03-31440. Airworthiness Directives; McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes, and C-9 (military) airplanes, that would have superseded an existing AD that currently requires repetitive ultrasonic or magnetic particle inspections to detect cracking of the engine pylon aft upper spar straps (caps); and if necessary, replacement of the strap with a new strap, or modification of the engine pylon rear spar straps, which constitutes terminating action for the repetitive inspections. The proposed AD also would have required new, improved repetitive ultrasonic inspections, and corrective actions if necessary. The proposed AD also would have required, among other items, a terminating action for the repetitive inspection requirements. This new action revises the proposed rule by adding airplanes to the applicability. The actions specified by this new proposed AD are intended to detect and correct such fatigue cracking, which could result in major damage to the adjacent structure of the pylon aft upper spar cap, and consequent reduced structural integrity of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 16, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-255-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. 99-NM-255-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 the proposed rule 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.

FOR FURTHER INFORMATION CONTACT:

Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

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 action may be changed in light of the comments received.

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 proposed 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 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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NM-255-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-114, Attention: Rules Docket No. 99-NM-255-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes, and C-9 (military) airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on May 10, 2000 (65 FR 30025). That NPRM proposed to supersede AD 78-01-16, amendment 39-3117 (43 FR 1300, January 9, 1978), which is applicable to certain McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes, and C-9 (military) airplanes. That NPRM would have continued to require repetitive ultrasonic or magnetic particle inspections to detect cracking of the engine pylon aft upper spar straps (caps); and if necessary, replacement of the strap with a new strap, or modification of the engine pylon rear spar straps, which constitutes terminating action for the repetitive inspections. That NPRM would have added new, improved repetitive ultrasonic inspections, and corrective actions, if necessary. That NPRM also would have required, among other items, a terminating action for the repetitive inspection requirements. That NPRM was prompted by additional reports of fatigue cracking in the subject area of these airplanes. Such fatigue cracking, if not corrected, could result in major damage to the adjacent structure of the pylon aft spar upper cap, and consequent reduced structural integrity of the airplane.

Actions Since Issuance of Previous Proposal

Since the issuance of that NPRM, the manufacturer has advised the FAA that the identified unsafe condition may also occur on additional airplanes with a certain configuration of the left and right pylon aft upper caps.

Explanation of New Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin (ASB) DC9-54A031, Revision 09, dated September 3, 2002. That ASB describes procedures for new repetitive ultrasonic or magnetic particle inspections of the engine pylon aft upper spar straps (caps) to detect cracking; and corrective actions if necessary. The corrective actions include reapplication of a sealant; modification of the rear spar upper strap (cap); and replacement of the bearing of the spar strap (cap) with a new annular groove bearing if necessary. Revision 09 contains information that is essentially the same as Revision 08, which was referenced in the previous NPRM as one of the applicable sources of service information. However, Revision 09 specifically references Boeing Service Bulletin DC9-54-031, Revision 05, dated April 25, 2003, as an additional source of service information.

We have also reviewed and approved Boeing Service Bulletin DC9-54-031, Revision 05, dated April 25, 2003. The service bulletin describes procedures for modification of the rear spar upper strap (cap), which would eliminate the need for the repetitive inspections specified in Boeing ASB DC9-54A031, Revision 09, dated September 3, 2002, discussed above. The modification includes installation of access doors on the pylon rear spars, if applicable; replacement of the strap on the pylon upper rear spar cap with a new strap having an annular groove bearing installed using new close tolerance attaching parts; and modification of the pylon-to-vibration isolator link. That service bulletin also adds airplanes to the effectivity of the service bulletin.

Accomplishment of the actions specified in the service bulletins described above is intended to adequately address the identified unsafe condition.

Comments Received

Due consideration has been given to the comments received in response to the NPRM:

Request To Revise and Update Service Information

One commenter requests that Revision 4 of “McDonnell Douglas Service Bulletin 54-031” be revised to specify the bearing part number (P/N) in conjunction with the pylon spar strap P/N.

Since the issuance of the original NPRM, we have reviewed and approved Revision 05, dated April 25, 2003, of Boeing Service Bulletin DC9-54-031, which specifies the bearing P/N. We have referenced Revision 05 of that service bulletin in this supplemental NPRM as a source of service information.

