[Federal Register Volume 67, Number 137 (Wednesday, July 17, 2002)]
[Proposed Rules]
[Pages 46932-46937]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-18025]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-57-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, 
-20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, 
that would have required, among other actions, various inspections to 
detect cracks of the cockpit enclosure window sill, and follow-on and 
corrective actions, as applicable. This new action revises the proposed 
rule by revising certain procedures and clarifying the proposed 
requirements. The actions specified by this new proposed 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. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by August 6, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-57-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-57-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from 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: Technical Information: 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.
    Other Information: Judy Golder, Airworthiness Directive Technical 
Editor/Writer; telephone (425) 687-4241, fax (425) 227-1232. Questions 
or comments may also be sent via the Internet using the following 
address: [email protected]. Questions or comments sent via the 
Internet as attached electronic files must be formatted in Microsoft 
Word 97 for Windows or ASCII text.

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 2000-NM-57-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. 2000-NM-57-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, -20, -30, -40, and -50 series 
airplanes and C-9 (military) airplanes was published as a notice of 
proposed rulemaking (NPRM) in the Federal Register on September 18, 
2000 (65 FR 56270). That NPRM would have required, among other actions, 
various inspections to detect cracks of the cockpit enclosure window 
sill, and follow-on and corrective actions, as

[[Page 46933]]

applicable. That NPRM was prompted by reports of cracking of the 
internal doublers and frame structure of the fuselage skin of the 
cockpit enclosure window sill. That condition, if not corrected, could 
result in rapid decompression of the fuselage and consequent reduced 
structural integrity of the airplane.

Actions Since Issuance of NPRM

    Since the issuance of that NPRM, the FAA has reviewed and approved 
Boeing Service Bulletin DC9-53-290, Revision 01, dated March 15, 2002. 
(The original NPRM referred to McDonnell Douglas Service Bulletin DC9-
53-290, dated December 14, 1999, as the appropriate source of service 
information for the proposed actions.) Revision 01 of the service 
bulletin incorporates changes made to a certain service rework drawing 
based on Non-Destructive Testing analysis and operator experience. 
These changes have resulted in the following revisions in Revision 01 
of the service bulletin:
     Changes to certain inspection methods and parts to be 
inspected.
     Clarification of certain inspection procedures, criteria, 
and areas.
     Revision of kit information and the addition of new kits 
and parts.
     Deferral of the inspection of certain parts that cannot be 
inspected without extensive disassembly of the airplane until the 
permanent repair is done.
    Revision 01 of the service bulletin now describes the following 
procedures:
     A visual inspection to determine if certain temporary 
repairs have been installed.
     A 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 replacement of cracked Zees with new parts.
     Visual, borescope, and HFEC inspections for cracking of 
the skins and frames.
    The service bulletin also describes applicable follow-on and 
corrective actions, which include:
     If no cracks and no previous repairs are found--Repeating 
the previously accomplished visual, borescope, and HFEC inspections for 
cracking (Condition 1, Option 1).
     If cracks within certain limits are found--Accomplishing a 
temporary repair (including installation of external doublers), and 
performing repetitive visual inspections for cracking of skins and 
external doublers and repetitive borescope and HFEC inspections for 
cracking of internal structure (Condition 2, Option 1).
     If certain existing temporary repairs are found--
Performing repetitive visual inspections for cracking of skins and 
external doublers and repetitive borescope and HFEC inspections for 
cracking of internal structure, accomplishing a one-time inspection of 
existing repairs of certain frames for growth of cracks beyond the 
repair angles, and replacing frames with new frames if necessary 
(Condition 3, Option 1).
    For all airplanes except those on which no cracking or previous 
temporary repair is found, the service bulletin recommends 
accomplishing a permanent repair (including visual and eddy current 
inspections, and repair replacement, or rework of various parts, if 
necessary). The recommended compliance time for such permanent repair 
varies by condition. Installing the permanent repair eliminates the 
need to perform repetitive inspections at the pre-permanent-repair 
intervals, but the service bulletin recommends eventual accomplishment 
of certain inspections to find cracks of the permanent repair area.
    Accomplishment of the actions specified in Revision 01 of the 
service bulletin is intended to adequately address the identified 
unsafe condition.

Comments

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

No Objection to Proposed AD

    One commenter, an operator, states that the proposed AD would not 
apply to its fleet and offers no additional comments on the original 
NPRM.
    Another commenter states that it has no objection to the proposed 
AD because it is anticipating that all affected airplanes in its fleet 
will be retired before the compliance time. However, the commenter did 
offer several comments on the original NPRM.

