[Federal Register Volume 59, Number 138 (Wednesday, July 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17196]
[[Page Unknown]]
[Federal Register: July 20, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-216-AD; Amendment 39-8973; AD 94-15-02]
Airworthiness Directives; McDonnell Douglas Model MD-11 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain McDonnell Douglas Model MD-11 series
airplanes, that currently requires inspections to verify the
installation of shear pins, shear pin retainers, and shear pin retainer
attaching parts in the aft end of the center pylon thrust link, and
repair, if necessary. That AD was prompted by a report that both shear
pins that attach the aft end of the center engine pylon thrust link to
the tail pylon were missing. This amendment adds inspections to verify
that the shear pin retainer attaching parts are tightened within
specified limits; and adds a terminating modification for those
inspections. This amendment also expands the applicability of the rule
to include additional airplanes. The actions specified by this AD are
intended to prevent structural damage to the engine mount structure,
which could lead to loss of airplane components.
DATES: Effective August 19, 1994.
The incorporation by reference of McDonnell Douglas Alert Service
Bulletin A54-31, Revision 1, dated June 3, 1993, as listed in the
regulations, is approved by the Director of the Federal Register as of
August 19, 1994.
The incorporation by reference of McDonnell Douglas Alert Service
Bulletin A54-31, dated September 17, 1992, as listed in the
regulations, was previously approved by the Director of the Federal
Register of November 2, 1992 (57 FR 47991, October 21, 1992).
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
CA 90801-1771, Attention: Business Unit Manager, Technical
Administrative Support, Dept. L51, M.C. 2-98. 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, 3229 East Spring Street, Long Beach,
California; or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer,
Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3229 East Spring Street, Long
Beach, California 90806-2425; telephone (310) 988-5324; fax (310) 988-
5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 92-23-03,
amendment 39-8403 (57 FR 47991, October 21, 1992), which is applicable
to certain McDonnell Douglas Model MD-11 series airplanes, was
published in the Federal Register on March 17, 1994 (59 FR 12558). The
action proposed to continue to require repetitive visual inspections to
verify the installation of the shear pins, the shear pin retainers, and
the shear pin retainer attaching parts in the aft end of the center
engine (No. 2) pylon thrust link. It also proposed (1) to add
repetitive inspections to verify that the shear pin retainer attaching
parts are tightened within specified limits; (2) to delete the
previously provided ``optional terminating action'' (which consists of
a one-time verification for tightness of the nuts of the four shear pin
retainer attaching bolts); and (3) to require eventual replacement of
the existing retainer and attaching parts with a new retainer and
attaching parts, as terminating action for the currently required
repetitive visual inspections and the proposed repetitive verifications
of tightness.
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 proposal.
The Air Transport Association (ATA) of America, on behalf of one
member operator, and the manufacturer request that the proposed AD be
revised to indicate that the 60-day repetitive inspection specified in
paragraph (a) and (b) be required only until either the initial
verification for tightness (of the shear pin retainer attaching parts),
the terminating action, or an FAA-approved repair is accomplished.
These commenters state that the FAA already has approved repairs
applicable to paragraphs (a) and (b) of the proposal, which have
consisted of the installation of new parts. New parts obviously will be
tightened upon installation; therefore, reinspection of the tightness
of these parts within 60 days appears to be unwarranted. The commenters
request that the repetitive interval for the inspection for
installation of parts be revised to 18 months in order to be consistent
with the recommendations of Phase 2 of the original issue of McDonnell
Douglas Alert Service Bulletin A54-71.
The FAA concurs in part with the commenter's request. Upon further
consideration of the procedures specified in the referenced service
bulletin, the FAA concurs that a 60-day repetitive inspection interval
is not necessary in certain situations, explained as follows:
Paragraphs (a)(1) and (b)(1)(i) of the final rule apply to
situations where the shear pins, shear pin retainers, and shear pin
retainer attaching parts have been inspected and found to be installed.
The FAA finds that inspections to verify the installation of these
parts must be repeated every 60 days, so long as there is no other
action accomplished that will ensure the tightness of the attaching
parts. These inspections for installation may be terminated, however,
when the initial verification for tightness of the shear pin retainer
attaching parts is accomplished in 18 months in accordance with
paragraph (c) of the rule; or when the terminating modification
described in paragraph (d) is installed, if earlier than 18 months.