Request for Clarification of Terminating Action

One commenter, an airline operator, states that multiple paragraphs in the original NPRM specify that modification per Revision 4 of “McDonnell Douglas Service Bulletin 54-031” constitutes terminating action of the repetitive requirements of the AD. The commenter notes, however, that AD 78-01-16, amendment 39-3117, requires replacement of the pylon strap with a heavy gauge lug and does not require use of the annular groove bearing. The commenter states that this contradicts Revision 4 of the service bulletin and paragraph (m) of the original NPRM, which specify installation of the annular groove bearing. The commenter requests clarification.

We acknowledge that clarification is necessary. We are aware that some operators of the subject airplanes have accomplished the actions specified in Revision 4 of McDonnell Douglas DC-9 Service Bulletin 54-31 or have had production equivalent installations of the spar strap (cap) with a pin-staked bearing. For those airplanes having a spar strap (cap) with a pin-staked bearing, paragraph (l) of this supplemental NPRM would require inspections for cracking, and modification if necessary, per Revision 05 of Boeing Service Bulletin DC9-54-031, dated April 25, 2003.

Request To Clarify Modification as a Terminating Action

That same commenter requests clarification of whether accomplishment of the modification using a pin-staked bearing, as described in Revision 4 of McDonnell Douglas DC-9 Service Bulletin 54-31, requires re-implementation of inspections of pylon straps until such time as the annular groove bearing is installed.

We agree that clarification is needed. As explained in the previous comment section, those airplanes having a spar strap (cap) with a pin-staked bearing would require inspections for cracking, and modification if necessary, in accordance with Revision 05 of Boeing Service Bulletin DC9-54-031, dated April 25, 2003. We have revised paragraph (l) of this supplemental NPRM to specify that the actions are to be accomplished per Revision 05, which describes installation of the annular groove bearing.

Request To Clarify Compliance Times for the Modification

Another commenter, also an airline operator, notes that paragraph (h) of the NPRM specifies compliance times for airplanes that have not had the modification to the spar cap accomplished and that have not had the spar cap replaced. The commenter further notes that paragraph (i) of the NPRM specifies compliance times for aircraft that have not had the modification of the spar cap accomplished but have had the spar cap replaced. The commenter points out that neither of those configurations apply to its fleet, since the spar cap has been modified on its fleet. The commenter assumes that if the spar caps have been previously modified, the NPRM would not be applicable to those airplanes. The commenter states that the reader of the NPRM should not have to make an assumption regarding applicability, and requests that the FAA clarify that the modified spar caps are not subject to the requirements of the NPRM.

We agree that clarification is needed. Paragraph (l) of this supplemental NPRM would require that, for airplanes (specified in Revision 05 of DC-9 Service Bulletin 54-031 as “Group 12” airplanes) on which the spar strap (cap) with a pin staked bearing per DC-9 Service Bulletin 54-31 has been installed or that have a production equivalent installed, it is necessary to perform an inspection of the pylon upper rear spar strap (cap) for bearing migration and correct staking and follow-on modification, if necessary, per Revision 05 of DC-9 Service Bulletin 54-031.

We also have further clarified paragraphs (k) and (l) of this supplemental NPRM to specify that if any cracking is detected, modification of the rear spar upper strap (cap) is required per Revision 05. We further specify in paragraph (n) of this supplemental NPRM that accomplishment of that modification per Revision 05 constitutes terminating action for the repetitive inspection requirements of the AD. As explained in the “Explanation of New Service Information” section of this supplemental NPRM, Boeing has also issued Alert Service Bulletin DC9-54A031, Revision 09, dated September 3, 2002, to reference accomplishment of the actions specified in Revision 05 of Service Bulletin DC9-54-031.

