Jump to content

Archived

This topic is now archived and is closed to further replies.

Guest EyeMWing

MD-11 Pitch Wobble

Recommended Posts

Guest EyeMWing

When holding altitude in any autopilot mode (well, not APPR/LAND - at least that I've observed) my MD-11 has a disturbing tendency to develop a harmonic-style nose-up/nose-down pattern. This "wobble" starts slow and becomes full-elevator-travel within a short while, and eventually actually dampens out and we return to smooth flight for a few minutes before starting up again. Characteristic of this is watching the VC's yokes jump instantaneously between forward and back positions, and the autothrottle servos (smoothly) trying to give chase. Interestingly, altitude tends to hold DEAD CONSTANT throughout all this maneuvering (even though you can see the jet pitching violently from both internal and external views), but occasionally wanders (usually upward) by a max of 300 feet (just enough for ATC to yell at me) and will hold there after the wobble settles until I command an altitude change.First thing I checked was weather - expecting turbulence. I usually run with ASX - I switched to the Fair Weather preset (with ASX off) and still had the same issue just as violently. As my machine is currently only single-core, the software developer in me wondered if each engine was being modeled as a different thread and if engines 1 and 3 weren't adjusting thrust out of sync with engine 2 as a result, causing them to alternately pitch the aircraft (there's no gauge activity to indicate that this is true) so I lit engine 2 ablaze (if I'm going to fly engine-out, I may as well practice the fire procedures, too) and continued to observe the same effect throughout level flight.Switching to hand-flight has been a reliable way to make the problem go away, so it's got to be a problem with autoflight. Any ideas?Additionally - not a request for support but instead a request for features, I often find myself wanting for a call/dismiss jetway button on the FMC shortcuts page(yes, I know, Ctrl-J does it - but still...) Also, bonus if I can set which of the two front doors it docks to. On the same note, you can summon the baggage trucks by opening the invisible door #2 (Shift-E+2)with the default FS keys, but instead of going to one of the MD-11's actual cargo doors, they'll happily go dock to the jetway door from underneath the plane.Thanks,Tony

Share this post


Link to post
Share on other sites

  • 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...