rbhojwani]

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

I’ve 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 they’ve done to the rotation law.

Thanks for any feedback! Have a good week.

[Fursty Ferret]

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

I’ve 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 they’ve 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.

[Pearly White]

You might enjoy this accident report (https://www.atsb.gov.au/media/5773456/ao-2016-046-final-report.pdf) about a tail strike on an Australian A320 on a cadet's first time as PF for the takeoff:

[Cough]

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)

[phantom menace]

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.

[EGPFlyer]

Absolutely none apart from a self study module (that wasn’t mandatory)

[speedrestriction]

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.

[speedbird787]

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.

[rbhojwani]

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?

[underfire]

you have a 68" turbine vs an 81" turbine, and you dont expect differences?

[rbhojwani]

you have a 68" turbine vs an 81" turbine, and you dont expect differences?

Well actually I do expect and have noticed several differences. I’m just trying to source a technical explanation for one point in particular.

[vilas]

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?

[underfire]

They added pitch damping for tail-strike control to take-off only, perhaps because Vnmu is only 80 kts.

[Fursty Ferret]

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.

[Check Airman]

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?

[vilas]

Laws and modes! More appropriately ground mode of normal law, much like direct law. Not a gee command.

[avoka]

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

[tubby linton]

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

[neilki]

We’re just seeing some more detail from Toulouse on Rotation mode in the neo; it’s 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...

[krismiler]

See this thread as well.

https://www.pprune.org/tech-log/621568-a321-tail-strike.html

[MD83FO]

the flare on the 321 NEO feels mushy causing a prolonged flare but i cant find anything on the books.
maybe thats why they keep quiet with boeing related matters.

[vilas]

the flare on the 321 NEO feels mushy causing a prolonged flare but i cant find anything on the books.
maybe thats why they keep quiet with boeing related matters. It's not neo but all sharklet aircraft are slippery in flare because of drag reduction. Because of that SAFETY FIRST states that for GS mini only 1/3 of ∆ wind is used unlike non sharklets aircraft which use full ∆wind.

[sonicbum]

It's not neo but all sharklet aircraft are slippery in flare because of drag reduction. Because of that SAFETY FIRST states that for GS mini only 1/3 of ∆ wind is used unlike non sharklets aircraft which use full ∆wind.

Are You sure about that ? Safety first #24 only discusses CEO vs NEO difference in the k factor.

[vilas]

Sonic check this one
https://safetyfirst.airbus.com/control-your-speed-during-descent-approach-and-landing/

[Check Airman]

Sonic check this one
https://safetyfirst.airbus.com/control-your-speed-during-descent-approach-and-landing/

That article doesn't mention sharklets, or did I miss something? Always more to know about this plane.

As an aside, I like the way they put it. "Stronger deceleration capability". Is that the PC way of saying underpowered? :O

[pineteam]

That article doesn't mention sharklets, or did I miss something? Always more to know about this plane.

As an aside, I like the way they put it. "Stronger deceleration capability". Is that the PC way of saying underpowered? :O

Interesting. I assume they are talking about the CEO without sharklets; Otherwise I don’t undestand how it’s possible. I don’t see how a NEO with engines of 81 inches diameter can not have a stronger deceleration. Lol

[vilas]

That article doesn't mention sharklets, or did I miss something? Always more to know about this plane.

As an aside, I like the way they put it. "Stronger deceleration capability". Is that the PC way of saying underpowered? :O
May be I mistook it as Sharklets in place of Neo. It says neo. But the effect is due to sharklets.

[sonicbum]

Sonic check this one
https://safetyfirst.airbus.com/control-your-speed-during-descent-approach-and-landing/

Hi vilas,

thanks, that's the one I was referring to. The k factor of .33 is applicable to the NEO but I can't see any reference to the CEOs with sharklets... unless I am missing something ?

Cheers.

[vilas]

Hi vilas,

thanks, that's the one I was referring to. The k factor of .33 is applicable to the NEO but I can't see any reference to the CEOs with sharklets... unless I am missing something ?

Cheers.
I misread it. It says Neo. But the effect is due to sharklets. As PT says higher fan diameter should offer more drag.

[sonicbum]

I misread it. It says Neo. But the effect is due to sharklets. As PT says higher fan diameter should offer more drag.

Makes sense, thanks.

[FlightDetent]

Airbus usually do not make that kind of mistakes in official documents. Writing NEO but meaning Sharklets, missing the hint there are probably more CEOs with sharklets than NEOs produced altogether.

Though I do agree with the sentiments above, I think we should not settle for a "typo" type explanation.

[vilas]

Airbus usually do not make that kind of mistakes in official documents. Writing NEO but meaning Sharklets, missing the hint there are probably more CEOs with sharklets than NEOs produced altogether.

Though I do agree with the sentiments above, I think we should not settle for a "typo" type explanation.
Somebody needs to ask Airbus on tech request.

[sonicbum]

Airbus usually do not make that kind of mistakes in official documents. Writing NEO but meaning Sharklets, missing the hint there are probably more CEOs with sharklets than NEOs produced altogether.

Though I do agree with the sentiments above, I think we should not settle for a "typo" type explanation.

Very true indeed. We do not operate NEOs but we do operate lots of sharklets CEOs and the related MSN FCOM has the same GS mini logic as the winglets ones. I guess it’s time to give our technical pilot a bit of work 😁

[FlightDetent]

It is in the article, understanding it becomes the hard part. With 6 landings on NEO combined, I am not qualified to draw opinions.

