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 revising the wiring of the selective calling (SELCAL) system. This action is necessary to prevent inadvertent very high frequency transmissions and subsequent loss of radio communications for airplane and/or airport operations; and to prevent inadvertent high frequency transmissions and subsequent electrical shock to ground service personnel and/or damage to the airplane during fueling operations or fuel tank maintenance. This action is intended to address the identified unsafe condition.