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Original Message
"Flight Control Feedback on modern Airliners"

Posted by DHamblin on 03-25-03 at 17:59z
Since you are the first 767 pilot I've been able to ask, what type (quality) of physical feedback do the modern flight control systems feed back to the pilot? I am aware of the stall "stick shaker" (say that a few times fast...) but wondered if the control feel is somehow changed to reflect speed etc.

Its interesting on my friends DC-8 as the elevator is free-pivoting; you are flying a control tab with the wheel which moves the elevator. While being stiff, it does impart some aerodynamic feedback to the pilot.

For example my little C150 being all direct cable and pulleys gives good feedback as to speed etc (controls easy and mushy, slow; firm and responsive, fast). So the plane helps you "feel" what it is doing.

While much of the larger planes seem to be "flight by numbers"; to me having no feed back through the controls would make it more difficult.

Dave Hamblin
(formerly DaveH on old site!)


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"RE: Flight Control Feedback on modern Airliners"
Posted by mark_hoffman on 03-25-03 at 21:32z
Well, much of what people like is what they are used to, and I am used to the feel of large jets, so I find the control feel of jets to be very good. Boeing aircraft have a very sophisticated control system that does indeed take aircraft speed into account. At low speeds it feel more "mushy" and more firm at high speeds just like a "real" airplane. The rudder also automatically programs from high to low authority as speed increases. Of course this is all artificial through the use of the hydralic control system and inputs from the Air Data Computers. One "real" cause of this change in control feel is the fact that the 767 has both inboard and outboard ailerons. The outboards are only unlocked below 250 kts, while the inboards are always in use.

I kind of disagree that flying larger planes is all "by the numbers". Of course we use strict speeds for different phases of flight, but that is due to the fact that our wieght changes much more than in a light aircraft, often my 200,000 lbs or more. But even so, you have a "feel" for the aircraft just like in your 150. I've often noticed a very small vibration or an odd way a control feels compared to another plane just like you would in a light plane.

Anyway, I hope I haven't been too long winded in my answer!

Mark


"RE: Flight Control Feedback on modern Airliners"
Posted by DHamblin on 03-26-03 at 01:05z
<<Anyway, I hope I haven't been too long winded in my answer!>>

Not at all! My background is engineering, so I am as fascinated with the "inside" of modern aircraft as the outside!!

Since I can't fly them myself I have to rely on willing individuals such as yourself.

Dave Hamblin
(formerly DaveH on old site!)