<< >> NASA ASRS Report 797661, August 2008

ZMP controller described TCAS RA at 5800; observing no traffic in vicinity; flight crew claiming several targets below on TCAS.

Attributes
ACN	797661
Time
Date	200808
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ste.airport
State Reference	WI
Altitude	msl single value : 5800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	SF 340B
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zmp.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller limited radar : 8 controller non radar : 8 controller radar : 8 controller time certified in position1 : 3 flight time total : 150
ASRS Report	797661
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne critical
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	Flight Crew Human Performance Navigational Facility ATC Human Performance Aircraft
Primary Problem	Ambiguous

Narrative:

Aircraft X was descending to 5000 ft into atw. I gave aircraft X a frequency change while they were still above 6000 ft. Shortly after that; aircraft X came back on the frequency and said they were responding to an RA and had climbed back to 6000 ft. I saw no targets within 5 mi of aircraft X. The nearest traffic I had was a C303 about 8 mi south of aircraft X going to osh at 5000 ft and a BE99 had passed underneath; opposite direction; at 4000 ft. The BE99 was 10 mi behind aircraft X when the RA happened. Aircraft X claimed to have several targets about 700 ft below them. I never saw any targets that close.

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• P50 controller described a TCAS RA event involving an IFR sd...

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Original NASA ASRS Text

Title: ZMP CTLR DESCRIBED TCAS RA AT 5800; OBSERVING NO TFC IN VICINITY; FLT CREW CLAIMING SEVERAL TARGETS BELOW ON TCAS.

Narrative: ACFT X WAS DSNDING TO 5000 FT INTO ATW. I GAVE ACFT X A FREQ CHANGE WHILE THEY WERE STILL ABOVE 6000 FT. SHORTLY AFTER THAT; ACFT X CAME BACK ON THE FREQ AND SAID THEY WERE RESPONDING TO AN RA AND HAD CLBED BACK TO 6000 FT. I SAW NO TARGETS WITHIN 5 MI OF ACFT X. THE NEAREST TFC I HAD WAS A C303 ABOUT 8 MI S OF ACFT X GOING TO OSH AT 5000 FT AND A BE99 HAD PASSED UNDERNEATH; OPPOSITE DIRECTION; AT 4000 FT. THE BE99 WAS 10 MI BEHIND ACFT X WHEN THE RA HAPPENED. ACFT X CLAIMED TO HAVE SEVERAL TARGETS ABOUT 700 FT BELOW THEM. I NEVER SAW ANY TARGETS THAT CLOSE.

Data retrieved from NASA's ASRS site as of May 2009 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.