Descending B757 crew responded to a climb RA from TCASII.

Attributes
ACN	498621
Time
Date	200101
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dtw.airport
State Reference	WI
Altitude	msl bound lower : 16400 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zob.artcc tower : mli.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 220 flight time total : 12000 flight time type : 700
ASRS Report	498621
Person 2
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne critical non adherence : published procedure
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 14000 vertical : 400
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance Aircraft
Primary Problem	ATC Human Performance

Narrative:

Descending to 17000 ft as cleared, thought we heard clearance to 11000 ft. Asked controller to 'verify flight abc' was cleared to 11000 ft. He came back with 'yes, flight abc cleared to 11000 ft.' I responded 'flight abc cleared to 11000 ft.' at approximately 17000 ft, got TA then RA. Descended to 16400 ft while reversing descent and climbing back to 17000 ft, clearing RA. It appears controller also had a flight 'back course' on frequency and had issued one of us an incorrect clearance. Called ATC on phone the next day and supervisor said controller had just messed up. We had correct clearance and acted correctly. Similar call signs continue to be a problem.

Original NASA ASRS Text

Title: DSNDING B757 CREW RESPONDED TO A CLB RA FROM TCASII.

Narrative: DSNDING TO 17000 FT AS CLRED, THOUGHT WE HEARD CLRNC TO 11000 FT. ASKED CTLR TO 'VERIFY FLT ABC' WAS CLRED TO 11000 FT. HE CAME BACK WITH 'YES, FLT ABC CLRED TO 11000 FT.' I RESPONDED 'FLT ABC CLRED TO 11000 FT.' AT APPROX 17000 FT, GOT TA THEN RA. DSNDED TO 16400 FT WHILE REVERSING DSCNT AND CLBING BACK TO 17000 FT, CLRING RA. IT APPEARS CTLR ALSO HAD A FLT 'BC' ON FREQ AND HAD ISSUED ONE OF US AN INCORRECT CLRNC. CALLED ATC ON PHONE THE NEXT DAY AND SUPVR SAID CTLR HAD JUST MESSED UP. WE HAD CORRECT CLRNC AND ACTED CORRECTLY. SIMILAR CALL SIGNS CONTINUE TO BE A PROB.

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.