Widebody transport flight crew took clearance meant for a similar numbered same company flight.

Attributes
ACN	120692
Time
Date	198908
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : svm
State Reference	MI
Altitude	msl bound lower : 29000 msl bound upper : 29700
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute airway : j70
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 6000 flight time type : 200
ASRS Report	120692
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Intermediate level off at FL290. Center was heard by crew to say, '(call sign) 88, turn right to 090 degrees, climb and maintain FL370' (our requested final). First officer acknowledged '(call sign) 88 turning right to 090 degrees, out of FL290, climbing to FL370.' while passing FL296 center asked our altitude, and when confirmed, controller said to descend immediately to FL290. We then discovered the clearance was meant for flight 80 of the same company, right behind us. No other problems encountered. Our flight topped out at FL297 before returning to FL290. This is the continuing problem of similar call signs. Companies could perhaps make a better effort at not so similar call signs. Controller said our readback was blocked by 80's readback. Who really knows if it was our misunderstanding or controller actually said and heard wrong call sign? I don't know the solution to this problem, but it's a big one

Original NASA ASRS Text

Title: WDB FLT CREW TOOK CLRNC MEANT FOR A SIMILAR NUMBERED SAME COMPANY FLT.

Narrative: INTERMEDIATE LEVEL OFF AT FL290. CENTER WAS HEARD BY CREW TO SAY, '(CALL SIGN) 88, TURN RIGHT TO 090 DEGS, CLB AND MAINTAIN FL370' (OUR REQUESTED FINAL). F/O ACKNOWLEDGED '(CALL SIGN) 88 TURNING RIGHT TO 090 DEGS, OUT OF FL290, CLBING TO FL370.' WHILE PASSING FL296 CENTER ASKED OUR ALT, AND WHEN CONFIRMED, CTLR SAID TO DSND IMMEDIATELY TO FL290. WE THEN DISCOVERED THE CLRNC WAS MEANT FOR FLT 80 OF THE SAME COMPANY, RIGHT BEHIND US. NO OTHER PROBS ENCOUNTERED. OUR FLT TOPPED OUT AT FL297 BEFORE RETURNING TO FL290. THIS IS THE CONTINUING PROB OF SIMILAR CALL SIGNS. COMPANIES COULD PERHAPS MAKE A BETTER EFFORT AT NOT SO SIMILAR CALL SIGNS. CTLR SAID OUR READBACK WAS BLOCKED BY 80'S READBACK. WHO REALLY KNOWS IF IT WAS OUR MISUNDERSTANDING OR CTLR ACTUALLY SAID AND HEARD WRONG CALL SIGN? I DON'T KNOW THE SOLUTION TO THIS PROB, BUT IT'S A BIG ONE

Data retrieved from NASA's ASRS site as of August 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.