Flight crew allegedly took clearance meant for another flight.

Attributes
ACN	145694
Time
Date	199005
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 100 flight time total : 4000 flight time type : 100
ASRS Report	145694
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 225 flight time total : 8500
ASRS Report	145858
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance other other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

At our time of departure our flight number is XX176. At the same time YY76 and 576 also depart. The area is so busy this time of day. The controllers speak too fast. Our initial climb clearance was to 5000'. We then thought we got a clearance to 13000'. Both of us heard it and the captain read it back. The next call from ATC said maintain 6000' as we were passing through 5500'. The captain called to confirm our original clearance to 13000' and the controller said that clearance was for YY576. Airlines should be restr at least in the terminal area, from having the similar flight numbers. It's easier to communicate in the en route phase but things are happening too fast in these busy terminal areas. Most times chicago controllers don't want you to read back clrncs because there is no room on the frequency.

Original NASA ASRS Text

Title: FLT CREW ALLEGEDLY TOOK CLRNC MEANT FOR ANOTHER FLT.

Narrative: AT OUR TIME OF DEP OUR FLT NUMBER IS XX176. AT THE SAME TIME YY76 AND 576 ALSO DEPART. THE AREA IS SO BUSY THIS TIME OF DAY. THE CTLRS SPEAK TOO FAST. OUR INITIAL CLIMB CLRNC WAS TO 5000'. WE THEN THOUGHT WE GOT A CLRNC TO 13000'. BOTH OF US HEARD IT AND THE CAPT READ IT BACK. THE NEXT CALL FROM ATC SAID MAINTAIN 6000' AS WE WERE PASSING THROUGH 5500'. THE CAPT CALLED TO CONFIRM OUR ORIGINAL CLRNC TO 13000' AND THE CTLR SAID THAT CLRNC WAS FOR YY576. AIRLINES SHOULD BE RESTR AT LEAST IN THE TERMINAL AREA, FROM HAVING THE SIMILAR FLT NUMBERS. IT'S EASIER TO COMMUNICATE IN THE ENRTE PHASE BUT THINGS ARE HAPPENING TOO FAST IN THESE BUSY TERMINAL AREAS. MOST TIMES CHICAGO CTLRS DON'T WANT YOU TO READ BACK CLRNCS BECAUSE THERE IS NO ROOM ON THE 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.