PPRuNe Forums - View Single Post - NTSB and Rudders
View Single Post
Old 28th Jul 2002, 18:02
  #61 (permalink)  
Wino
Union Goon
 
Join Date: Feb 2000
Location: New Jersey, USA
Posts: 1,097
Likes: 0
Received 0 Likes on 0 Posts
Yep thats exactly what I am saying.

The rudder load limiter in the A300 600 works by limiting the travel of the rudder pedals. The breakout forces are also increased .

On the ground the rudder pedals have a travel of around 8 inches in either direction. In flight the pedals are physically restricted from going further than the rudder travel required. So full throw of the rudder pedal around 250 knots is about 1 inch. The breakout force is higher than the force to reach the stop. so what happens is that the rudder becomes a toggle switch in flight. You get a choice of All or nothing. If you try and correct your all input from one side you will instantly go full travel the other way. There is no way to put in a coordinated amount of rudder without pushing with BOTH feet simultaneously to try and modulate the rudder. And it feels nothing like what you are used to when you are doing V1 cuts, crosswinds etc. Now who would push down with both feet if they didn't know?

They used to have a ratio type load limiter in the A300 b4 where normal travel at slow speed equaled normal pedal travel at high speed, with a different amount of rudder being applied so the rudder always feels the same. Boeing switched to that style of rudder load limiter from the 747 forward (IE 757 767 777) and depowered the rudder in the 727 and removed 1 completely from use so that though the 727 had a blocker limiter, force was also limited.

Some one mocked me for it, but the facts are Airbus had it right for the A300B4 and went wrong from there (All airbus rudders are blocker types)

Cheers
Wino
Wino is offline