03-24681. Airworthiness Directives; McDonnell Douglas Model DC-9-31 and DC-9-32 Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-31 and DC-9-32 airplanes. This action requires, among other actions, various inspections to detect cracks of the cockpit enclosure window sill, and follow-on and corrective actions, as applicable. This action is necessary to prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Effective October 20, 2003.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of October 20, 2003.

Comments for inclusion in the Rules Docket must be received on or before December 2, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-61-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-61-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 or 2000 or ASCII text.

The service information referenced in this AD may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA has received several reports of cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill on McDonnell Douglas Model DC-9 series airplanes. These airplanes had accumulated between 61,624 and 100,238 total flight cycles. The cause of such cracking has been attributed to high-cycle fatigue. Fatigue cracking of the subject area, if not corrected, could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Other Related Rulemaking

On October 11, 2002, the FAA issued AD 2002-21-09, amendment 39-12915 (67 FR 65303, October 24, 2002), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, which currently requires, among other actions, various inspections to detect cracks of the cockpit enclosure window sill, and follow-on and corrective actions, as applicable. That AD was prompted by reports of cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill. The actions required by that AD are intended to prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Since issuance of that AD, the FAA has determined that the same unsafe condition addressed in that AD may exist on certain additional Model DC-9-31 and DC-9-32 airplanes. The FAA was advised that four Model DC-9-31 and DC-9-32 airplanes (manufacturer's fuselage numbers 0268, 0505, 1039, and 1046) were omitted inadvertently from the applicability of AD 2002-21-09 because those airplanes had been excluded inadvertently from the effectivity of paragraph 1.A. of Boeing Service Bulletin DC9-53-290, Revision 01, dated March 15, 2002. Therefore, these additional airplanes are also subject to the same unsafe condition addressed in AD 2002-21-09.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003. The procedures specified by Revision 02 of the service bulletin are essentially the same as those procedures included in Boeing Service Bulletin DC9-53-290, Revision 01, dated March 15, 2002, as cited in AD 2002-21-09. However, this revision also adds four airplane fuselage numbers to the effectivity. No more work is necessary on the airplanes changed, as shown in Revision 01 of the service bulletin.

Accomplishment of the actions specified in AD 2002-21-09 is acceptable for compliance with the requirements of this AD.

Explanation of Requirements of the 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 prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane. This AD requires, among other actions, various inspections to detect cracks of the cockpit enclosure window sill, and follow-on and corrective actions, as applicable. The actions are required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

Difference Between Rule and Service Bulletin

Operators should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this AD requires the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

Changes to 14 CFR Part 39/Effect on the AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance (AMOCs). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in each individual AD.

Change to Labor Rate Estimate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Cost Impact

None of the airplanes 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 4 work hours to accomplish the required actions, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this AD would be $260 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-61-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

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2003-20-06 McDonnell Douglas: Amendment 39-13324. Docket 2003-NM-61-AD.

Applicability: Model DC-9-31 and DC-9-32 airplanes; fuselage numbers 0268, 0505, 1039 and 1046; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane, accomplish the following:

Note 1:

Where there are differences between the AD and the referenced service bulletin, the AD prevails.

Initial Inspections

(a) Before the accumulation of 40,000 total landings, or within 5,000 landings after the effective date of this AD, whichever occurs later, do the actions specified in paragraphs (a)(1) and (a)(2) of this AD per the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003.

(1) Do a general visual inspection to determine if any existing repair of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill has been accomplished before the effective date of this AD.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

(2) Do inspections to detect cracks or loose or missing fasteners of the cockpit enclosure window sill per paragraphs 3.B.1. through 3.B.6. of the Accomplishment Instructions of the service bulletin. The inspections include a general visual inspection to detect loose or missing fasteners or cracks of the upper nose skins of the cockpit; a high frequency eddy current (HFEC) inspection for cracking of Zees; and detailed, borescope, and HFEC inspections for cracking of the skins and frames.

Note 3:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required.”

Note 4:

If any cracked Zee is found during any inspection per paragraph (a)(2) of this AD, refer to paragraph (h) of this AD.

Condition 1 (No Previous Repair and No Crack)

(b) If no previous repair and no crack is found during the inspections required by paragraphs (a)(1) and (a)(2) of this AD: Do the actions specified in paragraph (b)(1) or (b)(2) of this AD, at the times specified in those paragraphs.

Condition 1, Option 1: Repetitive Inspections

(1) Condition 1, Option 1: Repeat the inspections required by paragraph (a)(2) of this AD every 5,000 landings, until paragraph (b)(2) of this AD is done. If any crack is found, before further flight, determine the applicable Condition as specified in the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003, and do the applicable actions required by this AD.

Condition 1, Option 2: Permanent Repair

(2) Condition 1, Option 2: Do paragraphs (b)(2)(i) and (b)(2)(ii) of this AD.