Refer to Revised Service Information and Clarify Requirements of 
Proposed AD

    One commenter makes numerous suggestions for revisions to the 
original NPRM. The commenter requests that the FAA revise the proposed 
AD to refer to Revision 01 of the service bulletin, described 
previously, ``or later approved revisions'' as the appropriate source 
of service information for the proposed actions. The commenter also 
suggests numerous editorial changes to the original NPRM.
    We concur that it is necessary to revise this supplemental NPRM to 
refer to Revision 01 of the service bulletin. Based on the new service 
bulletin and for further clarification, we have reordered and 
reidentified many of the paragraphs in this supplemental NPRM. We also 
have considered the commenter's editorial suggestions and, where we 
agree that they provide clarification, we have incorporated such 
changes. (Due to the extensive revisions of the original NPRM, we find 
it is necessary to reopen the comment period to give interested parties 
additional opportunity to comment on the proposal.)
    With regard to the commenter's request to refer to ``later approved 
revisions'' of the service bulletin, we do not concur. The use of that 
phrase violates Office of the Federal Register (OFR) regulations 
regarding approval of materials that are incorporated by reference. An 
AD may only refer to a service document that is submitted and approved 
by the OFR for ``incorporation by reference.'' For operators to use 
later revisions of the referenced document (issued after the 
publication of the AD), either the AD must be revised to refer to the 
specific later revisions, or request for approval of the use of the 
later revisions must be requested as an alternative method of 
compliance (AMOC) with the AD (e.g., under the provisions of paragraph 
(j)(1) of this supplemental NPRM). We have made no change to the 
supplemental NPRM in this regard.

Clarify Compliance Time for Airplanes With Previously Installed Repairs

    One commenter requests that we clarify the compliance time in 
paragraph (g)(1) of the original NPRM. (The provisions of paragraph 
(g)(1) of the original NPRM are included under paragraph (d)(1) of this 
supplemental NPRM.) Paragraph (g)(1) of the original NPRM applies to 
airplanes on which certain temporary repairs have been installed 
previously. That paragraph refers to other paragraphs in the original 
NPRM that specify accomplishment of various inspections within 2,000 
and 3,500 landings after installation of the temporary repair. The 
commenter points out that this proposed compliance time may conflict 
with the initial compliance time in paragraph (a)(1) of the original 
NPRM--i.e., the later of 40,000 total landings or 5,000 landings after 
the effective date of the AD. The commenter provides the example that, 
if a temporary repair was installed before the effective date of the 
proposed AD, and the initial inspection in the proposed AD was not done 
until after 3,500 landings after the effective date of the AD, the 
airplane would be out of

[[Page 46934]]

compliance with the proposed AD. The commenter states that the original 
NPRM should be revised to direct operators to accomplish repetitive 
inspections of existing temporary repairs at the applicable intervals, 
commencing at the time of the initial inspections specified in 
paragraph (a) of the proposed AD.
    We have reviewed paragraph (g)(1) of the original NPRM and concur 
that we need to clarify the compliance time for the requirements 
proposed in that paragraph. We have revised the relevant paragraphs in 
this supplemental NPRM to specify a compliance time for the general 
visual inspection of 2,000 landings after the temporary repair, or 
before further flight after accomplishment of the initial inspections 
specified in paragraph (a) of this supplemental NPRM, whichever is 
later, and a compliance time for the borescope and HFEC inspections of 
3,500 landings after the temporary repair, or before further flight 
after accomplishment of the initial inspections specified in paragraph 
(a) of this supplemental NPRM, whichever is later.

Clarify Appropriate Source of Repair Instructions

    One commenter requests that we revise several paragraphs of the 
original NPRM to refer to the correct section of the service bulletin 
for repair instructions. As an example, the commenter notes that 
paragraph (c) of the original NPRM, which describes actions for 
airplanes with cracking within certain limits, specifies to repair 
cracks per paragraph (b)(2) of the original NPRM. That paragraph, in 
turn, specifies accomplishment of the permanent repair specified in 
Condition 1, Option 2. However, Condition 1, Option 2 of the 
accomplishment instructions of the service bulletin provides repair 
instructions for airplanes with no cracks and no previous repairs. The 
commenter requests that we revise paragraphs (c), (f), (g)(2), and (i) 
of the original NPRM to refer to the correct source of repair 
instructions in the service bulletin.
    We concur. As explained previously, we have restructured this 
supplemental NPRM to take into account the changes in Revision 01 of 
the service bulletin, and this supplemental NPRM contains correct 
references to the repair instructions in the service bulletin.

