Jump to content

Sign in to follow this  
Guest JohnnyBoy35

Any way to extend flaps in VNAV?

Recommended Posts

Guest JohnnyBoy35

Hi there, I hope you're doing well. I'm wondering if it's possible to extend the flaps while still in VNAV mode? I notice that if I extend the flaps while still in VNAV it promptly disconects. Is there any way around this.. or should I just re-enable VNAV again once I've extended the flaps? I'd love to do the approach in to KASE RW15 which requires a final leg with a 9 degree glideslope on short final... Thank you in advance :-) And where's that juicy looking 747?!?!?!Sincerely, John P.Vancouver, CanadaLook at the final legs and crossing altitudes... http://forums.avsim.net/user_files/79880.jpg

Share this post


Link to post
Guest mpauli

Hi JohnHave you ever tried to reduce the speed in VNAV by pressing the speed intervention button (SPD INTV) on the MCP. Like that you stay in VNAV and doesn't get a VNAV disconnect due to overspeed cause I think that's your problem.In the erlier version of the sim the FMC reduced the speed automaticly each time you lowered the flaps one position. I don't know why it is not doing that anymore but I think the real one does it neither.So try the button. The VNAV sould stay active like that...Hope that helpsMartin

Share this post


Link to post

Hi,In addition to controlling your speed you should check your path. If your descend is 9 degrees it will certainly disconnect. Actually the FMC will try to meet any altitude restriction, but if the descend is to steep it will disconnect. Remember that the VNAV will disconnect if the path exceeds 6 degrees below 10000' and 7 above. VNAV is not always very keen on too many restrictions during descend, especially hard constraints as the FMC calculates from point to point. Restrictions to close to each other may lead to a disconnect as it need some time to descend.Have you tried V/S or LVL CHG on this one? If you have the -800/900 package you could also try to insert your altitude restricions as "at or above" commands according to charts for KASE. But you will always get a disconnect in VNAV on a steep des like 9 degrees. The FMC will warn with STEEP DES AFTER XXX.

Share this post


Link to post

In the Real McCoy :>> VNAV mode is terminated by selecting a different pitch mode or glideslope capture or extending the wing flaps beyond 15 degrees.Didn't check if PMDG I've done it right...

Share this post


Link to post
Guest autothrottle

Hi everybody,falconno said :>VNAV is not always very keen on too many restrictions during >descend, especially hard constraints as the FMC calculates from >point to point. Restrictions to close to each other may lead to a >disconnect as it need some time to descend.If you have hard constraints which are too hard for VNAV especially below FL100 where speed doesn't have to exceed 250 kts, which mode of descent is the most appropriate ? Because if you use V/S speed can exceed 250kts.Can you ask for a holding point if you are too high on the ddescent plan ?Thanks.

Share this post


Link to post

Hi againPersonally I prefer to use LVL CHG for altitude changes greater than 1000 ft in similar conditions, because I feel this gives me better speed management on these approaches. You can also do the same if you for some reason have to execute a steep descend. For minor altitude changes you can use V/S. At MDA you can disconnect the autopilot and try to intercept the landing profile. There may be other ways, but thats how I do it.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  
×
×
  • Create New...