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ButtahNBred

250/10000 Restriction not adhered

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Greetings everyone!

 

The 747-400 is much more complicated than the in-game default 747 that microsoft provides. I am able to control those birds and have them obey the speed restriction while they are under 10000 ft. The PMDG, however, immediately begins accelerating to cruise speed. Both LNAV and VNAV are illuminated and TO/GA is activated shortly after taking flight. In the FMC, I have my speed/trans set at 250/10000 and my speed/rest left blank. Should I input something into speed/rest or does that limit something else?

 

Thanks for any help!

 

--ButtahNBred


Dmytri Eck

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Page 12-43 of the PMDG Operating Manual says: “The transition speed/altitude defaults to 250/10000, but will change to reflect a higher performance limit speed of the aircraft if aircraft speed performance is a factor due to high gross weights.” Could this be your situation?


Dugald Walker

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TO/GA should be activated at the beginning of the takeoff roll. Not after takeoff unless the autothrottle is U/S. Take it easy on the engines.

 

The 744 is heavier than really any aircraft out there (not sure about the A380). So if you're heavy you're going to require a higher speed to climb below 10,000. If the FMC page says "276/.07" (meaning the min. climb speed is 276 knots or Mach .07) on the VNAV Climb page, it will climb to that speed and maintain that speed until 10,000. Then it will accelerate to the enroute climb speed up to cruise.

 

You can set a restriction on the VNAV Climb page of 250/10000. Just make sure that the aircraft has enough speed to stay airborne.


Kenny Lee
"Keep climbing"
pmdg_trijet.jpg

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I mainly do long haul cargo flights when using the 747 which means I am pretty heavy at t/o so the climb speed below 10000ft will never be slower than 260kias .

I would be risking to stall if forcing the plane to climb at a slower speed...


Thibault Dosunmu
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The >250 KIAS speeds are routine for the heavies. KIAH has a 280 KIAS notam, if you like trivia, which I think is related to this issue.


Dan Downs KCRP

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Page 12-43 of the PMDG Operating Manual says: “The transition speed/altitude defaults to 250/10000, but will change to reflect a higher performance limit speed of the aircraft if aircraft speed performance is a factor due to high gross weights.” Could this be your situation?

 

I don't believe that is my situation as I did not have any payload. I made sure that I kept the aircraft completely empty to ensure similar flight conditions for each test flight. Maybe I need to use the Speed restriction but how would I type in 250kts below 10000 ft into the FMC?

 

I mainly do long haul cargo flights when using the 747 which means I am pretty heavy at t/o so the climb speed below 10000ft will never be slower than 260kias .

 

How can you have a climb speed greater than 250 when there is a strict restriction below 10,000ft? Could you explain how this would occur in a real situation?

 

Not after takeoff unless the autothrottle is U/S

 

What do you mean by U/S?


Dmytri Eck

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ATC can give you approval to fly faster than 250kias.

 

Cant you just set Level change mode with 250 kias speed like in 737?


[color=#a9a9a9][size=1][size=4][img]http://forum.avsim.net/public/style_images/flags/rs.png[/img][/size] Lj. Prodanovic[/size][/color]

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how would I type in 250kts below 10000 ft into the FMC

 

Just type 250/10000 in the SPD REST line on the VNAV Climb page.

 

How can you have a climb speed greater than 250 when there is a strict restriction below 10,000ft? Could you explain how this would occur in a real situation?

 

The 250 below 10,000 feet is not a strict restriction. If you can stall at 250 knots you'd be in deep crap. If you're flying from LAX to Sydney, you could be near 870,000 pounds. You'd stall the aircraft.

 

What do you mean by U/S?

 

Unserviceable. Usually if a system is not working or maintenance requires it, the system will be in the logbook and the circuit breaker would be out collared so the crew knows.

 

ATC can give you approval to fly faster than 250kias.

 

Cant you just set Level change mode with 250 kias speed like in 737?

 

Regulations have changed that you don't need to inform ATC of a higher speed if needed on a heavy aircraft. However, it is prudent that you inform ATC accordingly.

 

The FL CH mode is an option that the OP can use.


Kenny Lee
"Keep climbing"
pmdg_trijet.jpg

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This has always been an issue with some simmers, fly the aircraft at it's clean speed. When flying an aircraft the size of a 747 your clean speed will likely be higher then 250kts at typical gross weights.


Rob Prest

 

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This has always been an issue with some simmers [...]

 

Yep. Aviation is a huge formula that never, ever wavers. Clearly.


Kyle Rodgers

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