A320 Thrust LIM Penalty

[Flyman35]

In Wing Anti Ice L(R) valve open PRO-ABN-30 P 6/18 there is a line: THRUST LIM PENALTY.

what consideration must be taken? and what does it mean?
I looked at the MMEL for the same FAULT and found:
APPROACH CLIMB PERFORMANCE:


WHEN THE ENGINE BLEED AIR SUPPLY SYSTEM IS OPEN:

Decrease maximum climb limiting weight by:


800 kg when OAT <= ISA +5
4900 kg when OAT > ISA +5

REF:MMEL 30-11-01A operational procedures

[Escape Path]

I’m bumping this. I had this MEL item last week, with exactly the same wording, and I couldn’t tell how we were supposed to apply this penalty.

We are using the FlySmart software, and there’s no option under the “MEL” menu in the landing performance app that corresponds to this item, and selecting the MEL item directly from the library so it would be transferred to the performance computation, showed “1 MEL item with no performance penalty”. The MEL operational procedure doesn’t provide any guideline on how to apply this penalty.

Does anyone have any insight into this? It would be much appreciated.

Regards!

[Lantirn]

Well its my first time that I see that, too.

Looking at the MEL and the flysmart what I understand is this:

Since one wing A/I valve is open, anti icing will be available if you need it by pressing the wing a/i pb. The penalty for a takeoff or G/A would be calculated and its the same when you select wing anti ice on, on the flysmart.

What is not written is that since one side will be on contniously, if you encounter icing buildup you will be flying with assymetric wing which is very dangerous. So I would put the thing on when in doubt about icing

[dream747]

I am also unable to find any reference on how exactly to apply this thrust limit penalty.

In addition to the take-off and and go-around performance mentioned above, another consideration would be the OEI ceiling. With total anti-ice on, the penalty can be as much as -4300 feet depending on ISA deviation and engine types.

Airbus has a table for the penalties in the event if engine anti-ice on or total anti-ice on, but not for wing anti-ice only. No idea why, or can we just infer and take the difference between the two for wing anti-ice on only?

[Lantirn]

Thrust limit penalty is applied when you account for wind anti ice on your performance.

My company uses airbus flysmart where you can select wing anti ice for takeoff or landing performance in the respective application.

Regarding the enroute consideration, there are 2 ways imho:

1) Just add the most restrictive choice (total A/I on). That would be the safer but not the optimum if it really messes up with your enroute driftdown terrain restrictions.

2) Add the additional weight penalty to your actual weight to find the driftdown altitude. E.g GW 70T. Penalty on single engine driftdown is -4200ft (OAT>15C) according to MEL. Calculate driftdown values for GW 65.8

Airbus flysmart in-flight app is a very easy EFB app to use if your company has it.

[MarkerInbound]

Airbus has a table for the penalties in the event if engine anti-ice on or total anti-ice on, but not for wing anti-ice only. No idea why, or can we just infer and take the difference between the two for wing anti-ice on only?

I'm not an Airbus person but if conditions were such that you needed wing heat wouldn’t you also have the engine heat on?

[Escape Path]

Lantirn The FlySmart software (which we use as well) does have an option to account for anti ice protection being used both on takeoff and landing. However, there’s no “wing anti ice only” option, since if you have wing AI on, you also have engine AI on (which answers MarkerInbound ’s question).

Is this the way we’re supposed to apply this penalty when using FS software? I.e.: applying the most restrictive scenario? This would complicate things a bit further, as we fly in mountainous areas with high go around gradients, and the particular aircraft that had that MEL item is an IAE powered aircraft. With weights a bit higher than fairly light, performance becomes an issue. Though we do have EOSIDs for most of these airports, which we could use…

I seem to remember that the FCOM had some performance tables that could be used in this case, and I did find them in previous FCOM versions. But they are removed from the current one…

[Lantirn]

What I would do is depending on the situation.

