SJ30-2 can apparently maintain sea-level pressure all the way to 41,000 ft. Not sure what's the reason behind it - certainly it doesn't come for "free".Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

Ok, as far as the real world flight, the plane was full, and had alot of fuel onboard as I already stated because we were expecting delays, boy was it a slow rotation! The gw was about 160,000 on the simulated flight.

>Ok, as far as the real world flight, the plane was full, and>had alot of fuel onboard as I already stated because we were>expecting delays, boy was it a slow rotation! The gw was>about 160,000 on the simulated flight.Being full of passengers is one thing but it's hard to judge the cargo load and the actual flight planned fuel.Anyway, for 160,000 lb GTOW, the Boieng All Engine Long Range Cruise Maximum Operating Altitude chart for the 737-800 gives 34,500 ft as the optimum initial cruise altitude for ISA conditions of +10C and below. As the fuel is burned off it will be able to climb higher. The FMC is correct in telling you the max alt is FL351 for the weight you're loading so there is nothing wrong with the PMDG 73NG FMC.The max weight for cruising at 41,000 ft is 110,000 lbs and for 39,000 ft is 123,500 lbs.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

Thats weird, the same situation happened today with a gw of 149000. But If you are looking at the official chart then I guess all is well, numbers dont lie! I suppose their was a very light cargo load on many 737 flights then.

>Thats weird, the same situation happened today with a gw of>149000. But If you are looking at the official chart then I>guess all is well, numbers dont lie! I suppose their was a>very light cargo load on many 737 flights then.Nothing weird at all. According to the boeing charts, it's OK! Like I said, to get higher you need to be lighter.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

12PSI! Thats gettin high! Do they need to go structural mods to do it? or just simply a lower fatigue life of 60k?

>12PSI! Thats gettin high! Do they need to go structural mods>to do it? or just simply a lower fatigue life of 60k?AFAIK no changes to the structure as this mod can be a retro fit. There is a 15,000 cycle fatigue penalty though.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

OK, I give up... I've been searching for performance data on the 737-800, I've looked in the manuals that come with the pmdg but I can only find the "Fuel load estimation" tables, and the methodology section saying "we will select FL370" where do you select this from? (yes I'm aware of the FL's dependant on dirction of flight)I cant find any MAX/OPT cruise Alts Vs. Gross weight.I'm trying to create an accurate FSbuild performance data file, I have the 600 and 700 from the FSBuild site and I have the one that comes with FSBuild, but if there is a better one out there please let me know. CheersGavin

What are you putting in the cost index box?

This is data from the Continental flight manual from 11/15/02.B737-800klbs opt / max180 --- 311 / 338175 --- 317 / 346170 --- 324 / 353165 --- 330 / 360160 --- 337 / 366155 --- 343 / 372150 --- 350 / 378145 --- 357 / 385140 --- 365 / 391135 --- 372 / 398130 --- 380 / 405125 --- 388 / 410120 --- 397 / 410The numbers for the -900 are identical for optimum alt and about 1000 ft lower for max alt.have fun James

Thanks for that James! Do you have any more performance data? Cruse fuel flow tables/graphs for altitudes and weights? perhaps an electronic version of the performance data? if not I'll just have to fly the thing and work it out lol.I normally use around 80 as my CI. I fly for Qantas VA but not 100% sure of their CI policy.CheersGavinQF221

In Australia, Virgin and Qantas operate the -800 at 390 and 400 regularly. Another factor determining how high you can go is the OAT and its relationship to the ISA teperature. Near the tropics and in summer in the mid latitudes the OAT can be 10 - 15 degrees above ISA which will have a significant effect on performance.NeilYPAD

Actually 12 is pretty high but not as high as you might think. The SJ30 can pressurize so well since it is basically a one piece fuselage made of composites. It has the record for presurizing under testing. They brought that bad boy up to 32 PSI on the testing and it was stated that it could have easily exceeeded that. Not bad huh? Also for all this FL410 stuff, it is a pain in butt for the pilots and for certification to get it certified for higher. If you captain or F/O has to go take a leak, you are supposed to wear your oxygen mask. Many planes can exceed what they are cetified for but its all about the cash it cost for Boeing ot recertify it. When designed most planes have the same systems as their predecessor but it costs HUGE sums of money to get certified. Jack