British Airways B744 at Miami on Apr 7th 2014, airspeed problem

A British Airways Boeing 747-400, registration G-CIVD performing flight BA-206 from Miami,FL (USA) to London Heathrow,EN (UK), was climbing out of Miami's runway 27 when the crew reported airspeed problems and requested to increase speed to 285 knots prematurely, then requested to stop the climb at 11,000 feet reporting they had instrument display problems. The continued in the general direction of London. After about 40 minutes at 11,000 feet the aircraft continued the climb and reached FL310 north of the Bahamas but immediately descended again to FL210 and returned to Miami. On approach to Miami the crew indicated they expected a normal landing and would be able to taxi in. The aircraft landed safely on Miami's runway 27 about 150 minutes after departure. The crew reported "perfectly serviceable on the ground" and stated they did not need further assistance.

A passenger reported gossip amongst passengers was the stick shaker went off during the flight prompting the return to Miami.