Narrative:

When cleared for takeoff on runway 25R at lax TCASII annunciated a solid white circle directly over the aircraft symbol on the TCASII scope with a plus 4/plus 5 (400 to 500 ft) above our altitude. As best as I can recall this annunciation remained over the aircraft symbol throughout the takeoff unusual attitude and recovery. I noted a helicopter flying to the south of runways 25L/right and this aircraft was also annunciated on TCASII. Takeoff was uneventful until 800 ft AGL -- when the PF called for normal climb checklists (after gear up, flight level change, set speed, flaps 5 degrees, climb power). As I performed these tasks, my eyes left the ADI and other instruments. I also turned on strobes and crosschecked engine instruments. Aircraft attitude at the time of flap reconfign was wings level, 15 degrees nose up, climbing at 1500-2000 FPM. When I returned my xchk to the flight instruments, I saw the following attitude 5-10 degrees left bank, nose 4-5 degrees nose below horizon, flight director bars commanding up and right, airspeed increasing rapidly through 180 KTS, altitude decreasing through 650 ft afl/MSL. Recognizing an unusual attitude, I commanded 'climb!!' the GPWS issued a mode 3 alert -- aural alert, 'don't sink,' 3 to 5 times before climb was resumed. After PF reversed sink to climb I noted parallel departure traffic off runway 24L. This aircraft was not a factor in this incident, as far as TCASII alerts or proximity to the aircraft. Based on my observations and judgement of the PF and TCASII, here is what I think occurred. TCASII was showing a false echo directly over the aircraft throughout takeoff, 'traffic, traffic' aural TCASII alert occurred at weight off wheels. Due to light reflection off of the front wind screen, I think the PF (sitting in the left seat) saw the reflection of lights and maybe parallel traffic off the right side of the aircraft in the front windscreen and focused solely on this as he pushed over, to avoid this phantom aircraft. I never saw any aircraft near us to dictate this action, and the TCASII traffic overhead just 'disappeared' once we climbed to 1000-1500 ft AGL. Lax tower never called out any conflict, only parallel departure traffic, which was well clear! Prevention? Xchk at night especially, takeoff at lax and elsewhere.

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Original NASA ASRS Text

Title: NIGHT TKOF WITH TCASII ISSUING FALSE INFO. CFTT.

Narrative: WHEN CLRED FOR TKOF ON RWY 25R AT LAX TCASII ANNUNCIATED A SOLID WHITE CIRCLE DIRECTLY OVER THE ACFT SYMBOL ON THE TCASII SCOPE WITH A PLUS 4/PLUS 5 (400 TO 500 FT) ABOVE OUR ALT. AS BEST AS I CAN RECALL THIS ANNUNCIATION REMAINED OVER THE ACFT SYMBOL THROUGHOUT THE TKOF UNUSUAL ATTITUDE AND RECOVERY. I NOTED A HELI FLYING TO THE S OF RWYS 25L/R AND THIS ACFT WAS ALSO ANNUNCIATED ON TCASII. TKOF WAS UNEVENTFUL UNTIL 800 FT AGL -- WHEN THE PF CALLED FOR NORMAL CLB CHKLISTS (AFTER GEAR UP, FLT LEVEL CHANGE, SET SPD, FLAPS 5 DEGS, CLB PWR). AS I PERFORMED THESE TASKS, MY EYES LEFT THE ADI AND OTHER INSTS. I ALSO TURNED ON STROBES AND XCHKED ENG INSTS. ACFT ATTITUDE AT THE TIME OF FLAP RECONFIGN WAS WINGS LEVEL, 15 DEGS NOSE UP, CLBING AT 1500-2000 FPM. WHEN I RETURNED MY XCHK TO THE FLT INSTS, I SAW THE FOLLOWING ATTITUDE 5-10 DEGS L BANK, NOSE 4-5 DEGS NOSE BELOW HORIZON, FLT DIRECTOR BARS COMMANDING UP AND R, AIRSPEED INCREASING RAPIDLY THROUGH 180 KTS, ALT DECREASING THROUGH 650 FT AFL/MSL. RECOGNIZING AN UNUSUAL ATTITUDE, I COMMANDED 'CLB!!' THE GPWS ISSUED A MODE 3 ALERT -- AURAL ALERT, 'DON'T SINK,' 3 TO 5 TIMES BEFORE CLB WAS RESUMED. AFTER PF REVERSED SINK TO CLB I NOTED PARALLEL DEP TFC OFF RWY 24L. THIS ACFT WAS NOT A FACTOR IN THIS INCIDENT, AS FAR AS TCASII ALERTS OR PROX TO THE ACFT. BASED ON MY OBSERVATIONS AND JUDGEMENT OF THE PF AND TCASII, HERE IS WHAT I THINK OCCURRED. TCASII WAS SHOWING A FALSE ECHO DIRECTLY OVER THE ACFT THROUGHOUT TKOF, 'TFC, TFC' AURAL TCASII ALERT OCCURRED AT WT OFF WHEELS. DUE TO LIGHT REFLECTION OFF OF THE FRONT WIND SCREEN, I THINK THE PF (SITTING IN THE L SEAT) SAW THE REFLECTION OF LIGHTS AND MAYBE PARALLEL TFC OFF THE R SIDE OF THE ACFT IN THE FRONT WINDSCREEN AND FOCUSED SOLELY ON THIS AS HE PUSHED OVER, TO AVOID THIS PHANTOM ACFT. I NEVER SAW ANY ACFT NEAR US TO DICTATE THIS ACTION, AND THE TCASII TFC OVERHEAD JUST 'DISAPPEARED' ONCE WE CLBED TO 1000-1500 FT AGL. LAX TWR NEVER CALLED OUT ANY CONFLICT, ONLY PARALLEL DEP TFC, WHICH WAS WELL CLR! PREVENTION? XCHK AT NIGHT ESPECIALLY, TKOF AT LAX AND ELSEWHERE.

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.