An MD83 flight crew gets 2 TCASII RA's off 1 aircraft while circling east of psp, ca.

Attributes
ACN	504800
Time
Date	200103
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : psp.airport
State Reference	CA
Altitude	agl bound lower : 3000 agl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : psp.tracon
Operator	common carrier : air carrier
Make Model Name	MD-83
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : vacating altitude
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : psp.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute : direct
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : cfi pilot : atp pilot : instrument
Experience	flight time last 90 days : 220 flight time total : 13000 flight time type : 10000
ASRS Report	504800
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	atc equipment other atc equipment : radar aircraft equipment : tcas other controllera other flight crewa
Resolutory Action	controller : issued advisory flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Airspace Structure Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

ATC vectored us high and close to the psp airport for a visual to runway 13R. When cleared for the visual, I turned east to allow room for the descent and the turn back to downwind. Wbound VFR traffic was called by ATC and appeared on TCASII. Visual contact was made. Passing this traffic, a 'reduce descent' RA was generated and followed. No other traffic was observed on the TCASII or called by ATC. I turned right to enter the downwind for runway 13R. During the turn a TCASII target appeared moving toward us. This target closed on us and again a 'reduce descent' RA was generated and followed. Visual contact with this 'second' target was never made nor did ATC ever call it. Once 'clear of conflict' the landing was made without further incident. Note: given the fact that there were never 2 TCASII targets ever present and ATC never advised of additional traffic and visual contact was never made with the second target, is it possible that it was in fact a 'false' target return from the traffic we had already passed caused by the TCASII antenna tilt/orientation change during our turn (25-30 degree bank)?

Original NASA ASRS Text

Title: AN MD83 FLC GETS 2 TCASII RA'S OFF 1 ACFT WHILE CIRCLING E OF PSP, CA.

Narrative: ATC VECTORED US HIGH AND CLOSE TO THE PSP ARPT FOR A VISUAL TO RWY 13R. WHEN CLRED FOR THE VISUAL, I TURNED E TO ALLOW ROOM FOR THE DSCNT AND THE TURN BACK TO DOWNWIND. WBOUND VFR TFC WAS CALLED BY ATC AND APPEARED ON TCASII. VISUAL CONTACT WAS MADE. PASSING THIS TFC, A 'REDUCE DSCNT' RA WAS GENERATED AND FOLLOWED. NO OTHER TFC WAS OBSERVED ON THE TCASII OR CALLED BY ATC. I TURNED R TO ENTER THE DOWNWIND FOR RWY 13R. DURING THE TURN A TCASII TARGET APPEARED MOVING TOWARD US. THIS TARGET CLOSED ON US AND AGAIN A 'REDUCE DSCNT' RA WAS GENERATED AND FOLLOWED. VISUAL CONTACT WITH THIS 'SECOND' TARGET WAS NEVER MADE NOR DID ATC EVER CALL IT. ONCE 'CLR OF CONFLICT' THE LNDG WAS MADE WITHOUT FURTHER INCIDENT. NOTE: GIVEN THE FACT THAT THERE WERE NEVER 2 TCASII TARGETS EVER PRESENT AND ATC NEVER ADVISED OF ADDITIONAL TFC AND VISUAL CONTACT WAS NEVER MADE WITH THE SECOND TARGET, IS IT POSSIBLE THAT IT WAS IN FACT A 'FALSE' TARGET RETURN FROM THE TFC WE HAD ALREADY PASSED CAUSED BY THE TCASII ANTENNA TILT/ORIENTATION CHANGE DURING OUR TURN (25-30 DEG BANK)?

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.