Narrative:

The newark 7 departure from runway 4L calls for a turn to 060 degree until 4 DME ieza then turn to 290 degree and level off at 2500 ft. So things happen very quickly. There were LLWS advisories although we did not hear any while listening to the tower frequency. The winds were 340/19 gusting to 29. I increased the rotation speed by 10 KTS on takeoff. At maximum thrust and 196000 pounds we accelerated very quickly. After lift off out of 400 ft I began the turn to 060 degree the airspeed had increased to 175 KTS. I increased the pitch to about 20 degree to bleed off the excess airspeed. At 800 ft I lowered the nose and called for flaps 1 and v-nav. As the airspeed increased to the flaps 1 degree to 0 degree retraction speed I called for flaps up. At this time the autoflt system went to altitude capture mode and the speed bug came back to existing speed. Also we hit an area of turbulence at this time and lost about 10-15 KTS. We had such a high rate of climb the autothrottle brought the thrust back trying to maintain 175 KTS (indicated speed at time of altitude capture) as we hit the turbulence we had a momentary stick shaker for a split second. I noticed the speed was 175 KTS. Zero flap maneuvering speed was 210 KTS and stall speed was 149 KTS. I pushed the throttles up and called for speed 250. The first officer set the speed and the autothrottles increased the thrust up to maximum thrust, I had leveled at 1500 ft AGL and increased the airspeed above zero flap maneuvering speed then continued the climb. There were no other stick shaker activations. This is a classic trap. Whenever there is a low altitude level-off the autoflt system will maintain existing airspeed at altitude capture. If you have not reached your next flap retraction speed or lose speed with a turbulence encounter you could end up like I did. With flaps up and speed well below your flap maneuvering speed. Next time I will use a manual speed control when the departure has a low altitude level off. Callback conversation with reporter revealed the following information: low level wind sheer was reported. The aircraft was light. The crew programmed full rated takeoff thrust, and full rated climb thrust. The captain used an overspeed rotation procedure on takeoff. Because of the low altitude level off on the SID, and the high climb rate the altitude capture began at 1500 ft. This occurred during flap retraction to flaps 0. This triggered the automatic throttle to hold existing speed and initiated a large power reduction. This coupled with the high body angle '20 degrees' caused a rapid speed bleed off and the stick shaker. Reporter has flown the B747-400 and reports this aircraft does not cause the automatic throttle to revert to existing speed during altitude capture from v-nav. The captain suggests this programming change be made on other FMC equipped aircraft.

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Original NASA ASRS Text

Title: B757-200 CREW HAD ACFT STICK SHAKER ACTUATE DURING ALT CAPTURE DEPARTING EWR.

Narrative: THE NEWARK 7 DEP FROM RWY 4L CALLS FOR A TURN TO 060 DEG UNTIL 4 DME IEZA THEN TURN TO 290 DEG AND LEVEL OFF AT 2500 FT. SO THINGS HAPPEN VERY QUICKLY. THERE WERE LLWS ADVISORIES ALTHOUGH WE DID NOT HEAR ANY WHILE LISTENING TO THE TWR FREQ. THE WINDS WERE 340/19 GUSTING TO 29. I INCREASED THE ROTATION SPEED BY 10 KTS ON TKOF. AT MAX THRUST AND 196000 LBS WE ACCELERATED VERY QUICKLY. AFTER LIFT OFF OUT OF 400 FT I BEGAN THE TURN TO 060 DEG THE AIRSPEED HAD INCREASED TO 175 KTS. I INCREASED THE PITCH TO ABOUT 20 DEG TO BLEED OFF THE EXCESS AIRSPEED. AT 800 FT I LOWERED THE NOSE AND CALLED FOR FLAPS 1 AND V-NAV. AS THE AIRSPEED INCREASED TO THE FLAPS 1 DEG TO 0 DEG RETRACTION SPEED I CALLED FOR FLAPS UP. AT THIS TIME THE AUTOFLT SYS WENT TO ALTITUDE CAPTURE MODE AND THE SPEED BUG CAME BACK TO EXISTING SPEED. ALSO WE HIT AN AREA OF TURB AT THIS TIME AND LOST ABOUT 10-15 KTS. WE HAD SUCH A HIGH RATE OF CLB THE AUTOTHROTTLE BROUGHT THE THRUST BACK TRYING TO MAINTAIN 175 KTS (INDICATED SPEED AT TIME OF ALTITUDE CAPTURE) AS WE HIT THE TURB WE HAD A MOMENTARY STICK SHAKER FOR A SPLIT SEC. I NOTICED THE SPEED WAS 175 KTS. ZERO FLAP MANEUVERING SPEED WAS 210 KTS AND STALL SPEED WAS 149 KTS. I PUSHED THE THROTTLES UP AND CALLED FOR SPEED 250. THE FO SET THE SPEED AND THE AUTOTHROTTLES INCREASED THE THRUST UP TO MAX THRUST, I HAD LEVELED AT 1500 FT AGL AND INCREASED THE AIRSPEED ABOVE ZERO FLAP MANEUVERING SPEED THEN CONTINUED THE CLB. THERE WERE NO OTHER STICK SHAKER ACTIVATIONS. THIS IS A CLASSIC TRAP. WHENEVER THERE IS A LOW ALT LEVEL-OFF THE AUTOFLT SYS WILL MAINTAIN EXISTING AIRSPEED AT ALT CAPTURE. IF YOU HAVE NOT REACHED YOUR NEXT FLAP RETRACTION SPEED OR LOSE SPEED WITH A TURB ENCOUNTER YOU COULD END UP LIKE I DID. WITH FLAPS UP AND SPEED WELL BELOW YOUR FLAP MANEUVERING SPEED. NEXT TIME I WILL USE A MANUAL SPEED CTL WHEN THE DEP HAS A LOW ALTITUDE LEVEL OFF. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: LOW LEVEL WIND SHEER WAS RPTED. THE ACFT WAS LIGHT. THE CREW PROGRAMMED FULL RATED TKOF THRUST, AND FULL RATED CLB THRUST. THE CAPT USED AN OVERSPEED ROTATION PROC ON TKOF. BECAUSE OF THE LOW ALT LEVEL OFF ON THE SID, AND THE HIGH CLB RATE THE ALT CAPTURE BEGAN AT 1500 FT. THIS OCCURRED DURING FLAP RETRACTION TO FLAPS 0. THIS TRIGGERED THE AUTO THROTTLE TO HOLD EXISTING SPEED AND INITIATED A LARGE POWER REDUCTION. THIS COUPLED WITH THE HIGH BODY ANGLE '20 DEGS' CAUSED A RAPID SPEED BLEED OFF AND THE STICK SHAKER. RPTR HAS FLOWN THE B747-400 AND RPTS THIS ACFT DOES NOT CAUSE THE AUTO THROTTLE TO REVERT TO EXISTING SPEED DURING ALT CAPTURE FROM V-NAV. THE CAPT SUGGESTS THIS PROGRAMMING CHANGE BE MADE ON OTHER FMC EQUIPPED ACFT.

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.