Topic Author
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?
Posts: 3094
Joined: Tue May 18, 1999 6:40 am

RE: Alpha-trim Protection

Fri Jul 21, 2000 12:20 pm


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".
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 !!

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!

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.

Who is online

Users browsing this forum: BobbyPSP, curlyheadboy, OMP777X, taru, Yahoo [Bot] and 2 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos