What was found
IAD - FLT 1823 - DURING APPROACH TO DCA WHEN NR 1 AUTOPILOT WAS DISCONNECTED, A/C FELT NOSE HEAVY AND STAB TRIM NOTED AT FULL NOSE DOWN. STAB TRIM THEN RAN TO FULL NOSE UP FOLLOWED BY NR 1 AND NR 2 STAB TRIM FAULTING. A/C DIVERTED TO IAD, LANDED W/O INCIDENT. FAULT TEST REVEALED NO FAULTS. PREVIOUS FAULT REVIEW REVEALED AP DISC/INH FMP, TRIM 1 FAIL TRIM SERVO/FAC 1, AP DISC/INH TRIM SERVO/FAC2. AFCS TESTS REVEALED NO SYSTEM FAULTS. PRECAUTIONARY REPLACED FLT AUGMENTATION COMPUTER. SYS GROUND CHECKED NORM OPS. ACCOMP FUNCTIONAL CHECK/MX FERRY FLT IAD/ORD WITH NO DEFECTS FOUND. SYS OPS CHECKED NORM AND A/C RETURNED TO SERV. (M)