B757 FLT CREW IS DISPATCHED WITH THE RIGHT FMC INOP WHICH DISTRACTS THE FO WHILE ATTEMPTING TO CHANGE MAP RANGE AND ACCEPT A DIRECT CLEARANCE FROM ATC.

Narrative

WE WERE DISPATCHED WITH AN ACFT THAT HAD AN MEL INSTALLED FOR A R FMC INOP. OUR PDC CONTAINED A SID; THE PNUTT 5 RNAV DEP. IT WAS LOADED INTO THE ONE WORKING FMS ALONG WITH THE DEP RWY 27R. WE CONFIGURED THE R FMC KEYPAD AND DISPLAY TO WORK THROUGH THE USE OF THE ALTERNATE FMC INST SOURCE SELECT SWITCH. MAP RANGE ON THE L SIDE WAS SET TO 5 MI. THE R SIDE WAS SET TO MATCH IN ORDER TO DISPLAY MAP DATA ON THE R SIDE LOWER EFIS DISPLAY. WE WERE GIVEN A TKOF CLRNC WITH A TURN TO 245 DEGS. ON CHK-IN WITH THE DEP CTLR; A CLRNC WAS GIVEN; 'DIRECT FUTBL AND RESUME THE PNUTT DEP.' AT THIS POINT; DIRECT PNUTT WAS ENTERED AND EXECUTED AND THE LNAV SWITCH ENGAGED. AS THE ACFT WAS IN A TURN TO PNUTT; I ATTEMPTED TO CHANGE THE RANGE ON THE R MAP DISPLAY BY SELECTING A LARGER RANGE. BECAUSE OF THE INOP FMC; A 'MAP DISPLAY RANGE' MESSAGE WAS THE ONLY THING DISPLAYED ON TOP OF THE NOW BLANK EFIS DISPLAY. I WAS ATTEMPTING TO VERIFY THE ACFT'S LATERAL PATH AT THE SAME TIME WE WERE QUESTIONING THE TURN TO PNUTT. AT THIS POINT WE QUESTIONED THE CTLR AND ASKED FOR A VERIFICATION. THE CTLR ANSWERED WHILE WE WERE STILL IN THE TURN THAT WE SHOULD BE DIRECT FUTBL. WE IMMEDIATELY BEGAN A R TURN BACK TO FUTBL. I ASKED THE CTLR FOR A HDG; WHICH HE GAVE. THE ACFT WAS RE-ESTABLISHED ON THE PNUTT DEP AND A FEW MINS LATER WE WERE CLRED DIRECT TO PNUTT. CAUSES CONTRIBUTING TO THIS RPT: 1) INOP FMC (R SIDE). 2) DIFFICULTY IN CHANGING EFIS MAP DISPLAY. AT A CRITICAL TIME WHEN ENHANCED SITUATIONAL AWARENESS WAS PARAMOUNT; THIS DISPLAY WAS UNAVAILABLE. 3) THE GIVEN CLRNC; 'DIRECT FUTBL AND RESUME THE PNUTT 5 DEP.' IN MY OPINION ONLY THE MORE EFFECTIVE CLRNC WOULD HAVE BEEN 'CLRED DIRECT FUTBL.' THIS IS DISTINCT AND LEAVES NO ROOM FOR MISINTERP AND IT IS UNDERSTOOD THAT THIS IS PART OF THE PNUTT 5 DEP FROM THE PDC. ONE OF THE MAIN FACTORS AFFECTING HUMAN PERFORMANCE THOUGH WAS THE INOP FMC. YOU ARE OPERATING ON AN RNAV SID WITH 1 FMC AND 1 SCREEN THAT NEEDS TO BE ADJUSTED FOR MAP RANGE ON THE OPERATING SIDE. THIS IS DIFFICULT IN A HIGH WORKLOAD ENVIRONMENT. A LOSS OF VISUAL SITUATIONAL AWARENESS VIA THE MAP DISPLAY MAKES THIS WORKLOAD EXPONENTIALLY LONGER. SUPPLEMENTAL INFO FROM ACN 780195: I WAS THE PF ON A RWY 27R TKOF AT ATL. WE WERE ASSIGNED A 250 DEG HDG BY TWR CTL. AFTER TKOF AND SWITCHING TO DEP CTL WE WERE CLRED TO FLY THE PNUTT DEP AND CLRED DIRECT TO THE FIRST FIX WHICH WAS FUTBL. THE FO WHO WAS THE PLT MONITORING APPARENTLY MISUNDERSTOOD AND SELECTED DIRECT TO PNUTT INTXN AND SELECTED LNAV. I HAD BEEN APPLYING MY ATTN TO FLYING THE ACFT AND CLEANING UP THE FLAPS AND SLAT TO THE CLB CONFIGN AND WHILE I THOUGHT THIS WAS AN UNUSUAL CLRNC; I HAVE RECEIVED IT BEFORE. I HESITATED MOMENTARILY AND THE FO STATED 'WE'RE CLRED DIRECT TO PNUTT' AND I DID RECALL THE CTLR SAYING SOMETHING ABOUT PNUTT; SO I BEGAN A TURN TO PNUTT WHICH WAS ABOUT A 160 DEG HDG. FUTBL WOULD HAVE BEEN ABOUT A 250 DEG HDG. DEP CTL SOON CALLED AND ASKED WHERE WE WERE GOING. WE SAID PNUTT AND HE STATED WE WERE CLRED TO FUTBL. I IMMEDIATELY STARTED A R TURN AND THE FO ASKED FOR A HDG. ATC ASSIGNED A 250 DEG HDG; AND TOLD US HE WOULD NEVER CLR US DIRECTLY TO PNUTT FROM THAT POS. NO OTHER ACFT WERE IN SIGHT OR ON OUR TCAS WHICH WAS ON 10 MI SCALE. A CONTRIBUTING FACTOR WAS THE FO'S FMC WAS INOP AND HE WAS USING THE CAPT'S ON HIS BOX. WHEN HE CHANGED RANGE RIGHT AFTER TKOF HIS ADI STATED MAP RANGE DISAGREEMENT AND ALL INDICATIONS ON IT DISAPPEARED. THIS DISTR HIM MOMENTARILY AT THE WRONG TIME.