What was found
INVESTIGATED PILOT REPORT OF LT (PILOT'S) INSTRUMENT PANEL CA ADC REVERSIONARY SWITCH BEING STUCK IN PLACE, UNABLE TO SWITCH FUNCTIONS. VERIFIED PN 4882-580 SWITCH ASSY. STUCK IN RECESSED POSITION. FOUND SWITCH ASSY. OPERATION BEING RESTRICTED BY EXCESSIVE LENGTH MOUNTING SCREW ATTACHING LT INBD DISPLAY'S (MFD) IMT-3010 MOUNT RACK TO STRUCTURE EXTENDING INTO ANNUNCIATOR ASSY BELOW. REPLACED DAMAGED ADC REVERSIONARY SWITCH AND AFFECTED IMT-3010 MOUNTING SCREW, SWITCH FUNCTIONS NORMAL. RECOMMEND MFG ADD A NOTE TO THE APPLICABLE PORTIONS OF THE PROLINE 21-EQUIPPED ACFT MM REGARDING USE OF CORRECT INSTRUMENT MOUNTING HARDWARE.