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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2007-28100; Directorate Identifier 2007-NM-103-AD; Amendment 39-15045; AD 2007-10-04] 
          - RIN 2120-AA64 

# AGENCY:

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

# ACTION:

Final rule; request for comments. 

# SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. This AD requires repetitive inspections to detect cracks in the horizontal stabilizer, and related investigative/corrective actions if necessary. This AD results from reports of cracks found in the horizontal stabilizer—in the upper and lower aft skin panels at the aft inboard corner at station XH = 8.2, and in the rear spar upper caps adjacent to the aft skin panel at station XH = 10.0. We are issuing this AD to detect and correct cracks in the upper and lower aft skin panels and rear spar upper caps, which, if not corrected, could lead to the loss of overall structural integrity of the horizontal stabilizer. 

# DATES:

This AD becomes effective May 23, 2007. 

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of May 23, 2007. 

We must receive comments on this AD by July 9, 2007. 

# ADDRESSES:

Use one of the following addresses to submit comments on this AD. 
      - DOT Docket Web site: Go to http://dms.dot.gov                          and follow the instructions for sending your comments electronically.                     
      - Government-wide rulemaking Web site: Go to http://www.regulations.gov                          and follow the instructions for sending your comments electronically.                     
      - Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
      - Fax: (202) 493-2251.
      - Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for service information identified in this AD. 

# 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 have received reports of cracks found in the horizontal stabilizer—in the upper and lower aft skin panels at the aft inboard corner at station XH = 8.2, and in the rear spar upper caps adjacent to the aft skin panel at station XH = 10.0. These cracks were found during maintenance visual inspections. 

The cause of the cracking is still under investigation. If not corrected, the cracked upper and lower aft skin panels and rear spar upper caps could lead to the loss of overall structural integrity of the horizontal stabilizer. 

## Relevant Service Information 

We have reviewed Boeing Alert Service Bulletin MD80-55A065, dated April 25, 2007. The service bulletin describes procedures for repetitive low- and high-frequency eddy current inspections to detect cracks of the horizontal stabilizer's upper and lower aft skin panels and rear spar upper caps. The service bulletin provides options for corrective action based on crack length, location, and repairability; these options include some combination of the following actions: 
    - Stop drilling the end of the crack;
    - Trimming the crack and installing a filler;
    - Installing a skin panel splice or rear spar upper cap splice;
    - Replacing the skin panel or rear spar upper cap with a new part; and
    - Repeating the inspection of the cracked area (including aft skin panels, skin panel splice, and rear spar upper cap).

The repetitive inspection intervals, which range from 200 to 2,600 flight cycles, depend on the option used. 

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. 

## FAA's Determination and Requirements of This AD 

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to detect and correct cracks in the upper and lower aft skin panels and rear spar upper caps, which, if not corrected, could lead to the loss of overall structural integrity of the horizontal stabilizer. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the AD and the Service Bulletin” below. 

## Differences Between the AD and the Service Bulletin 

The service bulletin specifies that any splice installed as part of a crack repair option be inspected within 20,000 flight cycles after the repair. But the service bulletin notes that the type, method, and repetitive interval for this inspection will be identified by Boeing at a later date. (See paragraph 1.E., note (a) of Tables 1 and 2 of the service bulletin.) To ensure continued safety, we have determined that this inspection and its repetitive interval must be adequately defined. Therefore, this AD requires that the inspection type, method, and repetitive interval be approved either by the FAA, or in accordance with data that meet the certification basis of the airplane and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings. 

                    For a crack that meets the Condition 2 criteria specified in Table 1 or Table 3 in paragraph 1.E. of the service bulletin, Options 1 and 2 specify temporary repairs followed by repetitive inspections of the area, but provide no                           ( print page 25961)                        terminating action for these repetitive inspections. In this case, this AD requires, within 4,000 flight cycles after the crack is detected, either installing a horizontal stabilizer aft skin panel splice or removing and replacing the horizontal stabilizer aft skin panel, in accordance with Option 3 or 4 of the applicable table, followed by the applicable repetitive inspections specified in Option 3 or 4. We have determined that this action is necessary to maintain the safety of the fleet.                 

