Significant Regulatory Activity

Air Safety Week, June 19, 2006

Engine/nacelle: Notice of proposed rulemaking (NPRM) -- Airbus A300 airplanes, equipped with General Electric CF6-50 series engines.

June 8, 2006 FR Doc. E6-8900 Docket No. FAA-2006-24958

This proposed AD would require modifying the airplane and the engine/nacelle to install a third line of defense, in accord with a manufacturer report, against inadvertent deployment of the thrust reverser in flight. This proposed AD would also require two other actions that must be accomplished before or concurrently with the modification: installing a structural change in the fan cowl to avoid interference; and installing a dedicated, shielded electrical circuit. Inadvertent deployment of the thrust reverser in flight could result in reduced controllability of the airplane.

There are only 30 affected U.S. airplanes with a fleet cost for the "third line of defense" being $27,600. However, the fan cowl installation would cost the fleet about $919,200 and the electrical circuit installation would cost about $1.1 million.

Comments on this proposed AD by July 10, 2006.

>>Contacts: Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; Tom Stafford, FAA, (425) 227-1622<<

Control column torque tube: NPRM -- Bombardier DHC-8-100, DHC-8-200, DHC- 8-300, and DHC-8-400 series airplanes.

June 8, 2006 FR Doc. E6-8898 Docket No. FAA-2006-24979

This proposed AD would require inspecting the left and right control column torque tube assemblies to determine the type of rivets installed and replacing incorrect or indeterminate type rivets with the correct type rivets. This proposed AD results from a report that incorrect rivets having lower than required strength were installed on the control column torque tube during production. FAA wants to prevent shear failure of control column torque tube rivets, which could cause unexpected decoupling of the elevators and large unwanted deflection of the free elevator, and consequent reduced controllability of the airplane.

Comments are due July 10.

There are 162 affected U.S. airplanes; the fleet cost for a rivet replacement could be as high as $215,460.

>>Contacts: Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada; Richard Beckwith, FAA, (516) 228-7302<<

Center tank: NPRM -- McDonnell Douglas 717-200 airplanes.

June 8, 2006 FR Doc. E6-8899 Docket No. FAA-2006-24978

This proposed AD would require modifying the fuel boost pump container of the center tank. This proposed AD results from fuel system reviews conducted by the manufacturer. FAA wants to prevent exposing the fuel pump container vapor area to electrical arcing during a fuel pump motor case or connector burn through, which could result in a fuel tank explosion.

Comments are due July 24.

This AD would affect 114 U.S. airplanes, fleet repair costs would be $148,770.

>>Contacts: Boeing, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, CA 90846, Attention: Data and Service Management, Dept. C1-L5A (D800- 0024); William Bond, FAA, (562) 627-5253<<

Fuel shutoff wires: Final rule -- Boeing 737-600, -700, -700C, -800, and -900 series airplanes.

June 12, 2006 FR Doc. 06-5205 Docket No. FAA-2005-20626

This AD requires replacing the fuel shutoff valve wires and conduit assemblies in the left and right engine strut aft fairing areas. An operator discovered many small chafe marks and exposed shield braid on fuel shutoff wires routed through a conduit in the wing. FAA wants to prevent exposed wires that could provide an ignition source in a flammable leakage zone and possibly lead to an uncontrolled fire or explosion.

This AD becomes effective July 17, 2006.

This AD will affect about 529 airplanes of U.S. registry; the estimated cost for U.S. operators is $2,723,292, or $5,148 per airplane.

>>Contacts: Boeing Commercial Airplanes, P.O. Box 3707, Seattle, WA 98124-2207; Doug Pegors, FAA, (425) 917-6504<<

Fatigue cracks: Final rule -- Boeing 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes.

June 12, 2006 FR Doc. 06-5207 Docket No. FAA-2006-24102

FAA is superceding an old AD that requires repetitive inspections for cracking of the station 800 frame assembly, and repair if necessary. This new AD retains the repetitive inspection requirements of the existing AD, but expands the area to be inspected. This AD also reduces the initial inspection threshold, removes the adjustment of the compliance threshold and repetitive interval based on cabin differential pressure, and adds airplanes to the applicability. There has been several reports of cracks of the station 800 frame assembly on airplanes that had accumulated fewer total flight cycles than the initial inspection threshold in the existing AD. FAA wants to detect and correct fatigue cracks that could extend and fully sever the frame, which could result in development of skin cracks that could lead to rapid depressurization of the airplane.

This AD becomes effective July 17, 2006.