Federal Aviation Administration September 8, 2006 – Federal Register Recent Federal Regulation Documents

We are adopting a new airworthiness directive (AD) for certain Raytheon Aircraft Company Model 390 airplanes. This AD requires you to inspect the spigot bearing, part number (P/N) MS14104-16, for the proper position in the spigot fitting assembly and to install the wing spigot bearing retainer kit, P/N 390-4304-0001. We are issuing this AD to detect spigot bearings that are not positioned flush with the fitting assembly. This condition could result in the spigot bearing becoming disengaged from the fitting assembly, which could cause motion between the wing and the fuselage and degrade the structural integrity of the wing attachment to the fuselage. This could lead to wing separation and loss of control of the airplane.

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) and SAAB 340B airplanes, that requires modification and repetitive inspections of the hot detection system of the tail pipe harness of the engine nacelles. The actions specified by this AD are intended to prevent false warning indications to the flightcrew from the hot detection system due to discrepancies of the harness, which could result in an unnecessary aborted takeoff on the ground or in-flight engine shutdowns. This action is intended to address the identified unsafe condition.

The FAA is superseding an airworthiness directive (AD) for Rolls-Royce Deutschland Ltd & Co KG (RRD) Tay 650-15 and Tay 651-54 turbofan engines. That AD currently establishes cyclic life limits for certain part number (P/N) stage 1 high pressure turbine (HPT) discs and stage 1 low pressure turbine (LPT) discs operating under certain flight plan profiles. This AD requires calculating and re-establishing the achieved cyclic life of stage 1 HPT discs, P/N JR32013 or P/N JR33838, and stage 1 LPT discs, P/N JR32318A, that have been exposed to different flight plan profiles. This AD also requires removing from service those stage 1 HPT discs and stage 1 LPT discs operated under Tay 650-15 engine flight plan profiles A, B, C, and D, and operated under Tay 651-54 engine datum flight profile, at reduced cyclic life limits, using a drawdown schedule. This AD results from RRD updating their low-cycle-fatigue analysis for stage 1 HPT discs and stage 1 LPT discs and reducing their cyclic life limits. We are issuing this AD to prevent cracks leading to turbine disc failure, which could result in an uncontained engine failure and damage to the airplane.