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Skidoo
10th Jul 2006, 13:52
Ran an MEL recently that called for one crew member to go to the back of the aircraft and check "full rudder movement" this occured on a CRJ 200 series a/c.

My question is as a pilot you can check movement but do you believe you could visually check FULL movement standing on the ground below the a/c?

Mad (Flt) Scientist
19th Jul 2006, 21:59
Apologies for the delay in responding.

If that is the same item as Im looking at, then the requirement is is for "visual operation of affected control surface for correct operation" and NOT for full motion as such. (Loss of cockpit rudder position indication)

I believe the philosophy is that the "before flight" control sweep, while it should be conducted to full travel, is intended to ensure that there are no jams or restrictions in the circuits and not necessarily to ensure full deflection (which in any event may be variable depending upon the rigging of a specific tail number).

Therefore, since you can't confirm motion during the control sweeps from the cockpit, someone needs to observe rudder motion externally. But checking that you have got precisely 25 degrees of travel isn't part of the expectation. (Given the small size of many cockpit indicators, I'd doubt you could reliably measure deflections to single digits, and I also believe that many control sweeps aren't carried out in a fashion that would do so).

I'd be prepared to argue that the observer would identify gross reductions in deflection (especially since they would invariably occur to one side only, so there would be an obvious left-right difference apparent), which would identify any safety issues associated with restricted travel, but neither could nor is expected to spot variations of a few degrees.