Request To Clarify the Intent of Paragraph (f) and (n) of the NPRM

One commenter questions whether paragraph (f)(2)(ii) of the NPRM is acceptable as terminating action for the requirements of the AD. The commenter requests that, if paragraph (f)(2)(ii) of the NPRM is acceptable as terminating action for the requirements of the AD, that such provision be added to paragraph (o) of the NPRM. (Paragraph (o) of the NPRM states that accomplishment of the modification required by paragraph (l) or (n) of the NPRM constitutes compliance with AD 96-10-11, amendment 39-9618 (61 FR 24675, May 16, 1996) and AD 72-09-01, amendment 39-2844 (42 FR 11235, February 28 1977).) For that same reason, the commenter also requests that a statement be added to paragraph (f)(2)(ii) of the NPRM indicating that, if the requirements of paragraph (f)(2)(ii) of the NPRM are accomplished, no further action is required by the AD. The commenter states that clarifying paragraph (f)(2)(ii) of the NPRM would eliminate any confusion as to whether further rework is required for previously modified airplanes. Additionally, the commenter states that paragraph (n) of the NPRM does not clearly specify that it does not apply to airplanes on which the modification specified in paragraph (f)(2)(ii) of the NPRM has been accomplished.

The FAA agrees that clarification of the intent of paragraphs (f) and (n) of the NPRM is necessary. The modification specified in paragraph (f)(2)(ii) of the NPRM does not specify or include certain actions that are described in Revision 05 of Boeing Service Bulletin DC9-54-031, which was described previously in this supplemental NPRM. We have determined that the actions specified in Revision 05 must be accomplished in order to terminate the actions specified in this supplemental NPRM. We have revised paragraph (f)(2)(ii) of this supplemental NPRM to clearly specify that accomplishment of the modification specified in that paragraph only terminates the inspections specified in paragraph (f)(2)(i) of this supplemental NPRM. For those reasons, no change in this regard is necessary to paragraph (o) of the supplemental NPRM. Additionally, we have revised paragraph (n) of this supplemental NPRM to clarify that all airplanes must accomplish the modification specified in paragraph (n) of this supplemental NPRM, regardless of whether or not the modification specified in paragraph (f)(2)(ii) of this supplemental NPRM has been accomplished previously.

Explanation of Change to Applicability

We have revised the applicability of the original NPRM to identify model designations as published in the most recent type certificate data sheet for the affected models. This change also is reflected in the Cost Impact section of this supplemental NPRM. In addition, the Cost Impact section has been updated to reflect the correct number of affected airplanes in the worldwide and U. S. fleet.

Conclusion

Since these changes expand the scope of the original NPRM, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Changes to 14 CFR Part 39/Effect on the Proposed 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. This 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 (i.e., paragraph (p)(1) of this supplemental NPRM). Note 6 of the original NPRM, which discusses AMOCs approved previously, has been incorporated into paragraph (p)(2) of this supplemental NPRM. Accordingly, Note 1, Note 5, and paragraph (g) of the original NPRM have been removed from this supplemental NPRM.

Change in Labor Rate Estimate

The FAA has recently reviewed the figures it has used over the past several years in calculating the economic impact of AD activity. In order to account for various inflationary costs in the airline industry, we find it appropriate to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, has been revised to reflect the increase in the specified hourly labor rate.

Cost Impact

There are approximately 577 Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 350 airplanes of U.S. registry would be affected by this proposed AD.

The ultrasonic inspection that is currently required by AD 78-01-16, and retained in this proposed AD, takes approximately 3 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this currently required action on U.S. operators is estimated to be $195 per airplane, per inspection cycle.

The new ultrasonic inspection that is proposed in this AD action would take approximately 4 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the new ultrasonic inspection proposed by this AD on U.S. operators is estimated to be $260 per airplane, per inspection cycle.

The new modification of the rear spar upper strap (cap) that is proposed in this AD action would take between approximately 349 and 412 work hours to accomplish (depending on the configuration of the affected airplane), at an average labor rate of $65 per work hour. The cost of required parts would be between approximately $1,865 and $7,947 per airplane. Based on these figures, the cost impact of the new modification proposed by this AD on U.S. operators is estimated to be between $24,550 and $34,727 per airplane.

For certain airplanes, the repetitive visual inspections of the upper rear spar (cap) for bearing migration and correct pin staking would take approximately 20 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of that inspection is estimated to be $1,300 per airplane, per inspection cycle.

