I thought this was a repeat mandatory AD for most Lycoming recip engines! 100 hrs insp for corrosion and cracks using eddy current or other non surface NDT (i.e. not dye pen)
Could be wrong or got my wires crossed here as it was being done while I was looking at an avionics snag on the same a/c. My normal a/c are alot bigger than 2-6 seaters.
A look at the FAA web site will soon give you an answer.