(i) Before further flight, do all actions associated with the permanent repair (including detailed and eddy current inspections of various parts; and repair, replacement, or rework of those parts, as applicable) per Condition 1, Option 2, of the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003. This terminates the repetitive inspections per paragraph (b)(1) of this AD.

Note 5:

Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003, refers to Boeing Service Rework Drawing SR09530268, Revision D, dated November 29, 2001, as an additional source of service information for identifying parts to be inspected, and repairing, replacing, or reworking those parts.

(ii) Within 40,000 landings after doing the permanent repair required by paragraph (b)(2)(i) of this AD, repeat the inspections specified in paragraph (a)(2) of this AD to detect any crack of the completed repair, per the Accomplishment Instructions of the service bulletin. If no crack is found, repeat the inspections specified in paragraph (a)(2) of this AD every 5,000 landings. If any crack is found, do paragraph (g) of this AD.

Condition 2 (Any Crack Within Flyable Limits for Temporary Repair)

(c) If any crack is found during the initial inspection required by paragraph (a)(2) of this AD, or during any repetitive inspection required by paragraph (b)(1) of this AD, and that crack is within the flyable limits specified in Condition 2 of the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003: Do the actions specified in paragraph (c)(1) or (c)(2) of this AD.

Note 6:

Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003, refers to Boeing Service Rework Drawing SR09530268, Revision D, dated November 29, 2001, as the source for determining flyable limits.

Condition 2, Option 1: Temporary Repair and Repetitive Inspections

(1) Condition 2, Option 1: Do paragraphs (c)(1)(i), (c)(1)(ii), (c)(1)(iii), and (c)(1)(iv) of this AD, at the times specified in those paragraphs.

(i) Before further flight, do the temporary repair (including installation of doublers) per Condition 2, Option 1, of the Accomplishment Instructions of the service bulletin.

(ii) Within 2,000 landings after doing the temporary repair, do a general visual inspection to detect cracks of the skins and external doublers. If no crack is found that is outside the flyable limits specified in Condition 2 of the Accomplishment Instructions of the service bulletin, repeat the inspection every 2,000 landings until paragraph (c)(2)(i) of this AD is done.

(iii) Within 3,500 landings after doing the temporary repair, do borescope and HFEC inspections to detect cracks of the internal structure. If no crack is found that is outside the flyable limits specified in Condition 2 of the Accomplishment Instructions of the service bulletin, repeat the inspection every 3,500 landings until paragraph (c)(2)(i) of this AD is done.

Note 7:

If any crack is found during any inspection per paragraph (c)(1)(ii) or (c)(1)(iii) of this AD, refer to paragraph (f) of this AD.

(iv) Except as provided by paragraph (f) of this AD, within 8,000 landings after doing the temporary repair, do the permanent repair specified in paragraph (c)(2) of this AD.

Condition 2, Option 2: Permanent Repair

(2) Condition 2, Option 2: Do paragraphs (c)(2)(i) and (c)(2)(ii) of this AD at the times specified in those paragraphs.

(i) Before further flight, do all actions associated with the permanent repair (including detailed and eddy current inspections of various parts; and repair, replacement, or rework of those parts, as applicable) per Condition 2, Option 2, of the Accomplishment Instructions of the service bulletin. This terminates the repetitive inspections required by paragraphs (c)(1)(ii) and (c)(1)(iii) of this AD.

(ii) Within 40,000 landings after doing the permanent repair required by paragraph (c)(2)(i) of this AD, repeat the inspections specified in paragraph (a)(2) of this AD to detect any crack of the completed repair, per the Accomplishment Instructions of the service bulletin. If no crack and no crack progression is found, repeat the inspections specified in paragraph (a)(2) of this AD every 5,000 landings. If any crack or crack progression is found, do paragraph (g) of this AD.

Condition 3 (Existing Temporary Repairs Per Certain Service Information)

(d) If any temporary repair is found during any inspection required by paragraph (a)(1) of this AD and that repair was accomplished per the service information identified in Condition 3 of the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003: Do the actions specified in paragraph (d)(1) or (d)(2) of this AD. Also, if the Station Y=83.550 frames have been repaired before the effective date of this AD per DC-9/MD-80 Structural Repair Manual, Section 53-03, Figure 34, or Boeing Service Rework Drawing S509530127, do a one-time inspection of the frames for crack growth emanating beyond the repair angles. If any crack progression is found, before further flight, replace the frames with new frames per the Accomplishment Instructions of the service bulletin.

Condition 3, Option 1: Repetitive Inspections

(1) Condition 3, Option 1: Do paragraphs (d)(1)(i), (d)(1)(ii), and (d)(1)(iii) of this AD at the times specified in those paragraphs.

