Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Confusion
Aircraft Equipment Problem Critical
Aircraft Equipment Problem Dissipated; General Maintenance Action
Aircraft
Following a reduced power takeoff; correctly computed for Runway XX and the correct aircraft weight; the Captain (while hand flying) commanded 'flaps up' at 1;000 AGL with airspeed at 170K and accelerating (a long green acceleration indication on both speed tapes) and with a rate of climb of 500 FPM. When I raised the flap handle from the 6.6 degree position to the 0 detent the stick shaker immediately activated with at least the Captain's PLI [Pitch Limit Indicator] indicating red (no confirmation can be given about the status of the First Officer's PLI). The speed tape was well above a stall indication on both sides. The Captain decreased the pitch attitude further to level flight with a slight descending bias and after the airspeed increased another ~10K the stick shaker ceased. Pitch was adjusted to achieve a normal climb rate and no further stick shaker events occurred during the flight. We believed our weight and balance calculations to be mostly accurate since the approach and landing on our inbound flight; with flaps set to 50 and airspeed flown at exactly computed Vref plus 5; was completely normal in all respects; with a large AOA margin indicated on the PLI throughout the entire approach and landing. We confirmed that the First Officer's takeoff data was accurate. No CFDS [Computer Flight Data System] faults indicated any confirmable problem with either the AOA system or FCC [Flight Control Computer]system. Maintenance ran the best diagnostic tests they could on the AOA systems and the stick shaker systems and could find no observable/measurable problem.
An MD-10 flight crew received an inexplicable stick shaker when retracting the flaps up from 6.6 degrees after takeoff.  An immediate lowering of angle of attack extinguished the warning after a gain of ~10KIAS.  Examination of weight and balance and performance data provided no explanation and a maintenance inspection was equally negative.