Explanation of Other Change Made to the Proposed AD

    Paragraph (j) of this supplemental NPRM (which appeared as 
paragraph (k) of the original NPRM) includes a new subparagraph. 
Paragraph (j)(2) of this supplemental NPRM is added to specify that 
``an AMOC for any inspection or repair required by this [proposed] AD 
that provides an acceptable level of safety may be used per data 
meeting the type certification basis of the airplane approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Los Angeles ACO, to make such findings.'' 
For a repair method to be approved, the approval must specifically 
reference this AD.

Explanation of New Requirements of Proposed AD

    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 accomplishment of the actions specified in 
Revision 01 of the service bulletin described previously, except as 
discussed below.

Differences Between Supplemental NPRM and Service Information

    Operators should note that, although the service bulletin specifies 
that the manufacturer should be contacted for disposition of certain 
repair conditions, this proposed AD would require the repair of those 
conditions to be accomplished in accordance with a method approved by 
the FAA.
    Also, the service bulletin specifies a ``visual'' inspection for 
cracking of the skins and frames. We find that the procedures involved 
in that inspection constitute a ``detailed'' inspection. A definition 
of ``detailed inspection'' is included in Note 4 of this supplemental 
NPRM.
    Further, though the service bulletin describes procedures for 
inspections to eventually be performed following installation of the 
permanent repair, the service bulletin does not clearly identify 
procedures for addressing any crack found in these follow-on 
inspections. Therefore, if any crack is found during the follow-on 
inspections after installation of the permanent repair, the proposed AD 
would require a repair to be accomplished in accordance with a method 
approved by the FAA.

Conclusion

    Since the changes described previously may expand the scope of the 
originally proposed rule, the FAA has determined that it is necessary 
to reopen the comment period to provide additional opportunity for 
public comment.

Cost Impact

    There are approximately 809 Model DC-9-10, -20, -30, -40, and -50 
series airplanes and C-9 (military) airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 572 airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 4 work hours per airplane to accomplish the proposed 
initial inspections, and that the average labor rate is $60 per work 
hour. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $137,280, or $240 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 proposed 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.

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.

[[Page 46935]]

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 2000-NM-57-AD.

    Applicability: Model DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-
15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, 
DC-9-32F (C-9A, C-9B), DC-9-33F, DC-9-34, DC-9-34F, DC-9-41, and DC-
9-51 airplanes; listed in Boeing Service Bulletin DC9-53-290, 
Revision 01, dated March 15, 2002; 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 (j) 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 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 2: 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 01, dated March 15, 2002.
    (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 3: 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 4: 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 5: 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, determine the 
applicable Condition as specified in the Accomplishment Instructions 
of Boeing Service Bulletin DC9-53-290, Revision 01, dated March 15, 
2002, 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 01, 
dated March 15, 2002. This terminates the repetitive inspections per 
paragraph (b)(1) of this AD.

    Note 6: Boeing Service Bulletin DC9-53-290, Revision 01, dated 
March 15, 2002, 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 01, 
dated March 15, 2002: Do the actions specified in paragraph (c)(1) 
OR (c)(2) of this AD.

    Note 7: Boeing Service Bulletin DC9-53-290, Revision 01, dated 
March 15, 2002, 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.

    Note 8: 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.

    (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

[[Page 46936]]

service bulletin, repeat the inspection every 3,500 landings until 
paragraph (c)(2)(i) of this AD is done.
    (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 01, dated March 15, 2002: 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 9: 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 01, dated March 15, 2002: 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 01, dated March 15, 
2002; 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 01, dated March 15, 
2002.

Previously Accomplished Inspections and Repairs

    (i) Inspections and repairs accomplished before the effective 
date of this AD per the Accomplishment Instructions of Boeing 
Service Bulletin DC9-53-290, dated December 14, 1999, are acceptable 
for compliance with the corresponding actions in this AD.

Alternative Methods of Compliance

    (j)(1) An alternative method of compliance (AMOC) 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.
    (2) An AMOC for any inspection or repair required by this AD 
that provides an acceptable level of safety may be used per data 
meeting the type certification basis of the airplane approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Los Angeles ACO, to make such findings.

    Note 10: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

Special Flight Permits

    (k) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a

[[Page 46937]]

location where the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on July 11, 2002.
Lirio Liu-Nelson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-18025 Filed 7-16-02; 8:45 am]
BILLING CODE 4910-13-U