Narrative:

(Boeing 757). En route to atl on the macey arrival, ZTL was having difficulty sequencing aircraft due to high traffic volume and conflicts. The ATC had been stepping us down from high altitude in small increments. As we approached atlanta I was flying the aircraft on autoplt and told the captain that the controller was going to put us in a bind if we did not get a lower altitude. At that time we were at FL230 with traffic below. I began to slow the aircraft from 325 KIAS to 300 KIAS in order to provide more time to accomplish the anticipated descent and crossing restr at womac, (normally 13000 ft and 250 KIAS). Eventually, we were given the crossing restr and I began an immediate descent using the autoplt (fl change mode), full speed brakes, and increased speed (340 KIAS). Due to the late descent clearance it was going to be very close but with the increased speed during the descent we would just make it. When the captain acknowledged the call ATC responded with yet another restr. Maintain 290 KIAS in the descent. At this point I advised the captain that we would not be able to comply with the crossing restr and maintain the newly assigned speed. I expected him to call ATC and coordinate relief of the speed restr. Computer generated descent projections and my manual calculations indicated that we would comply with the altitude restr (13000 ft) but would exceed the speed restr of 250 KIAS at womac. He did not respond so I advised him a second time that we were unable to comply with ATC restrs and he responded by saying push the nose over and let it build up some speed. I reminded him of the ATC speed restr of 290 KIAS to which he did not respond. At this point I stated we are unable to comply with the crossing restr and asked if he would get relief from ATC. He responded by telling me to push the nose over and to gain speed and I reminded him that we were still restr to 290 KIAS. As we completed the descent checklist I advised ATC that we were unable womac at 250 KIAS. The captain then disengaged the autoplt and pushed the nose over increasing speed to 320-330 KIAS. ATC responded to my call passing 14500 ft by clearing us to 11000 ft and then slow to 210 KIAS, eliminating the womac restrs. I acknowledged the ATC transmission. We leveled at 13000 ft with full speed brakes idle power short of womac and subsequently crossed at 290 KIAS (the same point, speed, and confign we would have crossed without exceeding the ATC assigned speed, had the captain not intervened). The captain released the controls and I asked him who was flying the aircraft. He did not respond. I then reconfigured the autoplt and continued the descent to 11000 ft where I slowed to 210 KIAS as assigned. ATC had issued a clearance that was impossible to comply with. As part of the flight crew I was aware of the problem and willing to bring it to the controller's attention in order to insure all parties were fully aware of situation and to provide for alternative solutions while complying in every way possible with ATC instructions. Every one needs to be in the communications loop. The controller needs to be aware of descent capabilities of various types of aircraft and avoid if at all possible placing someone in a position where they cannot physically comply with the instructions. Flcs need also be made more comfortable with ATC flexibility and not be afraid to seek assistance because they are afraid they will be embarrassed by what 'gets out of the cockpit' or fearing they will be violated by the FAA for something that is beyond their control. A dogmatic adherence to established policies and procedures is valuable and prudent until such time as all room for flexibility and adaptability is stalemated.

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Original NASA ASRS Text

Title: ACFT HELD HIGH THEN GIVEN XING RESTRS AND SPD RESTRS. UNABLE TO COMPLY.

