[Federal Register Volume 64, Number 223 (Friday, November 19, 1999)]
[Rules and Regulations]
[Pages 63187-63190]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30056]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-05-AD; Amendment 39-11428; AD 99-24-04]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series 
Airplanes and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9-80 series airplanes 
and Model MD-88 airplanes, that requires a one-time visual inspection 
to determine whether self-aligning nuts are installed at certain 
locations of the aft pressure bulkhead tee; and corrective actions, if 
necessary. This amendment is prompted by reports of failures of certain 
Hi-Lok pin fasteners of the aft pressure bulkhead tee due to 
installation of non-self-aligning nuts. The actions specified by this 
AD are intended to prevent failure of certain Hi-Lok pin fasteners and 
subsequent gouging of the aft pressure bulkhead tee, which could result 
in fatigue cracking and reduced structural integrity of the airplane.

DATES: Effective December 27, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 27, 1999.

ADDRESSES: The service information referenced in this AD may be 
obtained from The Boeing Company, 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 Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; or at the Office of the Federal Register, 
800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Carl Fountain, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (562) 627-5222; 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-9-80 series airplanes and Model MD-88 airplanes

[[Page 63188]]

was published in the Federal Register on February 2, 1999 (64 FR 8530). 
That action proposed to require a one-time visual inspection to 
determine whether self-aligning nuts are installed at certain locations 
of the aft pressure bulkhead tee; and corrective actions, if necessary.

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.

Support for the Proposal

    All commenters support the objectives of the proposal, however, 
some of the commenters request several changes.

Requests To Extend the Compliance Time

    Several commenters request that the proposed compliance time be 
revised from the proposed 24 months to 48 months.
    One of the commenters states that a 48-month compliance time will 
allow accomplishment of the actions required by the proposed AD ``in 
conjunction with an extended maintenance visit.'' The commenter also 
states that no discrepancies were found during inspections of the 
subject area during accomplishment of Corrosion Prevention and Control 
Program (CPCP) tasks. Additionally, no discrepancies were found during 
recent inspections of self-aligning bolts on out-of-service airplanes.
    Two commenters state that replacement of the self-aligning nuts and 
fasteners will require removal of the lavatory or engine. If non-self-
aligning nuts are found and both engines must be removed, the 
commenters state that accomplishment of the replacement within the 24-
month proposed compliance time could significantly disrupt aircraft 
availability.
    One commenter points out that the service bulletin recommends a 
compliance time of at the operator's earliest practical maintenance 
period. The commenter states that it does not schedule engine or 
lavatory removal during a 24-month interval maintenance visit. The 
commenter also states that the fastener failure in the subject area 
would be detected during inspections accomplished as part of the 
routine maintenance program. These inspections are generally 
accomplished at 48-months intervals. Gouges on the tee would be 
detected during the inspection mandated by AD 96-16-04, amendment 39-
9704 (61 FR 39860, July 31, 1996). The commenter states that, due to 
these thorough inspections that are routinely accomplished on its 
fleet, it does not believe that the requirements of the proposed AD 
should be an airworthiness concern.
    The FAA partially concurs. The FAA's intent was that the inspection 
be conducted during a regularly scheduled heavy maintenance visit for 
the majority of the affected fleet, when the airplanes would be located 
at a base where special equipment and trained personnel would be 
readily available, if necessary. Based on the information supplied by 
the commenters, the FAA now recognizes that 48 months corresponds more 
closely to the interval representative of most of the affected 
operators' normal maintenance schedules. Paragraph (a) of the final 
rule has been revised to reflect a compliance time of 48 months. The 
FAA does not consider that this extension will adversely affect safety. 
However, the FAA does not concur with the commenter that the 
requirements of this AD are not an airworthiness concern. The FAA finds 
that the requirements of this AD are necessary to address an identified 
unsafe condition, as discussed in the preamble of the proposed AD.

Request To Reference a Certain Information Notice

    One commenter requests that the proposed AD reference McDonnell 
Douglas Information Notice MD80-53-201 R02, dated October 21, 1998. The 
FAA concurs. The information notice clarifies information for parts for 
the SB09530201-7 kit that was inadvertently omitted on Revision 02 of 
Service Bulletin MD80-53-201, which is utilized in accomplishing the 
corrective actions required by paragraph (a)(2) of this AD. Therefore, 
the FAA has revised paragraph (a) of the final rule accordingly.

