DC9 takes evasive action for an RA with no reported traffic in class B airspace.

Attributes
ACN	453140
Time
Date	199910
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : dtw.airport
State Reference	MI
Altitude	msl single value : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d21.tracon tracon : n90.tracon
Operator	common carrier : air carrier
Make Model Name	DC-9 50
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : d21.tracon
Operator	Other
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 10280 flight time type : 8000
ASRS Report	453140
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	conflict : airborne critical other anomaly other
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	Airspace Structure Aircraft
Primary Problem	Ambiguous

Narrative:

TCASII RA descending from 8000 ft to 6000 ft. We got a TCASII RA 'climb now 1500 FPM.' we stopped the descent and started a climb and the RA command stopped and we got a clear of conflict advisory. RA lasted about 2 seconds. No visual sighting of the conflict aircraft. I reported the RA to approach. Approach reported no other aircraft within 5 mi of our aircraft. We then started our descent to 6000 ft as cleared.

Original NASA ASRS Text

Title: DC9 TAKES EVASIVE ACTION FOR AN RA WITH NO RPTED TFC IN CLASS B AIRSPACE.

Narrative: TCASII RA DSNDING FROM 8000 FT TO 6000 FT. WE GOT A TCASII RA 'CLB NOW 1500 FPM.' WE STOPPED THE DSCNT AND STARTED A CLB AND THE RA COMMAND STOPPED AND WE GOT A CLR OF CONFLICT ADVISORY. RA LASTED ABOUT 2 SECONDS. NO VISUAL SIGHTING OF THE CONFLICT ACFT. I RPTED THE RA TO APCH. APCH RPTED NO OTHER ACFT WITHIN 5 MI OF OUR ACFT. WE THEN STARTED OUR DSCNT TO 6000 FT AS CLRED.

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.