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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2009-0783; Directorate Identifier 2009-NM-081-AD; Amendment 39-16213; AD 2010-05-04]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final rule.

# SUMMARY:

We are adopting a new airworthiness directive (AD) for all Model MD-90-30 airplanes. This AD requires repetitive inspections for cracking of the overwing frames at stations 883, 902, 924, 943, and 962, left and right sides, and corrective actions if necessary. This AD results from reports of cracked overwing frames. We are issuing this AD to detect and correct such cracking, which could sever the frame, increase the loading of adjacent frames, and result in damage to adjacent structure and loss of overall structural integrity of the airplane.

# DATES:

This AD is effective April 1, 2010.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of April 1, 2010.

# ADDRESSES:

                        For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail                         *dse.boecom@boeing.com*; Internet                         *https://www.myboeingfleet.com.*

## Examining the AD Docket

                    You may examine the AD docket on the Internet at                     *http://www.regulations.gov;*                     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, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone 800-647-5527) is the Document 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:

Roger Durbin, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5233; fax (562) 627-5210.

# SUPPLEMENTARY INFORMATION:

## Discussion

                    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 Model MD-90-30 airplanes. That NPRM was published in the                     **Federal Register**                     on September 4, 2009 (74 FR 45785). That NPRM proposed to require repetitive inspections for cracking of the overwing frames at stations 883, 902, 924, 943, and 962, left and right sides, and corrective actions if necessary.                

## Comments

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

## Request To Revise Wording in the Summary Section and Unsafe Condition Paragraph of the NPRM

The Boeing Company requests that we revise the wording of the precipitating event in the Summary section and Unsafe Condition paragraph of the NPRM to clarify that the reported cracking was found on Model MD-80 airplanes, and that frames of the same design are installed on Model MD-90 airplanes. The commenter explains that the proposed revision will be in line with the first paragraph of the “Discussion” section of the NPRM. The commenter asserts that otherwise, the Summary section and paragraph (e) of the NPRM read that “Model MD-90 overwing frames have cracked,” which is not the case.

We agree that clarification might be necessary. While the commenter's proposed revision is more precise with respect to the history of the service difficulties, the Summary section of ADs is designed to provide only a brief description of the action being proposed. Likewise, the Unsafe Condition paragraph in the regulatory text of an AD is meant to be only a brief statement. Detailed background information is provided in the Discussion section of a proposed AD. We addressed the issues raised by the commenter in the Discussion section of the NPRM. That section is not restated in this final rule. We have not changed the AD in this regard.

## Request To Revise Wording in the Discussion Section of the NPRM

The Boeing Company requests that we revise the first sentence of the second paragraph of the “Discussion” section of the NPRM to read, “The cracked overwing frames on McDonnell Douglas Model MD-90-30 airplanes have the same design as those installed on Model MD-80 series airplanes.” The commenter explains that the proposed revision sounds more logical than how it reads in the NPRM and that the issue is the Model MD-90 frames cracking, not the Model MD-80 frames.

                    We agree that clarification is needed. The proposed revision would indicate that we have reports of cracks on Model MD-90-30 airplanes, which is not the case. As stated in the NPRM, the reports                           ( print page 8466)                        we received were of cracked frames on Model MD-80 airplanes. This AD is being issued because Model MD-90-30 airplanes have frames with the same design, and therefore, are also susceptible to the unsafe condition addressed by this AD. Regardless, the Discussion section of the NPRM is not restated in this final rule. No change to the AD is necessary in this regard.                

## Explanation of Name Change Made to This AD

We have revised this AD to identify the legal name of the manufacturer as published in the most recent type certificate data sheet for the affected airplane models.

## Explanation of Delegation Authorization Change Made to This AD

Boeing Commercial Airplanes has received an Organization Designation Authorization (ODA), which replaces their previous designation as a Delegation Option Authorization (DOA) holder. We have revised paragraph (h)(3) of this AD to delegate the authority to approve an alternative method of compliance for any repair required by this AD to the Boeing Commercial Airplanes ODA.

## Conclusion

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

## Explanation of Change to Costs of Compliance

Since issuance of the NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate.

## Costs of Compliance

We estimate that this AD affects 16 airplanes of U.S. registry. We also estimate that it takes about 10 work-hours per product to comply with this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $13,600, or $850 per product.

## Authority for This Rulemaking

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.

## Regulatory Findings

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.

# List of Subjects in 14 CFR Part 39

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

## Adoption of the Amendment

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

# PART 39—AIRWORTHINESS DIRECTIVES

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

Authority:49 U.S.C. 106(g), 40113, 44701.

§ 39.13 

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

**2010-05-04 McDonnell Douglas Corporation:**                             Amendment 39-16213. Docket No. FAA-2009-0783; Directorate Identifier 2009-NM-081-AD.                        

## Effective Date

(a) This airworthiness directive (AD) is effective April 1, 2010.

## Affected ADs

(b) None.

## Applicability

(c) This AD applies to all McDonnell Douglas Corporation Model MD-90-30 airplanes, certificated in any category.

## Subject

(d) Air Transport Association (ATA) of America Code 53: Fuselage.

## Unsafe Condition

(e) This AD results from reports of cracked overwing frames. We are issuing this AD to detect and correct such cracking, which could sever the frame, increase the loading of adjacent frames, and result in damage to adjacent structure and loss of overall structural integrity of the airplane.

## Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

## Inspections

(g) Before the accumulation of 20,000 total flight cycles, or within 60 months after the effective date of this AD, whichever occurs later: Do general visual and high frequency eddy current inspections for cracking of the overwing frames, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-53A031, dated April 10, 2009. Do the applicable corrective actions before further flight, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-53A031, dated April 10, 2009. Repeat the inspections thereafter at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-53A031, dated April 10, 2009.

## Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Roger Durbin, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5233; fax (562) 627-5210.

                            (2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District                                   ( print page 8467)                                Office. The AMOC approval letter must specifically reference this AD.                        

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Los Angeles ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and the approval must specifically refer to this AD.

## Material Incorporated by Reference

(i) You must use Boeing Alert Service Bulletin MD90-53A031, dated April 10, 2009, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

                            (2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail                             *dse.boecom@boeing.com;*                             Internet                             *https://www.myboeingfleet.com.*

(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,  SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152.

                            (4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to:                             *http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html*.                        

Issued in Renton, Washington, on February 16, 2010.

Stephen P. Boyd,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2010-3469 Filed 2-24-10; 8:45 am]

BILLING CODE 4910-13-P