FBW A320NEO take off flap question

User Support Hub Aircraft & Systems
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21

Yes, that is correct. Trim is manually set for takeoff as @PZL104 shared.

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22

Well, yeah. A misunderstanding for sure. Trim is necessary but not the entry THS in the Perf Menu.

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23

All good! We learn, we share!

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As has been noted, the THS entry in the TAKEOFF PERF page of the MCDU is optional. Some operators still have their pilots enter it, some don’t. It can serve as a reminder to the crew for what the pitch trim wheel should be set to, both by having the pilot enter it, and by triggering an alert on the E/WD for crew awareness if the actual pitch trim value differs from the MCDU THS value after engine start or during engine powerup for takeoff.

The primary reason for setting pitch trim for takeoff is to provide consistent and expected rotation characteristics. For example, with a forward cg and the pitch trim set to the nose down takeoff limit, the airplane may feel reluctant to rotate and rotate slower. Conversely, with an aft cg and the pitch trim set to the nose up takeoff limit, the airplane may want to rotate early and fast.

That having been said, as long as the pitch trim is set within the green band and the cg is within the cg limits, a safe takeoff can be conducted. And with the rotation law in the A320neo (and modeled in the A32NX), a consistent, repeatable rotation rate will be achieved for a given sidestick input, regardless of cg position, takeoff weight, flap position, thrust, etc., making the setting of an exact pitch trim before takeoff even less critical.

Regarding the MCDU THS entry, if you choose to enter it, acceptable formats are UP X.X, DN X.X, X.X UP, or X.X DN, where X.X is the pitch trim value, e.g,. 1.1. The trim vs cg chart for the A320neo is shown here:
Screenshot (1301)

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25

Worth noting that the scale in the image above is actually on the trim wheel itself. It’s a trivial thing to look what your ZFCOG is and dial up the appropriate pitch.

So just to be clear: the MDCU entry is informational only; it does not impact any flight systems, correct?

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Correct, it’s advisory only on the ecam when the values differ between software and hardware input.

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The take-off entry goes [1]/[1.XUP] X =the degrees up trim. In my last flight 1.4UP worked after calculating T/O CG.
Got the info from a close friend who’s a RW Airbus Captain.

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If you compare the scale on the trim wheel of the sim A320NEO to what I provided, you will see they are not the same. But again, since a precise trim setting is really not critical, you should be okay since any trim setting on the sim trim wheel will still be within the actual trim scale green band. The trim wheel scale is part of the Asobo model for the airplane, which is also in the FBW A32NX until FBW finishes a new, custom model.

Also, the trim should be set according to the takeoff cg, not the ZFW cg.

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My error. Set to TO cg not ZFWCG.. Edited my post.. All one needs to do is look at the trim wheel


Now having rolling cache problems. Cannot set it. Sim freeze. Anyone have a link to this problem? Search goes to old posts. This is since SU6

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Has anyone succeeded on setting flaps 1+F in the MCDU? for me the +/- key will only type the - sign and when entering the value 1F or 1-F in the Flaps/THS softkey it is not allowed.. 1 or F works tho

Also to set the flaps to 1+F I need to deploy to 2 and then retract one level, the first increase will give only the 1 position even while on ground

Using the default A32N on Xbox series X

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No need for the “F” in the MCDU. That’s the way it is in the real airplane, too.

As for the issue with setting 1+F on the ground, that issue exists with the PC version as well. It must have been introduced with one of the updates.

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32

Flaps 1 for take off is always Conf 1+F (slats+flaps).

The second value after the slash is the Trimmable Horizontal Stabilizer (tail wing) and you must set the value according to T.O. CG (Center of gravity) which is given to you on the load sheet.

While the CG value is a percentage (25-30), you need to enter a pitch angle single digit with decimal and UP or DN.

You can use the table already shared above and found on the QRH checklist.

But as opposed to what is said above, there is an approximation formula you can use:

(35 - TOCG) / 2

So a CG of 27.1 would give 4UP (DN for negative values)

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33

This doesn’t seem to work at all? :thinking:

Screenshot (1301)

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34

Oops
 sorry. The formula i shared is used on A330!!

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Use 1/1.4UP for the 320