Airworthiness directives: McDonald Douglas,
[Federal Register: April 7, 1999 (Volume 64, Number 66)]
[Rules and Regulations]
[Page 16805-16808]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07ap99-4]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-110-AD; Amendment 39-11110; AD 99-08-05]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9 and C-9 (Military) Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes. This amendment requires repetitive inspections to detect fatigue cracking of the fuselage frames and longerons 16R and 17R above the forward lower cargo door; repair, if necessary; and modification of the fuselage frames and longerons, if necessary, and follow-on repetitive inspections to detect fatigue cracking of the skin adjacent to the modification. This amendment is prompted by numerous instances of fatigue cracking of the fuselage frames and longerons. The actions specified by this AD are intended to prevent fatigue cracking of the fuselage frames and longerons 16R and 17R, which could result in reduced structural integrity of the airplane.
DATES: Effective May 12, 1999.
The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of May 12, 1999.
ADDRESSES: The service information referenced in this AD may be obtained from The Boeing Commercial Aircraft Group, Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los
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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, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5324; fax (562) 627-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes was published in the Federal Register on April 27, 1998 (63 FR 20548). That action proposed to require repetitive inspections to detect fatigue cracking of the fuselage frames and longerons 16R and 17R above the forward lower cargo door; repair, if necessary; and modification of the fuselage frames and longerons, if necessary, and follow-on repetitive inspections to detect fatigue cracking of the skin adjacent to the modification.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
One commenter indicates that it is not affected by the proposed rule.
Request To Extend Compliance Time
One commenter requests that the FAA extend the proposed compliance time for the initial inspection from 30,000 total landings, or within 3,000 landings after the effective date of this AD (whichever occurs later), to 30,000 total landings, or within 3,500 landings after the effective date of this AD (whichever occurs later). The commenter indicates that the 3,000-landing time limit will cause scheduling problems and will adversely affect operators. The commenter also states that an additional 500 landings would assure a smooth transition into the operators' maintenance program and would not cause additional safety concerns.
The FAA does not concur with the commenter's request. In developing an appropriate compliance time for the initial inspection, the FAA considered not only the degree of urgency associated with addressing the fatigue cracking of the fuselage frames and longerons, but other factors as well. Those factors include the recommendations of the manufacturer, and the practical aspect of accomplishing the initial inspection within an interval of time coinciding with normal scheduled maintenance for the majority of the affected operators. In that regard, the commenter did not provide any data to substantiate that an extension of the compliance time would not compromise safety. In view of those factors, and the amount of time that has already elapsed since issuance of the notice of proposed rulemaking, the FAA has determined that further delay of this inspection is, in general, not appropriate. The FAA may, however, approve a request for an adjustment of the compliance time under the provisions of paragraph (e) of this final rule if data are submitted to substantiate that such an adjustment would provide an equivalent level of safety.
Request To Extend/Eliminate Repetitive Inspection Interval for Modified Airplanes
One commenter requests that the proposed repetitive inspection interval for modified airplanes be extended or eliminated. The commenter states that incorporation of the modification of the fuselage frames and longerons 16R and 17R above the forward cargo door, in accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997, will improve the fatigue design of the longeron-to- frame attach points, thereby decreasing the probability of frame and longeron cracking that could result in secondary damage to the fuselage skin. The commenter also states that accomplishing the preventative modification should allow the repetitive inspection interval to be increased or should eliminate the need for repetitive inspections.
The FAA does not concur with the commenter's request. The FAA has coordinated this issue with the manufacturer and has determined that the repetitive inspections for modified airplanes are necessary to ensure an adequate level of safety for the transport airplane fleet. The cracking of the fuselage skin adjacent to the modification above the forward lower cargo door is fatigue-related, and the 19,000-landing repetitive inspection intervals were calculated based on fatigue and damage tolerance analysis. Therefore, no change to the final rule is necessary in this regard.
Request Credit for Previously Accomplished Work
Two commenters request credit for prior accomplishment of the proposed initial inspection. The commenters state that documented inspections were accomplished previously in accordance with AD 94-03- 01, amendment 39-8807 (59 FR 6538, February 11, 1994), or AD 96-13-03, amendment 39-9671 (61 FR 31009, June 19, 1996), per supplemental inspection document (SID) Report No. L26-008, Section 02, Volume II, Chapter 53-10-01, dated November 1987, using the same inspection method cited in the proposed AD, and in accordance with McDonnell Douglas Service Bulletin DC9-53-267, which was cited as the appropriate source of service information for accomplishment of the initial inspection.
