Wing spars are fairly accessable and moderately easy to inspect thoroughly.
It is the stuff that you can't get inside to see without ripping the
airplane completely apart that generally rise up and bite you. How do you
detect that an oil pump gear has a hairline fracture and is about to
self-destruct without pulling the back end of the engine apart? How do you
tell that a bladder cell is about to start leaking from an invisible
internal split in the cell wall? The stuff you can see is generally not the
problem ... but in the case of an invisible crack in a cylinder wall it was.

The answer is that there is no good answer except for a record of preventive
maintenance.

Jim


"Douglas Olson" wrote in message
ink.net...
Well, thank you for a mechanic's perspective on this.

Seeing as every piece of "how to buy a used airplane" literature
recommends
a mechanic's pre-buy, what do consider a real-world way for the amatuer to
avoid the big money pits like wing spar problems?