Controller confused similar sounding call signs.

Attributes
ACN	437517
Time
Date	199905
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : rdu.airport
State Reference	NC
Altitude	msl bound lower : 14000 msl bound upper : 15000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	Jetstream 32
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 290 flight time total : 17000 flight time type : 12000
ASRS Report	437517
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : far non adherence : published procedure
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

At 15000 ft ZDC told air carrier abcd to descend to 11000 ft. We answered and started down. About 14000 ft the controller came back with 'air carrier abcd say your altitude.' we answered and he said 'that was for air carrier accd.' we asked if he wanted us to go back to 15000 ft and he said 'no just stop at 13000 ft.' we did and he pointed out some traffic but it was far away and I don't believe a factor in this situation. We heard no accd on our frequency until later on. I believe the controller was talking on 2 frequencys and did not hear our response, that is assuming we answered accd call and I do not believe we did. My first officer and myself heard 'air carrier abcd descend to 11000 ft.' our company needs to keep the call signs different on flts that are flying at the same times. Abcd and accd are too similar and the controller needs to tell us he is talking to another aircraft of a similar call sign (they usually do). We heard no feedback as if we spoke over top of someone. Our company usually keeps the call signs different but, not in this case. I will inform them of this problem. I do not think we will be violated on this, it did not appear to present a big problem to the controller, but who knows?

Original NASA ASRS Text

Title: CTLR CONFUSED SIMILAR SOUNDING CALL SIGNS.

Narrative: AT 15000 FT ZDC TOLD ACR ABCD TO DSND TO 11000 FT. WE ANSWERED AND STARTED DOWN. ABOUT 14000 FT THE CTLR CAME BACK WITH 'ACR ABCD SAY YOUR ALT.' WE ANSWERED AND HE SAID 'THAT WAS FOR ACR ACCD.' WE ASKED IF HE WANTED US TO GO BACK TO 15000 FT AND HE SAID 'NO JUST STOP AT 13000 FT.' WE DID AND HE POINTED OUT SOME TFC BUT IT WAS FAR AWAY AND I DON'T BELIEVE A FACTOR IN THIS SIT. WE HEARD NO ACCD ON OUR FREQ UNTIL LATER ON. I BELIEVE THE CTLR WAS TALKING ON 2 FREQS AND DID NOT HEAR OUR RESPONSE, THAT IS ASSUMING WE ANSWERED ACCD CALL AND I DO NOT BELIEVE WE DID. MY FO AND MYSELF HEARD 'ACR ABCD DSND TO 11000 FT.' OUR COMPANY NEEDS TO KEEP THE CALL SIGNS DIFFERENT ON FLTS THAT ARE FLYING AT THE SAME TIMES. ABCD AND ACCD ARE TOO SIMILAR AND THE CTLR NEEDS TO TELL US HE IS TALKING TO ANOTHER ACFT OF A SIMILAR CALL SIGN (THEY USUALLY DO). WE HEARD NO FEEDBACK AS IF WE SPOKE OVER TOP OF SOMEONE. OUR COMPANY USUALLY KEEPS THE CALL SIGNS DIFFERENT BUT, NOT IN THIS CASE. I WILL INFORM THEM OF THIS PROB. I DO NOT THINK WE WILL BE VIOLATED ON THIS, IT DID NOT APPEAR TO PRESENT A BIG PROB TO THE CTLR, BUT WHO KNOWS?

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.