MD,
The autothrust will protect against overspeed if configured i.e. limit speed to VFE Next.......but when you select FLAP 0, there is no VFE Next so the autothrust will keep the thrust on to target 250 knots and,if level, easily out accelerate the SLAT retract with resulting overspeed.
Last edited by A4; 23rd June 2013 at 15:18.