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Guest joerg_744

Thrust lim FMC page

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Guest joerg_744

Hello,I'm not able to change the thrust limit setting when using FL/CH after take off. The FMC thrust lim page doesn't change to the inflight menu after liftoff.So there is no way to change the thrust limit for the rest of the flight.It only works when VNAV is armed before takeoff.Is this a known problem, or is it appearing here only?Kind regards,Joerg Wilms /EDDF

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Guest lbb

SORRY, A NERVOUS INDEX FINGER CAUSED THE SECOND MESSAGEHi JoergI get the same, although I'm pre 1.1 so don't know if that has changed anything.In my Boeing AOM it says that in flight the take-off derates are replaced by the other thrust limits, but on lift-off in the sim there are no changes to the page.With VNAV engaged the page changes the moment CLB kicks in. In view of the words in the AOM I wonder if that is correct. Perhaps in both cases the page should change directly when airborne.BTW, a work around for your case is to select THR on the MCP. You'll get CLB as limit and the page you want.Leo Bakker

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Guest lbb

Hi JoergI get the same, although I'm pre 1.1 so don't know if that has changed anything.In my Boeing AOM it says that in flight the take-off derates are replaced by the other thrust limits, but on lift-off in the sim there are no changes to the page.With VNAV engaged the page changes the moment CLB kicks in. In view of the words in the AOM I wonder if that is correct. Perhaps in both cases the page should change directly when airborne.BTW, a work around for your case is to select THR on the MCP. You'll get CLB as limit and the page you want.Leo Bakker

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Guest joerg_744

That is the FMC page, that I'm missing. I don't get this page when taking off without VNAV selected.Did you take off with VNAV armed?

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Guest Just747-400

We always t.o. with VNAV engaged. That

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Guest lbb

To say that you have to use VNAV in order to get the thrust limit page to work sounds rather odd to me. Yes, I know, SOP is to use VNAV but IMHO that's because it reduces workload, not to get the FMC to work properly. And besides, in the RW AOM it doesn't mention anything about the need for VNAV to be used.I think Joerg's observation is valid and in the real 744 it works differently.Leo Bakker

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Guest D17S

True story. Vnav is not necessary for the initial climb sequence at all. (Actually B-29s didn't have Vnav at all. It's a rather modern automation!) If you want to do it with the autopilot 'manually', set the MCP airspeed window to V2, engage the autothrottle and TO normally. Pitch will be in TOGA. Hand fly to V2. Once you're stable at V2, engage the AP and press FLCH. The AP will fly a speed on pitch climb to the MCP's airspeed window setting. If you want to climb at V2+10, dial it in. Thrust will stay at TO power. When you are ready to begin accelerating away from V2 (+10), just dial a faster airspeed into the MCP airspeed window. You will now be manually handling the FMC's automated "acceleration altitude" function from the FMC's TO page Lsk 1L. Now, as you bring the flaps up, just increase the airspeed with the MCP speed window. You are in control.When you are ready for climb power, press the THR button on the MCP Here, you are manually handling the FMC's automated "Thr Reduction" function from the TO page Lsk L3. Next, altitude will capture at the MCP's altitude window setting with ALT pitch mode. Again, this is the 'manual', non-Vnav method. Vnav would be capturing altitude in VNAV ALT or VNAV PATH. Airspeed will still be controlled with the MCP airspeed window and thrust will begin to jockey around to maintain airspeed in (now)level flight. But what happens to thrust limit when altitude captured. How about the AT mode in the right PDF window? Does thrust limit bump down to cruise or stay in climb? Why did it or why didn't it? Someone let us know?

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