[Federal Register Volume 63, Number 17 (Tuesday, January 27, 1998)] [Proposed Rules] [Pages 3852-3854] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 98-1858] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 97-NM-99-AD] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas Model DC-9-31 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-31 series airplanes. This proposal would require a one-time visual inspection to determine if all corners of the forward service door doorjamb have been modified previously, various follow-on repetitive inspections, and modification, if necessary. This proposal is prompted by reports of fatigue cracks found in the fuselage skin and doubler at the corners of the forward service door doorjamb. The actions specified by the proposed AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane. DATES: Comments must be received by March 13, 1998. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 97-NM-99-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Department C1-L51 (2-60). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California. 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 (562) 627-5324; fax (562) 627-5210. SUPPLEMENTARY INFORMATION: Comments Invited Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 97-NM-99-AD.'' The postcard will be date stamped and returned to the commenter. Availability of NPRMs Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 97-NM-99-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion The FAA has received reports of fatigue cracks in the fuselage skin and doubler at the corners of the forward service door doorjamb on Model DC-9-31 series airplanes. These cracks were discovered during inspections conducted as part of the Supplemental Structural Inspection Document (SSID) program, required by AD 96-13-03, amendment 39-9671 (61 FR 31009, June 19, 1996). Investigation revealed that such cracking was caused by fatigue-related stress. Fatigue cracking in the fuselage skin or doubler at the corners of the forward service door doorjamb, if not detected and corrected in a timely manner, could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane. Explanation of Relevant Service Information The FAA has reviewed and approved McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997. The service bulletin describes the following procedures: 1. Performing a one-time visual inspection to determine if the corners of the forward service door doorjamb have been modified; 2. For airplanes on which the modification specified in Service Bulletin DC9-53-288 has not been accomplished: Performing a low frequency eddy current (LFEC) or x-ray inspection to detect cracks of the fuselage skin and doubler at all corners of the forward service door doorjamb; 3. Conducting repetitive inspections, or modifying the corner skin of the doorjamb of the forward service door and performing follow-on action high frequency eddy current (HFEC) inspections, if no cracking is detected; 4. Performing repetitive HFEC inspections to detect cracks on the skin adjacent to any corner that has been modified; and 5. Modifying any crack that is found to be 2 inches or less in length at all corners that have not been modified and performing follow-on repetitive HFEC inspections. Accomplishment of the modification will minimize the possibility of cracks in the fuselage skin and doubler. [[Page 3853]] Explanation of Requirements of Proposed Rule Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require a one-time visual inspection to determine if all corners of the forward service door doorjamb have been modified previously, various follow-on repetitive inspections, and modification, if necessary. The one-time visual inspection, follow-on repetitive inspections, and modification would be required to be accomplished in accordance with the service bulletin described previously. Differences Between the Proposed Rule and the Relevant Service Information Operators should note that, although the service bulletin specifies that the manufacturer must be contacted for disposition of certain conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA. Cost Impact There are approximately 64 McDonnell Douglas Model DC-9-31 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 51 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed one-time visual inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the one-time visual inspection of the proposed AD on U.S. operators is estimated to be $3,060, or $60 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. Should an operator be required to accomplish the LFEC or x-ray inspection, it would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of any necessary LFEC or x-ray inspection is estimated to be $60 per airplane, per inspection cycle. Should an operator be required to accomplish the HFEC inspection, it would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of any necessary HFEC inspection is estimated to be $60 per airplane, per inspection cycle. Should an operator be required to accomplish the modification, it would take approximately 30 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $4,800 per airplane. Based on these figures, the cost impact of any necessary modification is estimated to be $6,600 per airplane. Regulatory Impact The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed 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) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. The Proposed Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: McDonnell Douglas: Docket 97-NM-99-AD. Applicability: Model DC-9-31 series airplanes, as listed in McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997, certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To detect and correct fatigue cracking in the fuselage skin or doubler at the corners of the forward service door doorjamb, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane, accomplish the following: Note 2: Where there are differences between the service bulletin and the AD, the AD prevails. Note 3: The words ``repair'' and ``modify/modification'' in this AD and the referenced service bulletin are used interchangeably. Note 4: This AD will affect Principal Structural Element (PSE) 