Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Cessna Model 441, 500, 550, and 560 series airplanes. This proposal would require replacement of outflow/safety valves with serviceable valves. This proposal is prompted by a report of cracking and subsequent failure of outflow safety valves in the pressurization system. The actions specified by the proposed AD are intended to prevent such cracking and subsequent failure of the outflow/safety valves, which could result in rapid decompression of the airplane.