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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2003-NM-170-AD, Amendment 39-13467; AD 2004-03-23] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule; request for comments. 

# SUMMARY:

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-200 and -300 series airplanes, that currently requires a one-time inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door where the door latch fittings attach between certain fuselage stations and water lines, and replacement of any cracked part with a new part having the same part number. This amendment continues to require the existing actions and corrects a reference to an incorrect fuselage station. The actions specified by the AD are intended to detect and correct cracking of the lower portion of the main deck cargo door frames, which could result in sudden depressurization, loss or opening of the main deck cargo door during flight, and loss of control of the airplane. 

# DATES:

Effective February 24, 2004. 

The incorporation by reference of a certain publication, as listed in the regulations, was approved previously by the Director of the Federal Register as of May 29, 2001 (66 FR 20380, April 23, 2001). 

Comments for inclusion in the Rules Docket must be received on or before April 9, 2004. 

# ADDRESSES:

                        Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-170-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address:                         *9-anm-nprmcomment@faa.gov.*                         Comments sent via fax or the Internet must contain “Docket No. 2003-NM-170-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.                     

The service information referenced in the proposed rule may be obtained from Pemco World Air Services, 100 Pemco Drive, Dothan, AL 36303. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

# FOR FURTHER INFORMATION CONTACT:

Don Buckley, Aerospace Engineer, Airframe and Propulsion Branch, ACE-117A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30337-2748, telephone (770) 703-6086; fax (770) 703-6097. 

# SUPPLEMENTARY INFORMATION:

On April 12, 2001, the FAA issued AD 2001-08-07, amendment 39-12184 (66 FR 20380, April 23, 2001), applicable to certain Boeing Model 737-200 and -300 series airplanes, to require a one-time inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door where the door latch fittings attach between certain fuselage stations and water lines, and replacement of any cracked part with a new part having the same part number. That action was prompted by reports that, during the inspections required by the existing AD, cracks were found in the reinforcing angles of the main deck cargo door frame. The requirements of that AD are intended to detect and correct cracking of the lower portion of the main deck cargo door frames, which could result in sudden depressurization, loss or opening of the main deck cargo door during flight, and loss of control of the airplane. 

## Actions Since Issuance of Previous Rule 

                    Since the issuance of that AD, several commenters point out a typographical error in paragraphs (a) and (b) of the AD. The first sentence of those paragraphs state, “ * * * at the location where the door latch fittings attach between fuselage station (FS) 361.86 and FS 298.12 * * *.” FS 298.12 is incorrect; the correct FS is 498.12, which is specified in the service bulletin cited in that AD (                    *i.e.*, Pemco Service Bulletin 737-52-003, Revision 2, dated September 13, 2000, including                           ( print page 5925)                        Attachment 1, dated August 10, 2000.) Because neither of the two airplanes affected by this action are on the U.S. Register, the public has not acted in reliance on the error. Therefore, public notice and comment are unnecessary, because the public would have no interest in commenting.                 

## Explanation of Requirements of Proposed Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design that may be registered in the United States at some time in the future, this AD is being issued to detect and correct cracking of the lower portion of the main deck cargo door frames, which could result in sudden depressurization, loss or opening of the main deck cargo door during flight, and loss of control of the airplane. This AD supersedes AD 2001-08-07 to require the existing one-time inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door where the door latch fittings attach between the correct fuselage stations and water lines, and replacement of any cracked part with a new part having the same part number. The actions are required to be accomplished in accordance with Pemco Service Bulletin 737-52-0037, Revision 2, dated September 13, 2000, including Attachment 1, dated August 10, 2000, described previously in AD 2001-08-07. 

## Cost Impact 

None of the Model 737-200 and -300 series airplanes equipped with a main deck cargo door installed in accordance with Supplemental Type Certificate SA2969SO affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future. 

Should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 500 work hours per airplane to accomplish the required inspection, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $32,500 per airplane. 

Should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 128 work hours per airplane to accomplish the replacement, at an average labor rate of $65 per work hour. Required parts will cost approximately $15,521 per airplane. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $23,841 per airplane. 

## Determination of Rule's Effective Date 

                    Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, prior notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the                     **Federal Register**                    .                 

## Comments Invited 

                    Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption                     **ADDRESSES**                    . All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.                 

Submit comments using the following format: 
    - Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
    - For each issue, state what specific change to the AD is being requested.
    - Include justification ( e.g. , reasons or data) for each request.                 

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. 

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-170-AD.” The postcard will be date stamped and returned to the commenter. 

## Regulatory Impact 

The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. 

                    For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption                     **ADDRESSES.**

# List of Subjects in 14 CFR Part 39

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

## Adoption of the Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by removing amendment 39-12184 ( 66 FR 20380, April 23, 2001), and by adding a new airworthiness directive (AD), amendment 39-13467 to read as follows: 

**2004-03-23 Boeing:**                             Amendment 39-13467. Docket 2003-NM-170-AD. Supersedes AD 2001-08-07, Amendment 39-12184.                         

