Airbus Corporate Jet (A319CJ) downsize?

[cptarianus]

Hello,

I would like to ask, why was A319CJ downsized with TF from 2 to 1.5 and Cargo space down to 4900kg?
Standard CEO Airbus have a cargo hold capable to carry up to 6786kg; A319CJ should be capable to carry up to 9807kg with 0 ACT option.

[joefremont]

I recently went through all the airbus aircraft adjusting there cargo volumes, using the rule that in the absence of any exact number the cap is 200 kg per cubic meter, which is actually quite generous. I was reading about the A319-LR and A319-Cj that they get extra range by adding extra fuel tanks in the cargo hold, so I recalculate for them by eliminating the smaller of there three holds.

[joefremont]

As for the ticket factors, not long ago I made a change so that aircraft could sometimes exchange economy seats with business and first class seats at less than the 2 or 4 to one ratio, when I did that I updated many of the aircraft to have lower ticket factors with better exchange factors for the seats. As a result the CJ has a 1.5 ticket factor and it’s 39 seats can all be first class

[joefremont]

Based on that chart, the kg/m3 is around 248.6. I came up with the 200 kg per m3 by analysing cargo aircraft and comparing there total volume to there max payload, maybe the below the floor cargo spaces can hold more weight on average. What does everyone thing, should we assume 250kg per m3 as the standard?

[cptarianus]

Yes, that's CJs problem. Those tanks are "variable", as they are basically cargo containers. You can remove and install them depending on your range requirement within 8 hours maintenance shift. For short-med leg you does not needs all 1 up to 5 of them. This basically can be simulated simply through MTOW with Central Tank still installed (as ACT 0 installed is not standard ATC and the instalation/removal is 48h work). Then go with the simple logic. Standard 6786kg cargo capacity as airliner A319 have (yes, 248.6kg/m3 is certified ratio for whole A320 family) and if You needs longer trip with CJ? You needs to go down with cargo capacity. Simple like that.

[joefremont]

Well there is the problem. Based on the MTOW you can have all 39 pax, a full load of fuel and a full cargo capacity. Right now I don't have a way to say, if you have more than X cargo you must reduce fuel except maybe by doing something funny with MTOW. But since I previously calculated using a 200kg/m3 ratio, I will recompute using a 250kg/m3 ratio.