PMA landing gear struts from Aerometals (Booth No. 2221) for MD 500 series helicopters have been excluded from a January 8 FAA Notice of Proposed Rule Making that would require inspection, rework or replacement of the forward and aft struts on the MD 500N. The proposal, which also covers the MD 300 and OH-6A, was prompted by five reported MD helicopter landing gear strut failures. The proposed AD is intended to detect a crack that could result in the failure of a strut and subsequent loss of control of the helicopter during landing. βWe discovered this potential problem in 1994 during development of our current PMA replacement strut,β said Rex Kamphefner, Aerometals general manager. βThe OEM design has a rivet hole at a highly stressed location.β