Two same acrs had call sign confusion in sct class B.

Attributes
ACN	488131
Time
Date	200010
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : smo.vor
State Reference	CA
Altitude	msl bound lower : 9700 msl bound upper : 10000
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-90 Series (DC-9-90) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : sadde 6
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other other vortac
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : sadde 6
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	488131
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
ASRS Report	488130
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued alert controller : issued new clearance flight crew : returned to assigned altitude
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

Socal approach call sign mix up. We were at 10000 ft, talking to socal approach turning inbound on the 261 degree radial into santa monica VOR on the sadde six arrival, and socal approach instructed us to descend to 7000 ft and switch frequency. We checked in with the new frequency and the new controller told us to climb back to 10000 ft. We were at 9700 ft at that time. He said to switch back to the previous frequency and said we answered the wrong call sign when we read back descend to 7000 ft and switch to the new frequency. We believe we heard the controller give us instructions with our call sign. The other aircraft call sign was abcd which was very similar. We hope to have planning choose different sounding call signs to avoid the confusion among pilots and controllers.

Original NASA ASRS Text

Title: TWO SAME ACRS HAD CALL SIGN CONFUSION IN SCT CLASS B.

Narrative: SOCAL APCH CALL SIGN MIX UP. WE WERE AT 10000 FT, TALKING TO SOCAL APCH TURNING INBOUND ON THE 261 DEG RADIAL INTO SANTA MONICA VOR ON THE SADDE SIX ARR, AND SOCAL APCH INSTRUCTED US TO DSND TO 7000 FT AND SWITCH FREQ. WE CHKED IN WITH THE NEW FREQ AND THE NEW CTLR TOLD US TO CLB BACK TO 10000 FT. WE WERE AT 9700 FT AT THAT TIME. HE SAID TO SWITCH BACK TO THE PREVIOUS FREQ AND SAID WE ANSWERED THE WRONG CALL SIGN WHEN WE READ BACK DSND TO 7000 FT AND SWITCH TO THE NEW FREQ. WE BELIEVE WE HEARD THE CTLR GIVE US INSTRUCTIONS WITH OUR CALL SIGN. THE OTHER ACFT CALL SIGN WAS ABCD WHICH WAS VERY SIMILAR. WE HOPE TO HAVE PLANNING CHOOSE DIFFERENT SOUNDING CALL SIGNS TO AVOID THE CONFUSION AMONG PLTS AND CTLRS.

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.