[pineteam]

Very true indeed. We do not operate NEOs but we do operate lots of sharklets CEOs and the related MSN FCOM has the same GS mini logic as the winglets ones. I guess it’s time to give our technical pilot a bit of work ��



I just checked my FCOM: For the CEO with wingtips fences and sharklets the GS logic is the same and for the NEO the GS logic is 1/3... Exactly as described in that Airbus magazine... Weird. I hope we can get an answer soon. =)

[Field In Sight]

Regarding the original posters question.

On the NEO, I don't notice any difference in the initial pitch up from the runway. However, approaching the initial climb pitch attitude, the required pull back on the stick is much less. This gives a tendency to overpitch if you don't anticipate it.

Not really noticed any difference on landing.

[Check Airman]

Regarding the original posters question.

On the NEO, I don't notice any difference in the initial pitch up from the runway. However, approaching the initial climb pitch attitude, the required pull back on the stick is much less. This gives a tendency to overpitch if you don't anticipate it.

So you're saying they modified it to fly more like the sim? :D

[OPEN DES]

I just checked my FCOM: For the CEO with wingtips fences and sharklets the GS logic is the same and for the NEO the GS logic is 1/3... Exactly as described in that Airbus magazine... Weird. I hope we can get an answer soon. =)

Higher residual thrust at idle on the NEO? Only flew it once.

[pineteam]

Higher residual thrust at idle on the NEO? Only flew it once.


Hi OPEN DES,

Only flew it once also haha. So can not really say. But that could be it.

[vilas]

There are different angles at work. One is the sharklets. However subtle it should make some difference during flare and touchdown from winglets. It did to 747-400 from classic, the 737 guys may opine about the 737-300 and NG. The other is engines.Between the CFM and IAE engines Ceo aircraft the IAE has more thrust at lower levels while CFM has higher thrust at higher levels. This is born out by OEI ceilings which are noticeably higher for CFM. That includes residual thrust. I know of one Airline where they find hard landing occurrences are much higher on the Neo with CFM but they are comparing with their CEOs which have IAE. The Neos have higher fan diameter and higher weight and they feel it tends to drop when thrust is closed. And yet according to Airbus the Neo deceleration is less as compared to CEO. So the correct answer can only come from the Airbus. Can someone get it?

[Nightstop]

On the NEO, I don't notice any difference in the initial pitch up from the runway. However, approaching the initial climb pitch attitude, the required pull back on the stick is much less. This gives a tendency to overpitch if you don't anticipate it.

Totally agree with that. Also, I’ve been landing the sharklet equipped A320 NEO a lot recently onto 30 metre runways, judging the flare to touchdown smoothly is a lot more challenging than the non NEO imho.

[FlightDetent]

@vilas you are describing the landing, and the opinions of my more experienced colleagues (albeit with PW) mirror your words. That is below 30 ft. If you cut the thrust on NEO to idle “IAE” style, the plane’d come to a standstill at around 10 feet.

Two different phases there.

The effect of decaying wind from which GS mini protects us is something that tends to happen below 150 ft, down to 25 I would say. Due to more lively thrust (whatever that is) the delta GS buffer needed reducing to 1/3 in order to prevent excessive energy at flare for the NEOs. That is my explanation of the article.

[safelife]

vilas, I think the difference is airspeed.
High airspeed, high idle thrust.
Descend with 280 kt idle thrust will still be high.
Cut the thrust at 20 feet doing 125 kt, residual thrust is far less.

[vilas]

About CFM 56 ceo having higher thrust than IAE at higher altitude there is a graph published by Airbus. About the rest I am also seeking an answer.

[PoppaJo]

Have any pilots been briefed by your carrier on this rotation difference when converting to the Neo?

Or just like MCAS, is it just a wait and find out?

We are 12 months out from the Neo and I’ve asked the question but nobody knows. We’ve had issues with cadets slamming 321 tails down the runway so this could essentially get ugly if not properly briefed.

[Check Airman]

Have any pilots been briefed by your carrier on this rotation difference when converting to the Neo?

Or just like MCAS, is it just a wait and find out?

We are 12 months out from the Neo and I’ve asked the question but nobody knows. We’ve had issues with cadets slamming 321 tails down the runway so this could essentially get ugly if not properly briefed.

We got a paragraph saying that there are differences.

[AerocatS2A]

Have any pilots been briefed by your carrier on this rotation difference when converting to the Neo?

Or just like MCAS, is it just a wait and find out?

We are 12 months out from the Neo and I’ve asked the question but nobody knows. We’ve had issues with cadets slamming 321 tails down the runway so this could essentially get ugly if not properly briefed.​​​​​​

We didn’t get anything regarding rotation differences and having flown it a number of times I don’t see any need to spell out the differences. If you are in the habit of flying the result rather than the input then it should be no issue at all, ie, raise the nose to 15° at the appropriate rate and let you hand do whatever is required to make that happen.

[Field In Sight]

​​​​​​

We didn’t get anything regarding rotation differences and having flown it a number of times I don’t see any need to spell out the differences. If you are in the habit of flying the result rather than the input then it should be no issue at all, ie, raise the nose to 15° at the appropriate rate and let you hand do whatever is required to make that happen.

I agree completely. It is definitely different, however my technique is the same. Pull back a bit, see what happens and then adjust accordingly.

[compressor stall]

FCOM has been reworded “based on customer feedback” jun 19 changes.

but the rotation “mode” technique is unchanged from CEOs. Renamed from law to a mode.

havent flown it, just the FCOM messenger.