53.09.033 of the DC-9 Supplemental Inspection Document (SID). (a) Prior to the accumulation of 50,000 total landings, or within 3,225 landings after the effective date of this AD, whichever occurs later, perform a one-time visual inspection to determine if the corners of the forward service door doorjamb have been modified. Perform the inspection in accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997. (b) For airplanes identified as Group 1 in McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997: If the visual inspection required by paragraph (a) of this AD reveals that the corners of the forward service door doorjamb have not been modified, prior to further flight, perform a low frequency eddy currrent (LFEC) or x-ray inspection to detect cracks of the fuselage skin and doubler at all corners of the forward service door doorjamb, in accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997. (1) Group 1, Condition 1. If no crack is detected during any LFEC or x-ray inspection required by paragraph (b) of this AD, accomplish the requirements of either paragraph (b)(1)(i) or (b)(1)(ii) of this AD, in accordance with the service bulletin. (i) Option 1. Repeat the LFEC inspection required by this paragraph thereafter at intervals not to exceed 3,225 landings, or the x-ray inspection required by this paragraph thereafter at intervals not to exceed 3,075 landings; or (ii) Option 2. Prior to further flight, modify the corner skin of the forward service door [[Page 3854]] doorjamb in accordance with the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform a high frequency eddy current (HFEC) inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. (A) If no crack is detected on the skin adjacent to the modification during the HFEC required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings. (B) If any crack is detected on the skin adjacent to the modification during any HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (2) Group 1, Condition 2. If any crack is found during any LFEC or x-ray inspection required by paragraph (b) of this AD, and the crack is 2 inches or less in length: Prior to further flight, modify/repair the corners of the doorjamb of the forward service door in accordance with the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform a HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. (i) If no crack is detected during the HFEC inspection required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings. (ii) If any crack is detected during any HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. (3) Group 1, Condition 3. If any crack is found during any LFEC or x-ray inspection required by paragraph (b) of this AD, and the crack is greater than 2 inches in length: Prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. (c) Group 2, Condition 1. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997: If the visual inspection required by paragraph (a) of this AD reveals that the corners of the forward service door doorjamb have been modified previously in accordance with the McDonnell Douglas DC-9 Structural Repair Manual, using a steel doubler, accomplish either paragraph (c)(1) or (c)(2) of this AD in accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997. (1) Option 1. Prior to the accumulation of 6,000 landings after accomplishment of that modification, or within 3,225 landings after the effective date of this AD, whichever occurs later, perform an HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. (i) If no crack is detected during the HFEC inspection required by paragraph (c)(1) of this AD, repeat the HFEC inspection thereafter at intervals not to exceed 3,000 landings. (ii) If any crack is detected during any HFEC inspection required by paragraph (c)(1) of this AD, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles ACO. (2) Option 2. Prior to further flight, modify the corner skin of the forward service door doorjamb in accordance with the service bulletin. Prior to the accumulation of 28,000 landings after accomplishment of the modification, perform an HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with the service bulletin. (i) If no crack is detected on the skin adjacent to the modification during the HFEC required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings. (ii) If any crack is detected on the skin adjacent to the modification during any HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (d) Group 2, Condition 2. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997: If the visual inspection required by paragraph (a) of this AD reveals that the corners of the forward service door doorjamb have been modified previously in accordance with McDonnell Douglas DC-9 Structural Repair Manual, using an aluminum doubler, prior to the accumulation of 28,000 landings after accomplishment of that modification, or within 3,225 landings after the effective date of this AD, whichever occurs later, perform an HFEC inspection to detect cracks on the skin adjacent to the modification, in accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997. (1) If no crack is detected on the skin adjacent to the modification during the HFEC required by this paragraph, repeat the HFEC inspection thereafter at intervals not to exceed 20,000 landings. (2) If any crack is detected on the skin adjacent to the modification during any HFEC inspection required by this paragraph, prior to further flight, repair it in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (e) Group 2, Condition 3. For airplanes identified as Group 2 in McDonnell Douglas Service Bulletin DC9-53-288, dated February 10, 1997: If the visual inspection required by paragraph (a) of this AD reveals that the corners of the forward service door doorjamb have been modified previously, but not in accordance with McDonnell Douglas Structural Repair Manual, prior to further flight, repair the corners in accordance with a method approved by the Manager, Los Angeles ACO. (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. (g) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Issued in Renton, Washington, on January 20, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-1858 Filed 1-26-98; 8:45 am] BILLING CODE 4910-13-U