Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 727-100 and 727-200 series airplanes. This proposal would require replacement of the installed autopilot pitch control computer with a modified computer, testing of the modified system, and revision of the Airplane Flight Manual (AFM). This action is necessary to prevent undesirable and potentially dangerous pitch oscillations during coupled instrument landing systems (ILS) approaches. This action is intended to address the identified unsafe condition.