dc10
Posts: 122
Joined: Sun Apr 01, 2007 11:53 pm

Alpha-trim Protection

Wed Jul 19, 2000 10:49 pm

Hi! I know the alpha-floor protection on Airbuses (is-it the same on Boeing?), but could you tell me what is the alpha-trim protection?
Thanks!
DC10
 
JETPILOT
Posts: 3094
Joined: Tue May 18, 1999 6:40 am

RE: Alpha-trim Protection

Fri Jul 21, 2000 12:20 pm

What???
 
Guest

RE: Alpha-trim Protection

Sat Jul 22, 2000 3:48 am

One of the autotrim features on the A300 is controlled by the FAC (flight augmentation computer). It's fully automatic and is active at high angles of attack and high mach numbers. It trims the nose down to increase the nose up pitch force on the yoke to prevent reaching an excessive angle of attack.

In pilot speak: It makes it harder to pull the stick back so you don't stall the wings. The pilot can however override this feature simply by using the electric trim switches on the yoke or trim wheel on the center pedesdal 

There's also protection derived from the autothrottles. They'll drive to the selected thrust limit when the alpha floor(high angles of attack) is reached. Called "thrust latch".
 
JETPILOT
Posts: 3094
Joined: Tue May 18, 1999 6:40 am

RE: Alpha-trim Protection

Sat Jul 22, 2000 4:37 am

I 'm still stuck in the 1960's flying the 727. I have never heard of such a system as the 727 has no such protection.

Thanks for the much needed explanation !!
 
Guest

RE: Alpha-trim Protection

Sat Jul 22, 2000 5:41 am

Ah yes, the venerable Boeing 7-2-7. An analog dinasuar slogging through a ditigal world.

I too was once stuck, like you, in the 60's, flying...dare I say, the same cable operated contraption like you! How medival. I was then shown the error of my ways. Why fly a simple anolog stick and rudder machine when you can fly one with so many d@#n computers that no mere mortal can possibly understand, let alone keep track of?

Automated systems such as FAC's, FADEC's, EFCU's, Autotrim systems featuring alpha, speed and stall trims. ECAM's, EICAS, PFD's...etc, etc, etc...have become common place.

Boy, now that I think about it, I sure do miss the old Boeings!  

Check please!

 
JETPILOT
Posts: 3094
Joined: Tue May 18, 1999 6:40 am

RE: Alpha-trim Protection

Sat Jul 22, 2000 1:00 pm

Even though I am still stuck in the 60's it's better than where I was a few years ago. I was stuck in the 50's on the DC8. The Juraisic Jet.

Our ramp was nicknamed "corrosion corner" by the ground controllers.

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