[Federal Register Volume 60, Number 103 (Tuesday, May 30, 1995)]
[Rules and Regulations]
[Pages 28037-28039]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12713]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-79-AD; Amendment 39-9242; AD 95-11-07]


Airworthiness Directives; McDonnell Douglas Model DC-10 Series 
Airplanes and KC-10A (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all McDonnell Douglas Model DC-10 series airplanes and 
KC-10A (military) airplanes, that requires inspections to detect 
cracking of H-11 attach bolts of the upper vertical stabilizer and 
replacement of these bolts and associated nuts with Inconel bolts and 
nuts. This amendment is prompted by failure of the attach bolts of the 
upper vertical stabilizer due to stress corrosion. The actions 
specified by this AD are intended to prevent undetected cracked or 
failed attach bolts that may lead to reduced structural integrity of 
the vertical stabilizer.

DATES: Effective June 29, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 29, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, 
Long Beach, California 90846, Attention: Technical Publications 
Business Administration, Department C1-L51 (2-60). This information may 
be examined at the 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 ; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Maureen Moreland, Aerospace Engineer, 
Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5238; fax (310) 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 all McDonnell Douglas Model DC-10 
series airplanes and KC-10A (military) airplanes was published in the 
Federal Register on September 19, 1994 (59 FR 47825). That action 
proposed to require inspections to detect cracking of H-11 attach bolts 
of the upper vertical stabilizer and replacement with Inconel attach 
bolts and associated nuts.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposed rule.
    The Air Transport Association of America, on behalf of one of its 
member operators, requests that the 18-month compliance time for the 
repetitive inspections required by proposed paragraph (a)(1) be 
extended to 24 months. The commenter states that this extension in the 
compliance time would coincide with regularly scheduled maintenance 
visits, and would result in savings of over $2,800 per airplane if 
operators were not required to ``special schedule'' these airplanes for 
the inspection.
    The FAA does not concur with the commenter's request to extend the 
compliance time. The FAA has determined that the compliance time, as 
proposed, represents the maximum interval of time allowable for the 
affected airplanes to continue to operate prior to accomplishing the 
required inspections without compromising safety. Further, the FAA's 
intent is to have the compliance time for the repetitive inspections 
coincide with the 18-month interval recommended by the manufacturer. 
Additionally, since the FAA has received an additional report of bolt 
failure, the FAA finds that the 18-month interval for the repetitive 
inspections is appropriate to ensure safety of the fleet.
    Additionally, the Service Action Requirements Document (SARD) that 
is referenced in this final rule was developed by McDonnell Douglas 
only after extensive and detailed consultations with large numbers of 
operators of Model DC-10 series airplanes. The compliance times were 
based on these consultations and developed in order to minimize the 
economic impact on operators without compromising the safety objectives 
of [[Page 28038]] this AD. Further, the FAA has received no data 
substantiating that an extension of the compliance time to 24 months 
would provide an acceptable level of safety.
    One commenter requests that the requirement to replace all H-11 
attach bolts and associated nuts within 5 years as proposed in 
paragraph (c) be revised to be an option. The commenter asserts that 
these bolts need not be replaced within 5 years since the cause of the 
failed bolts has been attributed to stress corrosion, not fatigue. 
Further, the commenter contends that the bolts are easily inspected and 
that damage would be easily detectable. Finally, the commenter believes 
that service history (three incidents of one failed bolt per airplane 
in over 20 years) supports its assertion that mandatory replacement of 
these bolts is unnecessary.
    The FAA does not concur. The FAA finds that bolt failure due to 
stress corrosion is less predictable than failure due to fatigue; 
therefore, the requirement to replace these bolts is even more crucial. 
Furthermore, the FAA does not consider that these inspections are easy 
to perform. Finally, although only one bolt has failed per airplane, 
thus far, the FAA has no technical data to substantiate preclusion of 
potential multiple failures of this bolt on any Model DC-10 series 
airplane. Additionally, the FAA has determined that long term continued 
operational safety will be better assured by actual modification of the 
airframe to remove the source of the problem, rather than by repetitive 
inspections. Long term inspections may not be providing the degree of 
safety assurance necessary for the transport airplane fleet. This, 
coupled with a better understanding of the human factors associated 
with numerous repetitive inspections, has led the FAA to consider 
placing less emphasis on special procedures and more emphasis on design 
improvements. The replacement requirement is in consonance with these 
considerations.
    Two commenters request that the cost estimate be revised, since it 
seems to be unrealistic. One of these commenters requests that the 
estimated cost of accomplishing the proposed actions include the time 
necessary to obtain access to the area, remove and re-install access 
doors, remove sealant from bolts, and remove and re-install bolts. The 
FAA does not concur. The appropriate number of work hours to accomplish 
the required actions (specified as 2 for the inspection and 8 for the 
replacement of the bolts) in the economic impact information, below, 
was provided to the FAA by the manufacturer based on the best data 
available to date. This number does not include the time required to 
gain access, remove parts, remove sealant from parts, and close up. The 
cost analysis in AD rulemaking actions typically does not include these 
costs, since there may be great variations in them from operator to 
operator.
    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, the FAA has determined that it is necessary to increase the 
labor rate used in these calculations from $55 per work hour to $60 per 
work hour. The economic impact information, below, has been revised to 
reflect this increase in the specified hourly labor rate.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been added to this final rule to clarify this long-standing 
requirement.
    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.
    There are approximately 426 McDonnell Douglas Model DC-10 series 
airplanes and KC-10A (military) airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 269 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 2 work hours per airplane to accomplish 
the required inspections at an average labor rate is $60 per work hour. 
Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $32,280, or $120 per airplane.
    It will take approximately 8 work hours per airplane to accomplish 
the required replacements at an average labor rate of $60 per work 
hour. Required parts will cost approximately $9,009 per airplane. Based 
on these figures, the total cost impact of the replacements 
requirements of this AD on U.S. operators is estimated to be 
$2,552,541, or $9,489 per airplane.
    Based on the above figures, the total cost impact of the inspection 
and replacement requirements of this AD on U.S. operators is estimated 
to be $2,584,821, or $9,609.
    The total 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.
    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:

    [[Page 28039]] Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 
49 U.S.C. 106(g); and 14 CFR 11.89.


Sec. 39.13   [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

95-11-07  McDonnell Douglas: Amendment 39-9242. Docket 94-NM-79-AD.

    Applicability: Model DC-10-10, -10F, -15, -30, -30F, -40, and -
40F series airplanes, and KC-10A (military) airplanes; 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 use the authority 
provided in paragraph (d) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent undetected cracked or failed attach bolts that may 
lead to reduced structural integrity of the vertical stabilizer, 
accomplish the following:
    (a) Within 12 months after the effective date of this AD, 
perform an ultrasonic inspection to detect cracking in the attach 
bolts of the upper vertical stabilizer, in accordance with McDonnell 
Douglas DC-10 Service Bulletin 55-20, Revision 2, dated August 4, 
1994, unless accomplished within the last 18 months prior to the 
effective date of this AD in accordance with McDonnell Douglas DC-10 
Service Bulletin 55-20, Revision 1, dated March 8, 1991, or Revision 
2, dated August 4, 1994.
    (1) If no cracking is detected in any bolt, repeat the 
inspection of the uncracked bolt thereafter at intervals not to 
exceed 18 months, until the requirements of paragraph (c) of this AD 
are accomplished.
    (2) If cracking is detected in any bolt, prior to further 
flight, replace the cracked bolt and associated nut with a new 
Inconel attach bolt and associated nut, in accordance with the 
service bulletin. No further action is required by this AD for the 
new Inconel bolts and associated nuts.
    (b) Compliance with the inspections required by paragraph (a) of 
this AD constitutes compliance with the inspections and reports 
required by paragraph (b) of AD 93-17-09, amendment 39-8680, for 
Principal Structural Element (PSE) 55.10.001/002. However, after 
installation of new Inconel bolts and associated nuts, in accordance 
with the requirements of paragraphs (a) and (c) of this AD, PSE 
55.10.001/002 must continue to be inspected in accordance with AD 
93-17-09.
    (c) Within 5 years after the effective date of this AD, replace 
all H-11 attach bolts and associated nuts of the upper vertical 
stabilizer with new Inconel attach bolts and associated nuts, in 
accordance with McDonnell Douglas DC-10 Service Bulletin 55-20, 
Revision 1, dated March 8, 1991; or Revision 2, dated August 4, 
1994. Such replacement constitutes terminating action for the 
requirements of this AD.
    (d) 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 Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Los Angeles ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (e) 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.
    (f) The inspections and replacement shall be done in accordance 
with McDonnell Douglas DC-10 Service Bulletin 55-20, Revision 1, 
dated March 8, 1991, or McDonnell Douglas DC-10 Service Bulletin 55-
20, Revision 2, dated August 4, 1994. 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 McDonnell Douglas Corporation, 3855 Lakewood 
Boulevard, Long Beach, California 90846, Attention: Technical 
Publications Business Administration, Department C1-L51 (2-60). 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport 
Airplane Directorate, Los Angeles Aircraft Certification Office, 
3960 Paramount Boulevard, Lakewood, California; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (g) This amendment becomes effective on June 29, 1995.

    Issued in Renton, Washington, on May 18, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12713 Filed 5-26-95; 8:45 am]
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