The FAA has revised paragraphs (a)(2) and (b)(1)(ii) of the final
rule, which apply to situations where any shear pin is missing or has
migrated, and any shear pin retainer or shear pin retainer attaching
part is missing. In such cases, an FAA-approved repair is required to
be installed; the FAA has determined that these approved repairs will
be such that no further inspections for installation of parts will be
necessary once the approved repair is installed. The FAA has revised
these paragraphs of the final rule to reflect this determination.
Additionally, the FAA has added new paragraphs (a)(3) and
(b)(1)(iii), which specify that, in situations where the shear pin
retainers or shear pin retainer attaching parts are missing or loose,
and the shear pin has not migrated, operators may accomplish a repair
in accordance with procedures specified as ``Condition II'' in
McDonnell Douglas Alert Service Bulletin A54-31, Revision 1, dated June
3, 1993. Subsequent to this repair, no further inspections for
installation of parts are required. These paragraphs have been added in
order to provide operators with an additional repair procedure that may
be used in lieu of obtaining prior FAA-approval of repairs (which was
the only option provided for in the proposal).
These same commenters contend that the 15-day compliance time for
the initial inspection required by proposed paragraph (b) is not
warranted for certain airplanes. The commenters point out that a
tightness check was accomplished on airplanes in Groups V and VI (as
specified in the referenced McDonnell Douglas service bulletin) prior
to delivery; therefore, an initial inspection for installation of the
subject parts should not be required for these airplanes. The
commenters request that, for these airplanes, only a ``re-
verification'' for tightness be required within 18 months.
Additionally, the commenters point out that an initial visual
inspection for installation of parts was accomplished on airplanes in
Group III and IV prior to delivery; therefore, the compliance time for
initial inspection for installation of parts required by this proposed
rule should be extended. The commenters suggest extending the initial
compliance time to 60 days, since this is the compliance time
recommended by the manufacturer in the referenced service bulletin.
The FAA concurs in part with the commenter's requests. The FAA
acknowledges that it is appropriate to revise paragraph (b) of the
final rule to differentiate between the requirements of the various
groups of airplanes specified in the referenced service bulletin:
As for airplanes in Groups III and IV, the FAA does not concur with
the commenter's request to extend the initial compliance time for the
inspection for installation of parts on these airplanes. While these
airplanes may have been inspected prior to delivery, and while the
manufacturer's revised service bulletin recommends a repetitive
inspection interval of 60 days, the FAA points out that the inspection
procedures described in that service bulletin have not been mandated
previously. Since the revised service bulletin was released over a year
ago, there is no way to guarantee that affected airplanes have been
repetitively inspected prior to the issuance of this final rule. In
light of this, the FAA considers a compliance time of 15 days necessary
in order to ensure that the accomplishment of what may be the first
repetitive inspection for some airplanes is carried out in a timely
manner. However, the FAA has revised the compliance terms of paragraph
(b)(1) to provide a ``grace period'' for operators of airplanes that
may have been visually (re-)inspected recently. The final rule now
reflects a compliance time for the initial visual inspection as
``within 15 days after the effective date of the AD, or prior to the
accumulation of 60 days since the last visual inspection, whichever
occurs later.''
As for airplanes in Groups V and VI, the FAA concurs that these
airplanes need not be subject to the initial inspection for
installation of parts as required by paragraph (b), as long as
repetitive verifications for tightness are conducted. Therefore, the
FAA has revised paragraph (b) by adding a new paragraph (b)(2), which
addresses these airplanes and allows them the option of either
repetitively inspecting for installation of parts (as originally
proposed), or conducting a verification for tightness within 18 months
after the last verification was performed. If operators of these
airplanes elect to perform the verification for tightness, it must be
repeated every 18 months until the terminating modification is
accomplished in accordance with paragraph (d) of the rule.
These same commenters request that proposed paragraph (c) be
revised to indicate that accomplishment of the verification for
tightness of the shear pin retainer attaching parts terminates the
requirement for the repetitive visual inspections for installation of
these same parts required by paragraph (a) and (b). The FAA concurs and
has revised paragraph (c) of the final rule accordingly.
