Did anyone hear of center of gravity affecting maximum allowed takeoff weight?. Some folks on some other forum claim that aircraft may be permitted to take off with higher MTOW when its CG is slightly aft (but still within prescribed limits). I wonder if anyone heard of such a thing.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://www.hifisim.com/images/asv_beta_member.jpg

Michael,Yes it does. If you check the 747's cfg you'll see that I inserted some notes (brief) in this section. In the MSFS world does not matter. Has only one aerodynamic body fully modelled...Best,Vangelis===================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com=====================================

(A) It's probably not important, but isn't Vmc figured (1)ISA, (2)MGTOW, and (3)aft CG? yes, it is, because with an aft CG ... And, (:( at aft CG, the a/c flies (a little) faster than with a forward CG. But, don't go looking for (:( in the perf charts.

In the 747-400UF that I fly, we are not permitted a greater maximum taxi or takeoff weight due to CG considerations. It's still the same number. Performance calculations (and the data that they are based on)are not so accurate that I'd want to ever go to a performance limit dependent on any theoretical CG limit. There are some max zero fuel weight limits which do restrict max takeoff weight. Probably only an issue in freighters.Your mileage may vary!Tom

To correct or clarify a minor misstatement (by me!) above.....In the 747-400 UF (freighter) that I fly, the max takeoff weight is 396893 kg. This is constant throught most of te CG range, but decreases slightly at very far forward or aft CG's. This is not due to the lifting capability of the plane, but certification control issues such as elevator power for rotation of flare, engine out dynamics etc.The freighter does not, as do the pax birds, have the tail tanks.Usually we fly the plane, for a loaded takeoff, at CG's ranging from 20 to 27% MAC. If the plane is empty, with little fuel, the CG is near the aft limits.

Great info. I really appreciate that.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://www.hifisim.com/images/asv_beta_member.jpg

Hi,Still a little precision. One of the advantages of 747-400 Freighter is the possibility "of playing" with the maxima of weight.If it is true that the MTOW is 396863 kg, in this configuration, the MZFW will be of 276691Kg and the MRWT (Maximum Ramp Weight)397800 kg.But it should be known that one can have a higher MZFW. Maximum ZFW can reach 288031 kg. In this configuration, the MTOW 367863Kg and the MRWT 369223 kg. Therefore, it will be possible to except charge more (except Forward Cargo zones A1,A2B1,C,D,E ans F. The Cumulative Load Limit decrease) but one will carry less fuel.The only maximum which cannot vary, it is the Maximum Landing Weight MLW: 302100KgAlain

Actually the max landing wt is 302,092 kg.....The odd numbers derived because Boeing originally did the certification weights in pounds.The variable zero fuel weight is a trap for the unwary, the weight and ballance sheets always need a scan to check that this has been correctly calculated (which it usually is). In practice, the ranges over which we fly the freighters and the fuel requirements (trans oceanic) make operation in this zone not too common.Tom

I have the loadsheets of an American cargo company and I confirm the MLW: 302100Kg.For the variability of the ZFW, it goes without saying the plane will have to be charged by respecting the new limits with zones and not to exceed the new MTOW and MRW. But I do not go into the details.Alain

For the variability of the ZFW, here an example of a flight JFK-FRA with a payload of 120405 kg. Block fuel:60000Kg and Taxi fuel: 1200Kghttp://62.210.160.29/ImgAlbums4/Images2/31...81853950867.jpghttp://62.210.160.29/ImgAlbums4/Images2/31...81854741137.jpgAlain

Hi Alain,That looks very familiar ;-)