AN ACR MD-88 FLEW WITH ITS INS OR IRS 'BATTERY' LIGHT ON.

Narrative

AN INS BATTERY LOW LIGHT MESSAGE CAME ON. THERE IS A CONFUSION WHETHER THIS IS A GO/NO-GO ITEM. EVEN A LINE CHK AIRMAN WHO I ASKED WAS CONFUSED. THERE ARE 2 ENG DRIVEN GENERATORS PLUS APU GENERATOR AVAILABLE OR NEED TO FAIL BEFORE THE LOSS OF THE INS. I HAVE LEARNED AFTER THE FACT THAT I MIGHT HAVE TAKEN THE ACFT INCORRECTLY; I WISH SOME OF THE LEGALITIES WERE NOT SO NEBULOUS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES THE MD-88 FOR A MAJOR UNITED STATES ACR ON OVERLAND RTES ONLY. SOME OF HIS ACR'S MD-88'S HAVE THE INS; AND OTHERS DO NOT. THE ACFT WITH THE INS USE IT AS THE PRIMARY ATTITUDE REF SYS IN ADDITION TO THE NAV CAPABILITIES. THE RPTR HAS NOT YET GOTTEN ANY SATISFACTION FROM HIS FLT SUPVRS; ALTHOUGH HE HAS ASKED FOR GUIDANCE. HE BELIEVES THAT THE MAINT PERSONNEL WERE TRYING TO HAVE HIM MOVE THE ACFT ONTO A STATION WHERE IT COULD BE FIXED. THE ACFT WITH INS HAVE ARRIVED 'ON THE PROPERTY' AFTER THE RPTR WENT TO SCHOOL ON THE ACFT. MOST CREWPERSONS HAVE NOT BEEN PROPERLY TRAINED IN ITS USE. SUPPLEMENTAL INFO FROM ACN 262858: DURING OUR PREFLT CHKLISTS; I NOTICED THE AMBER 'BATTERY FAIL' LIGHT ILLUMINATED ON THE #2 IRS MODE SELECT PANEL. AIR TFC CTLR IN THE JUMP SEAT. I ADVISED THE CAPT WE SHOULD NOT GO. FINALLY TOOK THE FLT PLAN (IT HAD THE DISPATCHER'S NUMBER ON IT) AND LEFT THE COCKPIT MENTIONING HE WAS CALLING THE DISPATCHER/MAINT COORDINATOR. 3-5 MINS LATER HE GOT INTO HIS SEAT; HE SAID 'WE HAVE DISPATCHER'S APPROVAL AND LET'S GO.' MY FRAME OF MIND WAS HE MUST HAVE FOUND SOMETHING VIA THE TELEPHONE CALL AND I MISSED IT IN THE BOOKS. THE LIGHT REMAINED 'ON' THROUGHOUT THE FLT. AT THE ARR STATION I DECIDED TO GET MY REF FOR FUTURE KNOWLEDGE. I ASKED THE CAPT FOR A REF. THIS WAS MY FIRST INDICATION THAT SOMETHING SEEMED WRONG. THE CAPT NEVER REALLY GAVE ME AN ANSWER AND KEPT AVOIDING THE DISCUSSION; ESPECIALLY THE 'DISPATCHER'S APPROVAL.' I DON'T REALLY KNOW IF THE CAPT EVER TALKED TO THE DISPATCHER.