Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Learjet Model 24, 25, 31, 35, 36, and 55 series airplanes, and Learjet Model 28 and 29 airplanes, that currently requires a revision to the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to prohibit flight above an altitude of 41,000 feet. The actions specified by that AD are intended to prevent cracking and subsequent failure of the outflow/safety valves, which could result in rapid decompression of the airplane. This action would require replacement of certain outflow/ safety valves, which, when accomplished, constitutes terminating action for the previously required AFM limitation.