Federal Aviation Administration October 3, 2012 – Federal Register Recent Federal Regulation Documents

We are revising an earlier proposed airworthiness directive (AD) that would supersede an existing AD for certain Airbus Model A318, A319, A320, and A321 series airplanes. For certain airplanes, that NPRM proposed repetitive inspections for cracks of the forward lug of each main landing gear (MLG) support rib 5 fitting and repair if necessary; and removing Model 318 airplanes from the applicability. That NPRM was prompted by reports of cracks found in the forward lug of the MLG support rib 5 fitting. This action revises that NPRM by adding Model A318 airplanes and others to the applicability; and requiring repetitive detailed inspections for cracks of the MLG support 5 fitting, and repair of any cracks. We are proposing this AD to prevent cracking in the forward lug of the MLG, which could result in failure of the lug and consequent collapse of the MLG during takeoff or landing. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737 airplanes. This AD was prompted by a report of a flightcrew not receiving an aural warning during a lack of cabin pressurization event. This AD requires incorporating design changes to improve the reliability of the cabin altitude warning system by installing a redundant cabin altitude pressure switch, replacing the aural warning module (AWM) with a new or reworked AWM, and changing certain wire bundles or connecting certain previously capped and stowed wires as necessary. For certain airplanes, this AD also requires prior or concurrent incorporation of related design changes by modifying the instrument panels, installing light assemblies, modifying the wire bundles, and installing a new circuit breaker, as necessary. We are issuing this AD to prevent the loss of cabin altitude warning, which could delay flightcrew recognition of a lack of cabin pressurization, and could result in incapacitation of the flightcrew due to hypoxia (a lack of oxygen in the body), and consequent loss of control of the airplane.

We are adopting a new airworthiness directive (AD) for certain of The Boeing Company Model 777 airplanes. This AD was prompted by heat damage and cracks at the pivot joint location of the main landing gear (MLG) inner cylinder/truck beam. This AD requires repetitive lubrication of the MLG pivot joints; repetitive detailed inspections of the outer diameter chrome on the center axles of the MLG for chicken- wire cracks, corrosion, and chrome plate distress; repetitive magnetic particle inspections of the outer diameter chrome on the center axles of the MLG for cracks; and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct cracking in the MLG center axle and shock strut inner cylinder lugs (pivot joint), which could result in fracture of the MLG pivot joint components and consequent collapse of the MLG.