What was found
(CAN) IN CRUISE WHEN PILOT NOTED VIBRATION WITH CONTROL STICK. VIBRATION BECAME MORE VIOLENT AND HE SLOWED AIRCRAFT. VIBRATION DID NOT GO AWAY, BUT WAS LESS VIOLENT. AIRCRAFT LANDED OK. IT APPEARS THAT THE ARM THAT CONNECTS TO CONTROL ROD BECAME DETACHED FROM THE SERVO TAB ALLOWING THE TAB TO FLAP VIOLENTLY. IT THEN BROKE INTO PIECES. THE ELEVATOR INTERMEDIATE SPAR BROKE IN 4 PIECES. THE TOP SKIN STARTED TO PULL AWAY FROM REAR TAB HINGE SPAR AND INTERMEDIATE SPAR. SUBMITTER NOTES THAT IF FLIGHT HAD CONTINUED MUCH LONGER THE ELEVATOR WOULD HAVE COME COMPLETELY APART.