Airworthiness Directives; Fokker Model F.28 Mark 0100. Final rule. SUMMARY: The FAA is superseding an existing airworthiness directive (AD), which applies to certain Fokker Model F.28 Mark 0100 airplanes. That AD currently requires revisions to the airplane flight manual (AFM) to include procedures to prohibit use of reverse engine thrust power settings between idle and emergency maximum and to prohibit stabilized engine operation in a certain engine speed range on the ground. This new AD continues to require revising the AFM to include certain procedures. This AD also requires removing the normal maximum (second) detent for the reverse thrust control. In addition, this AD requires revising the AFM to prohibit use of reverse thrust in flight and to limit operation of Max Reverse thrust. This AD results from issuance of mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. We are issuing this AD to prevent inadvertent operation in the prohibited stabilized engine speed range on the ground, which could result in uncontained engine fan blade failure due to high cycle fatigue cracking. DATES: This AD becomes effective August 3, 2009.

Airworthiness Directives; McDonnell Douglas Model MD-90-30. Final rule. This AD requires repetitive inspections for cracks of the upper aft skin panels on the horizontal stabilizer, and related investigative and corrective actions if necessary. This AD results from a report of cracks found in the aft skin panels on the upper right side of the horizontal stabilizer at the aft inboard corner. We are issuing this AD to detect and correct cracks in the fail-safe structure that may not be able to sustain limit load, which could result in the loss of overall structural integrity of the horizontal stabilizer. DATES: This AD is effective August 3, 2009.

Airworthiness Directives; Microturbo SA Saphir 2 Model 016 Auxiliary Power Units. Final rule; request for comments. SUMMARY: We are adopting a new airworthiness directive (AD) for these products, on which the exhaust thermal insulation has been replaced since January 1, 1995. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Due to a lapse in manufacturing quality control, the exhaust thermal insulation of certain Microturbo SA Saphir 2 model 016 auxiliary power units (APUs) may not meet the approved design standard, and may fail in service. The affected part numbers are 016-33-01 (Inner Thermal Insulation), 016-33-02 (Outer Thermal Insulation), and 016-33-03 (EGT Sensor Thermal Insulation). This condition, if not corrected, could result in rapid deterioration and physical breakdown of the exhaust thermal insulation, leading to loss of insulation efficiency and ultimately exposure of the hot APU exhaust section and risk of fire.We are issuing this AD to prevent rapid deterioration and physical breakdown of the exhaust thermal insulation, leading to loss of insulation efficiency and ultimately exposure of the hot APU exhaust section and risk of fire. DATES: This AD becomes effective July 14, 2009.

Airworthiness Directives; Turbomeca S.A. Arrius 2F Turboshaft Engines. Final rule. SUMMARY: The FAA is superseding an existing airworthiness directive (AD) for Turbomeca S.A. Arrius 2F turboshaft engines that have not incorporated Turbomeca Modification Tf75. That AD currently requires replacing the O-ring on the check valve piston in the lubrication unit at repetitive intervals. This AD requires the same repetitive replacements and would require incorporating Modification Tf75 as terminating action to the repetitive O-ring replacements. Modification Tf75 replaces the check valve piston with a piston design not requiring an O-ring. This AD results from the European Aviation Safety Agency (EASA) and Turbomeca S.A. mandating the incorporation of Modification Tf75. We are issuing this AD to prevent an uncommanded in-flight shutdown of the engine, which could result in a forced autorotation landing and damage to the helicopter. This AD becomes effective August 3, 2009.

Airworthiness Directives; Boeing Model 747. Final rule. SUMMARY: The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747 airplanes. That AD currently requires repetitive inspections to detect evidence of wear damage in the area at the interface between the vertical stabilizer seal and fuselage skin, and corrective actions, if necessary. The existing AD also provides for an optional terminating action for the repetitive inspections. For all Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, this new AD requires repetitive inspections for wear damage and cracks of the fuselage skin in the interface area of the vertical stabilizer seal and fuselage skin, a detailed inspection for wear damage and cracks of the surface of any skin repair doubler in the area, and corrective actions if necessary. For airplanes on which the fuselage skin has been blended to remove wear damage, this new AD requires repetitive external detailed inspections or high frequency eddy current inspections for cracks of the blended area of the fuselage skin, and corrective actions if necessary. This AD results from reports of wear damage on airplanes with fewer than 8,000 total flight cycles. In addition, there have been three reports of skin wear damage on airplanes that applied Boeing Material Specifications 10-86 Teflon-filled coating (terminating action per the existing AD). We are issuing this AD to detect and correct wear damage and cracks of the fuselage skin in the interface area of the vertical stabilizer seal and fuselage skin in sections 46 and 48, which could cause in-flight depressurization of the airplane. DATES: This AD becomes effective August 3, 2009.

Airworthiness Directives; British Aerospace Regional Aircraft Model HP.137 Jetstream Mk.1, Jetstream Series 200 and 3101, and Jetstream Model 3201. Final rule; request for comments. SUMMARY: This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: BAE systems have been notified by the MLG radius rod manufacturer, APPH Ltd, that a batch of incorrectly manufactured Buffer Springs (part number 184818) had been supplied to their parts distributor and MRO facilities in North America. There is a risk that any radius rod fitted with one of these incorrectly manufactured Buffer Springs could jam in an unlocked position. This condition, if not corrected, could result in MLG collapse. This AD requires actions that are intended to address the unsafe condition described in the MCAI. DATES: This AD becomes effective June 26, 2009.