ENG #3 GND IDLE RPM N1 OUT OF LIMITS.

Narrative

AN FAA INSPECTOR WAS ON THE JUMP SEAT. THE DEADHDG CAPT WAS ON THE SECOND JUMP SEAT. WE MADE A NORMAL 2 ENG TAXI TO RWY 35L AT DFW AND STOPPED BEHIND WAITING TFC FACING S NEAR THE DEP END OF THE RWY. AS THE TFC ADVANCED TOWARD THE RWY WE STARTED ROLLING FORWARD AND THE FAA INSPECTOR MADE THE COMMENT; 'HE ONLY LET THE ENG WARM UP FOR A MIN AND A HALF;' INDICATING THAT HE THOUGHT THE ENG ON THE AIRPLANE THAT WAS TAKING THE RWY FOR TKOF SHOULD HAVE BEEN WARMED UP LONGER. THE INSPECTOR VIOLATED THE 'STERILE COCKPIT' RULE BY MAKING THAT COMMENT WHILE WE WERE TAXIING. SINCE THE INSPECTOR HAD ALREADY GIVEN US (THE FLC) THE IMPRESSION OF TRYING TO NAIL US FOR ANY AND EVERY MINOR INADVERTENT INFRACTION HE COULD FIND; AND IN LIGHT OF THE INSPECTOR'S COMMENT; THE CAPT CHOSE TO IMMEDIATELY START THE REMAINING ENG #3. WE WERE ABOUT 5 MINS FROM TAKING THE RWY; SILL FACING S (WIND FROM BEHIND US). AFTER STARTING THE ENG; I CHKED THE ENG INSTS AND SAW NOTHING ABNORMAL; THEN ANSWERED THE 'DELAYED AFTER START CHKLIST;' WHICH INCLUDES 'ENG INSTS' AS ONE OF THE ITEMS. AFTER THAT; WE PROCEEDED TO ACCOMPLISH THE 'BEFORE TKOF' DUTIES; CHKLISTS; ETC; AS WE MADE THE 90 DEG L TURN TOWARD THE RWY HOLD SHORT LINE (WIND NO LONGER FROM BEHIND US); AND SAT THERE FOR SEVERAL MINS AWAITING OUR TURN FOR TKOF. SUBSEQUENT TKOF AND FLT CONTINUED UNEVENTFULLY. UPON REACHING CRUISE ALT THE INSPECTOR ASKED THE SO TO LOOK UP THE ENG LIMITATIONS IN HIS MANUAL (THE INSPECTOR SUBSEQUENTLY SAID HE KNEW THE LIMITATIONS BUT WANTED THE SO TO LOOK IT UP IN THE BOOK RATHER THAN JUST ASK ONE OF US WHAT THEY WERE). AFTER LOOKING UP THE LIMITATIONS; THE INSPECTOR PRODUCED A PIECE OF PAPER ON WHICH HE HAD WRITTEN SOME NUMBERS AND SAID THAT THE NUMBERS WERE THE ENG INST INDICATIONS BEFORE TKOF; WITH THE #3 N1 GND IDLE RPM BEING SLIGHTLY OUT OF LIMITS ON THE HIGH SIDE. ON 3 OCCASIONS I ASKED HIM IF HE WROTE THIS DOWN AFTER 3 MINS OF WARM-UP TIME AND HE SAID YES EACH TIME (WHICH WOULD HAVE BEEN WHEN WE WERE VERY BUSY WITH OTHER IMPORTANT DUTIES AND SOME TIME AFTER THE ITEM WAS CALLED FOR IN THE CHKLIST WHEN WE WERE FACING DOWNWIND; WHICH MIGHT HAVE AFFECTED THE RPM OF THE FAN. HE WENT ON TO MAKE SOME CLAIMS ABOUT THE IMPORTANCE OF THIS LIMITATION BEING RELATED TO CAT III; SAYING THAT IF THE GND IDLE IS TOO HIGH YOU MIGHT NOT BE ABLE TO STOP AND IF TOO LOW YOU MIGHT NOT BE ABLE TO GAR BECAUSE IT TAKES TOO LONG FOR THE ENG TO SPOOL UP FROM IDLE IF THE RPM IS TOO LOW. (FRANKLY I FOUND THIS TO BE AN ABSURD EXPLANATION CONSIDERING THAT THE ENGS ARE ACCELERATED AFTER LNDG FOR REVERSE THRUST AND IF THE ENG EVER GOT ANYWHERE NEAR IDLE ON A CAT III APCH WE WOULD HAVE LONG SINCE GONE-AROUND DUE TO AN UNSTABLE APCH. AND WHAT DOES VISIBILITY HAVE TO DO WITH GAR PERFORMANCE; OR STOPPING DISTANCE FOR THAT MATTER? THE OTHER CREWMEMBERS AND THE DEADHDG CAPT ON THE SECOND JUMP SEAT LATER AGREED TO THE ABSURDITY OF THIS EXPLANATION). NEVERTHELESS; THE INSPECTOR INDICATED THROUGH HIS EXPLANATION THAT HE THOUGHT IT WAS AN UNSAFE SIT TO HAVE THE GND IDLE RPM OUT OF LIMITS AND THAT HE THOUGHT THAT THE #3 WAS OUT OF LIMITS. WHILE I DON'T REMEMBER THE SPECIFIC NUMBERS I SAW; WHEN I CHKED THE INSTS AFTER START I LOOK FOR NORMAL AND WITHIN LIMITS; AND WHEN I CHKED THEM RIGHT AFTER START THEY LOOKED NORMAL AND WITHIN LIMITS. I CHKED THEM AND ANSWERED THE CHKLIST WHEN WE WERE FACING DOWNWIND AND THE INSPECTOR CHKED THEM WHEN WE WERE FACING XWIND AT LEAST 3 MINS LATER; WHICH MIGHT ACCOUNT FOR THE DISPARITY. RATHER THAN POINT OUT WHAT HE CONSIDERED TO BE AN UNSAFE SIT WHILE WE WERE ON THE GND AND COULD HAVE TAXIED BACK TO THE GATE FOR CORRECTIVE ACTION; THE INSPECTOR CHOSE TO WAIT UNTIL WE WERE IN FLT TO BRING OUT INADVERTENT OVERSIGHT TO OUR ATTN AND THEREBY MAKE HIMSELF EQUALLY RESPONSIBLE FOR ALLOWING THE FLT TO PROCEED. MY SUGGESTION FOR PREVENTING RECURRENCE OF THE SIT WOULD BE TO ADVISE THE FAA INSPECTOR THAT DESPITE WHAT HE MIGHT THINK; THE PRIMARY CONCERN OF PROFESSIONAL PLTS IS SAFETY. IF THERE IS A SAFETY RELATED PROB THAT IS INADVERTENTLY MISSED BY THE PLT AND THE INSPECTOR NOTICES IT; IT SHOULD BE BROUGHT TO THE ATTN OF THE CAPT IMMEDIATELY! FURTHER; THE INSPECTOR SHOULD BE ADVISED THAT HIS JOB IS TO OVERSEE THE OP TO SEE THAT IT IS SAFE; NOT TO SEE HOW MANY 'GOTCHAS' HE CAN CHALK UP. HIS ATTITUDE IN THE COCKPIT ADDED UNNECESSARY TENSION WHICH COULD ARGUABLY BE SAID TO DIMINISH THE LEVEL OF SAFETY.