Jump to content

Sign in to follow this  
JSACKS

Naughty VNAV below 10,000 passing waypoints

Recommended Posts

As part of my flight into KSFO today, I found that VNAV didn't behave nicely on approach from down to OSI (Woddside VOR). After passing DUXBY at 240/8000, VNAV did not descend me properly toward OSI; it dawdled in this segment of the descent, so to speak, and maintained a RoD of a mere -350 fpm instead of proceeding down smartly to 200/5000. I received no alerts anywhere on the FMC, or the PFD during this period. I could not figure it out. I finally hit FLCH and descended at an excessive -2300 fpm toward OSI and got a DRAG REQUIRED annunciation that I followed faithfully, and with judicious flap management as well, all went fine. Did I do something wrong with my waypoint management or was VNAV just being naughty for the evening?Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

Share this post


Link to post

Per:Thanks for your post and link. I shall study it later today.Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

Share this post


Link to post

OK, I looked at the linked thread. VNAV has worked well for me on most occasions, especially descent (!), and I am puzzled by the latest experience flying into KSFO.This evening, I repeated my approach into KSFO via PYE, Lozit, Duxby, OSI, etc. and at every waypoint from PYE (the first one from ToD and located at 14,000'), the descent in VNAV "stalled" and I had to "re-cycle" VNAV by clicking it OFF and then ON again a couple of moments later. This caused VNAV to work normally for each successive leg between restrictions. This has never happened before. I am sure it is a bug.Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

Share this post


Link to post

P.S. I should point out that VNAV has NOT disconnected at any time during these "stalled" descent legs, nor has it said DES PATH UNACHIEVABLE. Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.


    2%
    $540.00 of $25,000.00 Donate Now
×
×
  • Create New...