GLF5 responded to TCAS RA on intermittent target at 6000 entering holding at bdr VOR; ATC advised no...

Attributes
ACN	749852
Time
Date	200708
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : bdr.airport
State Reference	CT
Altitude	msl single value : 6000
Aircraft 1
Controlling Facilities	tracon : n90.tracon tower : mzbz.tower
Operator	general aviation : corporate
Make Model Name	Gulfstream V
Operating Under FAR Part	Part 91
Navigation In Use	other other vortac
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : multi engine pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 4950 flight time type : 440
ASRS Report	749852
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

We were entering a hold at the bridgeport VOR when we received a descend command from our TCAS. The display showed traffic ahead of us 400 ft above our altitude. The PF descended the plane in as commanded by the TCAS. According to the controller the only traffic in that area was well below our altitude; not above. While holding at the VOR this mysterious target appeared and disappeared several times; on each occasion the controller said there was no traffic in the area we described; at the VOR several hundred ft above us. The controller said the traffic in the area was several thousand ft below us. The plane has been checked out but no anomalies have been found nor has the plane issued RA's in error.

Original NASA ASRS Text

Title: GLF5 RESPONDED TO TCAS RA ON INTERMITTENT TARGET AT 6000 ENTERING HOLDING AT BDR VOR; ATC ADVISED NO TFC IN AREA.

Narrative: WE WERE ENTERING A HOLD AT THE BRIDGEPORT VOR WHEN WE RECEIVED A DSND COMMAND FROM OUR TCAS. THE DISPLAY SHOWED TFC AHEAD OF US 400 FT ABOVE OUR ALT. THE PF DSNDED THE PLANE IN AS COMMANDED BY THE TCAS. ACCORDING TO THE CTLR THE ONLY TFC IN THAT AREA WAS WELL BELOW OUR ALT; NOT ABOVE. WHILE HOLDING AT THE VOR THIS MYSTERIOUS TARGET APPEARED AND DISAPPEARED SEVERAL TIMES; ON EACH OCCASION THE CTLR SAID THERE WAS NO TFC IN THE AREA WE DESCRIBED; AT THE VOR SEVERAL HUNDRED FT ABOVE US. THE CTLR SAID THE TFC IN THE AREA WAS SEVERAL THOUSAND FT BELOW US. THE PLANE HAS BEEN CHKED OUT BUT NO ANOMALIES HAVE BEEN FOUND NOR HAS THE PLANE ISSUED RA'S IN ERROR.

Data retrieved from NASA's ASRS site as of January 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.

GLF5 responded to TCAS RA on intermittent target at 6000 entering holding at bdr VOR; ATC advised no traffic in area.