These commenters also request that proposed paragraph (d) be
revised to extend the compliance time for accomplishment of the
terminating modification from the proposed 3 years to 5 years. The
commenters consider this modification to be only an ``improvement
change,'' and operators should be allowed to install it during a
convenient and regularly scheduled maintenance period in order to avoid
special scheduling of airplanes and additional associated costs. The
FAA does not concur. In developing the compliance time for the
terminating action, the FAA considered not only the safety
implications, but the manufacturer's recommendations, the availability
of required modification parts, and the practical aspects of an orderly
modification of the fleet. In consideration of all of these items, the
FAA determined that 3 years is an appropriate interval that will
coincide with regularly scheduled maintenance periods (``C'' checks)
for the majority of the affected operators. However, under the
provisions of paragraph (f) of the final rule, the FAA may approve
requests for adjustments to the compliance time if data are submitted
to substantiate that such an adjustment would provide an acceptable
level of safety.
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 94 Model MD-11 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 42
airplanes of U.S. registry will be affected by this AD.
Accomplishment of the required inspections for installation of
parts will take approximately 4 work hours per airplane, at an average
labor rate of $55 per work hour. Based on these figures, the total cost
impact of these requirements of this AD on U.S. operators is estimated
to be $9,240, or $220 per airplane, per inspection.
Accomplishment of the required verification for tightness of the
shear pin retainer attaching parts will take approximately 6 work hours
per airplane, at an average labor rate of $55 per work hour. Based on
these figures, the total cost impact of these requirements of this AD
on U.S. operators is estimated to be $13,860, or $330 per airplane, per
verification.
Accomplishment of the required terminating modification will take
approximately 6 work hours per airplane, at an average labor rate of
$55 per work hour. Required parts will be provided by the manufacturer
at no cost to operators. Based on these figures, the total cost impact
of these requirements of this AD on U.S. operators is estimated to be
$13,860, or $330 per airplane.
The total cost impact figures discussed above are 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:
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 removing amendment 39-8403 (57 FR
47991, October 21, 1992), and by adding a new airworthiness directive
(AD), amendment 39-8973, to read as follows:
94-15-02 McDonnell Douglas: Amendment 39-8973. Docket 93-NM-216-AD.
Supersedes AD 92-23-03, Amendment 39-8403.
Applicability: Model MD-11 series airplanes; as listed in
McDonnell Douglas MD-11 Alert Service Bulletin A54-31, dated
September 17, 1992, and McDonnell Douglas MD-11 Alert Service
Bulletin A54-31, Revision 1, dated June 3, 1993; certificated in any
category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent structural damage to the engine mount structure,
which could lead to loss of airplane components, accomplish the
following:
(a) For airplanes listed in McDonnell Douglas MD-11 Alert
Service Bulletin A54-31, dated September 17, 1992: Within 15 days
after November 5, 1992 (the effective date of AD 92-23-03, amendment
39-8403), unless previously accomplished within the last 30 days,
perform a visual inspection of the thrust link of the center engine
forward mount to verify installation of the shear pins, the shear
pin retainers, and the shear pin retainer attaching parts in
accordance with McDonnell Douglas MD-11 Alert Service Bulletin A54-
31, dated September 17, 1992, or Revision 1, dated June 3, 1993.
(1) If shear pins, shear pin retainers, and shear pin retainer
attaching parts are installed, repeat the visual inspection
thereafter at intervals not to exceed 60 days until accomplishment
of paragraph (c) or (d) of this AD.
(2) If any shear pin retainer or shear pin retainer attaching
part is missing or loose, and if any shear pin has migrated, prior
to further flight, repair in accordance with a method approved by
the Manager, Los Angeles Aircraft Certification Office (ACO), FAA,
Transport Airplane Directorate.
(3) If any shear pin retainer or shear pin retainer attaching
part is missing or loose, and if no shear pin has migrated, prior to
further flight, repair in acordance with ``Condition II'' of
McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,
dated June 3, 1994.
