Near midair collision between a B737 on final visual approach to ord and a C172 passing 100 ft below...

Attributes
ACN	558793
Time
Date	200209
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : taffs
State Reference	IL
Altitude	msl single value : 2000
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : c90.tracon
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	558793
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
ASRS Report	558792
Events
Anomaly	conflict : nmac non adherence : far
Independent Detector	other flight crewa other flight crewb
Consequence	faa : reviewed incident with flight crew other
Miss Distance	horizontal : 0 vertical : 100
Supplementary
Problem Areas	Airspace Structure Flight Crew Human Performance ATC Human Performance ATC Facility
Primary Problem	Flight Crew Human Performance

Narrative:

Cleared visual approach runway 27R. Just outside of taffs, we received a TCASII advisory for traffic at our 10 O'clock position and an A320 was in that position flying the visual for runway 27L. The A320 was not a threat to our aircraft. We believed the A320 to be the reason for the advisory. Very shortly after concluding that the airbus was not a factor, we received an RA and I saw a C172 pass approximately 100 ft below us at the same 10 O'clock position as was noted of the airbus. After clear of the conflict, we continued the approach and advised ord tower of traffic description and position. There was no TA issued by the tower about the cessna. I contacted the tower supervisor by telephone and described the situation and he then advised me that the tower had just received a telephone call from a citizen complaining of a GA aircraft flying too close to arriving jet traffic at ord. I advised the supervisor of the aircraft description and the registration numbers. I told him that I was not 100% sure of the numbers, but those were the numbers that I recalled.

Original NASA ASRS Text

Title: NMAC BTWN A B737 ON FINAL VISUAL APCH TO ORD AND A C172 PASSING 100 FT BELOW.

Narrative: CLRED VISUAL APCH RWY 27R. JUST OUTSIDE OF TAFFS, WE RECEIVED A TCASII ADVISORY FOR TFC AT OUR 10 O'CLOCK POS AND AN A320 WAS IN THAT POS FLYING THE VISUAL FOR RWY 27L. THE A320 WAS NOT A THREAT TO OUR ACFT. WE BELIEVED THE A320 TO BE THE REASON FOR THE ADVISORY. VERY SHORTLY AFTER CONCLUDING THAT THE AIRBUS WAS NOT A FACTOR, WE RECEIVED AN RA AND I SAW A C172 PASS APPROX 100 FT BELOW US AT THE SAME 10 O'CLOCK POS AS WAS NOTED OF THE AIRBUS. AFTER CLR OF THE CONFLICT, WE CONTINUED THE APCH AND ADVISED ORD TWR OF TFC DESCRIPTION AND POS. THERE WAS NO TA ISSUED BY THE TWR ABOUT THE CESSNA. I CONTACTED THE TWR SUPVR BY TELEPHONE AND DESCRIBED THE SIT AND HE THEN ADVISED ME THAT THE TWR HAD JUST RECEIVED A TELEPHONE CALL FROM A CITIZEN COMPLAINING OF A GA ACFT FLYING TOO CLOSE TO ARRIVING JET TFC AT ORD. I ADVISED THE SUPVR OF THE ACFT DESCRIPTION AND THE REGISTRATION NUMBERS. I TOLD HIM THAT I WAS NOT 100% SURE OF THE NUMBERS, BUT THOSE WERE THE NUMBERS THAT I RECALLED.

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.