B757 first officer followed TCASII resolutions shortly after takeoff that proved to be false since neither TCASII nor departure control radar showed any aircraft in their area.

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Attributes
ACN	501425
Time
Date	200102
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : bos.airport
State Reference	MA
Altitude	msl bound lower : 4000 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : a90.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	climbout : initial
Route In Use	departure : other published ifr departure
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 174 flight time total : 14657 flight time type : 1025
ASRS Report	501425
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 181 flight time total : 16733 flight time type : 2955
ASRS Report	501850
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated flight crew : returned to original clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Shortly after takeoff from bos runway 22R, we were in a left turn and climbing and received a TCASII RA to 'descend.' I complied with the advisory as mandated to do so. ATC advised us that there was no traffic that was a factor. TCASII continued to give a 'descend, descend now' advisory. The TCASII display was showing traffic on our nose at our altitude. After being notified again from ATC that traffic was not a factor, I started a climbing left turn again and received a 'descend, crossing descend' advisory. After approximately 6000 ft MSL, the TCASII display went to a normal, no traffic condition. I never did receive a clear of conflict advisory. I believe this was a false TCASII RA. The TCASII display showed traffic on our nose, at our altitude, that was not moving on the display during the warnings. I don't know what caused the false warnings. The aircraft was deiced with type 1 prior to departure and the TCASII system tested ok during preflight. The problem was entered into the maintenance logbook and the system (TCASII) was deferred for repair. No previous history of this problem could be found in the maintenance logbook. It was very hard to start a climb as advised by ATC when the TCASII is telling us to descend. Not a good situation.

Original NASA ASRS Text

Title: B757 FO FOLLOWED TCASII RESOLUTIONS SHORTLY AFTER TKOF THAT PROVED TO BE FALSE SINCE NEITHER TCASII NOR DEP CTL RADAR SHOWED ANY ACFT IN THEIR AREA.

Narrative: SHORTLY AFTER TKOF FROM BOS RWY 22R, WE WERE IN A L TURN AND CLBING AND RECEIVED A TCASII RA TO 'DSND.' I COMPLIED WITH THE ADVISORY AS MANDATED TO DO SO. ATC ADVISED US THAT THERE WAS NO TFC THAT WAS A FACTOR. TCASII CONTINUED TO GIVE A 'DSND, DSND NOW' ADVISORY. THE TCASII DISPLAY WAS SHOWING TFC ON OUR NOSE AT OUR ALT. AFTER BEING NOTIFIED AGAIN FROM ATC THAT TFC WAS NOT A FACTOR, I STARTED A CLBING L TURN AGAIN AND RECEIVED A 'DSND, XING DSND' ADVISORY. AFTER APPROX 6000 FT MSL, THE TCASII DISPLAY WENT TO A NORMAL, NO TFC CONDITION. I NEVER DID RECEIVE A CLR OF CONFLICT ADVISORY. I BELIEVE THIS WAS A FALSE TCASII RA. THE TCASII DISPLAY SHOWED TFC ON OUR NOSE, AT OUR ALT, THAT WAS NOT MOVING ON THE DISPLAY DURING THE WARNINGS. I DON'T KNOW WHAT CAUSED THE FALSE WARNINGS. THE ACFT WAS DEICED WITH TYPE 1 PRIOR TO DEP AND THE TCASII SYS TESTED OK DURING PREFLT. THE PROB WAS ENTERED INTO THE MAINT LOGBOOK AND THE SYS (TCASII) WAS DEFERRED FOR REPAIR. NO PREVIOUS HISTORY OF THIS PROB COULD BE FOUND IN THE MAINT LOGBOOK. IT WAS VERY HARD TO START A CLB AS ADVISED BY ATC WHEN THE TCASII IS TELLING US TO DSND. NOT A GOOD SIT.

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.