What was found
(CAN) HORIZONTAL STABILIZER WAS REMOVED TO ACCESS RT FUSELAGE SIDE SKIN REPLACEMENT (COSMETIC) WITH STABILIZER REMOVED VISIBLE ACCESS TO AFT FUSELAGE STRUCTURE REVEALED A CRACK AT THE LT AFT STABILIZER ATTACH LONGERON PN 0712207-1 - REF. CESSNA 180-C I.P.C. FIG 35 ITEM 35. NOTE AIRCRAFT HAS BEEN OPERATED ON SKIS AND HANDLING OF THE HORIZONTAL STAB MAY BE A CONTRIBUTING FACTOR. THOUGH NOT CALLED FOR IN THE CESSNA INSPECTION CHECK SHTS, IT WOULD BE PRUDENT TO REMOVE BOTH VERTICAL AND HORIZONTAL STABILIZERS FOR BETTER VISUAL/INTERNAL INSPECTION ON A REGULAR BASIS. IE. 400 HRS/5 YEARS.