Narrative:

Flight XXX; a B737-800 ZZZ-ZZZ1. After takeoff near maximum gross weight; prior to flap retraction received a resolution advisory 'maintain vertical speed' with red area not to decrease to 1500 FPM or less rate of climb. Delayed thrust reduction and flap retraction to comply with RA and scanned for traffic. TCAS indicated a co-altitude target (red circle) less than .01 behind us. This occurred at 1000 ft MSL; and cleared up approximately 30 seconds later. Second RA occurred near 12000 ft MSL. Same target indication; a red circle co-altitude less than .01 behind us. Now the RA advised 'descend; descend; descend.' we started the descent; advising ATC of the RA and scanning for traffic. ATC advised us there was nothing in our vicinity; and TCAS was clean of targets for nearly 10 miles. Began to suspect EMI from cabin. Started to climb again -- ignoring the TCAS RA commands. The box was quiet. Recycled the transponder power. At 14000 ft; we got a third TCAS RA. Same display and descend callouts. We ignored them. Called cabin for a check of equipment that may have caused interference. Found passenger seated in first class with laptop on. Model hp 6220 with wireless function enabled. The passenger closed the lid when we were boarding on the ground; putting the laptop into standby/hibernate mode. Once he disabled the wireless function; all ok. The tech people should get a heads up on this. Guess the wireless function was trying to establish a connection and each time it did (or a fraction of the attempts) was interpreted as a TCAS signal. (Co-altitude; .01 behind us.) the display was a red circle; not a red square. No yellow or white circles prior to any RA events. Is the TCAS antenna cable shielded from internal (cabin computers) EMI? I have not seen an event like this before. What makes it hazardous -- is the rate of climb at departure; prior to acceleration and flap retraction and the 1500 FPM or greater rate of climb. (Transcon near maximum takeoff weight.) with the proliferation of wireless computers; I am sure we will be seeing this more often.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737-800 FLT CREW EXPERIENCED SEVERAL TCAS RA'S ALLEGEDLY GENERATED BY A WI-FI ENABLED LAPTOP COMPUTER.

Narrative: FLT XXX; A B737-800 ZZZ-ZZZ1. AFTER TKOF NEAR MAX GROSS WT; PRIOR TO FLAP RETRACTION RECEIVED A RESOLUTION ADVISORY 'MAINTAIN VERT SPD' WITH RED AREA NOT TO DECREASE TO 1500 FPM OR LESS RATE OF CLB. DELAYED THRUST REDUCTION AND FLAP RETRACTION TO COMPLY WITH RA AND SCANNED FOR TFC. TCAS INDICATED A CO-ALT TARGET (RED CIRCLE) LESS THAN .01 BEHIND US. THIS OCCURRED AT 1000 FT MSL; AND CLRED UP APPROX 30 SECONDS LATER. SECOND RA OCCURRED NEAR 12000 FT MSL. SAME TARGET INDICATION; A RED CIRCLE CO-ALT LESS THAN .01 BEHIND US. NOW THE RA ADVISED 'DSND; DSND; DSND.' WE STARTED THE DSCNT; ADVISING ATC OF THE RA AND SCANNING FOR TFC. ATC ADVISED US THERE WAS NOTHING IN OUR VICINITY; AND TCAS WAS CLEAN OF TARGETS FOR NEARLY 10 MILES. BEGAN TO SUSPECT EMI FROM CABIN. STARTED TO CLB AGAIN -- IGNORING THE TCAS RA COMMANDS. THE BOX WAS QUIET. RECYCLED THE XPONDER POWER. AT 14000 FT; WE GOT A THIRD TCAS RA. SAME DISPLAY AND DSND CALLOUTS. WE IGNORED THEM. CALLED CABIN FOR A CHK OF EQUIP THAT MAY HAVE CAUSED INTERFERENCE. FOUND PAX SEATED IN FIRST CLASS WITH LAPTOP ON. MODEL HP 6220 WITH WIRELESS FUNCTION ENABLED. THE PAX CLOSED THE LID WHEN WE WERE BOARDING ON THE GND; PUTTING THE LAPTOP INTO STANDBY/HIBERNATE MODE. ONCE HE DISABLED THE WIRELESS FUNCTION; ALL OK. THE TECH PEOPLE SHOULD GET A HEADS UP ON THIS. GUESS THE WIRELESS FUNCTION WAS TRYING TO ESTABLISH A CONNECTION AND EACH TIME IT DID (OR A FRACTION OF THE ATTEMPTS) WAS INTERPRETED AS A TCAS SIGNAL. (CO-ALT; .01 BEHIND US.) THE DISPLAY WAS A RED CIRCLE; NOT A RED SQUARE. NO YELLOW OR WHITE CIRCLES PRIOR TO ANY RA EVENTS. IS THE TCAS ANTENNA CABLE SHIELDED FROM INTERNAL (CABIN COMPUTERS) EMI? I HAVE NOT SEEN AN EVENT LIKE THIS BEFORE. WHAT MAKES IT HAZARDOUS -- IS THE RATE OF CLB AT DEP; PRIOR TO ACCELERATION AND FLAP RETRACTION AND THE 1500 FPM OR GREATER RATE OF CLB. (TRANSCON NEAR MAX TKOF WT.) WITH THE PROLIFERATION OF WIRELESS COMPUTERS; I AM SURE WE WILL BE SEEING THIS MORE OFTEN.

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.