Narrative:

On aug/xa/97 at approximately AB01, first officer and myself were operating flight, a B757, from aby to sdf. We were in cruise flight at an altitude of FL390 in positive control area controled by ZTL. The autoplt was engaged and the FMC indicated approximately 2 mins to a VNAV path capture which would maintain an approach descent. The aircraft would then cross an arrival restr programmed in the FMC for the louisville standiford airport. I requested the first officer to obtain a clearance for a lower altitude from ZTL which would allow the aircraft to descend normally without further flight path modification. I observed the first officer place FL280 in the altitude window and say cleared to FL280 'no discretion.' I then repeated what the first officer stated to me and believed that we were cleared to descend to FL280 at our discretion. Since the aircraft would start the programmed descent path in about 6 mi and I did not hear descend and maintain FL280 now, cruise flight at FL390 was maintained. At that point the first officer made no indication that there was any non compliance occurring with the flight clearance received. The first officer checked on with ZID controller who immediately stated 'I need for you to descend now. I still show you at FL390 sir. What altitude are you showing?' the first officer stated that we are descending and we are out of FL385. During the exchange an immediate descent was initiated. The controller gave us a turn to heading while we were descending and then another turn back into the traffic flow for an arrival into louisville. Descending through approximately FL280 we were requested to contact ZID when on the ground and given a phone number to be called. The flight continued without any further deviations and we landed safely at the louisville standiford airport. Once on the ground I called ZID as requested at approximately AB54 and left a message via the answering machine with the requested information. I then called again around AI45 and spoke with a representative and advised him of the above listed information as requested. He stated that there had been no 'traffic separation' problem at the time of the occurrence and that the term 'no discretion' was possibly confusing and should be questioned in the future. A debrief was conducted with first officer and we both concluded that the confusion arose from the interpretation of the term given 'no discretion.'

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Original NASA ASRS Text

Title: B757 FREIGHTER CAPT DELAYS DSCNT TO FL280 FROM FL390 AFTER CTLR HAD STATED 'NO DISCRETION.' FO HESITATED TO CALL ATTN TO THIS DELAYED DSCNT TO THE CAPT'S ATTN. NEXT AREA CTLR, ZID, GAVE THEM A REMINDER AND A NEW CLRNC, AND THEN SAID, 'CALL ME.'

Narrative: ON AUG/XA/97 AT APPROX AB01, FO AND MYSELF WERE OPERATING FLT, A B757, FROM ABY TO SDF. WE WERE IN CRUISE FLT AT AN ALT OF FL390 IN PCA CTLED BY ZTL. THE AUTOPLT WAS ENGAGED AND THE FMC INDICATED APPROX 2 MINS TO A VNAV PATH CAPTURE WHICH WOULD MAINTAIN AN APCH DSCNT. THE ACFT WOULD THEN CROSS AN ARR RESTR PROGRAMMED IN THE FMC FOR THE LOUISVILLE STANDIFORD ARPT. I REQUESTED THE FO TO OBTAIN A CLRNC FOR A LOWER ALT FROM ZTL WHICH WOULD ALLOW THE ACFT TO DSND NORMALLY WITHOUT FURTHER FLT PATH MODIFICATION. I OBSERVED THE FO PLACE FL280 IN THE ALT WINDOW AND SAY CLRED TO FL280 'NO DISCRETION.' I THEN REPEATED WHAT THE FO STATED TO ME AND BELIEVED THAT WE WERE CLRED TO DSND TO FL280 AT OUR DISCRETION. SINCE THE ACFT WOULD START THE PROGRAMMED DSCNT PATH IN ABOUT 6 MI AND I DID NOT HEAR DSND AND MAINTAIN FL280 NOW, CRUISE FLT AT FL390 WAS MAINTAINED. AT THAT POINT THE FO MADE NO INDICATION THAT THERE WAS ANY NON COMPLIANCE OCCURRING WITH THE FLT CLRNC RECEIVED. THE FO CHKED ON WITH ZID CTLR WHO IMMEDIATELY STATED 'I NEED FOR YOU TO DSND NOW. I STILL SHOW YOU AT FL390 SIR. WHAT ALT ARE YOU SHOWING?' THE FO STATED THAT WE ARE DSNDING AND WE ARE OUT OF FL385. DURING THE EXCHANGE AN IMMEDIATE DSCNT WAS INITIATED. THE CTLR GAVE US A TURN TO HDG WHILE WE WERE DSNDING AND THEN ANOTHER TURN BACK INTO THE TFC FLOW FOR AN ARR INTO LOUISVILLE. DSNDING THROUGH APPROX FL280 WE WERE REQUESTED TO CONTACT ZID WHEN ON THE GND AND GIVEN A PHONE NUMBER TO BE CALLED. THE FLT CONTINUED WITHOUT ANY FURTHER DEVS AND WE LANDED SAFELY AT THE LOUISVILLE STANDIFORD ARPT. ONCE ON THE GND I CALLED ZID AS REQUESTED AT APPROX AB54 AND LEFT A MESSAGE VIA THE ANSWERING MACHINE WITH THE REQUESTED INFO. I THEN CALLED AGAIN AROUND AI45 AND SPOKE WITH A REPRESENTATIVE AND ADVISED HIM OF THE ABOVE LISTED INFO AS REQUESTED. HE STATED THAT THERE HAD BEEN NO 'TFC SEPARATION' PROB AT THE TIME OF THE OCCURRENCE AND THAT THE TERM 'NO DISCRETION' WAS POSSIBLY CONFUSING AND SHOULD BE QUESTIONED IN THE FUTURE. A DEBRIEF WAS CONDUCTED WITH FO AND WE BOTH CONCLUDED THAT THE CONFUSION AROSE FROM THE INTERP OF THE TERM GIVEN 'NO DISCRETION.'

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.