B737-300 CREW HAD THE AIR GND SENSOR FAIL WHEN DEPARTING MSP.

Narrative

AFTER TKOF RWY 12R AT MSP; LNDG GEAR WOULD NOT RETRACT; HANDLE WOULD NOT MOVE PAST OFF. AFTER DISCUSSION WITH FO AND BASED ON DISCUSSION AT THE TRAINING CTR DURING RECENT PROFICIENCY CHK; DECIDED TO USE OVERRIDE TRIGGER TO RAISE GEAR; FOR SECOND SEGMENT CLB. GEAR RETRACTED NORMALLY WITH OVERRIDE. LEVELED OFF AT 7000 FT AND 210 KTS. REVIEWED LNDG GEAR WILL NOT RETRACT CHKLIST. AFTER DISCUSSION; DECIDED TO LOWER GEAR AND RETURN TO TKOF CONFIGN. MADE PA FIRST AND DISCUSSED SIT WITH FLT ATTENDANTS. GEAR LOWERED NORMALLY. RAN LNDG GEAR WILL NOT RETRACT IRREGULAR. BASED ON CHKLIST DECIDED TO RETURN TO MSP WITH GEAR LEFT DOWN. DID NOT DECLARE EMER; SINCE SAW NO NEED FOR ASSISTANCE OR EQUIP. TOLD FLT ATTENDANT CABIN ADVISORY. WHEN FLAPS 15 DEGS SELECTED GOT UNSILENCEABLE GEAR WARNING HORN. RESETTING AIR GND SENSE CIRCUIT BREAKER SILENCED HORN; BUT WAS AGAINST CHKLIST; SO RE-PULLED CIRCUIT BREAKER AND AURAL WARNING AS WELL TO SILENCE HORN. HAD 3 GREEN GEAR LIGHTS WHEN CIRCUIT BREAKER WAS RESET. LANDED NORMALLY. AFTER LNDG; CABIN DID NOT DEPRESSURIZE AND BOTH PACKS OVERHEATED AND TRIPPED. YET AUTO SPDBRAKES DEPLOYED WITH REVERSE THRUST ACTUATION; EVEN THOUGH THEY WEREN'T ARMED. SUPPLEMENTAL INFO FROM ACN 608477: AFTER TKOF AT MSP THE GEAR HANDLE WOULD NOT MOVE PAST 'OFF.' AFTER SOME DISCUSSION WE DECIDED TO RAISE THE GEAR USING THE OVERRIDE TRIGGER. WHEN WE LEVELED OFF AT 7000 FT WE RECONFIGURED THE ACFT AND RAN THE 'LNDG GEAR LEVER WILL NOT MOVE UP' CHKLIST. WE DETERMINED THE ACFT WAS STILL IN THE GND MODE. WE COMPLETED THE CHKLIST AND LANDED UNEVENTFULLY BACK AT MSP. DURING THE ENTIRE EVENT WE FOUND SEVERAL THINGS THAT SHOULD HAVE BEEN ADDRESSED IN THE FLT MANUAL. THE FIRST IS WHEN THE AIR/GND CIRCUIT BREAKER IS PULLED THE ACFT IS FORCED INTO THE FLT MODE. ON FINAL WHEN THE GEAR IS DOWN AND THE FLAPS ARE MOVED PAST 15 DEGS THE UNSAFE GEAR WARNING HORN SOUNDS AND IS UNSILENCEABLE. THEN ON LNDG THE ACFT DID NOT OPEN THE OUTFLOW VALVE WHEN GND WAS SELECTED.