Call sign confusion for 2 flts of the same air carrier departing atl.

Attributes
ACN	210935
Time
Date	199205
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 10000 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute airway : atl
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 2800 flight time type : 800
ASRS Report	210935
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Departing out of atl, flying air carrier 1 flight abcd we were level at 10000 ft awaiting climb clearance from departure. We saw traffic pass overhead at 11000 and subsequently understood departure to clear us to climb to 14000 ft (as is normal for this departure). The PNF (captain) acknowledged the instruction by repeating it back with our flight number as normal. The controller then continued issuing instructions to other aircraft. As we were climbing, another flight, possibly air carrier 1, flight abed, finally broke in and stated that he thought another aircraft had accepted his climb clearance. Departure then issued his climb instructions to 14000. Concerned that there had been some confusion between abcd and abed we then queried departure that we had understood we were cleared to 14000, and he verified that was fine. We are still not sure if we made an error in accepting another aircraft's climb clearance or if abed mistakenly thought the clearance had been for him. Contributing factors include similar sounding call signs and a congested frequency.

Original NASA ASRS Text

Title: CALL SIGN CONFUSION FOR 2 FLTS OF THE SAME AIR CARRIER DEPARTING ATL.

Narrative: DEPARTING OUT OF ATL, FLYING ACR 1 FLT ABCD WE WERE LEVEL AT 10000 FT AWAITING CLB CLRNC FROM DEP. WE SAW TFC PASS OVERHEAD AT 11000 AND SUBSEQUENTLY UNDERSTOOD DEP TO CLR US TO CLB TO 14000 FT (AS IS NORMAL FOR THIS DEP). THE PNF (CAPT) ACKNOWLEDGED THE INSTRUCTION BY REPEATING IT BACK WITH OUR FLT NUMBER AS NORMAL. THE CTLR THEN CONTINUED ISSUING INSTRUCTIONS TO OTHER ACFT. AS WE WERE CLBING, ANOTHER FLT, POSSIBLY ACR 1, FLT ABED, FINALLY BROKE IN AND STATED THAT HE THOUGHT ANOTHER ACFT HAD ACCEPTED HIS CLB CLRNC. DEP THEN ISSUED HIS CLB INSTRUCTIONS TO 14000. CONCERNED THAT THERE HAD BEEN SOME CONFUSION BTWN ABCD AND ABED WE THEN QUERIED DEP THAT WE HAD UNDERSTOOD WE WERE CLRED TO 14000, AND HE VERIFIED THAT WAS FINE. WE ARE STILL NOT SURE IF WE MADE AN ERROR IN ACCEPTING ANOTHER ACFT'S CLB CLRNC OR IF ABED MISTAKENLY THOUGHT THE CLRNC HAD BEEN FOR HIM. CONTRIBUTING FACTORS INCLUDE SIMILAR SOUNDING CALL SIGNS AND A CONGESTED FREQ.

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.