Summary
This document extends the period for public comment on the above-referenced NPRM that proposes the supersedure of two existing airworthiness directives (AD), applicable to certain Boeing Model 737 series airplanes. The NPRM proposes to require installation of a new rudder control system and changes to the adjacent systems to accommodate that new rudder control system. This proposal is prompted by FAA determinations that the existing system design architecture is unsafe due to inherent failure modes, including single-jam modes and certain latent failures or jams, which, when combined with a second failure or jam, could cause an uncommanded rudder hardover event and consequent loss of control of the airplane. Additionally, the current rudder operational procedure is not effective throughout the entire flight envelope. This extension of the comment period is necessary to assure that all interested persons have ample opportunity to present their views on the proposed requirementsof the NPRM.