What was found
ENROUTE, RECEIVED AMBER ALT. LIGHT IN PFD. F/O RECEIVED AMBER ALT; IAS LIGHTS ON PFD. RECEIVED A PITOT HEAT & WINDSHEAR DET FAIL ALERT LIGHT. AUTO THROTTLES & AUTOPILOT DISCONNECTED. RECEIVED SEL ELEV FEEL MAN, SEL FLAP LIM OVRD IND, SUSPECT OR ERRATIC CHECKLISTS, CAPTAINS A/S DATASHWED 270 KTS. WHILE F/O'S AIRPEED & STANDBY AIRSPEED WITHIN 5 KTS OF EACH OTHER. DESCENDED TO FL 240. F/O'S & STANDBY AIRSPEED UNRELIABLE. DETERMINED CADC 1 RELIABLE. FOLLOWED GRH & CADC 1 INDICATIONS TO RETURN, APPROACH, LANDING & TAXI BACK TO RAMP UNEVENTFUL. R & R NR 1 & 2 AIR DATA INERTIAL REF UNIT'S. PURGED PITOT & STATIC, CAPT, F/O AND AUX & LEAK CHECKED, NONE FOUND. R & R NR 2 FCC, ALL C/W IAW AMM.