@ BraceBrace:
I beg to disagree. On the type I fly (B744), the slip/skid indicator derives its information from the IRU, which is also the source for heading, wind, track angle, drift angle and ground speed information. That is information we usually put quite some significance on, so why would only the slip/skid information be inaccurate enough to be allowed to be dismissed? Boeing (and all other manufacturers) would get into hot water if they deliberately installed an indicator which would provide misleading information, especially in the middle of the PFD, which is the most important display of all.
As to your argument that I don't want to learn about the effects of the extra hazards that a slip would create on an aircraft of this size, let me assure you that I couldn't agree more. The point is however, that the aircraft already is in a slip in a high bank angle low speed turn, and that is why I have raised this topic here. This is not about trying to "tighten the turn", this is actually about getting rid of the slip and achieving coordinated flight. According to the slip/skid indicator the yaw damper does a pretty bad job at coordinating the turn at low speeds. As the airplane accelerates into higher speed ranges turns get more coordinated because of the increasing velocity of the airflow around the rudder. Just have a look at the slip/skid indicator at low speeds and then at high speeds, using the same bank angle. The difference might surprise you.