Enroute controller described a near separation loss when multiple same company aircraft with similar...

Narrative:

I was at D2 which the stratum is up to FL350. Rx I think had 2 similar sounding call signs air carrier abc and air carrier air data computer. From what I gather; they were both shipped to ry and when the ry controller changed the altitude of air carrier air data computer from FL360 to FL350 when he was in ry's airspace; air carrier abc; who was in rx's airspace took it and descended. At ry; a pvd was quickly put up when rx noticed the air carrier descending. We had an aircraft at FL150 deviating; but we were able to turn and descend him just in case because we had no idea why the air carrier was descending. Nothing at sector 2 could have been done different; but every day all the time we have way too many similar sounding call signs in our airspace from the same company; mostly. They depart the same airport; fly almost the same routes and it's very dangerous. They also have routes that converge and we have to call traffic; which can be quite dangerous if one slips on listening. Also; the sectors in our area were completely saturated and were filled with deviations for weather. A little flow into the area would help with so many dangerous situations.

Original NASA ASRS Text

Title: Enroute Controller described a near separation loss when multiple same company aircraft with similar sounding flight numbers confused instructions/read backs and caused the event.

Narrative: I was at D2 which the stratum is up to FL350. RX I think had 2 similar sounding call signs Air Carrier ABC and Air Carrier ADC. From what I gather; they were both shipped to RY and when the RY Controller changed the altitude of Air Carrier ADC from FL360 to FL350 when he was in RY's airspace; Air Carrier ABC; who was in RX's airspace took it and descended. At RY; a PVD was quickly put up when RX noticed the Air Carrier descending. We had an aircraft at FL150 deviating; but we were able to turn and descend him just in case because we had no idea why the Air Carrier was descending. Nothing at Sector 2 could have been done different; but every day all the time we have way too many similar sounding call signs in our airspace from the same company; mostly. They depart the same airport; fly almost the same routes and it's very dangerous. They also have routes that converge and we have to call traffic; which can be quite dangerous if one slips on listening. Also; the sectors in our area were completely saturated and were filled with deviations for weather. A little flow into the area would help with so many dangerous situations.

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	997922
Time
Date	201203
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Enroute
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types

Enroute controller described a near separation loss when multiple same company aircraft with similar sounding flight numbers confused instructions/read backs and caused the event.