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I worked on Russian Fighter aircraft where both the Rudder Pedals were mechanically interlinked i.e Captain applies force on his pedal than both pedals (Captain & First Officer) move & vice versa. Single Pedal sensor Unit (of course redundant sensors) senses the position and sends it to the Fly-By-Wire Computer for moving the control surfaces.

I would like to know if this is true for all aircraft (Fighter/Commercial, Boeing/Airbus, etc.) and if not, what are different implementations? Maybe different sensors for Captain/First Officer, different arch etc.

Also on the same lines, how does Pedal Feel operate i.e, does it takes a signal from pilot pedal sensor or from actuators to provide feel to the pilot/copilot?

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    $\begingroup$ I can't speak for all aircraft, but I'm pretty sure I read something about them being interconnected on the A320, which would be my "usual suspect" for "independent flight controls to confuse the heck out of the pilots" design. (Presumably like on the fighter aircraft you describe there is a single/redundant sensor unit to determine their position and "politely request" that the computers move the rudder as directed.) $\endgroup$
    – voretaq7
    Feb 20, 2014 at 6:28
  • $\begingroup$ @voretaq7: yep, there have been issues where the PNF has been resting their feet on the pedals and obstructing the pilot flying. On the A320, during flight control checks the PNF is meant to "follow" the pedal movement while the captain tests the rudder. $\endgroup$
    – Qantas 94 Heavy
    Feb 20, 2014 at 6:42
  • $\begingroup$ @Qantas94Heavy; this is part of the reason for checking for free control movements. It's less of an issue with a PNF, since they generally know what's going on, a passenger occupying the right seat might not however. $\endgroup$
    – falstro
    Mar 3, 2014 at 11:03
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    $\begingroup$ @voretaq7, in A320, rudder pedals and elevator trim are the mechanical backup, so they have direct hydraulic connection to the rudder. The other Airbus models have different backups though, so it might differ there (I have only read documents for A320, so I don't know the details for the other models). $\endgroup$
    – Jan Hudec
    May 7, 2017 at 19:50
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    $\begingroup$ I am curious about a fighter aircraft that has two pilots. Do you have a model name? $\endgroup$
    – Oleg Lobachev
    May 27, 2018 at 0:29

2 Answers 2

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In the EMB-145 and -135 the rudder controls are mechanically linked in the tail in an assembly that converts torque from the rudder cables to linear rod input into the rudder hydraulic control units. Up until this assembly the rudders are technically independent and the cables for each rudder are routed differently through the airframe so that a single point of damage does not render the rudder inop. The autopilot servo is only located on the captains rudder cables. Through the rear linkage both pilots rudder pedals will move together when either provides input.

Our other controls are a bit more interesting. The roll input is also linked, but it is linked at the control column, Each yoke independently controls its own aileron -- the CA yoke only flies the left aileron and the FO yoke the right aileron. It is only through the control column linkage that each yoke can control the whole airplane. It is done this way so that if there is a problem with a cable jamming, the control interlock can be disconnected and at least half control regained.

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All? I doubt there's anyone who knows all models of aircraft but it seems the norm at least.
How they operate depends on the aircraft of course. Anywhere from fully mechanical, direct linkage to the rudder through cables to directly driving hydraulic pumps that drive the rudder to driving sensors that feed data to the flight control computers which in turn drive electric motors that drive the hydraulic pumps that drive the rudder.

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    $\begingroup$ Well, there could be a safety requirement for the pedals behaving this or that way, then all the aircrafts would behave very similarly. $\endgroup$
    – yo'
    Feb 24, 2014 at 21:02

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