Airworthiness Directives; Parker Hannifan Airborne Dry Air Pumps, Conversion Kits, and Coupling Kits

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-23-01, which was sent previously to all known U.S. owners and operators of aircraft and engines equipped with certain Parker Hannifin Airborne dry air pumps, conversion kits, and coupling kits, utilizing part number (P/N) B1-19-1 flexible coupling that has a date code resembling a clockface and indicating a manufacture date of either ``12/97'' or ``5-6/98''. This AD requires replacing the affected flexible coupling with P/N B1-7-3 flexible coupling (part of Parker Hannifin flexible coupling kit, Airborne P/N 350). The AD resulted from reports of failure of the affected flexible coupling due to a manufacturing defect of this coupling. The actions specified by this AD are intended to prevent failure of the primary dry air pump caused by defective flexible coupling, which could result in loss of primary attitude and direction references during instrument flight rules (IFR) operations.