(i) Within 2,000 landings after doing the temporary repair, or before further flight after accomplishment of the initial inspections in paragraph (a) of this AD, whichever is later, do a general visual inspection to detect cracks of the skins and external doublers. If no crack is found that is outside the flyable limits specified in Condition 2 of the Accomplishment Instructions of the service bulletin, repeat the inspection every 2,000 landings until paragraph (d)(2)(i) of this AD is done.

Note 8:

If any crack outside the flyable limits is found during any inspection per paragraph (d)(1)(i) or (d)(1)(ii) of this AD, refer to paragraph (f) of this AD.

(ii) Within 3,500 landings after doing the temporary repair, or before further flight after accomplishment of the initial inspections in paragraph (a) of this AD, whichever is later, do borescope and HFEC inspections to detect cracks of the internal structure. If no crack is found that is outside the flyable limits specified in Condition 2 of the Accomplishment Instructions of the service bulletin, repeat the inspection every 3,500 landings until paragraph (d)(2)(i) of this AD is done.

(iii) Except as provided by paragraph (f) of this AD, within 8,000 landings after doing the temporary repair, or before further flight if more than 8,000 landings have been accumulated since the temporary repair, do the permanent repair specified in paragraph (d)(2)(i) of this AD.

Condition 3, Option 2: Permanent Repair

(2) Condition 3, Option 2: Do paragraphs (d)(2)(i) and (d)(2)(ii) of this AD at the times specified in those paragraphs.

(i) Before further flight, do all actions associated with the permanent repair (including detailed and eddy current inspections of various parts; and repair, replacement, or rework of those parts, as applicable) per Condition 3, Option 2, of the Accomplishment Instructions of the service bulletin. This terminates the repetitive inspections required by paragraphs (d)(1)(i) and (d)(1)(ii) of this AD.

(ii) Within 40,000 landings after doing the permanent repair required by paragraph (d)(2)(i) of this AD, repeat the inspections specified in paragraph (a)(2) of this AD to detect any crack of the completed repair, per the Accomplishment Instructions of the service bulletin. If no crack and no crack progression is found: Repeat the inspections specified in paragraph (a)(2) of this AD every 5,000 landings. If any crack or crack progression is found, do paragraph (g) of this AD.

Condition 4 (Existing Repairs Per Other Service Information)

(e) If any repair is found during any inspection required by paragraph (a)(1) of this AD, and the repair was not accomplished per the service information identified in Condition 4 of the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003: Before further flight, repair per a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA.

Condition 5 (Crack Outside Flyable Limits for Temporary Repair)

(f) If any crack is found during any inspection required by paragraph (a)(2), (b)(1), (c)(1)(ii), (c)(1)(iii), (d)(1)(i), or (d)(1)(ii) of this AD; and that crack is outside the limits specified in Condition 2 of the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003; and a permanent repair was not previously accomplished per this AD: Do paragraphs (f)(1) and (f)(2) of this AD at the times specified in those paragraphs.

(1) Before further flight, do all actions associated with the permanent repair (including detailed and eddy current inspections of various parts; and repair, replacement, or rework of those parts, as applicable) per Condition 5 of the Accomplishment Instructions of the service bulletin.

(2) Within 40,000 landings after doing the permanent repair required by paragraph (f)(1) of this AD, repeat the inspections specified in paragraph (a)(2) of this AD to detect any crack of the completed repair, per the Accomplishment Instructions of the service bulletin. If no crack and no crack progression is found, repeat the inspections specified in paragraph (a)(2) of this AD every 5,000 landings. If any crack or crack progression is found, do paragraph (g) of this AD.

Corrective Actions: Cracking Following Permanent Repair

(g) If any crack or crack progression is found during any inspection required by paragraph (b)(2)(ii), (c)(2)(ii), (d)(2)(ii), or (f)(2) of this AD: Before further flight, repair per a method approved by the Manager, Los Angeles ACO.

Corrective Action for Cracked Zee

(h) If any cracked Zee is found during any inspection performed per paragraph (a)(2) of this AD: Before further flight, replace the cracked Zee with a new part per the Accomplishment Instructions of Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003.

Credit for Accomplishment of Related AD 2002-21-09, Amendment 39-12915

(i) Accomplishment of the actions specified in AD 2002-21-09 is acceptable for compliance with the requirements of this AD.

Alternative Methods of Compliance

(j)(1) In accordance with 14 CFR 39.19, the Manager, Los Angeles ACO, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.

(2) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by a Boeing Company Engineering Representative (DER) who has been authorized by the Manager, Los Angeles ACO, to make such findings.

Incorporation by Reference

(k) Unless otherwise specified by this AD, the actions shall be done in accordance with Boeing Service Bulletin DC9-53-290, Revision 02, dated January 30, 2003. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles ACO, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(l) This amendment becomes effective on October 20, 2003.

Issued in Renton, Washington, on September 24, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.