The FAA concurs with the commenters' requests that an initial inspection accomplished prior to the effective date of this AD in accordance with AD 94-03-01 or AD 96-13-03 is acceptable for compliance with the initial inspection requirement in the final rule. However, the FAA notes that operators are always given credit for work accomplished previously if the work is performed in accordance with the existing AD by means of the phrase in the compliance section of the AD that states, ``Required as indicated, unless accomplished previously.'' Therefore, no change to the final rule is necessary in this regard.
Request To Revise Paragraph (b)(1) of the Proposed Rule
One commenter requests that paragraph (b)(1) of the proposed rule be revised to read, ``Option 1. Repeat the visual inspections in accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997, Paragraph 3.B. (SID Report No. L26-008, Volume II, Chapter 53-10-08, dated July 1997).'' The commenter states that paragraph (b)(1) of the proposal is unclear because the service bulletin does not specify the inspection procedure for the repetitive inspections.
The FAA concurs that clarification should be provided. The intent of paragraph (b)(1) is that operators repeat the visual inspection required by paragraph (a) of the AD. That paragraph requires accomplishment of the visual inspection specified in paragraph 3.B.1. of the Accomplishment Instructions of the service bulletin referenced by the commenter. Additionally, paragraph 3.B.1. of the service bulletin points to the SID report identified by the commenter. For clarification purposes, the FAA has revised paragraph (a) of the final rule to reference paragraph 3.B.1. of the service bulletin. In addition, the FAA has revised paragraph (b)(1) of the final rule to specify that the visual
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inspection to be repeated is that required by paragraph (a) of this AD.
Request To Revise Paragraphs (b)(2) and (c) of the Proposed Rule
This same commenter requests that paragraphs (b)(2) and (c) of the proposed rule be revised to define the inspection area and give operators the option to inspect the fuselage skin either internally or externally. The commenter interprets the repetitive inspection requirements of these paragraphs as being limited to the fuselage skin only, as shown in the shaded area in SID Report No. L26-008, Volume II, Chapter 53-10-08, dated July 1997, which does not include the longerons or frames.
The FAA concurs that clarification should be provided. The visual inspection specified in paragraphs (b)(2) and (c) of this AD is required to be accomplished in accordance with the inspection procedure specified in McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997. The intent of that inspection is to detect fatigue cracking of the fuselage skin adjacent to the modification. The only method for such inspection is an internal visual inspection of the inboard side of the fuselage, as specified in SID Report No. L26-008, Volume II, Chapter 53-10-08, dated July 1997 (which is referenced in the service bulletin as the appropriate inspection procedure for accomplishment of the visual inspection). Any crack will initiate at the frames and longerons, and the repair area cannot be seen from the outside. Therefore, the inspection must be accomplished internally to detect cracking of the skin adjacent to the repair.
For clarification purposes, the FAA has revised paragraph (b)(2) of the final rule to reference paragraph 3.B.1.D. of the Accomplishment Instructions of the service bulletin. Paragraph (c) of the final rule also has been revised to reference paragraph 3.B.1.D.(5) of the Accomplishment Instructions of the service bulletin. [Paragraphs 3.B.1.D. and 3.B.1.D.(5) reference the SID specified above for accomplishment of the visual inspection.]
Request To Allow Operator Approval of Certain Repairs
The same commenter requests that the FAA revise paragraphs (b)(2)(ii) and (c)(2) of the proposed AD to permit repairs of any cracked structure found on subsequent inspections to be accomplished by the operators in accordance with FAA-approved data, rather than in accordance data approved by the Manager of the Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. The commenter states that the findings and repair methods could be submitted to the Los Angeles ACO for subsequent review.
The FAA does not concur with the commenter's request. Access to the type design data is needed for repair data approval, and operators do not have such access. Therefore, the FAA has determined that to maintain an acceptable level of safety for the affected fleet, repair or modification of any cracked structure referenced in paragraphs (b)(2)(ii) and (c)(2) of this AD must be approved by the Manager, Los Angeles ACO. No change to the final rule is necessary in this regard.
