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Guest georg

VNAV ALT

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So, what it is, the Styles menu option? You can select wether its of or on, but I cant see what it really does.BTW, I saw in a video that in reality they can push on the ALT knob to start descend on VNAV for example. Something regarding to this maybe?

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VNAV ALT is a temporary level of mode like ALT HOLD but cooler! Try this, in a climb (works in descents too but for this example a climb) set the MCP to an altitude something other than the FMC crz altitude. So my crz alt is 390 and I set the MCP to 15000, the aircraft levels off and STAYS IN VNAV. To resume your climb simply reset the MCP to your crz altitude (OR any other altitude above your current altitude like if you need to revise you crz alt to lower etc) and push the ALT INTV button! Do NOT try to lower your crz altitude with ALT INTV, this will cause a DES NOW situation just like the real deal. If you want to LOWER your criuse altitude simply reset the MCP altitude window with the criuse page up and showing and line select the altitude into the crz line and hit EXECU![h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

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Thank you!! Will try it out. So, to get the ALT INTV function to work, the VNAV ALT must be turned on from Styles?Where is it located in the manual? I looked yesterday quickly over all manuals, but didnt find there. Thats why I asked here.

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Hi, try look in the PMDG introduction manual, page 16-17.

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You don't need VNAV ALT option to use ALT INTV. VNAV ALT uses ALT INTV to resume climb/descent, but ALT INTV is something on its own.anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

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Do NOT try to lower your crz altitude with ALT INTV,>this will cause a DES NOW situation just like the real deal.>If you want to LOWER your criuse altitude simply reset the MCP>altitude window with the criuse page up and showing and line>select the altitude into the crz line and hit EXECU!This seems to disagree with the provided manual, which says:When pushed during cruise, the ALT window value will be transferred to the FMC flightplan and the new altitude becomes the cruise altitude. If in VNAV ALT or VNAV PTH modes, VNAV will automatically initiate the required climb or descent. (page 9-14).Sounds to me as though:cruising along at FL350dialing FL310 into the MCP altitude windowPressing ALT INTVShould reset the FMC cruise altitude to 310 and begin the descent from 350.Randy, the manual says (on the same page) that selecting a lower altitude in the MCP and pressing the ALT SEL knob when you're cruising within 50 nm of your top of descent point will initiate DES NOW. Hopefully you're confused between ALT INTV and pressing the ALT SEL knob.Anthony, can you confirm?

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Hmm okay.. but finally.. which one is realistic? VNAV ALT enabled or disabled?

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Well, the manual seems to have a bug :-)Randy is correct. ALT INTV with *lower* alt during cruize will initiate a DES NOW.anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

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>Well, the manual seems to have a bug :-)>>Randy is correct. ALT INTV with *lower* alt during cruize will>initiate a DES NOW.>>anthony>Thanks, Anthony. My apologies for doubting Randy, and go flog your manual writers and peer reviewers!

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So my crz alt is 390 and I set the MCP to 15000, the aircraft levels off and STAYS IN VNAV. Negative! If you set the MCP to a lower ALT than the cruise ALT in the FMC the autopilot does not stay in VNAV but switches to ALT HLD.What you described above is exactly how it works on the 747-400 so I expected to have this now modeled on the 737-800 also. :-)So how do I know which airline style supports VNAV ALT? ___________________________Best Regards,Bodo M

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Ah just found this looking for something else, Bodo I have a question for you, What do you think VNAV ALT means? VNAV ALT IS the pitch mode for aircraft equipped with VNAV ALT in this situation, ALT HOLD does not apply in this case. FMA says FMC SPD/VNAV ALT and the 744 is not always like the NG.[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

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