Jump to content

Sign in to follow this  

Autoflight misbehaviour

Recommended Posts

Fellows,Since the installation of the -400F and the latest patch, I have been experiencing a change of behaviour from the autopilot mode. I have to say I am using FSUIPC ver 3.53 and Activesky Ver 6 patched. This has happened twice both of them from the RR engines however(Cargolux & BA PAX. With everything going accordingly and some hours (realtime) into the flights, I hit turbulance and all of a sudden the commands will change to FLCH and starts a decend and will not take any cammands given there after. Even with full CRZ settings engage, speed is reduced with the 'stickshaker" going off all over. This with FMC program to a FLXX, but FLCH will decend the Aircraft to the lowest possible Altitude and continuing even if I set a higher ALT on the MCP, it will not honor that command. Again no inputs from the pilot is accepetd if this occurs. Is anybody else experiencing this? ThnxGus

Share this post

Link to post
Guest D17S

Turbulence? Well maybe that too, but you were back playing cards with the loadmasters, weren't you? Ahh, the adventure! During an extreme under speed situation, coach AFS (autoflight system) will kick out the VNAV PATH/SPD mode team and swap in its relief pitcher "FLCH SPD" and its power hitter "THR" to save the day. You probably noticed your airspeed was way down. I call this maneuver the "Falling Leaf." THR will take power to EICAS thrust limit. FLCH SPD will pitch down to regain some airspeed, but then once it gets some, pitch back as it attempts to trade this newly acquired zoom for altitude. Of course this pitch up just slows the airplane down again and the cycle continues . . . all the way to the dirt. The "FLCH" and "SPD" parts of the FLCH SPD pitch mode are fighting each other. The FLCH part wants to reacquire your MCP altitude and the SPD part wants to accelerate. Speed has the highest priority, so the initial maneuver is to pitch down. Once FLCH SPD thinks it

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.

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