MD Helicopters of Mesa, Ariz., said five MD 600Ns have exhibited cracks in the tailcone attachment area, and that an inspection bulletin is forthcoming to operators of the 53 aircraft currently flying. Concern over the cracks surfaced following the discovery of damage to the Notar-system tailcone attachment structure during a routine inspection of the MD 600N operated by the Los Angeles County Sheriff’s department. The probe focused on bolts in the lower attachment flange, with special attention being paid to the amount of torque applied to them.