A.floor and Crazy autopilot After takeoff

I bought the A320/21 prolouge. During the fmgs programming I noticed a yellow message in the scratch pad coming up a few times wich says:unable flight level. I tried fl150 and it didn’t work. After the liftoff a.floor engages and the plane pulls up hardly. Then it goes into a fall and then it climbs again and it goes like this all the time. I noticed that in the ecam the landing mode was already active, but I had my flaps and gear up and the fmgs was still in climb.

Thank you !


  • Hi Rainer,

    It would be really useful to know what your flight plan was.
    The unable flight level message appears when the MCDU calculates the Top of Climb would be after Top of Descent, therefore you wouldn't actually make it to your cruise altitude.
  • My flight plan was: Lgsm-lark1c- larki-dct-varix-vari2c- Lgav

    I just wanted to make a quick test flight
  • In the pre flight manager there was about 80miles cruise on fl280. And the plane didn't take fl150
  • Thanks Rainer.
    There are a lot of variables here too, such as aircraft weight and weather. Did you change the weight of the aircraft at all?
  • I changed the weight of the aircraft at the beginning so that the tow of the aircraft was about the half.
  • I think the plane didn't find the cruise or the vertical mode. But I really have no idea
  • So, after take off you should reduce thrust to Climb (CLB) and engage autopilot. Click the altitude select knob so that Op Clb appears above the vertical horizon. This is optimum climb, where the autopilot works out the best climb vs. speed and controls the climb up to the selected altitude. If there are altitude constraints on your departure, it will take this into account too.
  • You have a lot of fuel onboard for a landing. Do you fill out the INIT pages? This gives the aircraft vital information for it to calculate V Speeds and manage the different stages of flight.
  • Yes, I filled out all necessary pages for takeoff and cruise. All pictures are taken + or - 2 minutes from takeoff. I have tried it many times but always the same problem. After the lift off the airplane plays roller coaster, and in a.floor I don't have any controls. I also can't get out of a.floor mode
  • And the plane didn't calculate v speeds automatically, you say in your post the computer calculates it. I'm sorry for my English, I am from Germany.
  • I will test this later to try and understand what is happening.
    The aircraft can calculate the V Speeds, right click on the buttons next to each V Speed section and it will fill in the correct speed automatically.
  • Ohh, I didn't right click it. But it didn't solve the problem with a.floor and the strange maneuvers
  • Alpha Floor (A.Floor) is the low speed protection system, so for it to engage the airspeed must be dangerously low. A.Floor is an Auto Throttle mode only, and when activated provides TOGA-equivalent thrust to the engines. A.Floor can be activated by the aircraft even when Auto Throttle is disengaged.

    That said, in your screenshots provided, I noticed you don't have Autopilot or Auto Throttle engaged - you should be using both systems to maximise your efficiency in terms of fuel, speed and climb, as well as reducing your workload as a pilot.

    I have just completed a test flight using your flight plan above, between LGSM and LGAV with no issues.
  • I can't engage the autopilot because the airplane was not stable enough. And I deactivated auto throttle to get out of a.floor. I try to reinstall the product later, maybe there was an issue in the installation.
    Thank you for your support, I will write you back if I try the reinstall.
  • I trie to make a video to show it better to you.
  • When you reinstall the product, make sure you run it as an Administrator and restart your computer afterwards.
  • After a reinstall everything runs smoothly. Thanks for your quick support!
  • No problems Rainer, I'm glad it is working :)
  • having the same problem
  • Have you tried the above suggestions Callum?
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