A newly designed circuit board is now available for Citation 525 and a few Citation 560 operators that have been required since late last year to disengage their pitch trim and autopilot servo circuit breakers to prevent a possible runaway trim. The FAA has proposed mandatory replacement of the breakers, installation of which is covered under warranty for the Model 525. The original AD stemmed from the July 22 ditching of a Citation 525 in which a runaway pitch trim was implicated.