What was found
(CAN) MODE C ALTITUDE REPORTING INTERMITTENTLY REPORTS FALSE ALTITUDES. VISUAL INSP FOUND A CHAFED MODE C A1 CODE WIRE IN THE ALTITUDE ENCODER WIRING. WIRE WAS CHAFFING (DUE TO VIBRATION) ON THE THROTTLE CABLE DIRECTLY BEHIND THE CENTER RADIO PANEL. WIRE WAS REPAIRED AND CHAFE PROTECTION WAS ADDED TO THE WIRE HARNESS. MODE C DATA INTEGRATION CHECK WAS PERFORMED IAW CARS STD 571 APPENDIX F, ITEM K.