What was found
CABIN OVERHEAD CTR PANEL REMOVED FOR PROGRESSIVE INSP. DURING FLAP & AILERON CABLE INSPECTION, FLAT SPOTS WERE NOTICED ON 2 AILERON CONTROL CABLES. ROLLED CABLES FOR BETTER VIEW OF CONTACT POINT WITH PULLEYS, WAS ABLE TO CATCH FRAYED WIRES WITH A RAG & COULD SEE A SUBSTANTIAL GROOVE IN THE CARRY-THRU CABLE. CABLE TENSIONS WERE WITH PROPER SPECS & AREA CLEAN & FREE OF DIRT/DEBRIS. PLASTIC PULLEYS INSPECTED, THEY WERE CLEAN & FREE TO ROLL. PROBLEM SEEMS TO HAPPENING DURING NORMAL FLT TRAINING SCHOOL USE & HAS BEEN NOTICED TO BE HAPPENING WITH ALL OF OUR ACFT WITH SIMILAR ACFT TT. CAUSE OF PROBLEM CAN BE ATTRIBUTED TO PULLEYS, THEY ARE MADE FROM A HARD WHITE PLASTIC MATERIAL. BRAIDED STAINLESS STEEL CABLES ARE RUBBING AGAINST PULLELYS INSTEAD OF ROLLING ON THEM. THIS CAUSES THE CABLES TO FLAT SPOT AT FIRST & THEN CUT A GROOVE DEEP INTO THE CABLE. THERE IS ALSO NO NOTICEABLE CABLE DEFLECTION WHERE CABLES CONTACT PULLEYS, SEEMS PULLEY DIAMETER IS TOO SMALL. SUGGEST REPLACING PLASTIC PULLEYS WITH A STANDARD PHENOLIC PULLEYS THAT ARE USED IN ALL OTHER AREAS OF THE ACFT.