Air carrier assigned lower but has TCASII RA as descends.

Attributes
ACN	184559
Time
Date	199107
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 9000 msl bound upper : 9200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord tower : abe
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : private pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 4400 flight time type : 1400
ASRS Report	184559
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Inbound to ord we were cleared step-down altitudes from FL330 to 11000 ft. From 11000 ft we were cleared to 9000 ft approximately 30 mi west of ord and center handed us off to approach control. Upon leveling off at 9000 ft TCAS issued a TA immediately followed by a RA to climb. Soon after we initiated the climb, TCAS advised us we were clear of traffic. We had only climbed to 9200 ft and immediately returned to 9000 ft. TCAS showed the traffic at 400 ft in relation to us and when we called approach they said they had traffic in our area at approximately 8700 ft and that center probably shouldn't have cleared us to 9000 ft. If we hadn't of had TCAS we would never have known the traffic was there because we never saw any aircraft and ATC never issued an advisory. TCAS worked as published for us!

Original NASA ASRS Text

Title: ACR ASSIGNED LOWER BUT HAS TCASII RA AS DSNDS.

Narrative: INBND TO ORD WE WERE CLRED STEP-DOWN ALTS FROM FL330 TO 11000 FT. FROM 11000 FT WE WERE CLRED TO 9000 FT APPROX 30 MI W OF ORD AND CENTER HANDED US OFF TO APCH CTL. UPON LEVELING OFF AT 9000 FT TCAS ISSUED A TA IMMEDIATELY FOLLOWED BY A RA TO CLB. SOON AFTER WE INITIATED THE CLB, TCAS ADVISED US WE WERE CLR OF TFC. WE HAD ONLY CLBED TO 9200 FT AND IMMEDIATELY RETURNED TO 9000 FT. TCAS SHOWED THE TFC AT 400 FT IN RELATION TO US AND WHEN WE CALLED APCH THEY SAID THEY HAD TFC IN OUR AREA AT APPROX 8700 FT AND THAT CENTER PROBABLY SHOULDN'T HAVE CLRED US TO 9000 FT. IF WE HADN'T OF HAD TCAS WE WOULD NEVER HAVE KNOWN THE TFC WAS THERE BECAUSE WE NEVER SAW ANY ACFT AND ATC NEVER ISSUED AN ADVISORY. TCAS WORKED AS PUBLISHED FOR US!

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.