Jump to content
Sign in to follow this  
jakov

Losing speed and overspeed

Recommended Posts

I just had a weird flight with my 737-800. It was a flight from EBBR to LEBL. At FL360 the NGX suddenly started losing speed. It fell from 260 to 210, MPC showed BUFFET ALERT and the plane started descending rapidly. I disconnected the A/P and A/T and floored it. After a brief struggle I managed to get the plane leveled and the speed climbed up a bit. I engaged A/T, but when I tried to engage A/P, it wouldn't start. There were no failures present. Also, it was almost unflyable by hand, almost like the plane is caught in a microburst. My hardware setup (X52PRO) is working flawlessly. I tried to download new weather in FSX since sometimes it helps resolve these types of problems, but it didn't help. The slightest yoke move resulted in vertical speeds ranging from +4500 or -5000 and high bank angles.

I tried the same flight again. This time, however, the speed suddenly went up from 260 to 360! Of course, I got overspeed warning. Again, I paused the FSX, downloaded new weather and it this time it worked. I applied speed brakes and let the plane slow down. For some reason it didn't disintegrate in the air since it took me at least a minute to slow down. And now, while I'm writing, the plane started losing speed again, but not too much.

 

So, my questions are:

 

1. Why didn't the A/P start after my brief struggle in the first flight? I am sure that there are some limitations when A/P will not engage. What are they?

2. I am aware that using FSX weather is not the best option and I know that losing speed and overspeed are FSX related issues. But can the weather engine in FSX be tweaked somehow so it doesn't happen again? I am not using any add-ons because my computer is not quite capable of running add-ons smoothly.

 

Thanks!

 

Jakov J.

Share this post


Link to post
Share on other sites

Regarding question number one, the autopilot won't engage if the flight controls are not centered. From what you described, it appears you were having momentaneous high sensitivity of your controls, so even when centered, they must still have been moving the controls within FSX, not allowing the AP to engage.


Matheus Mafra

Share this post


Link to post
Share on other sites

Regarding question 2: No, it's impossible. You should get at least FSUIPC or AS2012 or best both of them :) Weather engines will not affect performance unless you use high quality textures that come with them. AS2012 WDC mode will smooth out all winds, but will cause other problems, like wrong runway assignments etc, Smooth Cloud Transitions with smoothing from FSUIPC is best of both worlds in my opinion. There are other weather engines out there but I don't use them, so can't say how they work etc.

Share this post


Link to post
Share on other sites

Grzegorz,

 

thanks for your reply! I'll try to work something out with FSUIPC at least. I have an unregistered version, so for a start, I'll just get it registered.

 

Cheers!

 

Jakov J.

Share this post


Link to post
Share on other sites

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.
×
×
  • Create New...