The cost impact figures discussed above are 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Should an operator elect to accomplish the optional magnetic particle inspection that would be provided by this AD action, it would take approximately 7 work hours to accomplish it, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this action would be $455 per airplane, per inspection cycle.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

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.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing amendment 39-3117 (43 FR 1300, January 9, 1978), and by adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 99-NM-255-AD. Supersedes AD 78-01-16, Amendment 39-3117.

Applicability: Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes, as listed in Boeing Service Bulletin DC9-54-031, Revision 05, dated April 25, 2003; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct fatigue cracking, which could result in major damage to the adjacent structure of the pylon aft spar upper cap, and consequent reduced structural integrity of the airplane; accomplish the following:

Restatement of Certain Requirements of AD 78-01-16, Amendment 39-3117

Compliance Times

(a) For airplanes that have accumulated 35,000 or more total landings as of February 13, 1978 (the effective date of AD 78-01-16): Within 600 landings after February 13, 1978, unless already accomplished within the last 1,800 landings, and thereafter at intervals not to exceed 2,400 landings, accomplish the actions specified in paragraph (f) of this AD.

(b) For airplanes that have accumulated between 30,000 and 34,999 total landings inclusive, as of February 13, 1978: Within 900 landings after February 13, 1978, unless already accomplished within the last 1,500 landings, and thereafter at intervals not to exceed 2,400 landings, accomplish the actions specified in paragraph (f) of this AD.

(c) For airplanes that have accumulated between 25,000 and 29,999 total landings inclusive, as of February 13, 1978: Within 1,200 landings after February 13, 1978, unless already accomplished within the last 1,200 landings, and thereafter at intervals not to exceed 2,400 landings, accomplish the actions specified in paragraph (f) of this AD.

(d) For airplanes that have accumulated between 15,000 and 24,999 total landings inclusive, as of February 13, 1978: Within 2,000 landings after February 13, 1978, unless already accomplished within the last 400 landings, and thereafter at intervals not to exceed 2,400 landings, accomplish the actions specified in paragraph (f) of this AD.

(e) For airplanes that have accumulated less than 15,000 total landings as of February 13, 1978: Within 2,000 landings after the accumulation of 15,000 total landings, and thereafter at intervals not to exceed 2,400 landings, accomplish the actions specified in paragraph (f) of this AD.

Repetitive Inspections and Corrective Actions

(f) For airplanes having fuselage numbers 1 through 851 inclusive: At the times specified in paragraphs (a) through (e) of this AD, except as provided by paragraph (l) of this AD, perform an ultrasonic inspection of the engine pylon aft upper spar straps (caps), part number (P/N) 9958154-5/-6 or P/N 9958154-37/-38, to detect cracking; in accordance with paragraph 2.B of McDonnell Douglas DC-9 Service Bulletin A54-31, Revision 1, dated December 22, 1976; or in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA.

(1) If there is evidence of cracking, the magnetic particle inspection specified in paragraph 2.C of the service bulletin may be used to confirm the evidence of cracking.

(2) If any cracking is detected, prior to further flight, accomplish either paragraph (f)(2)(i) or (f)(2)(ii) of this AD in accordance with the service bulletin.

(i) Replace the strap with a new strap, P/N 9958154-5/-6 or P/N 9958154-37/-38, and repeat the inspection thereafter at intervals not to exceed 15,000 landings. Or,

(ii) Modify the engine pylon rear spar straps (caps) in accordance with McDonnell Douglas DC-9 Service Bulletin 54-31, dated August 24, 1976. Accomplishment of the modification constitutes terminating action for the repetitive inspection requirements specified only in paragraph (f)(2)(i) of this AD.

Note 1:

Modification of the engine pylon rear spar straps (caps) accomplished prior to the effective date of this AD in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A54-31, Revision 2, dated December 22, 1977; Revision 3, dated June 20, 1986; Revision 4, dated March 26, 1987; Revision 5, dated March 25, 1991; or Revision 6, dated November 23, 1992; is considered acceptable for compliance with the requirements of paragraph (f)(2)(ii) of this AD.

