Federal Aviation Administration August 9, 2006 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by an airworthiness authority of another country to identify and correct an unsafe condition on an aviation product. The proposed AD would require actions that are intended to address an unsafe condition described in the MCAI.

The FAA proposes to adopt a new airworthiness directive (AD) for certain Lockheed Model L-1011 series airplanes. This proposed AD would require a one-time detailed inspection of the C112 harness clamp assembly for proper installation, a one-time detailed inspection of the C112 and C162 harness assemblies for damage, and corrective actions if necessary. This proposed AD results from a report of electrical arcing of the essential bus feeder cables behind hinged circuit breaker panel CB3 P-K. We are proposing this AD to prevent arcing of essential bus feeder cables due to improper installation of the harness C112 clamp assembly, which could result in loss of electrical systems and smoke and/or fire behind the CB3 P-K hinged circuit breaker panel in the flight compartment.

The FAA proposes to revise an earlier proposed airworthiness directive (AD) that applies to certain Air Tractor, Inc. (Air Tractor) Models AT-502, AT-502A, AT-502B, and AT-503A airplanes, which proposes to supersede AD 2002-26-05. AD 2002-26-05 lowers the safe life for the wing lower spar caps for Models AT-502, AT-502A, AT-502B, and AT-503A airplanes and those that incorporate or have incorporated Marburger Enterprises, Inc. (Marburger) winglets. AD 2002-26-05 also requires you to eddy-current inspect the wing lower spar caps immediately before modifying to correct any crack in a bolt hole before it extends to the modified center section of the wing and report the results of the inspection to the FAA if cracks are found. AD 2002-11-05 R1 currently requires similar action on Model AT-501 airplanes. Since issuing the earlier NPRM, we determined that Model AT-501 airplanes should be added to the Applicability section of this proposed AD and that this proposed AD should also supersede AD 2002-11-05 R1. We have revised the alternative method of compliance (AMOC) to include inspection procedures for airplanes that have or have had Marburger winglets installed. We have also updated the safe life of the replacement and new production spar cap based on additional data we have received from the manufacturer. Since these actions impose an additional burden over that proposed in the earlier NPRM, we are reopening the comment period to allow the public the chance to comment on these additional actions.

We propose to adopt a new airworthiness directive (AD) for certain Air Tractor, Inc. (Air Tractor) Models AT-502, AT-502A, AT- 502B, AT-602, AT-802, and AT-802A airplanes. This proposed AD would require you to repetitively visually inspect the rudder and vertical fin hinge attaching structure for loose fasteners, any cracks in the rudder or vertical fin skins, spars, hinges or brackets, or corrosion. The AD would also require you to replace any damaged parts found as a result of the inspection and install an external doubler at the upper rudder hinge. Installation of the external doubler at the upper rudder hinge is terminating action for the repetitive inspection requirements. This proposed AD results from two reports (one Model AT-602 airplane and one Model AT-802A airplane) of in-flight rudder separation from the vertical fin at the upper attach hinge area, and other reports of Models AT-502B, AT-602, and AT-802/802A airplanes with loose hinges, skin cracks, or signs of repairs to the affected area. We are proposing this AD to detect and correct loose fasteners; any cracks in the rudder or vertical fin skins, spars, hinges or brackets, or corrosion of the rudder and vertical fin hinge attaching structure. Hinge failure adversely affects ability to control yaw and has led to the rudder folding over in flight. This condition could allow the rudder to contact the elevator and affect ability to control pitch with consequent loss of control of the airplane.

The FAA is adopting a new airworthiness directive (AD) for all McDonnell Douglas Model MD-90-30 airplanes. This AD requires installing a clamp, bonding jumper assembly, and attaching hardware to the refueling manifold in the right wing refueling station area. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent arcing on the in-tank side of the fueling valve during a lightning strike, which could result in an ignition source that could ignite fuel vapor and cause a fuel tank explosion.

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR series airplanes. This AD requires doing repetitive inspections of engine struts 1 through 4, as applicable, for heat discoloration, cracking, buckling, or wrinkling. This AD also requires doing a conductivity test to detect the extent of the heat damage and an inspection to detect cracking of the heat-discolored, buckled, or wrinkled area; and repair; if necessary. This AD results from reports of heat damage and cracking of the skin and internal structure adjacent to and aft of the precooler exhaust vent on several engine struts. We are issuing this AD to detect and correct cracking, buckling, wrinkling, or heat damage of the skin and internal structure of the engine struts, which could result in extensive damage to the engine struts and consequent possible separation of an engine from the airplane during flight.