Narrative:

The main issue was multiple similar sounding call signs. One aircraft took the others clearance. This took place on sector 24 (altitude limits of FL360 and up) at denver center ZDV. There was a band of chop and turbulence on the western half of the sector in the higher altitudes. Most west bound aircraft would request to descend to the low flight level 300s to get out of the bumps. Some of the east bound aircraft would remain at altitude since they had already been dealing with the bad rides for a while. Air carrier xxyx was west bound at FL400 and getting close to the area most aircraft started requesting a descent. Air carrier XXXX at FL410; east bound; had just come over from los angles center ZLA sector 32. The confusion was in the two similar sounding call signs. The frequency and workload was high due to so many aircraft requesting altitude changes. Many altitude descents were being given too many aircraft. During this time; air carrier XXXX requested lower. Also; during this time; air carrier xxyx was descended to FL380 and told to expect lower clear of traffic. Air carrier XXXX took air carrier xxyxs clearance and started to descend. Air carrier xxyx said they did not want lower yet. It was then discovered that air carrier XXXX was the one descending. When questioned; air carrier XXXX stated they had requested FL310; and were descending to that altitude. Understanding that they took the other aircrafts clearance; I pointed out that the clearance was only to FL380. Air carrier XXXX stated that they had not read back the clearance; and that they had just started descending. At this point it was determined that traffic was not a factor; and air carrier XXXX was assigned a descent to FL360 and to expect lower with the next sector. Though traffic was not an issue; it is questionable whether air carrier XXXX was clear of the ZLA sector 32/ZDV sector 24 boundary prior to starting the descent. As an additional note; before these two aircraft were out of the sector; air carrier xyyx entered the sector. There were now three company aircraft within the same sector with similar call signs: xyyx; XXXX; and xxyx. Recommendation; both controllers and pilots need to be extremely aware when complexity is high. The controller is trying to keep the sector running. The pilots (in this situation) are uncomfortable due to the turbulence and just want to move. So everyone is just a bit rushed. Of course; the controller needs to keep awareness up of who is saying what. However; it is also always important for an impatient pilot to make sure they are hearing something actually being said to them; as versus what they want. Also; I think at issue here is such similar call signs by the same company (air carrier xyyx; air carrier XXXX; air carrier xxyx). There were two similar ones at the time of this situation; and a third came into the sector while the other two were still there. I realize aircraft are crisscrossing all over the country at different times on different routes. Even if this was just a fluke; the airline needs to consider this.

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Original NASA ASRS Text

Title: ZDV controller described a confused operations period when several same company similar sounding call sign aircraft were on the frequency; asking for different altitudes; all resulting in a possible airspace infraction.

Narrative: The main issue was multiple similar sounding call signs. One aircraft took the others clearance. This took place on Sector 24 (altitude limits of FL360 and up) at Denver Center ZDV. There was a band of chop and turbulence on the western half of the sector in the higher altitudes. Most west bound aircraft would request to descend to the low Flight Level 300s to get out of the bumps. Some of the east bound aircraft would remain at altitude since they had already been dealing with the bad rides for a while. Air Carrier XXYX was west bound at FL400 and getting close to the area most aircraft started requesting a descent. Air Carrier XXXX at FL410; east bound; had just come over from Los Angles Center ZLA Sector 32. The confusion was in the two similar sounding call signs. The frequency and workload was high due to so many aircraft requesting altitude changes. Many altitude descents were being given too many aircraft. During this time; Air Carrier XXXX requested lower. Also; during this time; Air Carrier XXYX was descended to FL380 and told to expect lower clear of traffic. Air Carrier XXXX took Air Carrier XXYXs clearance and started to descend. Air Carrier XXYX said they did not want lower yet. It was then discovered that Air Carrier XXXX was the one descending. When questioned; Air Carrier XXXX stated they had requested FL310; and were descending to that altitude. Understanding that they took the other aircrafts clearance; I pointed out that the clearance was only to FL380. Air Carrier XXXX stated that they had not read back the clearance; and that they had just started descending. At this point it was determined that traffic was not a factor; and Air Carrier XXXX was assigned a descent to FL360 and to expect lower with the next sector. Though traffic was not an issue; it is questionable whether Air Carrier XXXX was clear of the ZLA Sector 32/ZDV Sector 24 boundary prior to starting the descent. As an additional note; before these two aircraft were out of the sector; Air Carrier XYYX entered the sector. There were now three company aircraft within the same sector with similar call signs: XYYX; XXXX; and XXYX. Recommendation; both Controllers and Pilots need to be extremely aware when complexity is high. The Controller is trying to keep the sector running. The Pilots (in this situation) are uncomfortable due to the turbulence and just want to move. So everyone is just a bit rushed. Of course; the Controller needs to keep awareness up of who is saying what. However; it is also always important for an impatient pilot to make sure they are hearing something actually being said to them; as versus what they want. Also; I think at issue here is such similar call signs by the same company (Air Carrier XYYX; Air Carrier XXXX; Air Carrier XXYX). There were two similar ones at the time of this situation; and a third came into the sector while the other two were still there. I realize aircraft are crisscrossing all over the country at different times on different routes. Even if this was just a fluke; the airline needs to consider this.

Data retrieved from NASA's ASRS site as of April 2012 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.