Note 2:

Ultrasonic or magnetic particle inspection of the engine pylon aft upper spar straps (caps) accomplished prior to the effective date of this AD in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A54-31, Revision 2, dated December 22, 1977; Revision 3, dated June 20, 1986; Revision 4, dated March 26, 1987; Revision 5, dated March 25, 1991; or Revision 6, dated November 23, 1992; is considered acceptable for compliance with the inspection requirements of paragraph (f) of this AD, as applicable.

New Requirements of This AD

Ultrasonic Inspections

(g) For airplanes on which the modification/replacement specified in paragraph (n) of this AD has not been accomplished, and on which the spar strap replacement specified in paragraph (f)(2)(i) of this AD has not been accomplished: Except as provided by paragraph (m) of this AD, perform an ultrasonic inspection of the engine pylon aft upper spar straps (caps) to detect cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin DC9-54A031, Revision 09, September 3, 2002; at the time specified in paragraph (g)(1), (g)(2), (g)(3), or (g)(4) of this AD, as applicable. Accomplishment of the ultrasonic inspection constitutes terminating action for the repetitive inspection requirements of paragraphs (a) through (f), including paragraph (f)(2)(i) of this AD.

(1) For airplanes that have accumulated less than 25,000 total landings as of the effective date of this AD: After the accumulation of 15,000 total landings but before the accumulation of 25,000 total landings, or within 2,000 landings or 6 months after the effective date of this AD, whichever occurs latest.

(2) For airplanes that have accumulated 25,000 to 29,999 total landings as of the effective date of this AD: Within 1,200 landings or 6 months after the effective date of this AD, whichever occurs later.

(3) For airplanes that have accumulated 30,000 to 34,999 total landings as of the effective date of this AD: Within 900 landings or 6 months after the effective date of this AD, whichever occurs later.

(4) For airplanes that have accumulated 35,000 or more total landings as of the effective date of this AD: Within 600 landings or 6 months after the effective date of this AD, whichever occurs later.

(h) For airplanes on which the modification/replacement specified in paragraph (n) of this AD has not been accomplished, and on which the spar strap replacement specified in paragraph (f)(2)(i) of this AD has been accomplished: Except as provided by paragraph (m) of this AD, perform an ultrasonic inspection of the engine pylon aft upper spar straps (caps) to detect cracking, in accordance with Boeing Alert Service Bulletin DC9-54A031, Revision 09, dated September 3, 2003; at the time specified in paragraph (h)(1), (h)(2), (h)(3), or (h)(4) of this AD, as applicable. Accomplishment of the ultrasonic inspection constitutes terminating action for the repetitive inspection requirements of paragraphs (a) through (f) of this AD.

(1) For airplanes that have accumulated less than 25,000 total landings since installation of the new spar strap (cap): After the accumulation of 15,000 landings since installation of the new spar strap (cap) but before the accumulation of 25,000 landings since installation of the new spar strap (cap), or within 2,000 landings or 6 months after the effective date of this AD, whichever occurs latest.

(2) For airplanes that have accumulated between 25,000 and 29,999 landings since installation of the new spar strap (cap): Within 1,200 landings or 6 months after the effective date of this AD, whichever occurs later.

(3) For airplanes that have accumulated between 30,000 and 34,999 landings since installation of the new spar strap (cap): Within 900 landings or 6 months after the effective date of this AD, whichever occurs later.

(4) For airplanes that have accumulated 35,000 or more landings since installation of the new spar strap (cap): Within 600 landings or 6 months after the effective date of this AD, whichever occurs later.

Note 3:

Ultrasonic or magnetic particle inspection of the engine pylon aft upper spar straps (caps) accomplished prior to the effective date of this AD per McDonnell Douglas DC-9 Alert Service Bulletin DC9-54A031, Revision 07, dated August 26, 1999; or Revision 08, dated January 31, 2000; is considered acceptable for compliance with the requirements of paragraph (g) or (h) of this AD, as applicable.

If No Cracking Is Detected—Repetitive Inspections

(i) If no cracking is detected during the ultrasonic inspection required by paragraph (g) or (h) of this AD, before further flight, reapply sealant that was removed to accomplish those inspections, per Boeing Alert Service Bulletin DC9-54A031, Revision 09, dated September 3, 2002. Thereafter, repeat the inspection specified in paragraph (g) or (h) of this AD, as applicable, at intervals not to exceed 2,400 landings until the modification of the rear spar upper strap (cap) specified in paragraph (n) of this AD has been accomplished.

