Potential conflict between opposite direction descending traffic.

Attributes
ACN	297858
Time
Date	199503
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rfd
State Reference	IL
Altitude	msl bound lower : 12000 msl bound upper : 12800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Route In Use	arrival other enroute airway : ord
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	other : unknown
Flight Phase	descent other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	297858
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	297859
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were approximately 10 mi from krena intersection on arrival to ord. We were cleared to 10000 ft and were through 14000 ft when ATC told us to expedite to 12000 ft. We reconfirmed that 12000 ft was our new clearance limit and it was confirmed. Just after this point we got a TCASII RA alert for traffic at our 12.00 position -- the RA directed a descent -- we had the aircraft in sight and it appeared to be at our altitude and descending. Our TCASII changed to climb RA which we responded to and climbed to approximately 12-800 ft then returned to 12000 ft after the RA event. We notified ATC of our response to the RA and that we had climbed. The traffic appeared to get within less than a mi of our position at our altitude. Supplemental information from acn 297859: we then saw an airplane at 12 O'clock about 5 NM and it appeared above and TCASII said it was descending. We got a RA, the captain responded by remaining visual and when it gave us a climb he initiated a climb as I informed center. The airplane passed about 1 NM and 500 or more ft below us as we climbed to 12-800 ft. We remained in visual contact with the other aircraft at all times during the RA.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT BTWN OPPOSITE DIRECTION DSNDING TFC.

Narrative: WE WERE APPROX 10 MI FROM KRENA INTXN ON ARR TO ORD. WE WERE CLRED TO 10000 FT AND WERE THROUGH 14000 FT WHEN ATC TOLD US TO EXPEDITE TO 12000 FT. WE RECONFIRMED THAT 12000 FT WAS OUR NEW CLRNC LIMIT AND IT WAS CONFIRMED. JUST AFTER THIS POINT WE GOT A TCASII RA ALERT FOR TFC AT OUR 12.00 POS -- THE RA DIRECTED A DSCNT -- WE HAD THE ACFT IN SIGHT AND IT APPEARED TO BE AT OUR ALT AND DSNDING. OUR TCASII CHANGED TO CLB RA WHICH WE RESPONDED TO AND CLBED TO APPROX 12-800 FT THEN RETURNED TO 12000 FT AFTER THE RA EVENT. WE NOTIFIED ATC OF OUR RESPONSE TO THE RA AND THAT WE HAD CLBED. THE TFC APPEARED TO GET WITHIN LESS THAN A MI OF OUR POS AT OUR ALT. SUPPLEMENTAL INFO FROM ACN 297859: WE THEN SAW AN AIRPLANE AT 12 O'CLOCK ABOUT 5 NM AND IT APPEARED ABOVE AND TCASII SAID IT WAS DSNDING. WE GOT A RA, THE CAPT RESPONDED BY REMAINING VISUAL AND WHEN IT GAVE US A CLB HE INITIATED A CLB AS I INFORMED CTR. THE AIRPLANE PASSED ABOUT 1 NM AND 500 OR MORE FT BELOW US AS WE CLBED TO 12-800 FT. WE REMAINED IN VISUAL CONTACT WITH THE OTHER ACFT AT ALL TIMES DURING THE RA.

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.