Federal Aviation Administration March 5, 2007 – Federal Register Recent Federal Regulation Documents

The FAA is superseding two existing airworthiness directives (ADs), that apply to certain Bombardier Model CL-600-2B16 (CL-604) airplanes and Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. These models may be referred to by their marketing designations as RJ100, RJ200, RJ440, CRJ100, CRJ200, CRJ440, and CL-65. One existing AD requires replacing the horizontal stabilizer trim control unit (HSTCU) with a new HSTCU. The other existing AD requires revising the airplane flight manual (AFM) to advise the flightcrew of procedures to follow in the event of stabilizer trim runaway, and in the event of MACH TRIM, STAB TRIM, and horizontal stabilizer trim malfunctions; and revising the AFM to require a review of the location of certain circuit breakers. That AD also requires doing a functional check of the stabilizer trim system and installing circuit breaker identification collars, and provides an optional terminating action. This new AD requires the previously optional terminating action and requires further revisions to the AFM. This AD also requires the removal of certain AFM revisions. This AD results from reports of trim problems including uncommanded trim, trim in the opposite direction to that selected, loss of trim position indication and, in one case, potential loss of trim disconnect capability. We are issuing this AD to prevent these events, which could result in conditions that vary from reduced controllability of the airplane to loss of control of the airplane.

The FAA adopts a new airworthiness directive (AD) for certain Mooney Airplane Company, Inc., Models M20M and M20R airplanes. This AD requires you to remove the upper left and upper right engine mount attaching hardware, cut out and remove the upholstery and insulation between the fuselage tubular frame and the firewall, and replace the upper left and upper right engine mount attaching hardware with the new parts kit. This AD results from failure of the engine mount attaching hardware to maintain torque as a result of firewall insulation and upholstery being compressed between the fuselage tubular frame and the firewall at the upper left and upper right engine mount attach points. We are issuing this AD to prevent the upper right and upper left engine mounting hardware from losing torque, which could result in a reduction in engine mount load carrying capability and could lead to engine mount failure.

The FAA is adopting a new airworthiness directive (AD) for certain McDonnell Douglas Model 717-200 airplanes. This AD requires replacing certain attaching hardware of the bulkhead nipple assemblies of the left and right wing vent boxes with new electrical bonding attaching hardware, doing resistance testing of the new electrical bonds, and doing fuel leakage testing of the reworked nipple assemblies. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to provide a conductive path, from the bulkhead nipple assemblies of the left and right wing vent boxes to the airframe structure inside the wing fuel tanks, to dissipate high- amperage lightning-induced currents, which might otherwise create an ignition source for fuel vapors inside the wing vent boxes and lead to an explosion of the fuel tanks.

The FAA is adopting a new airworthiness directive (AD) for GE CF6-80C2 series turbofan engines. This AD requires replacing certain installed part number (P/N) and serial number (SN) cast titanium weld- repaired forward engine mount platforms and cast titanium forward mount yokes, with a forged titanium or a non-welded cast titanium part. This AD results from the discovery of cracks, in a weld-repaired area on a forward engine mount platform and a forward engine mount yoke, found during a fluorescent penetrant inspection (FPI). These parts were weld- repaired during manufacture. We are issuing this AD to prevent cracks in the forward engine mount platform and forward engine mount yoke that could result in possible separation of the engine from the airplane.