Why such MESSAGES: MAX RUNWAY WEIGHT EXCEEDED: 58.4 appears, when LW is 66.5T and MaxLW is 67.4T. There is OK in Performance & Tools sheet.
LANDING PERFORMANCE
C-GTLT A320-271N PW1127G-JM
RUNWAY AND WEATHER:
APT EPKK/KRK WIND 254/06
RWY 25/+0 HW/XW 6/ 0
LENGTH 2550 OAT 17
LDA 2312 QNH 1016
ELEV 791 RWY COND DRY
INPUTS:
WEIGHT 66.5 FLAPS FULL
VREF ADD 5 BRAKES AUTO LOW
METHOD INFLIGHT REVERSE YES
OUTPUTS:
ACTUAL LANDING DISTANCE 2021 M
FACTORED LANDING DISTANCE 2560 M
FACTORED DISTANCE MARGIN -248 M
RWY LIM 58.4 FLAPS FULL
VAPP 142 BRAKES AUTO LOW
MESSAGES:
MAX RUNWAY WEIGHT EXCEEDED: 58.4
The factored landing distance is 2560 meters for your weight, whereas the available landing distance is 2312 meters, giving a negative safety margin of minus 248 meters.
The indicated weight of 58.4 tons is the maximum weight for which the factored landing distance would be 2312 meters or less at the selected braking setting.
It appears you manually selected autobrake low; if you leave it on optimum it’s likely you can make the factored landing distance fit within the available landing distance (with autobrake medium being selected by the performance tool).
Regards,
Tim
@SimBrief if I manually select AB LOW e.g. in the conditions above, the graphical overview (landing limits section) says no, gives the maximum weight and says limited by FIELD; I’m not sure how real world tools would present it, but would it perhaps make sense to indicate it’s limited by the selected braking setting instead (in cases where AB MED or MAX MAN braking would make landing permissible)?
Regards,
Tim
Hi Tim, possibly, though that would also require backend updates to calculate more than just the selected brake setting. Will be considered for a future update, thanks.
There is mismatch between it and what tollis a320neo calculator shows. There is still quite long margin to land at the same parameters. I can confirm that I have to roll quite long distance to exit the runway and my flare is quite loooong. 
Can you provide a screenshot of the ToLiSS landing report on the EFB for comparison?
Also it’s likely ToLiSS uses the full runway length of 2550 meters instead of the LDA of 2312 (which is not available in the X-Plane apt.dat used by the ToLiSS).
Regards,
Tim
The ToLiSS doesn’t know the highlighted area (anything before the touchdown zone — TDZ on the chart) is not available for landing.
Regards,
Tim
Toliss sees 2311m. BRK MODE has to be switch into MED. At LO weight is too high/rwy too short.
However factored LD is 1536m vs. REQ LD 1454m
Simbrief shows 1446m act. distance vs. factored equal 1901m.
I’m guessing the difference comes from the flare calculation resulting in a different factored distance?
Regards,
Tim
@SimBrief I found this:
Based on this, it seems the 7-second flare is part of the ALD/OLD, as opposed to part of the margin between ALD and Factored Landing Distance?
Regards,
Tim
Hmm, I don’t see that here. Maybe I missed it, but from what I can tell on page 2:
ALD for dry/wet runways is derived from flight tests. The 7 second flare distance is only considered for ALDs on contaminated runways.
However, all of the OLDs (dry, wet, and contaminated) use the 7 second air distance.
Ignoring the contaminated case (since SimBrief doesn’t support this anyways), basically the ALDs use an air distance of 1,000 ft (perfect touchdown in the TDZ, no float). Whereas OLD will use an air distance of roughly 1,650 ft (500 m, 7 seconds at ~140kts), so about 650 ft more air distance than the ALD. Following the touchdown, the deceleration rate and rollout distance is the same for both ALD and OLD, however the OLD then gets factored by an additional 15%.
At least that’s how I read it?
Yes, it’s only included in the ALDs for contaminated runways, but not in the others, presumably because it’s not necessary?
And it looks like it’s included in all the OLDs indeed. But it seems to be incorporated in the OLD, not as part of the OLD → FOLD margin (whereas Simbrief is seemingly placing the 7-second flare in the margin instead).
Regards,
Tim
Ah I think I see what you mean.
SimBrief is returning ALD → FOLD in its landing calculations. i.e. the 2 distances it is displaying are ALD → FOLD, the logic being that ALD is the best case you can realistically achieve, and FOLD is what you need to plan for.
OLD would be somewhere in between, 15% less than FOLD, but it doesn’t really serve a purpose to display it. Since all of your calculations need to be based on the 15% factored OLD anyways.
Maybe that clears it up? Or am I still missing the point 
With all that said, I’m not sure it really has anything to do with the reported issue:
I’m not sure what factor the ToLiss is using here, somewhere in the neighborhood of 5% looks like? Seems kind of low, even if they are displaying the OLD → FOLD instead of the ALD → FOLD. And their “REQ LD” seems to mostly align with the ALD.
I hadn’t looked at the ToLiSS numbers, that does seem like a low margin between required and factored indeed.
Regards,
Tim