If there is icing, that means that you will need also engine anti ice on, thats no brainer. So you use "total" for the takeoff, thats my opinion.

Now if there is a day where you dont need the wing anti icing, you can improvise and get creative but I after consultation with the maintenance of course. Taking off with the respective bleed off (and crossbleed shut) would keep you off the penalty and then select it on after clean up. But I wouldnt do it by myself, better get advice from your technical pilot and maintenance.

[TheEdge]

You basically fly with E/Anti Ice On and get to burn extra fuel, that should be already accounted as extra in the OFP as per MEL.

[Escape Path]

What I would do is depending on the situation.

If there is icing, that means that you will need also engine anti ice on, thats no brainer. So you use "total" for the takeoff, thats my opinion.

Now if there is a day where you dont need the wing anti icing, you can improvise and get creative but I after consultation with the maintenance of course. Taking off with the respective bleed off (and crossbleed shut) would keep you off the penalty and then select it on after clean up. But I wouldnt do it by myself, better get advice from your technical pilot and maintenance.

I get your point. However, what my 6 years on the Bus have taught me is that this is not a mechanical aircraft; there’s way too many software logics for each of the systems, quite a bit of them are interconnected, and things can get pretty messy pretty quickly if you start flipping switches around.

We still haven’t found a way to implement this penalty though. Our best guess seems to be to select total anti ice for landing on the FS software, as it is the only way we can account for wing anti ice on.

[Seanliao71]

I noticed that in A320 MEL 30-11-01A "Wing anti-ice control valve inoperative in the open position": Only the RH wing anti-ice valve may be inoperative in the open position for dispatch. Does anyone know the reason? The Left side wing anti-ice valve is not allowed to be kept on open position because the APU bleed valve is upstream of the cross-bleed valve? Thank you very much.

[AArob]

With a fault in the wings, the values default to the closed position. A fault in the engine anti ice system does the opposite in defaults in the open position. The thrust limit penalty is marginal but there is a fuel penalty to be aware of if engine antiice has left on for the remainder of the fight I believe it's 2.5%.

[k.swiss]

I noticed that in A320 MEL 30-11-01A "Wing anti-ice control valve inoperative in the open position": Only the RH wing anti-ice valve may be inoperative in the open position for dispatch. Does anyone know the reason? The Left side wing anti-ice valve is not allowed to be kept on open position because the APU bleed valve is upstream of the cross-bleed valve? Thank you very much.

Yes good question also ! No idea had it too.

[dream747]

For the case of the wing anti-ice control valve stuck in the open position MEL, are there any performance penalties for take-off performance? Logically speaking I thought there should be (similar to engine anti-ice valve open) but there is no mention of take-off performance penalty in the MEL. Why is this so?

Neither is there any option to select this in the MEL tab in the take-off Flysmart application. There is one for engine anti-ice valve open though.

The only way I can do so is to select both engine and wing anti-ice on in the performance page for the calculations.

[Jwscud]

Because the MEL requires you to follow the ECAM which in turn directs you to select the corresponding engine bleed OFF. With the engine bleed OFF there is no performance penalty. Though you would be wise to look at the single engine bleed MEL and use Packs OFF or the APU bleed for takeoff.

[hans brinker]

2) Add the additional weight penalty to your actual weight to find the driftdown altitude. E.g GW 70T. Penalty on single engine driftdown is -4200ft (OAT>15C) according to MEL. Calculate driftdown values for GW 65.8

It looks like you subtracted the penalty from the GW. If it was a penalty on the GW it would be an addition not a subtraction. The reason it is a subtraction is that is not a weight penalty but an altitude penalty. What you calculate do is calculate the the driftdown for your GW of 70T, and you subtract the penalty of 4200 feet from that number to find the corrected driftdown. Your method would give a higher driftdown after a penalty, because of the lower GW, so obviously wrong. And you are subtracting feet from tonnes.... (sorry if harsh, but if you take the time to comment, at least do a gross error check)