Request To Reference Earlier Versions of Referenced Service 
Bulletin

    One commenter requests that the FAA allow accomplishment of the 
proposed requirements in accordance with McDonnell Douglas Service 
Bulletin MD80-53-201, dated July 6, 1988, and Revision 1, dated March 
22, 1991, in addition to Revision 02, dated July 20, 1998. The FAA 
concurs. The FAA points out that NOTE 2 of the proposed AD, which is 
retained in the final rule, states ``inspections, and repair of the aft 
pressure bulkhead tee longeron end fittings prior to the effective date 
of this AD, in accordance with McDonnell Douglas Service Bulletin MD80-
53-201, dated July 6, 1988, or Revision 1, dated March 22, 1991, are 
considered acceptable for compliance with the actions required by 
paragraph (a) of this AD.'' Therefore, no change to the final rule is 
necessary.

Requests To Revise Corrective Action in Paragraph (a)(2) of the 
Proposal

    Two commenters request that paragraph (a)(2) of the proposed AD be 
revised to read ``if incorrect nuts are installed at longeron fittings 
19, 22, and 29, inspect fitting for gouges and repair or replace 
fitting per service bulletin 53-201.'' The commenters state that at 
longersons 19, 22, and 29, if non-self-aligning nuts are installed, the 
longeron end fitting would be gouged and not the tee fitting.
    The FAA concurs with the commenters request that paragraph (a)(2) 
of the final rule be revised to require inspection of the bulkhead tee 
and/or longeron end fittings for gouges. The FAA's intent, as indicated 
under the header of ``Explanation of Requirements of Proposed Rule'' in 
the preamble of the proposed AD, was that ``the proposed AD would 
require accomplishment of the actions specified in the service bulletin 
* * *'' Therefore, the FAA has revised paragraph (a)(2) of the final 
rule to read ``if any nut is determined to be non-self-aligning, prior 
to further flight, remove the existing nut and perform a one-time 
visual inspection to detect gouges in the aft pressure bulkhead tee on 
station Y=1338.000 and longeron end fitting, as applicable, in 
accordance with the service bulletin.''

Request To Allow Approval of Repairs by Designated Engineering 
Representative

    One commenter requests that the proposed AD be revised to include a 
provision for approval of repairs for gouges beyond the limits of the 
referenced service bulletin by a Boeing Designated Engineering 
Representative (DER) instead of the Manager of the Los Angeles Aircraft 
Certification Office (ACO). The commenter asserts that this provision 
will result in a more efficient and timely repair approval process.
    The FAA does not concur. While DER's are authorized to determine 
whether a design or repair method complies with a specific requirement, 
they are not currently authorized to make the discretionary 
determination as to what the applicable requirement is. However, the 
FAA has issued a notice (N 8110.72, dated March 30, 1998), which 
provides guidance for delegating authority to certain type certificate 
holder structural DER's to approve alternative methods of compliance 
for AD-required repairs and modifications of individual airplanes. The 
FAA is

[[Page 63189]]

currently working with Boeing, Douglas Products Division (DPD), to 
develop the implementation process for delegation of approval of 
alternative methods of compliance in accordance with that notice. Once 
this process is implemented, approval authority for alternative methods 
of compliance can be delegated without revising the AD.

