DC9-30 crew had a TCASII RA in ZAU class a.

Attributes
ACN	583618
Time
Date	200306
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : msn.vortac
State Reference	WI
Altitude	msl single value : 23000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 30
Operating Under FAR Part	Part 121
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 : 200 flight time total : 17000 flight time type : 2000
ASRS Report	583618
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure non adherence : far other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb other other : 3
Resolutory Action	flight crew : took evasive action none taken : detected after the fact
Supplementary
Problem Areas	Company FAA
Primary Problem	Company

Narrative:

At cruise at FL230 over msn VOR the TCA's issued an RA to climb, which I followed to about 23700 ft, then was issued a clear of conflict from TCA's. The first officer told ZAU we were doing a climb a required climb for an RA. Center advised us they had no traffic below us within 50 mi and 1 target above us at FL250. We had an FAA inspector in the cockpit jump seat who said we did the correct thing. He thought the RA came from a radio shop doing an altimeter check from below us that gave our TCASII erroneous information.

Original NASA ASRS Text

Title: DC9-30 CREW HAD A TCASII RA IN ZAU CLASS A.

Narrative: AT CRUISE AT FL230 OVER MSN VOR THE TCA'S ISSUED AN RA TO CLB, WHICH I FOLLOWED TO ABOUT 23700 FT, THEN WAS ISSUED A CLR OF CONFLICT FROM TCA'S. THE FO TOLD ZAU WE WERE DOING A CLB A REQUIRED CLB FOR AN RA. CTR ADVISED US THEY HAD NO TFC BELOW US WITHIN 50 MI AND 1 TARGET ABOVE US AT FL250. WE HAD AN FAA INSPECTOR IN THE COCKPIT JUMP SEAT WHO SAID WE DID THE CORRECT THING. HE THOUGHT THE RA CAME FROM A RADIO SHOP DOING AN ALTIMETER CHK FROM BELOW US THAT GAVE OUR TCASII ERRONEOUS INFO.

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.