Narrative:

Received descent clearance from dulles approach to 11000 ft on EMI arrival to bwi. As PNF, I read back both 'eleven thousand' and 'one-one thousand' per aim. Passing 12400 ft, iad approach asked why we weren't maintaining 13000 ft. I answered, 'because you cleared us to 11000 ft.' note: we had a jump seat rider and all 3 of us distinctly heard 11000 ft in his clearance. Controller was adamant about 13000 ft. He had conflicting traffic climbing to 12000 ft ahead of us. We climbed back to 12000 ft (had slipped below 12000 ft by now). Controller told climbing aircraft to level at 11000 ft. Stayed at least 1000 ft above traffic. Notes: 11000 ft is normal clearance at this point. Controller just forgot and did his normal thing, dulles approach controllers are notoriously inefficient, to be polite. Usually seem to be new. According to one dulles controller, they don't like working with my airline and some have a deliberate program of putting us last. Could any of this have been a factor? I don't know. Supplemental information from acn 484620: the captain and first officer were flying B757-200, air carrier X flight sep/xa/00, from den-bwi. A jump seater was present. He was a senior operations specialist from commercial radio. He was monitoring the frequency. Dulles approach control, transmitting on frequency 123.82 told air carrier X to descend from 15000 ft to 11000 ft. The altitude was read back, installed in the altitude window on the MCP, confirmed by the first officer and a descent was begun. Passing 12000 ft dulles approach inquired, 'are you descending to 13000 ft?' we responded, 'negative we were assigned 11000 ft.' the controller said 'no, you were assigned 13000 ft, climb now to 12000 ft.' the autoplt was disconnected and an immediate climb to 12000 ft was accomplished. In the meantime, an air carrier Y flight was assigned vectors and acquired us visually. The flight crew and the omc was sure that the assigned altitude was 11000 ft. The first officer was sure because he was planning on reaching the next fix at the recommended altitude of 11000 ft. I feel that the controller assigned an altitude in error, and then made some professional and calculated calls to remedy the situation. Good fix.

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Original NASA ASRS Text

Title: B757 CREW HAD IAD APCH CTLR MISSPEAK THE INTENDED ALT IN IAD CLASS E.

Narrative: RECEIVED DSCNT CLRNC FROM DULLES APCH TO 11000 FT ON EMI ARR TO BWI. AS PNF, I READ BACK BOTH 'ELEVEN THOUSAND' AND 'ONE-ONE THOUSAND' PER AIM. PASSING 12400 FT, IAD APCH ASKED WHY WE WEREN'T MAINTAINING 13000 FT. I ANSWERED, 'BECAUSE YOU CLRED US TO 11000 FT.' NOTE: WE HAD A JUMP SEAT RIDER AND ALL 3 OF US DISTINCTLY HEARD 11000 FT IN HIS CLRNC. CTLR WAS ADAMANT ABOUT 13000 FT. HE HAD CONFLICTING TFC CLBING TO 12000 FT AHEAD OF US. WE CLBED BACK TO 12000 FT (HAD SLIPPED BELOW 12000 FT BY NOW). CTLR TOLD CLBING ACFT TO LEVEL AT 11000 FT. STAYED AT LEAST 1000 FT ABOVE TFC. NOTES: 11000 FT IS NORMAL CLRNC AT THIS POINT. CTLR JUST FORGOT AND DID HIS NORMAL THING, DULLES APCH CTLRS ARE NOTORIOUSLY INEFFICIENT, TO BE POLITE. USUALLY SEEM TO BE NEW. ACCORDING TO ONE DULLES CTLR, THEY DON'T LIKE WORKING WITH MY AIRLINE AND SOME HAVE A DELIBERATE PROGRAM OF PUTTING US LAST. COULD ANY OF THIS HAVE BEEN A FACTOR? I DON'T KNOW. SUPPLEMENTAL INFO FROM ACN 484620: THE CAPT AND FO WERE FLYING B757-200, ACR X FLT SEP/XA/00, FROM DEN-BWI. A JUMP SEATER WAS PRESENT. HE WAS A SENIOR OPS SPECIALIST FROM COMMERCIAL RADIO. HE WAS MONITORING THE FREQ. DULLES APCH CTL, XMITTING ON FREQ 123.82 TOLD ACR X TO DSND FROM 15000 FT TO 11000 FT. THE ALT WAS READ BACK, INSTALLED IN THE ALT WINDOW ON THE MCP, CONFIRMED BY THE FO AND A DSCNT WAS BEGUN. PASSING 12000 FT DULLES APCH INQUIRED, 'ARE YOU DSNDING TO 13000 FT?' WE RESPONDED, 'NEGATIVE WE WERE ASSIGNED 11000 FT.' THE CTLR SAID 'NO, YOU WERE ASSIGNED 13000 FT, CLB NOW TO 12000 FT.' THE AUTOPLT WAS DISCONNECTED AND AN IMMEDIATE CLB TO 12000 FT WAS ACCOMPLISHED. IN THE MEANTIME, AN ACR Y FLT WAS ASSIGNED VECTORS AND ACQUIRED US VISUALLY. THE FLC AND THE OMC WAS SURE THAT THE ASSIGNED ALT WAS 11000 FT. THE FO WAS SURE BECAUSE HE WAS PLANNING ON REACHING THE NEXT FIX AT THE RECOMMENDED ALT OF 11000 FT. I FEEL THAT THE CTLR ASSIGNED AN ALT IN ERROR, AND THEN MADE SOME PROFESSIONAL AND CALCULATED CALLS TO REMEDY THE SIT. GOOD FIX.

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.