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Guest abrahamchan

744 VNAV Problem

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Dear all,Recently I discoverd my PMDG744 have several Autopilot VNAV problems. Please help.1. After takeoff and engaging the A/P at 1000ft, LNAV VNAV switch on, the vertical mode is VNAV SPD instead of the usual VNAV PTH mode. (I had FD, A/T, LNAV, VNAV armed before takeoff)2. Even though setting Speed trans 240/10000 in VNAV descend page,the plane was still at 260-270kts by 10000ft. Strangely, A/T mode kept on 'HOLD'. I was forced to use speedbrakes to slow down,,,3. After installing PMDG744F, i discovered the main ECIAS display was modified on the 744 Pax version. The place for the engine N1 was replaced by EPR display, and the N1 got smaller, just under the EPR display. (which is like the one in Cargo version)Thank you for helping me.Yours sincerely, Abraham Chan

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Can't help you with the first two, as I've never seen that before. On the third one, that's because you choose a plane that uses EPR as it's main engine indicator. In otherwords, it's supposed to do that. Choose the GE engines instead of the P&W or RR.

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1. While you climb with VNAV VNAV SPD is the correct A/P pitch mode. The aircraft will give you full thrust and keeps the calculated speed with climbing to a higher altitude. When you reach TOC pitch mode will automatically switch to VNAV PTH as it follows the given altitude profile of the FMC. This is not a bug, this is a feature :-) @lex

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Perfectly right !Have a look at track lesson 4 about VNAV modes...

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