Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Proposed rule; withdrawal.

SUMMARY:

The FAA withdraws a notice of proposed rulemaking (NPRM) that proposed a new airworthiness directive (AD), which would have applied to certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. For certain airplanes, the NPRM would have required a one-time inspection for damage of the hydraulic actuator rod ends and actuator attach fittings on the thrust reversers, and repair or replacement if necessary. For all airplanes, the NPRM would have required repetitive inspections for damage of the hydraulic actuator rod ends, attach bolts, and nuts; repetitive inspections for damage of fitting assemblies, wear spacers, and actuator attach fittings on the thrust reverser; repetitive measurements of the wear spacer; and corrective actions if necessary. Since the NPRM was issued, the manufacturer notified us that an assumption regarding a failure mode of the rod ends or attachment fittings for the thrust reverser actuator used in the original safety assessment was incorrect. A new safety analysis was conducted and we determined that this issue is no longer a safety concern. Accordingly, the NPRM is withdrawn.

DATES:

As of February 25, 2016, the proposed rule, which was published in the Federal Register on March 22, 2011 (76 FR 15864), is withdrawn.

ADDRESSES:

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2011-0254; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD action, the NPRM (76 FR 15864, March 22, 2011), the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone 800-647-5527) is the Docket Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Tak Kobayashi, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6499; fax: 425-917-6590; email: Takahisa.Kobayashi@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with a notice of proposed rulemaking (NPRM) for a new AD for certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. The NPRM published in the Federal Register on March 22, 2011 (76 FR 15864) (“the NPRM”). For certain airplanes, the NPRM would have required a one-time inspection for damage of the hydraulic actuator rod ends and actuator attach fittings on the thrust reversers, and repair or replacement if necessary. For all airplanes, the NPRM would have required repetitive inspections for damage of the hydraulic actuator rod ends, attach bolts, and nuts; repetitive inspections for damage of fitting assemblies, wear spacers, and actuator attach fittings on the thrust reverser; repetitive measurements of the wear spacer; and corrective actions if necessary.

The NPRM was prompted by reports of in-service damage of the attachment fittings for the thrust reverser actuator. The proposed actions were intended to detect and correct such damage, which could result in actuator attach fitting failure, loss of the thrust reverser auto restow function, and consequent loss of control of the airplane.

Actions Since NPRM Was Issued

Since we issued the NPRM, the manufacturer has notified us that an assumption regarding a failure mode of the attachment fittings for the thrust reverser actuator used in the original safety assessment was incorrect. It was originally assumed that all hydraulic actuators attached to the thrust reverser have the failure mode (failure of the hydraulic actuator rod end or attach fitting due to severe wear-out) addressed in the NPRM. Based on field reports and design review, the manufacturer found that certain hydraulic actuators do not have this failure mode. Based on this new manufacturer finding, a new safety analysis was conducted and we determined that this issue is no longer a safety concern.

FAA's Conclusions

Upon further consideration, we have determined that the safety concern identified in the NPRM does not affect The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes identified in the NPRM. Accordingly, the NPRM is withdrawn.

Withdrawal of the NPRM does not preclude the FAA from issuing another related action or commit the FAA to any course of action in the future.

Regulatory Impact

Since this action only withdraws an NPRM, it is neither a proposed nor a final rule and therefore is not covered under Executive Order 12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Withdrawal

Accordingly, we withdraw the NPRM, Docket No. FAA-2011-0254, Directorate Identifier 2010-NM-180-AD, which was published in the Federal Register on March 22, 2011 (76 FR 15864).