B737 FLT CREW IS DISPATCHED WITH AN INOP GPS SYS.

Narrative

ON APCH WE DISCOVERED THAT ALTHOUGH THERE WAS NO MASTER CAUTION OR AMBER GPS LIGHT; THE R GPS HAD NO SIGNAL. THE GPS WAS MEL'ED. AS WE PUSHED OUT; A CHK SHOWED THAT THE GPS SIGNAL WAS NORMAL. I ASKED MAINT IF THE MEL COULD BE EXPEDITIOUSLY SIGNED OFF. HE INDICATED HE THOUGHT SO; BUT WOULD NEED TO CONTACT MAINT CTL. WE RECEIVED WORD THAT IT WOULD TAKE ABOUT 1/2 HR. DISPATCH CONTACTED US BY PHONE PATCH. IMMEDIATELY THE PRESSURE WAS ON TO GO. DISPATCH TOLD US THE WX WAS GOOD ENOUGH FOR NON-RNP OPS AND THAT THERE WAS NO OPERATIONAL REASON THEY COULD SEE FOR US NOT TO GO. (SOMEWHERE ALONG HERE; VARIOUS AGENCIES -- DSO; MTX; AND I AM NOT SURE WHO ELSE; WERE INVOLVED EITHER DIRECTLY ON THE PARCH OR THROUGH THE DISPATCHER. IT WAS HARD TO RECOGNIZE INDIVIDUAL VOICES.) I SAID THAT OUR OP IS TRAINED AND BASED ON RNAV PROCS. THEREFORE; THAT FUNCTION SHOULD BE RESTORED IF POSSIBLE TO RUN THE FLT IN THE MOST SAFE AND EFFICIENT MANNER. DELAY BECAME THE ONLY ISSUE OF IMPORTANCE; ACTUALLY IT WAS THE ISSUE FROM THE BEGINNING OF THE PHONE PATCH. I WAS TOLD THAT RETURNING TO THE GATE WOULD 'DELAY THE AIRPLANE;' LIKE I WAS NOT AWARE OF THAT FACT. WE KNEW OUR DAY WAS LONG ALREADY AND IN ANY INSTANCE WE CERTAINLY WOULD NOT DELAY NEEDLESSLY. FROM A FATIGUE STANDPOINT; HAVING THE NORMAL MANS OF NAV OPERATING WOULD ENHANCE THE OP. IT WAS REPEATED TO ME THAT THERE WERE NO WX OR OTHER OPERATIONAL ISSUES PREVENTING US FROM GOING WITHOUT GETTING THE MEL DELETED. WE STATED WE KNEW THERE WERE NO OTHER ISSUES; BECAUSE WE HAD ALREADY PUSHED. WE WERE BOMBARDED FOR DEMANDS TO KNOW WHY WE WOULD WANT TO GET THE GPS SIGNED OFF; WHY WE WOULD DELAY; ETC. THE TWO OF US; THE PLTS; SAT AND LOOKED AT EACH OTHER IN DISBELIEF OVER WHAT WAS HAPPENING. THERE WAS ALMOST A PANIC ABOUT DELAY BEING RELATED TO US. OUR POINT OF VIEW WAS NOT EVEN ACKNOWLEDGED. I DOUBTED WE WERE EVEN BEING LISTENED TO. I FELT LIKE WE WERE BEING PUMMELED BY QUESTIONS AND ACCUSATIONS; AND THAT THE WHOLE RESPONSE WAS OUT OF CTL. THE MECH CONTACTED US AND TOLD US IT WOULD TAKE AT LEAST 1 HR BECAUSE HE WAS THE ONLY ONE ON DUTY. WITH THIS INFO; WE DECIDED WE SHOULD GO BECAUSE THAT WAS TOO LONG OF A DELAY. SUPPLEMENTAL INFO FROM ACN 701475: WE ARE ALL ACUTELY AWARE HOW FAST MARGINAL CONDITIONS CAN CHANGE IN SE; AS WE WERE ACUTELY AWARE THAT DAY. FALLING ON PRIOR EXPERIENCE TO FIND OUR 'COMFORT LEVEL' AS A CREW IS WHAT WE PLTS COLLECTIVELY DO ON A DAILY BASIS. TO HAVE THE SAFETY AND COMFORT LEVEL QUESTIONED DOES NOT SEEM TO BE THE APPROPRIATE ACTION WE EXPECT FROM DSO AND DISPATCH.