Someone asked me off list how to use the control surface gauge:

The gauge is nothing more than a device to provide three specific length 
measurements that are associated with measuring movement in our control 
surfaces.? So if you look at the cut out to the left of where it says rudder, 
the distance between that cut out is 1/2".? The fact that it's a cut is of? no 
further significance.? To use the gauge, it is positioned perpendicular to the 
trailing edge of the control surface and the movement is checked against the 
appropriate value on the gauge which is a maximum.? Unless you are very steady, 
I find it useful to hold the gauge fixed against some non-moving part of the 
aircraft during these measurements.? For instance, when checking rudder 
movement, the gauge can be held firmly on the elevator.? It's important to have 
the Service Memorandums? (and in the case of rudder, the AD) since they provide 
very specific instructions on the conditions under which these movements are 
checked.? For example, for the rudder, we are not really measuring free play, 
but rather deflection under a specific load.? Further, along with rudder 
movement we are also listening for sounds that might suggest damage that would 
require further action.? In the case of the ailerons and elevator we 
specifically do not want to introduce deflection which would cause a false 
reading.? Note that this can all be done just fine with a ruler.? The gauge 
just makes it more convenient. 

I think it's in the interest of safety for owners to find every way they can to 
get involved in maintenance of their aircraft. Having said that though, I 
probably should also point out that at least in my interpretation, in the 
United States, this would not fall under owner maintenance but would require at 
least an airframe rating.? This would also apply (in my interpretation) to 
checking cable tensions, a topic that we discussed a while back.? For non A&Ps 
the best thing is to establish a good working relationship with your A&P.

As a final note, Kevin Gassert contacted me concerning the prospect of having 
these gauges available for the folks that might want them at the EOC 
convention.? I volunteered to try to mass produce these from card stock.? They 
will probably look something like the attached picture.? Since I'm raiding my 
wife's scrapbooking stash, they will most likely be available in a symphony of 
pastels :-).

Cheers,
Bill






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