B737. ATC got same air carrier and similar call signs confused. He descended the wrong aircraft.

Attributes
ACN	473593
Time
Date	200005
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zme.artcc
State Reference	TN
Altitude	msl bound lower : 28000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zme.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 15300 flight time type : 1600
ASRS Report	473593
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : published procedure non adherence : far
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to assigned airspace
Supplementary
Problem Areas	FAA ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

Captain's turn to fly, my turn to talk. At FL350, we started encountering light chop, so the captain picked up the microphone and asked center for a ride report at lower altitudes. Center handed us off to next sector at that point. Previous controller had been confused between our flight (air carrier xyz) and another flight (same air carrier yzx). Captain checked in to next frequency and asked for ride report. Controller advised that rides were better lower. Captain asked for descent to FL240. ATC said 'air carrier xyz, descend to and maintain FL280.' so we started the descent. At about FL340, ATC said 'air carrier xyz, maintain FL350.' I said, 'we were cleared to FL280.' center responded by saying, 'negative, maintain FL350.' we were given a turn for the climb. Shortly after, we heard center say, 'same air carrier yzx, descend to and maintain FL280.'

Original NASA ASRS Text

Title: B737. ATC GOT SAME ACR AND SIMILAR CALL SIGNS CONFUSED. HE DSNDED THE WRONG ACFT.

Narrative: CAPT'S TURN TO FLY, MY TURN TO TALK. AT FL350, WE STARTED ENCOUNTERING LIGHT CHOP, SO THE CAPT PICKED UP THE MIKE AND ASKED CTR FOR A RIDE RPT AT LOWER ALTS. CTR HANDED US OFF TO NEXT SECTOR AT THAT POINT. PREVIOUS CTLR HAD BEEN CONFUSED BTWN OUR FLT (ACR XYZ) AND ANOTHER FLT (SAME ACR YZX). CAPT CHKED IN TO NEXT FREQ AND ASKED FOR RIDE RPT. CTLR ADVISED THAT RIDES WERE BETTER LOWER. CAPT ASKED FOR DSCNT TO FL240. ATC SAID 'ACR XYZ, DSND TO AND MAINTAIN FL280.' SO WE STARTED THE DSCNT. AT ABOUT FL340, ATC SAID 'ACR XYZ, MAINTAIN FL350.' I SAID, 'WE WERE CLRED TO FL280.' CTR RESPONDED BY SAYING, 'NEGATIVE, MAINTAIN FL350.' WE WERE GIVEN A TURN FOR THE CLB. SHORTLY AFTER, WE HEARD CTR SAY, 'SAME ACR YZX, DSND TO AND MAINTAIN FL280.'

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.