If Cracking Is Suspected

(j) If any evidence of cracking is suspected during any inspection required by paragraph (g) or (h) of this AD, before further flight, confirm the existence of cracking by accomplishing the actions specified in paragraph (m) of this AD.

If Cracking Is Detected

(k) If any cracking is detected during any inspection required by paragraph (g) or (h) of this AD, before further flight, modify the rear spar upper strap (cap) in accordance with paragraph (n) of this AD. Accomplishment of the modification constitutes terminating action for the requirements of paragraphs (g) and (h) of this AD.

Inspection for Migration of Bearings

(l) For airplanes identified as Group 12 airplanes in Boeing Service Bulletin DC9-54-031, Revision 05, April 25, 2003, on which the modification specified in paragraph (n) of this AD has not been accomplished: Perform a general visual inspection for migration of the bearings and the correct pin staking, per the service bulletin at the time specified in paragraph (g) or (h) of this AD, as applicable.

Note 4:

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.”

(1) If none of the bearings have migrated and the pin staking is correct, repeat the general visual inspection at intervals not to exceed 2,400 landings until the straps are modified per Boeing Service Bulletin DC9-54-031, Revision 05, April 25, 2003.

(2) If any bearing has migrated or the pin staking is incorrect, before further flight, accomplish the modification specified in paragraph (n) of this AD. Accomplishment of that modification constitutes terminating action for the repetitive inspection requirements of this AD.

Acceptable Method of Compliance

(m) At the times specified in the applicable paragraph of this AD, it is permissible to perform a magnetic particle inspection of the engine pylon aft upper spar strap (cap) for cracks in lieu of accomplishing the ultrasonic inspection required by paragraph (g) or (h) of this AD; in accordance with Boeing Alert Service Bulletin DC9-54A031, Revision 09, dated September 3, 2002.

(1) If no cracking is detected, before further flight, replace the bearing on the spar strap (cap) with a new annular groove bearing, in accordance with the service bulletin. Thereafter, repeat the inspection specified in paragraph (g) or (h) of this AD, as applicable, at intervals not to exceed 2,400 landings until the modification of the rear spar upper strap (cap) specified in paragraph (n) of this AD has been accomplished.

(2) If any cracking is detected, before further flight, accomplish the modification of the rear upper spar strap (cap) required by paragraph (n) of this AD.

Terminating Modification

(n) For all airplanes: Prior to the accumulation of 100,000 total landings, or within 6 months after the effective date of this AD, whichever occurs later, modify the rear spar upper strap (cap) in accordance with Boeing Service Bulletin DC9-54-031, Revision 05, dated April 25, 2003. Accomplishment of the modification described in Revision 05 of that service bulletin constitutes terminating action for the repetitive inspection requirements of this AD.

Compliance With Certain Other Airworthiness Directives

(o) Accomplishment of the modification required by paragraph (n) of this AD constitutes compliance with the following:

(1) The actions specified in McDonnell Douglas Service Bulletin 54-27, Revision 4, dated April 2, 1990, that are required by AD 96-10-11, amendment 39-9618 (which references “DC-9/MD80 Aging Aircraft Service Action Requirements Document” (SARD), McDonnell Douglas Report MDC K1572, Revision B, dated January 15, 1993, as the appropriate source of service information for accomplishment of the modification); and,

(2) The requirements of AD 72-09-01, amendment 39-2844 (which references McDonnell Douglas Service Bulletin 54-31, dated August 24, 1976; and McDonnell Douglas Service Bulletin 54-27, Revision 4, dated April 2, 1990; as appropriate sources of service information for accomplishment of the modification).

Alternative Methods of Compliance

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

(2) Alternative methods of compliance, approved previously in accordance with AD 78-01-06, amendment 39-3117, are approved as alternative methods of compliance with the corresponding provisions of this AD.

(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 a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Los Angeles ACO, to make such findings.

Issued in Renton, Washington, on December 12, 2003.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.