Request To Revise Cost Impact

    One commenter requests the FAA revise the Cost Impact paragraph. 
The commenter states that, while its true that the inspections take one 
hour, significant additional time will be required for removal of the 
lavatories, sidewall panels, cargo liners, and other components. The 
commenter also states that the cost estimate does not reflect the time 
associated with repairs that may require the removal of the engines, 
replacement of discrepant fasteners, and inspections required upon 
fastener removal.
    The FAA does not concur. The economic analysis of the AD is limited 
only to the cost of actions actually required by the rule. It does not 
consider the costs of ``on condition'' actions, such as repairing a 
crack if one is detected during a required inspection (``repair, if 
necessary''). Such ``on-condition'' repair actions would be required to 
be accomplished--regardless of AD direction--in order to correct an 
unsafe condition identified in an airplane and to ensure operation of 
that airplane in an airworthy condition, as required by the Federal 
Aviation Regulations. In addition, the FAA recognizes that, in 
accomplishing the requirements of any AD, operators may incur 
``incidental'' costs in addition to the ``direct'' costs. The cost 
analysis in AD rulemaking actions, however, typically does not include 
incidental costs, such as the time required to gain access and close 
up; planning time; or time necessitated by other administrative 
actions. Because incidental costs may vary significantly from operator 
to operator, they are almost impossible to calculate. Therefore, no 
change to the final rule is necessary.

Explanation of Change Made to Proposal

    The FAA has clarified the inspection requirement contained in the 
proposed AD. Whereas the proposal specified a visual inspection, the 
FAA has revised this final rule to clarify that its intent is to 
require a general visual inspection. Additionally, a note has been 
added to the final rule to define that inspection.

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 previously 
described. 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 1,042 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 695 airplanes of U.S. 
registry will be affected by this AD, that it will take approximately 1 
work hour per airplane to accomplish the required inspection, and that 
the average labor rate is $60 per work hour. Based on these figures, 
the cost impact of the inspection required by this AD on U.S. operators 
is estimated to be $41,700, or $60 per airplane.
    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.

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:

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:

99-24-04 McDonnell Douglas: Amendment 39-11428. Docket 99-NM-05-AD.

    Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 
(MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88 
airplanes; as listed in McDonnell Douglas Service Bulletin MD80-53-
201, Revision 02, dated July 20, 1998; 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 (b) 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 failure of certain Hi-Lok pin fasteners and 
subsequent gouging of the aft pressure bulkhead tee, which could 
result in fatigue cracking and reduced structural integrity of the 
airplane, accomplish the following:

Inspection

    (a) Within 48 months after the effective date of this AD, 
perform a one-time general visual inspection to determine whether 
self-aligning nuts are installed at certain locations of the aft 
pressure bulkhead tee, in accordance with McDonnell Douglas Service 
Bulletin MD80-53-201, Revision 02, dated July 20, 1998, as revised 
by Information Notice MD90-53-201 R02, dated October 21, 1998.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as ``A visual examination of an interior or exterior

[[Page 63190]]

area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light, 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 all nuts installed are self-aligning, no further action 
is required by this AD.
    (2) If any nut is determined to be non-self-aligning, prior to 
further flight, remove the existing nut and perform a one-time 
visual inspection to detect gouges in the aft pressure bulkhead tee 
on station Y=1338.000 and longeron end fitting, as applicable, in 
accordance with the service bulletin.
    (i) If no gouge is detected, prior to further flight, install 
new self-aligning nuts in accordance with the service bulletin.
    (ii) If any gouge is detected that is within the repair limits 
specified in the service bulletin, prior to further flight, repair 
the gouge and install new self-aligning nuts in accordance with the 
service bulletin.
    (iii) If any gouge is detected that is outside the repair limits 
specified in the service bulletin, prior to further flight, repair 
in accordance with a method approved by the Manager, Los Angeles 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.

    Note 3: Inspections, and repair of the aft pressure bulkhead tee 
longeron end fittings prior to the effective date of this AD, in 
accordance with McDonnell Douglas Service Bulletin MD80-53-201, 
dated July 6, 1988, or Revision 1, dated March 22, 1991, are 
considered acceptable for compliance with the actions required by 
paragraph (a) of this AD.

Alternative Methods of Compliance

    (b) 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 4: 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

    (c) 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.

Incorporation by Reference

    (d) Except as provided by paragraph (a)(2)(iii) of this AD, the 
actions shall be done in accordance with McDonnell Douglas Service 
Bulletin MD80-53-201, Revision 02, dated July 20, 1998. 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 The Boeing Company, 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 
90712; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on December 27, 1999.

    Issued in Renton, Washington, on November 10, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-30056 Filed 11-18-99; 8:45 am]
BILLING CODE 4910-13-U