DC9 flight crew on approach has TCASII alert of traffic directly above.

Attributes
ACN	319838
Time
Date	199510
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : iah
State Reference	TX
Altitude	msl bound lower : 1700 msl bound upper : 1700
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tower : iah
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 12000
ASRS Report	319838
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 0
Supplementary
Primary Problem	Ambiguous

Narrative:

Flight from bro to iah, first officer flying, cleared for ILS runway 27 approach at 2000 ft. Turned over to iah tower, cleared to land. Advised of traffic crossing 1000 ft above and observed on TCASII. Started down the GS with gear down. At about 1700 ft, I noticed on TCASII the previously called traffic was right above us and descending. Immediately a second tower voice gave us a right turn to 360 degree and the TCASII gave us a descend RA, tower called an immediate right turn in an urgent voice. Separation was achieved. Incident reported to company system control and safety. At this point, I don't know if the error was ATC or flight crew.

Original NASA ASRS Text

Title: DC9 FLC ON APCH HAS TCASII ALERT OF TFC DIRECTLY ABOVE.

Narrative: FLT FROM BRO TO IAH, FO FLYING, CLRED FOR ILS RWY 27 APCH AT 2000 FT. TURNED OVER TO IAH TWR, CLRED TO LAND. ADVISED OF TFC XING 1000 FT ABOVE AND OBSERVED ON TCASII. STARTED DOWN THE GS WITH GEAR DOWN. AT ABOUT 1700 FT, I NOTICED ON TCASII THE PREVIOUSLY CALLED TFC WAS RIGHT ABOVE US AND DSNDING. IMMEDIATELY A SECOND TWR VOICE GAVE US A R TURN TO 360 DEG AND THE TCASII GAVE US A DSND RA, TWR CALLED AN IMMEDIATE R TURN IN AN URGENT VOICE. SEPARATION WAS ACHIEVED. INCIDENT RPTED TO COMPANY SYS CTL AND SAFETY. AT THIS POINT, I DON'T KNOW IF THE ERROR WAS ATC OR FLC.

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.