Department of Transportation February 24, 2011 – Federal Register Recent Federal Regulation Documents

We propose to supersede an existing airworthiness directive (AD) that applies to The Boeing Company Model 767-200, -300, and -300F series airplanes. The existing AD currently requires inspections to detect cracking or corrosion of the fail-safe straps between the side fitting of the rear spar bulkhead at body station 955 and the skin; and follow-on and corrective actions. Since we issued that AD, we have received additional reports of cracks in 51 fail-safe straps on 41 airplanes; we have also received a report of a crack found in the ``T'' fitting that connects the fail-safe strap to the outboard edge of the pressure deck. This proposed AD would expand the applicability, and would add an inspection for cracking in the fail-safe strap, and repair or replacement if necessary. We are proposing this AD to detect and correct fatigue cracking or corrosion of the fail-safe straps and the ``T'' fittings, which could result in cracking of adjacent structure and consequent reduced structural integrity of the fuselage.

This notice contains a summary of a petition seeking relief from specified requirements of 14 CFR. The purpose of this notice is to improve the public's awareness of, and participation in, this aspect of FAA's regulatory activities. Neither publication of this notice nor the inclusion or omission of information in the summary is intended to affect the legal status of the petition or its final disposition.

These special conditions are issued for the Embraer Model EMB- 135BJ (Legacy 650) airplanes, modified in accordance with design-change application (DCA) 0145-000-00020-2008/FAA (the most current FAA- approved revision; hereafter referred to as ``the DCA''). This Model EMB-135BJ airplane, as modified by the DCA, is commonly referred to as the Legacy 650 airplane. It will have a novel or unusual design feature associated with engine size and the potential torque load imposed by sudden engine-stoppage conditions. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires sealing the fasteners on the front and rear spars inside the left and right main fuel tanks and on the rear spar and lower panel of the center fuel tank. That AD also requires inspections of the wire bundle support installations to verify if certain clamps are installed and if Teflon sleeving covers the wire bundles inside the left and right equipment cooling system bays, on the left and right rear spars, and on the left and right front spars; and corrective actions if necessary. This new AD also requires sealing the additional fasteners on the rear spar inside the left and right main fuel tanks. This AD was prompted by a fuel system review conducted by the manufacturer. We have received reports from the manufacturer that additional fasteners in the main fuel tanks must be sealed for lightning strike protection. We are issuing this AD to detect and correct improper wire bundle support installation and sleeving and to prevent improperly sealed fasteners in the main and center fuel tanks from becoming an ignition source, in the event of a fault current or lightning strike, which could result in a fuel tank explosion and consequent loss of the airplane.

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires repetitively inspecting the elevator control tabs for discrepancies and, if any discrepancies are found, taking necessary corrective actions to bring all discrepancies within acceptable tolerances. This AD also requires reporting certain inspection results to the FAA. This AD was prompted by an evaluation of revisions to the manufacturer's maintenance manual that adds new repetitive inspections of the elevator control tabs. To require compliance with these inspections for U.S. owners and operators we are mandating the inspections through the rulemaking process. We are issuing this AD to add new repetitive inspections of the elevator control tabs. If these inspections are not done, excessive free-play in the elevator control tabs could develop. This condition could lead to loss of tab control linkage and severe elevator flutter. Such elevator flutter could lead to possible loss of control.

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a general visual inspection for damage of wiring (including chafing, pinched wires, and exposed wires) and correct routing of wires in the left and right circuit breaker panels, and related investigative and corrective actions if necessary. This AD results from reports of wire damage on the pilot and copilot circuit breaker panels caused by a short circuit between chafed wiring and the circuit breaker panel forward mounting bracket. We are issuing this AD to detect and correct damaged or misrouted wires, which could result in a short circuit and the loss of systems associated with the wiring (including fire suppression function for one engine and essential avionics systems).