What was found
(CAN) DURING AN INSPECTION OF THE EMPENNAGE OF DASH 8-311 THE RUDDERS WERE MANUALLY MOVED FROM SIDE TO SIDE. WHEN IT WAS PUSHED FULL RT, TRAVEL A LARGE CRACK APPROXIMATELY TWO INCHES LONG WAS EXPOSED. THIS CRACK BEGAN AT THE LOWER EDGE OF THE L/E SKIN AND CONTINUED FOR APPROXIMATELY TWO INCHES IN AND UPWARD DIRECTION. UPON A CLOSER INSPECTION THE ROW OF RIVETS SECURING THE LOWER EDGE OF THIS L/E SKINS TO THE BOTTOM FRAME HAD BEEN SHEARED ON BOTH LT AND RT FORWARD SKINS.