*Applicability:*                             Model 737-200 and -300 series airplanes, equipped with a main deck cargo door installed in accordance with                                   ( print page 5926)                                Supplemental Type Certificate (STC) SA2969SO; certificated in any category.                         

*Compliance:*                             Required as indicated, unless accomplished previously.                         

To detect and correct cracking of the lower portion of the main deck cargo door frames, which could result in sudden depressurization, loss or opening of the main deck cargo door during flight, and loss of control of the airplane; accomplish the following: 

## Actions Addressing Door Frames or Reinforcing Angles That Have Been Replaced 

(a) For airplanes on which any door frame or reinforcing angle at the location where the door latch fittings attach between fuselage station (FS) 361.86 and FS 498.12 and water line (WL) 202.35 and WL 213.00 has been replaced before the effective date of this AD: Do the actions specified in paragraphs (a)(1) and (a)(2) of this AD per the Accomplishment Instructions of Pemco Service Bulletin 737-52-0037, Revision 2, dated September 13, 2000, including Attachment 1, dated August 10, 2000. 

(1) Within 3,000 flight cycles after accomplishment of the replacement, do a high frequency eddy current (HFEC) inspection to detect cracks of the replaced lower frames or replaced reinforcing angles of the main deck cargo door, as applicable. 

(i) If no crack is detected, repeat the HFEC inspection thereafter at intervals of 1,300 flight cycles on the replaced part. 

(ii) If any crack is detected, before further flight, replace the cracked part with a new part having the same part number per the service bulletin. Within 3,000 flight cycles after accomplishment of the replacement, do the HFEC inspection required by paragraph (a)(1) of this AD. 

(2) Before or upon the accumulation of 7,000 total flight cycles on any lower frame or reinforcing angle of the main deck cargo door, replace the lower frame or reinforcing angle, as applicable, with new parts. Within 3,000 flight cycles after accomplishment of the replacement, do the HFEC inspection required by paragraph (a)(1) of this AD. 

## Actions Addressing Door Frames or Reinforcing Angles That Have Not Been Replaced 

(b) For airplanes on which any door frame or reinforcing angle at the location where the door latch fittings attach between FS 361.86 and FS 498.12 and WL 202.35 and WL 213.00 has not been replaced before the effective date of this AD: Within 1,300 flight cycles after accomplishment of the HFEC inspection required by AD 2000-17-51, amendment 39-11877, do the action specified in either paragraph (b)(1) or (b)(2) of this AD, as applicable, per the Accomplishment Instructions of Pemco Service Bulletin 737-52-0037, Revision 2, dated September 13, 2000, including Attachment 1, dated August 10, 2000. 

(1) For airplanes that have accumulated less than 7,000 total flight cycles since installation of STC SA2969SO: Do an HFEC inspection to detect cracks of the lower frames and reinforcing angles of the main deck cargo door where the door latch fittings attach between FS 361.86 and FS 498.12 and WL 202.35 and WL 213.00. 

(i) If no crack is detected, do the actions specified in paragraphs (b)(1)(i)(A) and (b)(1)(i)(B) of this AD. 

(A) Repeat the HFEC inspection thereafter at intervals of 1,300 flight cycles on the airplane, but not to exceed the accumulation of 7,000 total flight cycles on the airplane. 

(B) Before the accumulation of 7,000 total flight cycles on the airplane, replace the lower frame and reinforcing angle with new parts per the service bulletin. Within 3,000 flight cycles after accomplishment of the replacement, do the HFEC inspection required by paragraph (a)(1) of this AD. 

(ii) If any crack is detected, before further flight, replace the cracked part with a new part having the same part number per the service bulletin. Within 3,000 flight cycles after accomplishment of the replacement, do the HFEC inspection required by paragraph (a)(1) of this AD. 

(2) For airplanes that have accumulated 7,000 or more total flight cycles since installation of STC SA2969SO: Replace the lower frames and reinforcing angles with new parts. Within 3,000 flight cycles after accomplishment of the replacement, do the HFEC inspection required by paragraph (a)(1) of this AD. 

## Alternative Methods of Compliance 

(c)(1) In accordance with 14 CFR 39.19, the Manager, Atlanta Aircraft Certification Office (ACO), FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. 

(2) Alternative methods of compliance, approved previously in accordance with AD 2000-17-51, amendment 39-11877, are approved as alternative methods of compliance with the initial HFEC inspection required by paragraph (a)(1) of this AD. 

## Incorporation by Reference 

(d) The actions shall be done in accordance with Pemco Service Bulletin 737-52-0037, Revision 2, dated September 13, 2000, including Attachment 1, dated August 10, 2000. This incorporation by reference was approved previously by the Director of the Federal Register as of May 29, 2001 (66 FR 20380, April 23, 2001). Copies may be obtained from Pemco World Air Services, 100 Pemco Drive, Dothan, AL 36303. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

## Effective Date 

(e) This amendment becomes effective on February 24, 2004. 

Issued in Renton, Washington, on January 30, 2004. 

Kalene C. Yanamura, 

Acting Manager,  Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 04-2575 Filed 2-6-04; 8:45 am] 

BILLING CODE 4910-13-P