Controller report of evasive action taken in response to TCASII RA. No traffic within 40 mi.

Attributes
ACN	258012
Time
Date	199305
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : azo
State Reference	MI
Altitude	msl bound lower : 29000 msl bound upper : 30000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	258012
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude 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
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

This happened a while back, but due to continuing TCASII problems, I've decided to report it. I was working an air carrier flight ord-elx-crl that had just leveled off at FL290. There was absolutely no traffic within 30 NM of the medium large transport, and that was same direction at FL330! Pilot reported out of FL290 for FL300 due to an RA. I queried pilot where TCASII showed traffic. Captain responded that he didn't see where but it was gone and they were descending back to FL290. I advised the crew of the only 2 aircraft around -- 30 NM ahead 4000 ft above. TCASII, I believe, will some day cause an in-flight accident, either with terrain or with 2 aircraft. The TCASII doesn't know the full situation at all times, and that is a major, possibly fatal flaw. It is for me as a human air traffic controller, and it is for TCASII as a computerized, backseat air traffic controller.

Original NASA ASRS Text

Title: CTLR RPT OF EVASIVE ACTION TAKEN IN RESPONSE TO TCASII RA. NO TFC WITHIN 40 MI.

Narrative: THIS HAPPENED A WHILE BACK, BUT DUE TO CONTINUING TCASII PROBS, I'VE DECIDED TO RPT IT. I WAS WORKING AN ACR FLT ORD-ELX-CRL THAT HAD JUST LEVELED OFF AT FL290. THERE WAS ABSOLUTELY NO TFC WITHIN 30 NM OF THE MLG, AND THAT WAS SAME DIRECTION AT FL330! PLT RPTED OUT OF FL290 FOR FL300 DUE TO AN RA. I QUERIED PLT WHERE TCASII SHOWED TFC. CAPT RESPONDED THAT HE DIDN'T SEE WHERE BUT IT WAS GONE AND THEY WERE DSNDING BACK TO FL290. I ADVISED THE CREW OF THE ONLY 2 ACFT AROUND -- 30 NM AHEAD 4000 FT ABOVE. TCASII, I BELIEVE, WILL SOME DAY CAUSE AN INFLT ACCIDENT, EITHER WITH TERRAIN OR WITH 2 ACFT. THE TCASII DOESN'T KNOW THE FULL SIT AT ALL TIMES, AND THAT IS A MAJOR, POSSIBLY FATAL FLAW. IT IS FOR ME AS A HUMAN AIR TFC CTLR, AND IT IS FOR TCASII AS A COMPUTERIZED, BACKSEAT AIR TFC CTLR.

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.