NEED HELP ASAP

Guest · Posted: Mon May 15, 2006 8:46 am Post subject: NEED HELP ASAP

Right now i am flying in the 747-400 Climbing to FL400. Autopilot is set right VS is set 1800ft per min yet my FD sored up and i staled, i recoverd by turning of AP but what went wrong??? my power was fine also.

davidmac1 · Posted: Mon May 15, 2006 8:52 am Post subject:

have you tried it again? did the same thing happen?

CrashGordon · Chief Captain Joined: Jun 20, 2005 Posts: 4709

This has been discussed many times before. As your altitude increases, you must reduce your v/s. Otherwise, the a/p tries to maintain an unsustainable rate of climb, by pitching the nose up further. Your airspeed drops and you stall.
_________________
CrashGordon
CEO, Omega-Air Virtual airlines

CRJCapt · Posted: Mon May 15, 2006 12:47 pm Post subject:

Most commercial aircraft can't climb to their maximum cruising altitude when fully loaded, they have to burn off fuel before reaching a final cruise altitude by step climbing (leveling off at a lower altitude for a short time). This is not a problem because ATC will normally level an aircraft at intermediate altitudes during a normal flight for air traffic reasons. Commercial aircraft also avoid climbing utilizing VS. Normally aircraft climb using a form of airspeed hold that allows the VS to vary as the aircraft climbs. Large jet engines, as do almost all engines, lose power as the aircraft climbs higher. Most large commercial aircraft can't maintain 1800 FPM all the way to the maximum altitude of the aircraft, they may only be climbing at a few hundred FPM when they reach maximum altitude. If they're very heavy, they won't even reach their maximum altitude.

Flight simulator (default aircraft) don't have a way to climb at a specific airspeed. As you climb, reduce your VS so that you maintain the correct airspeed in the climb. You can also just set 500 FPM, that should get you to most altitudes without problems.

Below 10,000 ft-----------------250 KIAS
10,000 ft. - FL280---------------290 to 310*
FL280- Final cruise alt.----Mach .70 to .75*
*Varies with aircraft type and load. Aircraft manufactures determine exact speeds, these are approximations.

Jets are fastest around FL280-FL 290. Above that they travel slower but burn less fuel. At high altitude, aircraft fly in reference to the speed of sound(Mach 1.0). The speed of sound varies with temperature, traveling slower in colder air. It's colder at FL400 than at FL300. An aircraft that is flying at Mach .80 would be moving thru the air faster at FL300 than FL400. Fuel burn would be higher at the lower altitude. A good efficient altitude that balances speed and fuel is about FL330-FL340. On long flights you will want to fly higher to save fuel and increase range. Winds aloft also play a part in altitude selection. Smile

edr1073 · Posted: Mon May 15, 2006 3:30 pm Post subject: Guest,as noted by the other

posts and did you set your ealism settings to a different setting? It happened to me also till I dicovered that is what happen to mine. As stated aircraft have limts to the climb rate based on load of PAX, CARGO, and FUEL consumption.
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Regards,
Ed
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(='.'=)

Guest · Posted: Tue May 16, 2006 2:19 pm Post subject:

My guess is that you are overloaded.

The default 747 - 400 can go a long ways on a little fuel. Calculate your fuel before you leave, and you will be amazed at how much weight you save by not having 300000pounds of fuel on board.

I regularly fly the long haul routes over the pacific (Denver CO to Sydney Australia) 7250 miles Approx. I only take on 250000 pounds of fuel for that flight (approximately 217000 pounds needed for the flight). I can climb to FL400 at 1800 fpm successfully the entire time. I will still have a lot of fuel left when I get there, but I want to play it safe since there is a lot of open water between Denver and Sydney.

Less weight!!!!!!

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