What was found
PILOT WAS FORCED TO LAND DUE TO SMOKE IN COCKPIT. INSP REVEALED ALTERNATOR POWER WIRE (WIRE NR PB-10) FROM ALT TO THE ALT OUTPUT CIRCUIT BREAKER TO BE HEAT DAMAGED. WIRE IS AN EIGHT-GAUGE SHIELDED WIRE WITH ALTERNATOR OUTPUT POWER IN THE CENTER CONDUCTOR AND THE SHIELDING GROUNDED TO AIRFRAME GROUND. FOR AN UNKNOWN REASON, SHIELDING CHAFED THROUGH TO POWER CONDUCTOR AND CAUSED A DIRECT SHORT TO GROUND. APPROX 6 INCHES OF THE WIRE SHOWED DAMAGE, INSULATION MELTED OFF BETWEEN POWER CONDUCTOR AND SHIELDING AND MUCH OF THE SHIELDING MISSING DUE TO ARCING. DAMAGED SECTION OF WIRE REPLACED WITH MIL-W-22759/16-8, AND SHIELDING INSPECTED ADJACENT TO DAMAGED AREA. NO OTHER CHAFING OR DEFECTS NOTED. (X)