[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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