September 2, 2010 – Federal Register Recent Federal Regulation Documents

This document publishes in the Federal Register an amendment adopting Emergency Airworthiness Directive (AD) 2010-12-51, which was sent previously to all known U.S. owners and operators of the specified Agusta model helicopters by individual letters. This AD requires, before further flight, removing the forward boot from the hub-locking nut (nut) and inserting a gauge between the tail rotor control rod (rod) and nut until the gauge stops. This AD then requires, depending on the depth measurement from the face of the nut, either reidentifying the tail rotor gearbox (TGB) with a new part number (P/N) or replacing the TGB and the associated parts with airworthy parts. This AD is prompted by a report of a missing rod bushing (bushing) from a 90- degree TGB installed on a Model AW119 MKII helicopter. The Agusta Model A119 helicopters also have the affected TGB installed; therefore, they are also included in the applicability of this AD. The actions specified by this AD are intended to detect a missing bushing in the TGB and to prevent abnormal vibration, damage to the tail rotor system, loss of the yaw control function, and subsequent loss of control of the helicopter.

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated 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:

We are superseding an existing airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated 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:

We are adopting a new airworthiness directive (AD) for certain Model 737-100 and -200 series airplanes. This AD requires repetitive inspections for cracking and damaged fasteners of certain fuselage frames and stub beams, and corrective actions if necessary. For certain airplanes, this AD also requires repetitive inspections for cracking of the inboard chord fastener hole of the frame at body station 639, stringer S-16, and corrective actions if necessary. For certain airplanes, this AD also requires an inspection to determine the edge margin of the lower chord. For airplanes with a certain short edge margin, this AD requires repetitive inspections for cracking, and corrective actions if necessary; replacing the lower chord terminates the repetitive inspections. This AD requires an eventual preventive modification. For certain airplanes, doing the modification or a repair terminates the repetitive inspections for the repaired or modified frame only. For airplanes on which the modification or repair is done at certain body stations, this AD requires repetitive inspections for cracking of certain frame webs and inner and outer chords, and corrective actions if necessary. For certain other airplanes, this AD requires a modification which includes reinforcing the body frame inner chords, replacing the stub beam upper chords and attach angles, and reinforcing the stub beam web. This AD results from reports of fatigue cracks at certain frame sections, in addition to stub beam cracking, caused by high flight cycle stresses from both pressurization and maneuver load. We are issuing this AD to detect and correct fatigue cracking of certain fuselage frames and stub beams, and possible severed frames, which could result in reduced structural integrity of the frames. This reduced structural integrity can increase loading in the fuselage skin, which will accelerate skin crack growth and result in rapid decompression of the fuselage.