Explanation of Changes to Final Rule
Paragraph (d) of the final rule has been revised to provide clarification. The revised paragraph states that accomplishment of the inspection requirements of this AD constitutes terminating action for inspections of Principal Structural Element 53.09.055A (defined in McDonnell Douglas Report No. L26-008, DC-9 Supplemental Inspection Document, Report No. L26-008, Section 2 of Volume III-95, dated September 1995). As a result of this revision, the FAA also has removed NOTE 2 of the proposal; this note is no longer necessary.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
There are approximately 887 airplanes of the affected design in the worldwide fleet. The FAA estimates that 582 airplanes of U.S. registry will be affected by this AD. It will take approximately 1 work hour per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on this figure, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $34,920, or $60 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the 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 modification, it would take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $860 or $713 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of the modification is estimated to be as high as $1,100 and as low as $953 per airplane.
Should an operator be required to accomplish the follow-on inspection of the fuselage skin, it would take approximately 1 work hour per airplane to accomplish the inspection, at an average labor rate of $60 per work hour. Based on this figure, the cost impact of the follow-on inspection on U.S. operators is estimated to be $60 per airplane, per inspection cycle.
Regulatory Impact
The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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:
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PART 39--AIRWORTHINESS DIRECTIVES
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The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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Section 39.13 is amended by adding the following new airworthiness directive:
99-08-05 McDonnell Douglas: Amendment 39-11110. Docket 98-NM-110- AD.
Applicability: Model DC-9 and C-9 (military) series airplanes, as listed in McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 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 (e) 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 prevent fatigue cracking of the fuselage frames and longerons 16R and 17R, which could result in reduced structural integrity of the airplane, accomplish the following:
(a) Prior to the accumulation of 30,000 total landings, or within 3,000 landings after the effective date of this AD, whichever occurs later, perform a visual inspection to detect fatigue cracking of the fuselage frames and longerons 16R and 17R above the forward lower cargo door, in accordance with paragraph 3.B.1. of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997.
(b) Condition 1. If no cracking is detected during the inspection required by paragraph (a) of this AD, accomplish the requirements of either paragraph (b)(1) or (b)(2) of this AD, in accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997.
(1) Option 1. Repeat the visual inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 19,000 landings. Or
(2) Option 2. Prior to further flight, modify the fuselage frames and longerons 16R and 17R. Prior to the accumulation of 19,000 landings after accomplishment of the modification, perform the visual inspection specified in paragraph 3.B.1.D. of the Accomplishment Instructions of the service bulletin to detect fatigue cracking of the skin adjacent to the modification.
(i) If no cracking is detected, repeat the visual inspection thereafter at intervals not to exceed 19,000 landings.
(ii) If any cracking is detected, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.
(c) Condition 2. If any cracking is detected during the inspection required by paragraph (a) of this AD, prior to further flight, repair the cracked area and modify the fuselage frames and longerons 16R and 17R; in accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997. Prior to the accumulation of 19,000 landings after accomplishment of the modification, perform the visual inspection specified in paragraph 3.B.1.D.(5) of the Accomplishment Instructions of the service bulletin to detect fatigue cracking of the skin adjacent to the modification, in accordance with the service bulletin.
(1) If no cracking is detected, repeat the visual inspection thereafter at intervals not to exceed 19,000 landings.
(2) If any cracking is detected, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles ACO.
(d) Accomplishment of the inspections required by this AD constitutes terminating action for the inspections of Principal Structural Element 53.09.055A (reference McDonnell Douglas Model DC- 9 Supplemental Inspection Document, Report No. L26-008, Section 2 of Volume III-95, dated September 1995), as required by AD 96-13-03, amendment 39-9671.
(e) 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.
(f) 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.
(g) Except as provided by paragraphs (b)(2)(ii) and (c)(2) of this AD, the actions shall be done in accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated October 20, 1997. 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, Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). Copies may be inspected 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on May 12, 1999.
Issued in Renton, Washington, on March 30, 1999. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 99-8329Filed4-6-99; 8:45 am]
BILLING CODE 4910-13-U
