Originally Posted by
flyandive
The problem with the 100/200 is it uses a flexible drive shaft driven by a single electric motor under the fuselage with brakes at the end of the drive shaft to hold it in each position. The drive shaft tends to twist as it moves along the length of the wing which in turn twists the flaps. The 700/900 uses a torque tube in stead of a flexible drive cable so it can not twist. It has one (dual channel?) motor for the flaps and one for the slats. So in essence the design is the same but the 700/900 uses a metal control rod to manipulate the actuators instead of a cable. H46Bubba can probably elaborate.
You got it right. The problem with the -200 is due to water or de-icing fluid penetrating the actuator and freezing. That's why flap fails are primarily a winter pain in the ass. That's why Comair wants the flaps up during de-icing or until just before taking the runway, in order to prevent as much water contamination as possible. We also designed our own o-ring to provide as much as a seal as possible. Bombardier is little help when it comes to fixing their design flaws and crappy manufacturing.