We have coordinated these differences with Boeing. 

## FAA's Determination of the Effective Date 

Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days. 

## Comments Invited 

                    This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the                     **ADDRESSES**                     section. Include “Docket No. FAA-2007-28100; Directorate Identifier 2007-NM-103-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.                 

                    We will post all comments we receive, without change, to                     *http://dms.dot.gov,*                     including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the                     **Federal Register**                     published on April 11, 2000 (65 FR 19477-78), or you may visit                     *http://dms.dot.gov.*

## Examining the Docket 

                    You may examine the AD docket on the Internet at                     *http://dms.dot.gov,*                     or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after the Docket Management System receives them.                 

## 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 

We have determined that 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 the regulation:

1. Is not a “significant regulatory action” under Executive Order 12866; 

2. Is not a “significant rule” under the 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. 

                    We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the                     **ADDRESSES**                     section for a location to examine the regulatory evaluation.                 

# 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD): 

**2007-10-04 McDonnell Douglas:**                             Amendment 39-15045. Docket No. FAA-2007-28100; Directorate Identifier 2007-NM-103-AD.                         

## Effective Date 

(a) This AD becomes effective May 23, 2007. 

## Affected ADs 

(b) None. 

## Applicability 

(c) This AD applies to all McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes; certificated in any category. 

## Unsafe Condition 

(d) This AD results from reports of cracks found in the horizontal stabilizer—in the upper and lower aft skin panels at the aft inboard corner at station XH = 8.2, and in the rear spar upper caps adjacent to the aft skin panel at station XH = 10.0. We are issuing this AD to detect and correct cracks in the upper and lower aft skin panels and rear spar upper caps, which, if not corrected, could lead to the loss of overall structural integrity of the horizontal stabilizer. 

## Compliance 

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

## Repetitive Inspections 

(f) Do eddy current inspections to detect cracks in the horizontal stabilizer, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD80-55A065, dated April 25, 2007. 

(1) Do the initial inspections before the accumulation of 20,000 total flight cycles, or within 854 flight cycles after the effective date of this AD, whichever occurs later. 

(2) Except as required by paragraphs (g) and (h) of this AD: Do all applicable repetitive inspections and related investigative and corrective actions in accordance with, and at the times specified in, the service bulletin. 

## Exceptions to Service Bulletin Specifications 

                            (g) Where Boeing Alert Service Bulletin MD80-55A065, dated April 25, 2007, specifies inspecting any skin panel splice or cap splice installed as part of a crack repair                                   ( print page 25962)                                option: This AD requires the initial inspection within the compliance time specified in the service bulletin, but the inspection type, method, and repetitive interval must be done with FAA approval in accordance with the procedures specified in paragraph (i) of this AD.                         

(h) For airplanes on which any detected crack meets the Condition 2 criteria specified in Table 1 or Table 3 in paragraph 1.E. of Boeing Alert Service Bulletin MD80-55A065, dated April 25, 2007: If Option 1 or 2 is selected as the corrective action, either install a horizontal stabilizer aft skin panel splice or remove and replace the horizontal stabilizer aft skin panel within 4,000 flight cycles after accomplishing Option 1 or 2, in accordance with Option 3 or 4 of the applicable table, and repeat the inspection thereafter at the time specified in Option 3 or 4, as applicable. 

## Alternative Methods of Compliance (AMOCs) 

(i)(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. 

(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 appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. 

(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 an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who 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 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD. 

## Material Incorporated by Reference 

                            (j) You must use Boeing Alert Service Bulletin MD80-55A065, dated April 25, 2007, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for a copy of this service information. You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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/​cfr/​ibr-locations.html.*

Issued in Renton, Washington, on May 1, 2007. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, Aircraft Certification Service. 

 [FR Doc. E7-8768 Filed 5-7-07; 8:45 am] 

BILLING CODE 4910-13-P