Airworthiness Directives; McDonnell Douglas Model MD-90 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90 series airplanes, that requires a one-time detailed visual inspection to detect fatigue cracking of certain longerons and the attaching frames of the lower left nose; and repair, if necessary. This amendment also requires installation of a preventive modification. This amendment is prompted by several reports of fatigue cracking of certain longerons and the attaching frames. The actions specified by this AD are intended to prevent such fatigue cracking, which could result in reduced structural integrity of the fuselage, and consequent loss of pressurization of the airplane.