ZSU controller voiced concern regarding the continued use of similar sounding call signs by aircraft...

Narrative:

Similar sounding call signs are going to cause a serious accident if action is not taken. I estimate 20 plus aircraft in my sector during the time of incident. The sector should have been de-combined but the flm was not engaged. I issued a descent clearance to air carrier zxx from FL330 to FL310 to get them under the A330 who was descending to FL320 landing mdpc. Opposite direction to air carrier zxx was air carrier XXX at FL340 who took the descent clearance for air carrier zxx; FL340 descending to FL310. So air carrier zxx is still at FL330 with the A330 converging and descending through FL340 for FL320. It was too late to stop the descent of the A330. I screamed at air carrier zxx to begin the descent thinking the pilot thought it was a pd. Air carrier XXX heard this and realized what was going on meanwhile he was opposite to air carrier zxx. Now these two were both descending to FL310. Air carrier zxx barely got under the A330 in time and now air carrier XXX started climbing back up to FL340. Air carrier XXX said I had told them initially to descend to FL310 and they had read it back. Regardless who did what; that was very close and unsafe and was a direct result of this similar sounding call sign madness that plagues our industry. Please make this situation a top priority to mitigate. ZSU has the same call signs everyday and it is reported dozens of times and nothing happens.

Original NASA ASRS Text

Title: ZSU Controller voiced concern regarding the continued use of similar sounding call signs by aircraft operating within their airspace citing a recent conflict resulting from similar sounding call signs.

Narrative: Similar sounding call signs are going to cause a serious accident if action is not taken. I estimate 20 plus aircraft in my sector during the time of incident. The sector should have been de-combined but the FLM was not engaged. I issued a descent clearance to Air Carrier ZXX from FL330 to FL310 to get them under the A330 who was descending to FL320 landing MDPC. Opposite direction to Air Carrier ZXX was Air Carrier XXX at FL340 who took the descent clearance for Air Carrier ZXX; FL340 descending to FL310. So Air Carrier ZXX is still at FL330 with the A330 converging and descending through FL340 for FL320. It was too late to stop the descent of the A330. I screamed at Air Carrier ZXX to begin the descent thinking the pilot thought it was a PD. Air Carrier XXX heard this and realized what was going on meanwhile he was opposite to Air Carrier ZXX. Now these two were both descending to FL310. Air Carrier ZXX barely got under the A330 in time and now Air Carrier XXX started climbing back up to FL340. Air Carrier XXX said I had told them initially to descend to FL310 and they had read it back. Regardless who did what; that was very close and unsafe and was a direct result of this similar sounding call sign madness that plagues our industry. Please make this situation a top priority to mitigate. ZSU has the same call signs everyday and it is reported dozens of times and nothing happens.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1006907
Time
Date	201204
Local Time Of Day	1801-2400
Place
Locale Reference	ZSU.ARTCC
State Reference	PR
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	A330
Operating Under FAR Part	Part 129
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types

ZSU controller voiced concern regarding the continued use of similar sounding call signs by aircraft operating within their airspace citing a recent conflict resulting from similar sounding call signs.