Enroute controller described an unauthorized descend and airspace incursion when a same company airc...

Narrative:

[We had] air carrier XXXX en route to wyoming; and air carrier xyxx en route to colorado both on frequency at the same time. Air carrier xyxx handed off to sector 1 for descent clearance to FL340 as per the fop for aircraft landing colorado. Air carrier xyxx given the frequency change to sector 1; air carrier XXXX answered the frequency change instead and the read back was missed. Air carrier XXXX checked in at sector 1 at FL380 and the sector 1 controller acknowledged air carrier XXXX and issued a descent clearance to FL340. Air carrier XXXX inquired about rides at FL340; the controller at sector 1 then called air carrier XXXX; air carrier xyxx and issued a frequency change to sector 3 and told the pilot to inquire about rides there. Air carrier XXXX accepted the descent clearance and frequency change where it was noticed that the incorrect aircraft was descending to FL340 and violating the airspace of sector 4. Appropriate action was taken to correct the descent and air carrier XXXX was climbed back up to FL380 and air carrier xyxx was descended to FL340 and shipped to the appropriate frequency. Have this air carrier change similar sounding call signs if they anticipate the aircraft being in the same sector at the same time.

Original NASA ASRS Text

Title: Enroute Controller described an unauthorized descend and airspace incursion when a same company aircraft with a similar sounding flight number initiated a descent issued to another company aircraft.

Narrative: [We had] Air Carrier XXXX en route to Wyoming; and Air Carrier XYXX en route to Colorado both on frequency at the same time. Air Carrier XYXX handed off to Sector 1 for descent clearance to FL340 as per the FOP for aircraft landing Colorado. Air Carrier XYXX given the frequency change to Sector 1; Air Carrier XXXX answered the frequency change instead and the read back was missed. Air Carrier XXXX checked in at Sector 1 at FL380 and the Sector 1 Controller acknowledged Air Carrier XXXX and issued a descent clearance to FL340. Air Carrier XXXX inquired about rides at FL340; the Controller at Sector 1 then called Air Carrier XXXX; Air Carrier XYXX and issued a frequency change to Sector 3 and told the pilot to inquire about rides there. Air Carrier XXXX accepted the descent clearance and frequency change where it was noticed that the incorrect aircraft was descending to FL340 and violating the airspace of Sector 4. Appropriate action was taken to correct the descent and Air Carrier XXXX was climbed back up to FL380 and Air Carrier XYXX was descended to FL340 and shipped to the appropriate frequency. Have this Air Carrier change similar sounding call signs if they anticipate the aircraft being in the same sector at the same time.

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	997923
Time
Date	201203
Local Time Of Day	0001-0600
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	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Airspace Violation All Types Deviation - Procedural Clearance

Enroute controller described an unauthorized descend and airspace incursion when a same company aircraft with a similar sounding flight number initiated a descent issued to another company aircraft.