HiI am having a problem with the default 747. When I try to climb above to FL300 or higher, the speed falls dangerously low, until it, quite literally, falls out of the sky. Anyone know a fix? I would really like a reply within the next week. Thanks

That also happens with the real 747 if you try and climb to that altitude before having burned off enough fuel to enable you to do so, since you will weigh too much and not be able to generate enough lift at a typical climb speed. So in short, the ''fix'' you are looking for is to take the right amount of fuel for the trip you are making (plus some reserve for about a 45 minute diversion), and then watch the fuel contents before going up to your intended maximum cruise altitude, and don't try and climb at something stupid like 1,500 feet per minute when up there, the air is too thin to make that possible. You should bear in mind that 'service ceiling' is defined as the altitude where the aircraft can still climb at 100 feet per minute when at full thrust in ISA conditions, and service ceiling is really a brochure figure, which should not be regarded as an indication of what the aircraft can always do, especially with 450 passengers on board, full fuel tanks, and on a warm day! Although the 747 has a service ceiling of about 43,000 feet, it's quite common for aircraft such as the 747 to begin their cruise on long journeys at somewhere around the 30,000 feet mark, and then climb up to perhaps something like 35-37,000 feet later in the cruise when they have burned off some fuel (often in stages), and so it's not unknown for aircraft setting off on long journeys to request a lower than cleared cruise altitude initially, until they are a bit less weighty. A 747 can indeed attain Mach 0.85 quite happily at 35,000 feet, but as with the real thing, you will need to burn some fuel off before you venture up there. Climbing much higher than 37,000 feet is not really worth the waste in fuel it would take to get up higher owing to the extra thrust required in order to do so. So it is also the case that if a 747 has a good deal of fuel on board and weighs something like 320 tons it's much safer and indeed far more economical to stay at 30,000 until some of that weight is burned off before attempting to climb higher. That is in fact true for a lot of airliners incidentally. Al

If you were flying the PMDG 744 then the FMC would tell you the optimal FS and the max FL for your current gross weight. Cheers, - jahman.

Al, Great explanation, as usual Anyway, if you have 100% fuel dont expect to get straight to your cruise altitude. Due to the thinner air it is harder to climb which has been explained Perhaps you are too heavy, or using something like 3000 FPM for the whole accent. Try lowering it to 1000 after 18000 and reduce fuel/passenger loads.

That's not a bug or a problem. You can't fly it properly.

To add to the other comments: When you fly the B747 (as with other a/c of course), always be conscious of decreasing speed and engine thrust limits as you climb. In other words, as altitude increases, you will need to increase your speed (watching that you don't go into the red at N2). If you're nudging the red (ie. 90% thrust at N2), then you need to decrease your rate of climb to maintain a safe balance. If you are flying at max. take-off weight, then you will probably have requested a FL320 ceiling. Stay with that until you see that you can get a further clearance from ATC to increase the altitude. One way that I monitor this, is by watching the fuel weight remaining and also the angle of attack (AOA). Knowing the B747 generally has a higher AOA than other heavy airliners, I usually fly at the specified altitude, until my AOA drops to between 4.0 and 4.3 degrees. At this point, I will request an altitude increase of approx. 2000 ft. So even with an increased AOA and a speed at .84 Mach IAS, the cruise at a higher altitude ensures that the a/c is flying at the altitude and fuel economy expected from it. In case you're wondering about the rather high AOA when cruising, I have actually tested this when on a flight between YPPH and EGLL (via VTBD) in a B747-400. It's probably common amongst us simmers, to observe, analyse, and even offer opinions, when flying as a passenger in a real a/c. Amongst the many aspects of the flight that I analyse, one is the aircraft's attitude. I tend to walk up and down the aisles frequently (some believing I'm over-zealous about keeping the blood flow going, or even the result of a weak bladder), but in fact testing the amount of AOA with the a/c. When I walk down to the tail section, I notice that it is definitely easier than walking from there to my seat, though of course, I could never tell the amount in degrees. I wish they would put out this information also along with the other bits on the screen. And this is observed whilst the a/c has reached its cruise altitude, and not in climb profile. So don't be concerned about the 747 not flying level (as long as you keep it within proper limits). However, adjust your speed and AOA as altitude increases, ensuring that your cruise speed remains between .82 to .85 Mach IAS. Chris David

Ok just one question...What is AOA?

AOA = Angle of Attack. Cheers, - jahman.

Can someone please explain clearly - in plain English - what to do to get to a reasonable altitude. I can't cruise at FL270.

That's not a bug or a problem. You can't fly it properly.

Not a very helpful comment!

Can someone please explain clearly - in plain English - what to do to get to a reasonable altitude. I can't cruise at FL270.

Can't really make it any plainer than I have done already, but I'll condense it for you; your plane is too heavy - probably with too much fuel and payload - and you are possibly climbing too steeply. Reduce the payload and climb at a slower rate. There is no escaping the fact that flying an airliner requires you to study and understand some stuff, even in a flight sim. If that wasn't the case, anyone could train to be an airline Captain in a week and there would be no skill or prestige to the job at all. Al

Some usefull information... http://www.deltava.org/library/B747 DVA Manual.pdf You will find a table of the Optimum and Maximum FLs towards the end.

Can someone please explain clearly - in plain English - what to do to get to a reasonable altitude. I can't cruise at FL270.

Have you done any of the lessons that come with the software? I think you need to do some serious study. I know you are young, but you should learn the lessons - hey we all started out somehow and you will get some smart remarks, but take it one step at a time.