A 2-inch crack was found on the R/H aft wing spar (P/N 0523400-51) beneath its inboard flap track attachment, traversing the lower rivet holes. The submitting mechanic speculates fatigue as the cause. His recommendation is “...all C172s with more than 8,000 hours total time be inspected by borescope or other acceptable means at the rear wing spar around the flap track attach area.”

Part Total Time: 12,474.4 hours.