AD 2009-09-07

This AD is effective June 11, 2009.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of June 11, 2009.

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207; telephone 206-544-9990; fax 206-766-5682; e-mail DDCS@boeing.com; Internet https://www.myboeingfleet.com.

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6440; fax (425) 917-6590.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That NPRM was published in the Federal Register on October 8, 2008 (73 FR 58906). For all airplanes, that NPRM proposed to require repetitive overhaul of the retract actuator beam of the main landing gear (MLG). For certain airplanes, that NPRM proposed to require repetitive inspections for damage of the retract actuator beam, and related investigative and corrective actions if necessary.

We gave the public the opportunity to participate in developing this AD. We considered the comments received from the commenters.

Boeing concurs with the contents of the NPRM.

Continental Airlines (CAL) asks that we not mandate overhaul of the retract actuator beam using the instructions specified in the Accomplishment Instructions of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008. CAL states that the reason for release of Boeing Service Bulletin 737-32A1355, Revision 2, is Boeing's concern regarding shop process deficiencies at some repair facilities where correct overhaul procedures were not followed. CAL finds this reasoning detrimental to all operators that follow correct overhaul procedures at their repair facilities.

CAL landing gear components, including the retract actuator beams of the left and right main landing gear, are time controlled per the Boeing 737-300/-500 Maintenance Program and are scheduled to be overhauled at 10-year intervals at an FAA-approved landing gear overhaul facility. CAL also makes the following recommendations regarding Boeing Service Bulletin 737-32A1355, Revision 2:

• The stripping of all chrome and nickel plating specified in Step 4 of Figure 2 should be included as an option, as in the Boeing 737 Component Maintenance Manual (CMM), Section 32-00-05.

• The nital etch inspection of machined surfaces specified only in Step 9 of Figure 2 should not be limited to machined surfaces.

• The stress relieving of the part specified in Step 10 of Figure 2 should be an optional step, as specified in Boeing 737 CMM, Section 32-00-05.

• The shot peening of the entire part specified in Step 12 of Figure 2 should be limited to the machined areas of the part since the geometry of the actuator beam does not allow for effective shot peening of the entire area.

• A caution note for arc burns associated with grounding (similar to Step 14) should be included in Step 13 of Figure 2.

We disagree that using the instructions specified in the Accomplishment Instructions of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, to perform the overhaul of the retract actuator beam should not be mandated. Revision 2 of Boeing Service Bulletin 737-32A1355 references improved overhaul procedures, and those procedures are required by this AD. However, according to the provisions of paragraph (i) of this AD, we may approve a request for using different overhaul procedures if the request includes data that prove that those procedures would provide an acceptable level of safety. We have not changed the AD in this regard.

We acknowledge the request for changes to Boeing Service Bulletin 737-32A1355, Revision 2. At the present time, Boeing has not issued a revised service bulletin with the changes. However, if Boeing Service Bulletin 737-32A1355, Revision 2, is revised after issuance of this AD, we might consider approving the revised service bulletin as an alternative method of compliance (AMOC) with the requirements of this AD. We have not changed the AD in this regard.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD as proposed.

We estimate that this AD affects 652 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new AD: