ACFT MAINT DISCREPANCY OVERLOOKED AS FACILITY MAINT PROC USES MEL REQUIREMENTS FOR RELEASING ACFT AFTER SCHEDULED MAINT. ACFT EQUIP PROB MALFUNCTION. FUEL DUMPED.

Narrative

ACFT INBOUND TO IAH AT APPROX XA00 WAS OPERATING UNDER A MEL INSTALLED BY CONTRACT MAINT IN SAF. UPON ACFT ARR; MAINT REMOVED AND REPLACED #1 ENG START VALVE IN AN EFFORT TO CLR THE MEL. UPON ACFT DEP; THE #1 ENG START VALVE LIGHT ILLUMINATED AND THE CREW FOLLOWED ABNORMAL PROCS. WHEN ACFT DEPARTED IAH AFTER OUR PERFORMING A MANUAL START PER MEL; ALL INDICATIONS OF A NORMAL START WERE ATTAINED. UPON RETURN TO IAH THE #1 ENG START VALVE AGAIN WAS REPLACED WHICH WAS NO HELP. THE SOLENOID WAS ALSO REMOVED AND REPLACED. NO HELP. THE ACTUAL CAUSE OF THE START VALVE FAILURE WAS A WIRING PROB AT THE START VALVE. WHILE PERFORMING THE WORK ON THE FIRST START VALVE; WE HAD VISUALLY CHKED THE CANNON PLUG FOR ANY OBVIOUS DEFECTS AND NONE WERE NOTED. AFTER CHANGING THE START VALVE; WE DID NOT HAVE ADDITIONAL TIME TO TROUBLESHOOT AS THE ACFT WAS ALREADY BEYOND DEP TIME AND WITH IT ALREADY BEING DEFERRED; WE DISPATCHED THE ACFT PER MEL. SUPPLEMENTAL INFO FROM ACN 317704: #1 START VALVE LIGHT CAME ON AFTER LIFTOFF; INDICATING A POSSIBLE VALVE THAT FAILED. OUR PROC IS TO SHUT DOWN AFFECTED ENG AND RETURN TO ARPT OF DEP OR THE MOST SUITABLE ARPT IN TIME. WE HAD TO DUMP 25000 LBS OF FUEL TO REDUCE OUR WT FOR LEGAL LNDG WT. AN EMER WAS DECLARED. CALLBACK CONVERSATION WITH RPTR ACN 317704 REVEALED THE FOLLOWING INFO: THE RPTR IS CONVINCED THAT THE STARTER VALVE LIGHT WAS A FALSE INDICATION; HOWEVER; THE B727-200 PROCS REQUIRE THE ENG TO BE SHUT DOWN. THE FUEL DUMP AND OTHER PROCS WERE COMPLETED AS REQUIRED AND THE 2 ENG WAS ROUTINE. THE MECHS WERE UNABLE TO REPAIR THE ACFT IN A TIMELY MANNER SO THE FLC AND PAX CHANGED TO ANOTHER ONE AND PRESSED ON.