Airworthiness Directives; Saab AB, Saab Aerosystems Model 340A (SAAB/SF340A) and SAAB 340B Airplanes Modified in Accordance With Supplemental Type Certificate (STC) ST00224WI-D, ST00146WI-D, or SA984GL-D

الملخص

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires inspecting the fuselage surface for corrosion and cracking behind the external adapter plate of the antennae installation, and repair if necessary. This AD was prompted by a report of a crack found behind the external adapter plate of the antennae during inspection. Similar cracking was found on two additional airplanes, and extensive corrosion was found on one airplane. We are issuing this AD to detect and correct corrosion and cracking behind the external adapter plate of the antennae of certain damage-tolerant structure, which could result in reduced structural integrity and consequent rapid depressurization of the airplane.