[Mark Hislop]

David:

I don't think cracks in these areas are uncommon. When I bought my plane in 1996, there were repairs (welds) in the same areas your photos show. Fortunately, no cracks since then. I am careful to only open the doors at speeds lower than the 160mph allowed, typically at 120mph. I don't know if this has an affect, but like I say, no crack in 15 years.