Air carrier Y had less than standard separation from aircraft Z. System error.

Attributes
ACN	202239
Time
Date	199202
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gve
State Reference	VA
Altitude	msl bound lower : 29600 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : mia
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 3 controller radar : 22
ASRS Report	202239
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 15420 vertical : 1400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I issued a clearance to air carrier X to FL330, air carrier Y acknowledged for the clearance and I missed the readback. Contributing factors: I had to ask air carrier X what his planned mach speed would be at FL350 before I could climb him. When I called air carrier X I transposed last 2 digits of his flight number to air carrier Y. It was at this time that air carrier Y (without giving his flight number gave me his planned mach speed at FL350, he was also requesting FL350). Air carrier Y climbed, when conflict alert triggered I descended air carrier Y to FL290, he was at FL296, which resolved the confliction between air carrier Y and another aircraft Z at FL310. Corrective action: I should never have missed the readback when air carrier Y acknowledged the clearance for air carrier X. Air carrier X should have been paying attention when I cleared him to FL330 not air carrier Y. Air carrier Y should have been paying attention to the flight numbers when the clearance was issued.

Original NASA ASRS Text

Title: ACR Y HAD LTSS FROM ACFT Z. SYS ERROR.

Narrative: I ISSUED A CLRNC TO ACR X TO FL330, ACR Y ACKNOWLEDGED FOR THE CLRNC AND I MISSED THE READBACK. CONTRIBUTING FACTORS: I HAD TO ASK ACR X WHAT HIS PLANNED MACH SPD WOULD BE AT FL350 BEFORE I COULD CLB HIM. WHEN I CALLED ACR X I TRANSPOSED LAST 2 DIGITS OF HIS FLT NUMBER TO ACR Y. IT WAS AT THIS TIME THAT ACR Y (WITHOUT GIVING HIS FLT NUMBER GAVE ME HIS PLANNED MACH SPD AT FL350, HE WAS ALSO REQUESTING FL350). ACR Y CLBED, WHEN CONFLICT ALERT TRIGGERED I DSNDED ACR Y TO FL290, HE WAS AT FL296, WHICH RESOLVED THE CONFLICTION BTWN ACR Y AND ANOTHER ACFT Z AT FL310. CORRECTIVE ACTION: I SHOULD NEVER HAVE MISSED THE READBACK WHEN ACR Y ACKNOWLEDGED THE CLRNC FOR ACR X. ACR X SHOULD HAVE BEEN PAYING ATTN WHEN I CLRED HIM TO FL330 NOT ACR Y. ACR Y SHOULD HAVE BEEN PAYING ATTN TO THE FLT NUMBERS WHEN THE CLRNC WAS ISSUED.

Data retrieved from NASA's ASRS site as of July 2007 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.