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VNAV cannot be engaged after takeoff

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Hi All, I tried the great manual of Fred from Denver to LAX and the takeoff and crusie were all ok except I had great difficulty with the autoland. Whenever, I try to set a flap or put the gear down. Plane started to climb and accelerate thus rendering autolanding impssible. It took 3 go arounds to land. I experienced this both in my first tutorial flight KDEN-KLAX and afterwards.Another anomaly is that when my PFD shows the FL330 and MCP is fixed on 33000, flightsim flight level was reading 33540, despite I had standard QNH 29.92. Why I am flying that much higher?Tonight I tried to make a local flight. When I take off and try to engage VNAW, the FMC light on main paanel is illuminated and in FMC I see VNAV DISCONENCTED - UNABLE CRZ ALT message Different flight plans, (depts arrs) and SID STARS resulted in same too and I had to make my flight without VNAV. Again autoland problems, I sit on the localiser perfectly and reduce spped to 180 KIAS, after GS establish I put the speed to VREF APP SPEED and try to lower the flaps and when lower the flaps or lower the gear and in a sudden the plane leaves the glideslope and strat climbing and accelerating. Any insight will be appreciated. Best regards Musashi

>Hi All,Hi Musashi,>Another anomaly is that when my PFD shows the FL330 and MCP is>fixed on 33000, flightsim flight level was reading 33540,>despite I had standard QNH 29.92. Why I am flying that much>higher?That is perfectly normal. FS assumes your altitude from the local QNH. If that differs from standard 29.92 the altitude reported by FS will also differ.>When I take off and try to engage VNAW, the FMC light on main>paanel is illuminated and in FMC I see VNAV DISCONENCTED ->UNABLE CRZ ALT message>Different flight plans, (depts arrs) and SID STARS resulted in>same too and I had to make my flight without VNAV.This could possibly be caused by alt constraints in the flight plan or something else that the FMS doesn't like. Please attach a flight plan that you have problems with and I'm sure someone can tell you what the problem is. There is a known problem with altitude constraints attached to saved flight plans. The work around for this is to delete your altitude constraints and re-enable them. The guys at PMDG is working on a patch for this latter problem.>Again autoland problems, I sit on the localiser perfectly and>reduce spped to 180 KIAS, after GS establish I put the speed>to VREF APP SPEED and try to lower the flaps and when lower>the flaps or lower the gear and in a sudden the plane leaves>the glideslope and strat climbing and acceleratingDo you have VOR/LOC and G/S modes indicated on top of your PFD? This sounds really strange. Maybe a screenshot? Anyone else having ideas?Hope it helps,

Mats Johansson
PMDG Flight Test Dept
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Hi,Thanks for your help,Ok if FS reads the altimeter from local QNH, I would believe that the rocky mountains around KDEN would give abour 600 feets of difference in my altimeter.Yes I tried the SID's and STAR's sent by fred and there was a 1800 ft restraint at my first navaid after leaving the rwy.I will clear it and retry. May be thats why no flights starting from LTBA did work.Yes VOR/LOC and GS are properly visible on PFDI align the localiser and catch the GS so APP light on MCP goes off. bbut when I lover flap or gear the VO/LOCK button abvoe APP button on MCP is lites on and plane starts cimbing and accelerating.I managed rather weird landings, becasue I press the app key again and it cathces the GS again and same story again.I will prepare the screenshots when I get home tonight and send to youCheersMusashi

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