Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-90-30 series airplanes. This proposal would require modification of the main battery ground stud and installation of a nameplate which indicates torque requirements for the ground stud nut. This action is necessary to prevent the ground stud nut from being inadequately tightened or becoming loose, which could result in electrical arcing between the ground stud and the adjacent structure, leading to damage to electrical or electronic equipment or possibly to fire in the airplane. This action is intended to address the identified unsafe condition.