DC9 crew had TCASII RA in ZAU class a.

Attributes
ACN	444422
Time
Date	199907
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : svm.vortac
State Reference	MI
Altitude	msl bound lower : 21500 msl bound upper : 21800
Environment
Flight Conditions	VMC
Weather Elements	Thunderstorm Turbulence
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zau.artcc artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : intermediate altitude
Route In Use	enroute airway : j70.airway
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zau.artcc
Make Model Name	Commercial Fixed Wing
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 9500 flight time type : 480
ASRS Report	444422
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne critical non adherence : published procedure non adherence : required legal separation non adherence : far
Resolutory Action	flight crew : took evasive action
Miss Distance	horizontal : 18000 vertical : 800
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error Inter Facility Coordination Failure

Narrative:

While flying from detroit to ord we were given clearance to climb to FL230 and clearance to join J-70 on heading of 300 degrees from ZOB. We were handed off to ZAU and checked on and reported our clearance from ZOB. While joining J-70 and climbing through FL215, ZAU told us to maintain FL210. I leveled and began descending as we reported 'out of FL215 for FL210.' approximately 10 seconds later, we received a TA and RA to descend. I increased descent rate to 1500 FPM and was clear of conflict at FL210. We reported the RA to ZAU. ZAU asked what altitude we had been cleared to previously. We told him FL230. ZAU cleared us to FL230. The traffic on TCASII was at our 10 O'clock position and 2 1/2 - 3 mi and initially showed red +300 ft. The total duration of the resolution was about 8 seconds. There was 1 thunderstorm cell south of us about 15 mi. I think the traffic was deviating north of the cell and became a conflict with us.

Original NASA ASRS Text

Title: DC9 CREW HAD TCASII RA IN ZAU CLASS A.

Narrative: WHILE FLYING FROM DETROIT TO ORD WE WERE GIVEN CLRNC TO CLB TO FL230 AND CLRNC TO JOIN J-70 ON HDG OF 300 DEGS FROM ZOB. WE WERE HANDED OFF TO ZAU AND CHKED ON AND RPTED OUR CLRNC FROM ZOB. WHILE JOINING J-70 AND CLBING THROUGH FL215, ZAU TOLD US TO MAINTAIN FL210. I LEVELED AND BEGAN DSNDING AS WE RPTED 'OUT OF FL215 FOR FL210.' APPROX 10 SECONDS LATER, WE RECEIVED A TA AND RA TO DSND. I INCREASED DSCNT RATE TO 1500 FPM AND WAS CLR OF CONFLICT AT FL210. WE RPTED THE RA TO ZAU. ZAU ASKED WHAT ALT WE HAD BEEN CLRED TO PREVIOUSLY. WE TOLD HIM FL230. ZAU CLRED US TO FL230. THE TFC ON TCASII WAS AT OUR 10 O'CLOCK POS AND 2 1/2 - 3 MI AND INITIALLY SHOWED RED +300 FT. THE TOTAL DURATION OF THE RESOLUTION WAS ABOUT 8 SECONDS. THERE WAS 1 TSTM CELL S OF US ABOUT 15 MI. I THINK THE TFC WAS DEVIATING N OF THE CELL AND BECAME A CONFLICT WITH 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.