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CHIINHK

PMDG747 LNAV

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Hello follow simmers.How are you?It's my first time post my questions.If i do make any mistake pls excuse me.About 2 months ago I brought a pmdg747 and I love it.However I do have some questions regrading the LNAV.This is something I had encounter.When I input all the information to FMC,I can activate VNAV and the light is stay on and activate even before the plane takeoff,however sometime I am not able to activate LNAV for some reason.For example,I am able to activate the LNAV in some routes,like the other night I flew from Tokyo to Sapporo,after the plane tookoff.ATC instruct me turn right to 060 degree,after a while ATC told me turn left to 030 degree resume own navgation,then i click on LNAV to activate it,sometime it take me few times to activate it.Like tonight I try fly from New York to Van Couver,after I tookoff the atc told me head to 135 degree,after that the atc told me resume own navgation,but this time I am not able to activate the LNAV.I need to mention I didn;t input information on dep/arr page,is it the reason why the LNAV won't activate?If so then I do not understand why when I flew from tokyo to sapporo I didn;t input the info on dep/arr page but I was able to activate the LNAV?Pls let me know when i did wrong and or sometime I miss?Thank's,the other question is how can I activate LNAV before the plane takeoff?Because I was able to activate the VNAV.Thank you.

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Welcome to the forums! Please sign your name to your posts though, its a rule here.For your fist question, can you post a full biography of one of your flights to demonstrate this. Post everything you did, the problem is often caused from forgetting to turn something on.To your second question, VNAV and LNAV should not be active for takeoff. The only autopilot functions that are allowed to be on during takeoff is TO/GA (plus auto-throttle and the Flight-director but they aren't really "autopilot" functions).

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Perhaps he means he has armed VNAV & VNAV prior to takeoff . LNAV wont activate unless you're on the correct intercept heading. You can select the fix you want to fly to and then select direct to in the Route FMC page, or in the Legs page re-select the fix you are flying to and then select LNAV

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LNAV wont activate unless you're on the correct intercept heading.
Not true.You can activate LNAV within 10nm of the first waypoint in any direction.You don't have to be heading towards it at all.

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Not true.You can activate LNAV within 10nm of the first waypoint in any direction.You don't have to be heading towards it at all.
I'd like to see that :) You could arm LNAV, but whether it becomes active on the FMA's is a different story. Pasted below is straight from F.C.O.M of Qantas.• LNAV activates when the aircraft is 50 feet above runway elevation and:• within 2.5 NM of the active leg• when not within 2.5 NM of the active leg but on an intercept headingto the active leg, remains armed then activates when approaching theactive leg• when active, displays LNAV in green on PFD roll flight modeannunciator• selection of LNAV with the aircraft not on a heading to intercept the activeleg, displays NOT ON INTERCEPT HEADING in the CDU scratch pad• LNAV maintains current heading when:• passing the last active route waypoint• passing the last waypoint prior to a route discontinuity• passing the last route offset waypoint• activating the inactive route or activating an airway intercept and notwithin LNAV engagement criteria

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When I said activate I meant arm, a.k.a pushing the button in.I think we're getting terms mixed up.

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.I need to mention I didn;t input information on dep/arr page,is it the reason why the LNAV won't activate?If so then I do not understand why when I flew from tokyo to sapporo I didn;t input the info on dep/arr page but I was able to activate the LNAV?Pls let me know when i did wrong and or sometime I miss?Thank's,the other question is how can I activate LNAV before the plane takeoff?Because I was able to activate the VNAV.Thank you.
i have that too sometimes and it is usually solved by entering a take off runway and an anticipated arrival runway via the DEP/ARR page. Also make sure route discontinueties are taken care off. and sometimes pressing the LSK1L button on the 1st LEGS page to copy the first waypoint and then clickin it again to double confirm it wil enable LNAV again.

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Also make sure route discontinueties are taken care off. and sometimes pressing the LSK1L button on the 1st LEGS page to copy the first waypoint and then clickin it again to double confirm it wil enable LNAV again.
I was about to mention that nobody had mentioned something along these lines until I saw you post it. I'd say the issue is a combination of both - the intercept heading and having the correct waypoint listed at the top of the legs page.

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When I said activate I meant arm, a.k.a pushing the button in.I think we're getting terms mixed up.
Not we :( As I try to fly the PMDG 744 as "Real as it gets." I try and use the correct terminolgy. As I've said in previous posts, learn your FMA's (Flight Mode Anunciations). They were pressed home to me in the Full Motion Sim. These are what you see above the PFD. You will then know what status your Thrust, Roll and Pitch are in. Always call the modes out aloud as they change or become active. For example, as the PF just getting airbourne (If everythings set), you will call "LNAV." Then a short time later you will call, THRUST REF, VNAV SPEED."Hope this all helps.Buzz.

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Hello follow simmers.How are you?It's my first time post my questions.If i do make any mistake pls excuse me.About 2 months ago I brought a pmdg747 and I love it.However I do have some questions regrading the LNAV.This is something I had encounter.When I input all the information to FMC,I can activate VNAV and the light is stay on and activate even before the plane takeoff,however sometime I am not able to activate LNAV for some reason.For example,I am able to activate the LNAV in some routes,like the other night I flew from Tokyo to Sapporo,after the plane tookoff.ATC instruct me turn right to 060 degree,after a while ATC told me turn left to 030 degree resume own navgation,then i click on LNAV to activate it,sometime it take me few times to activate it.Like tonight I try fly from New York to Van Couver,after I tookoff the atc told me head to 135 degree,after that the atc told me resume own navgation,but this time I am not able to activate the LNAV.I need to mention I didn;t input information on dep/arr page,is it the reason why the LNAV won't activate?If so then I do not understand why when I flew from tokyo to sapporo I didn;t input the info on dep/arr page but I was able to activate the LNAV?Pls let me know when i did wrong and or sometime I miss?Thank's,the other question is how can I activate LNAV before the plane takeoff?Because I was able to activate the VNAV.Thank you.
Hi, it can also happen when you forget to click Activate and Exec button to confirm loaded route.

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