A cpr light transport crew reports that they have doubts about traffic that caused a TCASII RA.

Attributes
ACN	256693
Time
Date	199311
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dqo
State Reference	DE
Altitude	msl bound lower : 11000 msl bound upper : 13400
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other cruise other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 13000
ASRS Report	256693
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp
Experience	flight time last 90 days : 75 flight time total : 9000 flight time type : 760
ASRS Report	257190
Events
Anomaly	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 other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 1500
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

While in cruise flight at 11000 ft just no of the dqo VOR (V433) in IMC, ATC advised me that we had traffic below climbing to 10000 ft. ATC further indicated that he was not talking with the aircraft and assumed that this aircraft was going to stop his climb at 10000 ft. A few moments after receiving this transmission we had a TA on our TCASII which showed a target at the 2-3 O'clock position and 1700 ft below our altitude. What seemed to be only a few seconds later, we experienced an RA with instructions to 'climb, climb, climb,' immediately followed by 'increase climb.' the 'increase climb' mode on our TCASII commands a minimum climb speed of 2500-3000 FPM. At approximately 13200-13400 ft the TCASII gave the 'clear of conflict' command at which time I began a descent back to 11000 ft. To this day, I do not know what caused the problem. However, if it was a false signal received by the TCASII or some type of TCASII fault, then fixes to the TCASII system must be completed as soon as possible before major midair collisions occur. Supplemental information from acn 257190: we're climbing at something over 3000 FPM looking at each other, wondering why we're getting such a warning on traffic at such a distance. At 13100 ft we got the 'clear of conflict' command. Our climb peaked at 13400 ft. We advised ATC and went back down to 11000 ft. ATC asked what our TCASII had displayed. We told him that for the duration of the entire incident we had only that 1 target displayed at 3 O'clock. In my opinion the only bad element of the entire situation was created by the TCASII.

Original NASA ASRS Text

Title: A CPR LTT CREW RPTS THAT THEY HAVE DOUBTS ABOUT TFC THAT CAUSED A TCASII RA.

Narrative: WHILE IN CRUISE FLT AT 11000 FT JUST NO OF THE DQO VOR (V433) IN IMC, ATC ADVISED ME THAT WE HAD TFC BELOW CLBING TO 10000 FT. ATC FURTHER INDICATED THAT HE WAS NOT TALKING WITH THE ACFT AND ASSUMED THAT THIS ACFT WAS GOING TO STOP HIS CLB AT 10000 FT. A FEW MOMENTS AFTER RECEIVING THIS XMISSION WE HAD A TA ON OUR TCASII WHICH SHOWED A TARGET AT THE 2-3 O'CLOCK POS AND 1700 FT BELOW OUR ALT. WHAT SEEMED TO BE ONLY A FEW SECONDS LATER, WE EXPERIENCED AN RA WITH INSTRUCTIONS TO 'CLB, CLB, CLB,' IMMEDIATELY FOLLOWED BY 'INCREASE CLB.' THE 'INCREASE CLB' MODE ON OUR TCASII COMMANDS A MINIMUM CLB SPD OF 2500-3000 FPM. AT APPROX 13200-13400 FT THE TCASII GAVE THE 'CLR OF CONFLICT' COMMAND AT WHICH TIME I BEGAN A DSCNT BACK TO 11000 FT. TO THIS DAY, I DO NOT KNOW WHAT CAUSED THE PROB. HOWEVER, IF IT WAS A FALSE SIGNAL RECEIVED BY THE TCASII OR SOME TYPE OF TCASII FAULT, THEN FIXES TO THE TCASII SYS MUST BE COMPLETED ASAP BEFORE MAJOR MIDAIR COLLISIONS OCCUR. SUPPLEMENTAL INFO FROM ACN 257190: WE'RE CLBING AT SOMETHING OVER 3000 FPM LOOKING AT EACH OTHER, WONDERING WHY WE'RE GETTING SUCH A WARNING ON TFC AT SUCH A DISTANCE. AT 13100 FT WE GOT THE 'CLR OF CONFLICT' COMMAND. OUR CLB PEAKED AT 13400 FT. WE ADVISED ATC AND WENT BACK DOWN TO 11000 FT. ATC ASKED WHAT OUR TCASII HAD DISPLAYED. WE TOLD HIM THAT FOR THE DURATION OF THE ENTIRE INCIDENT WE HAD ONLY THAT 1 TARGET DISPLAYED AT 3 O'CLOCK. IN MY OPINION THE ONLY BAD ELEMENT OF THE ENTIRE SIT WAS CREATED BY THE TCASII.

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.