Narrative: (BOEING 757). ENRTE TO ATL ON THE MACEY ARR, ZTL WAS HAVING DIFFICULTY SEQUENCING ACFT DUE TO HIGH TFC VOLUME AND CONFLICTS. THE ATC HAD BEEN STEPPING US DOWN FROM HIGH ALT IN SMALL INCREMENTS. AS WE APCHED ATLANTA I WAS FLYING THE ACFT ON AUTOPLT AND TOLD THE CAPT THAT THE CTLR WAS GOING TO PUT US IN A BIND IF WE DID NOT GET A LOWER ALT. AT THAT TIME WE WERE AT FL230 WITH TFC BELOW. I BEGAN TO SLOW THE ACFT FROM 325 KIAS TO 300 KIAS IN ORDER TO PROVIDE MORE TIME TO ACCOMPLISH THE ANTICIPATED DSCNT AND XING RESTR AT WOMAC, (NORMALLY 13000 FT AND 250 KIAS). EVENTUALLY, WE WERE GIVEN THE XING RESTR AND I BEGAN AN IMMEDIATE DSCNT USING THE AUTOPLT (FL CHANGE MODE), FULL SPD BRAKES, AND INCREASED SPD (340 KIAS). DUE TO THE LATE DSCNT CLRNC IT WAS GOING TO BE VERY CLOSE BUT WITH THE INCREASED SPD DURING THE DSCNT WE WOULD JUST MAKE IT. WHEN THE CAPT ACKNOWLEDGED THE CALL ATC RESPONDED WITH YET ANOTHER RESTR. MAINTAIN 290 KIAS IN THE DSCNT. AT THIS POINT I ADVISED THE CAPT THAT WE WOULD NOT BE ABLE TO COMPLY WITH THE XING RESTR AND MAINTAIN THE NEWLY ASSIGNED SPD. I EXPECTED HIM TO CALL ATC AND COORDINATE RELIEF OF THE SPD RESTR. COMPUTER GENERATED DSCNT PROJECTIONS AND MY MANUAL CALCULATIONS INDICATED THAT WE WOULD COMPLY WITH THE ALT RESTR (13000 FT) BUT WOULD EXCEED THE SPD RESTR OF 250 KIAS AT WOMAC. HE DID NOT RESPOND SO I ADVISED HIM A SECOND TIME THAT WE WERE UNABLE TO COMPLY WITH ATC RESTRS AND HE RESPONDED BY SAYING PUSH THE NOSE OVER AND LET IT BUILD UP SOME SPD. I REMINDED HIM OF THE ATC SPD RESTR OF 290 KIAS TO WHICH HE DID NOT RESPOND. AT THIS POINT I STATED WE ARE UNABLE TO COMPLY WITH THE XING RESTR AND ASKED IF HE WOULD GET RELIEF FROM ATC. HE RESPONDED BY TELLING ME TO PUSH THE NOSE OVER AND TO GAIN SPD AND I REMINDED HIM THAT WE WERE STILL RESTR TO 290 KIAS. AS WE COMPLETED THE DSCNT CHKLIST I ADVISED ATC THAT WE WERE UNABLE WOMAC AT 250 KIAS. THE CAPT THEN DISENGAGED THE AUTOPLT AND PUSHED THE NOSE OVER INCREASING SPD TO 320-330 KIAS. ATC RESPONDED TO MY CALL PASSING 14500 FT BY CLRING US TO 11000 FT AND THEN SLOW TO 210 KIAS, ELIMINATING THE WOMAC RESTRS. I ACKNOWLEDGED THE ATC XMISSION. WE LEVELED AT 13000 FT WITH FULL SPD BRAKES IDLE PWR SHORT OF WOMAC AND SUBSEQUENTLY CROSSED AT 290 KIAS (THE SAME POINT, SPD, AND CONFIGN WE WOULD HAVE CROSSED WITHOUT EXCEEDING THE ATC ASSIGNED SPD, HAD THE CAPT NOT INTERVENED). THE CAPT RELEASED THE CTLS AND I ASKED HIM WHO WAS FLYING THE ACFT. HE DID NOT RESPOND. I THEN RECONFIGURED THE AUTOPLT AND CONTINUED THE DSCNT TO 11000 FT WHERE I SLOWED TO 210 KIAS AS ASSIGNED. ATC HAD ISSUED A CLRNC THAT WAS IMPOSSIBLE TO COMPLY WITH. AS PART OF THE FLC I WAS AWARE OF THE PROB AND WILLING TO BRING IT TO THE CTLR'S ATTN IN ORDER TO INSURE ALL PARTIES WERE FULLY AWARE OF SIT AND TO PROVIDE FOR ALTERNATIVE SOLUTIONS WHILE COMPLYING IN EVERY WAY POSSIBLE WITH ATC INSTRUCTIONS. EVERY ONE NEEDS TO BE IN THE COMS LOOP. THE CTLR NEEDS TO BE AWARE OF DSCNT CAPABILITIES OF VARIOUS TYPES OF ACFT AND AVOID IF AT ALL POSSIBLE PLACING SOMEONE IN A POS WHERE THEY CANNOT PHYSICALLY COMPLY WITH THE INSTRUCTIONS. FLCS NEED ALSO BE MADE MORE COMFORTABLE WITH ATC FLEXIBILITY AND NOT BE AFRAID TO SEEK ASSISTANCE BECAUSE THEY ARE AFRAID THEY WILL BE EMBARRASSED BY WHAT 'GETS OUT OF THE COCKPIT' OR FEARING THEY WILL BE VIOLATED BY THE FAA FOR SOMETHING THAT IS BEYOND THEIR CTL. A DOGMATIC ADHERENCE TO ESTABLISHED POLICIES AND PROCS IS VALUABLE AND PRUDENT UNTIL SUCH TIME AS ALL ROOM FOR FLEXIBILITY AND ADAPTABILITY IS STALEMATED.

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.