A 330 OVERWEIGHT LANDING DISTANCE?
 

In A 330, Landing Distance calculations without failure requires an aditional distance for overweight cases.

For example, in QRH page:
In Flight Performance > In Flight Landing > Landing distance without Failure > Landing Distance -DRY [FPE-IFL-LD 1/6], below the presented table for reference weight, there is another box shows additional (+) distance when the Overweight Landing Procedures are applied.

The reference weight itself is already an Overweight mass. And the table presents the distance factors to add or subtract if the actual weight is different.

The Overweight Landing Procedure does not require any additional speed factor or any technique which may cause to extend the landing distance additionally.

My question is: What could be the reason for another additional distance when Overweight Landing Procedures are applied?

From the FCTM...

So you are striving to minimise brake use and achieve a relatively smooth touchdown. Both are known to extend landing distance...

There is a requirement to touch down at less than 360ft/mt. This is likely to increase the landing distance. This is Airbus explanation.

Mmmmmm so why have the addition already in the table for weight above 190 tonnes then???

Another wonderful example of Airbus logic in their manuals....

Weight above MLW will obviously require greater landing distance because of higher Vls, in addition due to longer float and delay in braking requires additional distance.
The actual reply from Airbus quoted below:
The 'Overweight Ldg Proc' correction is for:
- A potential longer airborne phase in order to achieve the required max V/S at touchdown, and
- The delay in application of brakes until after Nose Landing Gear touchdown.

Thanks for all answers,

Vilas & Cough, what I understand, your explanations assume manual/modualting brakings. However, this does not explain why we are adding this OW Landing Procedure extra distance to AUTOBRAKE LOW/MEDIUM setting, because these setting are already assures a certain decelartion rate (at least for dry runway).

By now, I couldn`t find any explanation in offical docs like FCOM&QRH; just some Airbus presentations which are not offical, yet do not mention how to use OW factor.

Another Wonderful(!) Airbus Logic as Nitpicker mentions: For the Landing Distance with Failure cases, there is not such an overweight extra distance factors, though that distances assume Max Manual Brakings.

Wonderful (ill-)Logic.

I have just read your message after my previous message.

Vilas, that makes sense, any reference for that. Thanks

360ft/min is coming from certification. at MTOM the gear system has to be able to sustain this ROD.
at MLW it is 720 ft/min..hence the difference in the airborne phase of the landing distance.

OW landing distance with failure. Airbus clarification below:
The reason is that with the first performance databases used to calculate the In Flight Landing Distances (IFLD) with failure, the conservatism linked to the in-flight failure was enough. Therefore, at that time, there was no need to apply any additional margin. But now, with the latest performance databases, the modeling of the in-flight failure impact has been reviewed, and for some failures, the conservatism linked to the failure may be lower than the conservatism linked to the Overweight Landing Procedure. In that case, an Overweight Landing Procedure correction should be added.
Please note that a study is already on-going to add the Overweight Landing Procedure corrections in the QRH for the IFLD tables with failure. The new tables and method are presented during Regional Seminars this year.
In the meantime, in the case of Overweight Landing Procedure, the flight crew can use the Overweight Landing Procedure correction published in the QRH (For the In-Flight Landing Distances without failure) to calculate the Landing Distance with an in-flight failure.

WHY DOES THIS HAVE TO BE SO DAMN COMPLICATED.....:{

Give me back my 777 any day......

I try and make ALL my landings at less than 360 feet per minute. Don't know what it is really because I'm not looking at the VSI when I hit the ground.
I struggle to see that 1 kilogram above maximum landing weight will add several hundred metres to the landing distance. Another part of this problem is that when you have a problem I.e. engine failure, you don't need the extra additive. You just use the above and below weight correction.