Need help: Most fuel-efficient operation of the 744.

[Guest ColdBear]

Hi there,First of all I suggest you to read this http://www.wingfiles.com/files/performance...performance.pdfSecend I did the YSSY-EGLL in the 777-200LR( or -300LR) with full fuel and a typical load. Try to get a hand of some SigWX charts and plan your route on that. I see already that there are serveral jetwinds that would help you, if you laid your route that way. also there are many cyclones in the vicinity of Japan and China. you might also, if you want to get as real as posible check NOTAM/SNOWTAM and plan your route wery carefully. Here at 00UTC, as I see it, you sould fly down thrue europe and then in the northern Kasakhstan then further east to china and mongolia then finally head south thru Vietnam and Malaysia and finally towards Australia.Regards,Martin

[Chaos81 110]

>but ATC practically never allows you to do things like that.I'm well aware of they. The only time BA does it is over the ocean.I mentioned it here because I didn't figure Mark cared much about over land procedures and just wanted to make it to Sydney.

[Tabs 2,790]

The absolute most efficient step-climb profile possible would actually be a quick climb to the initial OPT altitude and then a constant slow climb over the course of the flight as the OPT moves upward in real time.Maybe they'll allow this someday if ATC technology ever catches up to the planes themselves...

[Guest D17S]

Ya know, that would be an interesting experiment. This might be just a case where an actual flight might provide some additional information. First, fully preload the FMC with the enroute winds. Then note the FMC's fuel prediction, waypoint by waypoint. Then do the entire crz phase in a quaisy V/S mode. . . at a --- say --- 10 FPM /ROC (Yes, there's way). You'd have to do a little arithimetic to get that number, i.e., feet (climb) from initial cruise alt to final cruise alt / time from initial cruise to final cruise. The experiment would show how much better the fuel economy would be if a "Constant Climb" cruise profile was followed. Once you got the cruise climb setup, the FMC would immediately tell you the story. If 'fuel remaining' started tracking above the pre-noted FMC predictions, the constant climb was working. But once again, this must be flown in a tightly controlled MSFS enviroment. The wind numbers that the airplane was encountering (in real time) must have been pre-loaded into the FMC in preflight. I have relitive confidence that model is close enough to actually tell this real life story. Hummm.

[markadeane 272]

Sam, how would one do a 10 FPM rate of climb? Multiples of 100 are all I see. Would it be a case of engaging FLC for a certain speed and setting thrust JUST so the rate of climb was 10 FPM?As for the environment, I'm cheating a little here and setting the winds aloft to a constant tailwind (or tailish anyway), not too high, maybe 20-25 knots.

[Guest D17S]

Establish cruise. Use any speed on pitch mode (i.e., VNAV SPD or FLCH) that will get thrust into Hold (or disco the AT). Set your altitude to the final step climb and then use thrust to adjust rate. It's the same principle as the AFS's variable rate FLCH mode. Whatever you decide for winds, just set these winds, -- waypoint by waypoint -- into the FMC during preflight. The FMC will tell you if you have enough fuel right there. It's sure more fun to actually fly this, but sadly, the FMC is telling you the result (that is short of some glitch in the PC's computer programs). These modern, real-life aircraft computer systems (like the one we 'play' with here) have pretty much resolved the adventure factor . . . but it needs to be resolved when you have 400 folks suspended over the icy North Atlantic at FL 390. However, the flight could show if a "Constant Climb" cruise profile saves gas. That's worth an actual test flight.

[Guest snyperAL]

I tried this exact same flight, without any thought or planning, just an empty 744 / 747 (why 744?) full of fuel at an ozzie airport and a rough bearing..(i cant even remember if it was the 400f or not lol...Anyway i landed in some country i cannot pronounce, once my wheels hit the deck i lost both outer engines, through lack of fuel. upon taxiiing i can only say i took a short cut and went through a puddle, this was deceptively deep and i err crashed!still some lessons are hard learnt, and i now sit gawping at my freshly printed chapter 2 Cruise and FUEL PLANNING. As far as light reading goes its not exactly tom clancy, still, it sure is interestingThis line intentionally blankAlan