Federal Aviation Administration September 3, 2008 – Federal Register Recent Federal Regulation Documents

The FAA is revising an earlier proposed airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. The original NPRM would have required replacing the aero/fire seals of the blocker doors on the thrust reverser torque boxes on the engines with new, improved aero/fire seals. The original NPRM resulted from a report that the top three inches of the aero/fire seals of the blocker doors on the thrust reverser torque boxes are not fireproof. This action revises the original NPRM by adding airplanes to the applicability statement and requiring a one-time inspection to determine the part numbers of the aero/fire seals. We are proposing this supplemental NPRM to prevent a fire in the fan compartment (a fire zone) from migrating through the seal to a flammable fluid in the thrust reverser actuator compartment (a flammable fluid leakage zone), which could result in an uncontrolled fire.

This action corrects two errors in the airspace description contained in a Final Rule that was published in the Federal Register on Friday, July 25, 2008 (73 FR 43351), Airspace Docket No. 08-AAL-16.

This Rule establishes, amends, suspends, or revokes Standard Instrument Approach Procedures (SIAPs) and associated Takeoff Minimums and Obstacle Departure Procedures for operations at certain airports. These regulatory actions are needed because of the adoption of new or revised criteria, or because of changes occurring in the National Airspace System, such as the commissioning of new navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed to provide safe and efficient use of the navigable airspace and to promote safe flight operations under instrument flight rules at the affected airports.