(b) For airplanes listed in McDonnell Douglas MD-11 Alert
Service Bulletin A54-31, Revision 1, dated June 3, 1993, and not
subject to the requirements of paragraph (a) of this AD, accomplish
the following:
(1) For airplanes specified as Groups III and IV in that service
bulletin: Within 15 days after the effective date of this AD or
prior to the accumulation of 60 days since the last visual
inspection performed before the effective date of this AD in
accordance McDonnell Douglas MD-11 Alert Service Bulletin A54-31,
Revision 1, dated June 3, 1993, or equivalent, whichever occurs
later, perform a visual inspection of the thrust link of the center
engine forward mount to verify installation of the shear pins, the
shear pin retainers, and the shear pin retainer attaching parts in
accordance with McDonnell Douglas MD-11 Alert Service Bulletin A54-
31, Revision 1, dated June 3, 1993.
(i) If shear pins, shear pin retainers, and shear pin retainer
attaching parts are installed, repeat the visual inspection
thereafter at intervals not to exceed 60 days until accomplishment
of paragraph (c) or (d) of this AD.
(ii) If any shear pin retainer or shear pin retainer attaching
part is loose or missing, and if any shear pin has migrated, prior
to further flight, repair in accordance with a method approved by
the Manager, Los Angeles Aircraft Certification Office (ACO), FAA,
Transport Airplane Directorate.
(iii) If any shear pin retainer or shear pin retainer attaching
part is loose or missing, and if no shear pin has migrated, prior to
further flight, repair in accordance with ``Condition II'' of
McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,
dated June 3, 1993.
(2) For airplanes specified as Groups V and VI in that service
bulletin: Accomplish the procedures specified in either paragraph
(b)(2)(i) or (b)(2)(ii) of this AD:
(i) Accomplish the visual inspection(s) and necessary follow-on
procedures specified in paragraph (b)(1) of this AD, or
(ii) Prior to the accumulation of 18 months since the last
verification for tightness of the shear pin retainer parts was
accomplished, or within 6 months after the effective date of this
AD, whichever occurs later, verify that the tightness of the shear
pin retainer parts is within the limits specified in accordance with
McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,
dated June 3, 1993. Repeat the verification for tightness thereafter
at intervals not to exceed 18 months until the accomplishment of
paragraph (d) of this AD.
(c) For all airplanes, except those subject to paragraph
(b)(2)(ii) of this AD: Within 18 months after the effective date of
this AD, verify that the tightness of the shear pin retainer
attaching parts is within the limits specified in accordance with
McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,
dated June 3, 1993. Repeat this verification thereafter at intervals
not to exceed 18 months until accomplishment of paragraph (d) of
this AD. Accomplishment of the verification for tightness required
by this paragraph constitutes terminating action for the repetitive
inspections for installation of parts required by paragraphs (a) and
(b) of this AD.
(d) For all airplanes: Within 3 years after the effective date
of this AD, replace the existing retainer and bolts with safety wire
with a new retainer and new bolts with safety wire in accordance
with McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision
1, dated June 3, 1993. Accomplishment of this replacement
constitutes terminating action for the repetitive actions required
by paragraphs (a), (b) and (c) of this AD.
(e) Within 15 days after detecting any discrepancy during any
inspection or verification action required by this AD, submit a
report of the inspection results to the Manager, Los Angeles ACO,
FAA, Transport Airplane Directorate, 3229 East Spring Street, Long
Beach, California 90806-2425; fax (310) 988-5210. Information
collection requirements contained in this regulation have been
approved by the Office of Management and Budget (OMB) under the
provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et
seq.) and have been assigned OMB Control Number 2120-0056.
(f) 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.
(g) The actions shall be done in accordance with McDonnell
Douglas MD-11 Alert Service Bulletin A54-31, dated September 17,
1992; and McDonnell Douglas MD-11 Alert Service Bulletin A54-31,
Revision 1, dated June 3, 1993. The incorporation by reference of
the former service bulletin was approved previously by the Director
of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1
CFR part 51, as of November 2, 1992 (57 FR 47991, October 21, 1992).
The incorporation by reference of the latter service bulletin 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, P.O. Box 1771, Long Beach, CA 90801-
1771, Attention: Business Unit Manager, Technical Administrative
Support, Dept. L51, M.C. 2-98. 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, 3229 East Spring Street, Long
Beach, California; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on August 19, 1994.
Issued in Renton, Washington, on July 11, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-17196 Filed 7-19-94; 8:45 am]
BILLING CODE 4910-13-U