Many customers have come to us complaining that their 190/195 is “directionally challenged”. Comments have ranged from the aircraft consistently darting off in one direction to being directionally unstable at lower speeds but, better at high speed or vise-versa. Consistently we have found the main gear substantially out of alignment.
Many aircraft have no alignment shims at all (probably due to previous axle removal/replacements resulting in omission of shims). The main gear allows for a reasonable range of adjustment using shims. When removing axles always keep track of shim orientation and left vs. right. Some of these shims are wedged vertically and horizontally.
The vertical alignment of the trail strut allows for no adjustment and my guess is that most are not mounted vertical, even from the factory. Of all the ones we have checked to date, only a few have been vertical.
When looking at the geometry of the tail wheel/strut, it appears to me this could cause directional instability favoring one direction. Unfortunately, this alignment must be done when drilling the holes through the aft bulkhead for lower strut mounting brackets. In extreme cases, it would be possible to drill new holes that would be totally independent from the existing holes (we have found these lower brackets up to 7/16 inches off). We do not recommend drilling additional holes as this bulkhead has proven to be weak in design in this area (see aft tailcone bulkhead page.)