Flight crew reports erroneous readouts from TCASII TA RA's on non intruder aircraft.

Attributes
ACN	264669
Time
Date	199402
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 10000 msl bound upper : 10800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 5500 flight time type : 111
ASRS Report	264669
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 100
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Our assigned altitude was 10000 ft MSL and we had just passed 9000 ft with a vvi of 500 FPM and an IAS of 240 KTS. As we approached 9500 ft, TCASII issued a TA for a target at 2 O'clock, 5 mi, 900 ft below us. Approaching 10000 ft TCASII issued an RA -- 'monitor vertical speed,' followed almost immediately by 'climb, climb, climb.' the RA mode then shifted to 'climb, crossing climb' and directed a climb of over 2000 FPM. Although the WX was excellent, we were unable to see any traffic in the 1-2 O'clock position because we were looking straight into the late afternoon sun. We followed TCASII guidance -- per company procedures -- through our assigned altitude to approximately 10800 ft. We then saw our traffic coming out of the sun at 1-2 O'clock. It was an md-88 in a left turn about 1/2 mi away and above us. This other airplane, we later learned, was at 11000 ft through the entire encounter. Both the PNF and the jumpseat observer confirmed that the original TA and RA were issued on a target displayed on the screen as below us. The traffic we eventually saw was above us the entire time.

Original NASA ASRS Text

Title: FLC RPTS ERRONEOUS READOUTS FROM TCASII TA RA'S ON NON INTRUDER ACFT.

Narrative: OUR ASSIGNED ALT WAS 10000 FT MSL AND WE HAD JUST PASSED 9000 FT WITH A VVI OF 500 FPM AND AN IAS OF 240 KTS. AS WE APCHED 9500 FT, TCASII ISSUED A TA FOR A TARGET AT 2 O'CLOCK, 5 MI, 900 FT BELOW US. APCHING 10000 FT TCASII ISSUED AN RA -- 'MONITOR VERT SPD,' FOLLOWED ALMOST IMMEDIATELY BY 'CLB, CLB, CLB.' THE RA MODE THEN SHIFTED TO 'CLB, XING CLB' AND DIRECTED A CLB OF OVER 2000 FPM. ALTHOUGH THE WX WAS EXCELLENT, WE WERE UNABLE TO SEE ANY TFC IN THE 1-2 O'CLOCK POS BECAUSE WE WERE LOOKING STRAIGHT INTO THE LATE AFTERNOON SUN. WE FOLLOWED TCASII GUIDANCE -- PER COMPANY PROCS -- THROUGH OUR ASSIGNED ALT TO APPROX 10800 FT. WE THEN SAW OUR TFC COMING OUT OF THE SUN AT 1-2 O'CLOCK. IT WAS AN MD-88 IN A L TURN ABOUT 1/2 MI AWAY AND ABOVE US. THIS OTHER AIRPLANE, WE LATER LEARNED, WAS AT 11000 FT THROUGH THE ENTIRE ENCOUNTER. BOTH THE PNF AND THE JUMPSEAT OBSERVER CONFIRMED THAT THE ORIGINAL TA AND RA WERE ISSUED ON A TARGET DISPLAYED ON THE SCREEN AS BELOW US. THE TFC WE EVENTUALLY SAW WAS ABOVE US THE ENTIRE TIME.

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.