What was found
AIR RETURN - PILOTS REPORTED A LIGHTNING STIKE ON THE NOSE WHICH RESULTED IN A RUNWAWAY RUDDER BOOST SITUATION IF THE RUDDER BOOST SWITCH WAS "ON". RUDDER BOOST ACTIVATES AND STAYED ACTIVATED. MAINTENANCE PLACED THE ISSUE ON MEL 22-2 CAT.C C/N 34624 AT THE TIME. AIRFRAME LIGHTNING STRIKE INSPECTION WAS COMPLIED WITH PER MM 05-50-00 AND PROPELLER INSPECTION PER PROP MM 61-01-02. NO DAMAGE WAS FOUND. MAINTENANCE SUBSEQUENTLY REMOVED AND REPLACED THE RT TRANSDUCER IAW MM 27-21-00. OPERATIONAL CHECKS WERE GOOD.