As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN FOR ISIS UNRELIABLE- SHOWING AS MUCH AS 30 DEGREE NOSE DOWN WHILE STRAIGHT AND LEVEL AND UP TO 90 DEGREE BANKS L/R WHEN STRAIGHT. ATTITUDE INDICATION AFFECTED ONLY. SPEED AND ALTITUDE OK. REMOVED AND REPLACED ISIS IAW AMM 34-14-01. A/C OK FOR SERVICE, OPS CHECK GOOD.