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High pitch

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Hello!Searched the forum for this subject but didn't find anything, so I decided to start a new thread.A few minutes after takeoff last night, I engaged the autopilot and the plane suddenly pitched up (very rapidly) to about 20 degrees. I couldn't control the pitch until I engaged VNAV which solved the problem.I had set up all LNAV and VNAV information correctly, armed the A/T and engaged FD before takeoff, my MCP SPD was set to V2 + 7 and I used 22k derated takeoff thrust.I don't see a reason why this happened since I only engaged the A/T, not any pitch mode.Regards,

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Can anyone at least tell me if this is a known issue or if this has been discussed before? Or am I alone with this problem?

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Guest Ian_Riddell

Not sure what you mean, Antti.... In one sentence you say you engaged the A/P, but in another, you say you only engaged the A/T.Can you clarify, please?Thanks.Cheers.Ian.

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Oops sorry :) It is supposed to read A/P, A/T was armed before takeoff.

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>Hello!>>Searched the forum for this subject but didn't find anything,>so I decided to start a new thread.>>A few minutes after takeoff last night, I engaged the>autopilot and the plane suddenly pitched up (very rapidly) to>about 20 degrees. I couldn't control the pitch until I engaged>VNAV which solved the problem.>>I had set up all LNAV and VNAV information correctly, armed>the A/T and engaged FD before takeoff, my MCP SPD was set to>V2 + 7 and I used 22k derated takeoff thrust.>>I don't see a reason why this happened since I only engaged>the A/T, not any pitch mode.>>>Regards, You did not engage any pitch mode? What do you CMD in TO mode? Please set V2 in the IAS/MACH window not v2 + 7, it is ALWAYS V2. The F/D will command V2 + 20. On the coming patch you can now move the IAS /MACH selector one click and the MCP window speed will go V2 + 20 along with the Magenta SPD BUG. When you select a CMD in TO mode the AP will go default LVL CH just like the real deal. Make SURE you are not too SLOW or the plane will PITCH very high upon LVL CH engagement, so speed up and retract your flaps BEFORE engagement of the AP. As a side note, 20 degrees is not uncommon (under manual flight on TO), look at Southwest, I see some extreme looking take offs all the time here at KSJC ;) Now that being said please wait a bit for the patch, it has many refinements in this area. [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

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Thanks Randy,No, I did not engage VNAV or any other pitch mode, because I was still under the VNAV engagement alt. However, when I engaged VNAV the problem went away, so I think it was the LVL CHG that caused it.Actually I had just retracted the flaps but my speed was just a little over 200kts. Maybe that was the problem then but it still was an agressive pitch-up.Btw, wouldn't it be better if no pitch mode would engage until the pilot selects it from the MCP? I wonder why Boeing ended up doing it this way, though I'm sure they had their reasons.

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Yes the A/P is VERY agressive even on the REAL bird, one of the NG pilot testers confirms this as does NG pilots on PPRUNE forums on this very subject. It's now a bit modified from what you have in SU1 (A/P engagement). Following correct and proper NG flying techniques will help you to know what to expect. Hopefully the manual will be out soon to answer many questions on this complex add-on ;) [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

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