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Guest Sartori23

VNAV question possible problem

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Shouldn't the VNAV speed change over from IAS to Mach automatically?If it is supposed to, it hasn't on the past couple of flights. I've had to exit VNAV, set the MCP to Mach, then return to VNAV mode. Carl Moore

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Well I was at FL350, so that isn't it. :)Carl Moore

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well, i got a new VNAV problem. If i set a cruiz altitude off 33000ft and set 9000 feet on the MCP window. Then i activate VNAV before 9000ft, VNAV levels off with MCP SPD and ALT HOLD, when it should level off with FMC SPD and ALT HOLD. However, if i then set 33000ft in the MCP window and push VNAV again, the FMC shows the message "CHECK MCP ALTITUDE" and VNAV will not engage.I have checked with my 737NG Computer Based Training and it says that the aircraft should level off with FMC SPD and ALT HOLD at 9000ft, in this instance. I never seem to get a problemfree VNAV function.Can anyone help me?Roar Nicolaisen

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Yup, running SU1-1.Carl MooreI've attached the flightplan incase anyone want to try to replicate the problem.

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Yes the FMA should be FMC SPD/ALT HOLD if you level off at any altitude other than your set CRZ ALT. I don't know about your problem trying to reengage after this level off, I will check. For now you can do a couple of things which do almost the same thing. Set the constraint on a waypoint and leave the MCP to the CRZ ALT, the FMA will show FMC SPD and vanv with stay engaged. Or, the aircraft will go MCP SDP ALT HOLD and once you want to resume, reengage VANV but you seem to have a issue on this one. I suggest that you go LVL CHG, start climbing and MAKE SURE you are at the target climb speed before engaging VANV. As for the correct mode, it's coming and is known, we *might* see VNAV spd intervention also ;) [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-8/196432/winglets_lg.jpg [h3] AMD XP 2200 |MUNCHKIN 512 DDR RAM |ECS[/b ][i] K7S5A MB[/i] |GF2 MX 32 MEG and still runs GOOD!|WIN XP PRO |MITSUBISHI DIAMOND PLUS 91 19"[/h3]

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Nice, VNAV speed intervention=) any plans for ALT intervention to? Thanks, i will try your tips with VNAV.

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