ZMP controller described a clearance event when two company aircraft were on the reporter's frequenc...

Narrative:

Working sector 11; I took the hand off on aircraft Y climbing from low altitude sector 9 into my high altitude sector 11. Aircraft Y was out of about FL190; climbing to 230. The data block indicated FL340; as per letter of agreement. A company aircraft checked on. I climbed it to FL340; which it read back. A few seconds later; aircraft Y checked on; again; with a different voice; climbing out of FL190 to 230. I issued FL340 again; and thought about it. I quick-looked sector 9; and saw that they were much busier than I was. Moreover; they had a company aircraft X climbing out of FL205; with FL340 in the data block; southbound towards sector 18. On a hunch I asked if aircraft X was also on my frequency. They were; and it was the voice of the first company aircraft. I immediately told them to maintain FL230 'only'; and to return to their previous frequency. They read it back and left my frequency. At no time did aircraft X violate another controller's airspace. But it could have. Recommendation; I'm not sure. We all need to listen harder; I suppose.

Original NASA ASRS Text

Title: ZMP Controller described a clearance event when two company aircraft were on the reporter's frequency; one improperly. When the prior sector had assigned a frequency change; both aircraft took it.

Narrative: Working Sector 11; I took the hand off on Aircraft Y climbing from low altitude Sector 9 into my high altitude Sector 11. Aircraft Y was out of about FL190; climbing to 230. The data block indicated FL340; as per letter of agreement. A company aircraft checked on. I climbed it to FL340; which it read back. A few seconds later; Aircraft Y checked on; again; with a different voice; climbing out of FL190 to 230. I issued FL340 again; and thought about it. I quick-looked Sector 9; and saw that they were much busier than I was. Moreover; they had a Company Aircraft X climbing out of FL205; with FL340 in the data block; southbound towards Sector 18. On a hunch I asked if Aircraft X was also on my frequency. They were; and it was the voice of the first company aircraft. I immediately told them to maintain FL230 'only'; and to return to their previous frequency. They read it back and left my frequency. At no time did Aircraft X violate another controller's airspace. But it could have. Recommendation; I'm not sure. We all need to listen harder; I suppose.

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.

Attributes
ACN	876680
Time
Date	201003
Local Time Of Day	1801-2400
Place
Locale Reference	ZMP.ARTCC
State Reference	MN
Aircraft 1
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

ZMP controller described a clearance event when two company aircraft were on the reporter's frequency; one improperly. When the prior sector had assigned a frequency change; both aircraft took it.