Narrative:

On takeoff ktys at 1000 ft AGL (2000 ft MSL) wind shear guidance system activated. Airspeed dropped from 190 KTS to 142 KTS (V2). First officer followed guidance plus wind shear recovery techniques. After approximately 5 seconds airspeed started to increase and continued climb. There were no obvious signs of wind shear. A fast moving cold front came through the evening before. There were some rain showers approximately 60-70 mi southeast and sometimes at night. The winds just above the surface are much different. In this case, the FMS did not show any significant wind. The wind shear guidance system helped by eliminating any doubt as to the cause of lost performance and probably saved several seconds of recovery time since it was not expected. Also, we had elected to use normal instead of alternate power which put us approximately 35000 pounds under maximum takeoff weight versus 6000 pounds under maximum takeoff weight. The reason for this was knowledge about strange night time winds at night in mountainous areas and the possibility of unknown thunderstorm since we were first flight of day. At no time was recovery in doubt, but if it happened 30 seconds earlier at liftoff it would have been interesting.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLC OF AN MLG ACR ACFT ENCOUNTERED WIND SHEAR DURING INITIAL CLB ON DEP RESULTING IN A MOMENTARY LOSS OF ACFT AIRSPD CTL AND THE ACTIVATE OF THE WIND SHEAR WARNING INDICATION.

Narrative: ON TKOF KTYS AT 1000 FT AGL (2000 FT MSL) WIND SHEAR GUIDANCE SYS ACTIVATED. AIRSPD DROPPED FROM 190 KTS TO 142 KTS (V2). FO FOLLOWED GUIDANCE PLUS WIND SHEAR RECOVERY TECHNIQUES. AFTER APPROX 5 SECONDS AIRSPD STARTED TO INCREASE AND CONTINUED CLB. THERE WERE NO OBVIOUS SIGNS OF WIND SHEAR. A FAST MOVING COLD FRONT CAME THROUGH THE EVENING BEFORE. THERE WERE SOME RAIN SHOWERS APPROX 60-70 MI SE AND SOMETIMES AT NIGHT. THE WINDS JUST ABOVE THE SURFACE ARE MUCH DIFFERENT. IN THIS CASE, THE FMS DID NOT SHOW ANY SIGNIFICANT WIND. THE WIND SHEAR GUIDANCE SYS HELPED BY ELIMINATING ANY DOUBT AS TO THE CAUSE OF LOST PERFORMANCE AND PROBABLY SAVED SEVERAL SECONDS OF RECOVERY TIME SINCE IT WAS NOT EXPECTED. ALSO, WE HAD ELECTED TO USE NORMAL INSTEAD OF ALTERNATE PWR WHICH PUT US APPROX 35000 LBS UNDER MAX TKOF WT VERSUS 6000 LBS UNDER MAX TKOF WT. THE REASON FOR THIS WAS KNOWLEDGE ABOUT STRANGE NIGHT TIME WINDS AT NIGHT IN MOUNTAINOUS AREAS AND THE POSSIBILITY OF UNKNOWN TSTM SINCE WE WERE FIRST FLT OF DAY. AT NO TIME WAS RECOVERY IN DOUBT, BUT IF IT HAPPENED 30 SECONDS EARLIER AT LIFTOFF IT WOULD HAVE BEEN INTERESTING.

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.