[Federal Register: September 16, 2005 (Volume 70, Number 179)]
[Rules and Regulations]
[Page 54612-54616]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16se05-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-20364; Directorate Identifier 2004-NM-186-AD;
Amendment 39-14274; AD 2005-19-09]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Boeing Model 747 airplanes. This AD requires repetitive
inspections of the dual side braces (DSBs), underwing midspar fittings,
and associated parts; other specified actions; and corrective actions
if necessary. This AD also provides an optional terminating action for
the inspections and other specified actions. This AD is prompted by
reports of corroded, migrated, and rotated bearings for the DSBs in the
inboard and outboard struts, a report of a fractured retainer for the
eccentric bushing for one of the side links of a DSB, and reports of
wear and damage to the underwing midspar fitting on the outboard strut.
We are issuing this AD to prevent the loss of a DSB or underwing
midspar fitting load path, which could result in the transfer of loads
and motion to other areas of a strut, and possible separation of a
strut and engine from the airplane during flight.
DATES: This AD becomes effective October 21, 2005.
The incorporation by reference of a certain publication listed in
the AD is approved by the Director of the Federal Register as of
October 21, 2005.
ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.
Docket: The AD docket contains the proposed AD, comments, and any
final disposition. You can examine the AD docket on the Internet at
http://dms.dot.gov, or in person at the Docket Management Facility
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the U.S.
Department of Transportation, 400 Seventh Street SW., room PL-401,
Washington, DC. This docket number is FAA-2005-20364; the directorate
identifier for this docket is 2004-NM-186-AD.
FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437;
fax (425) 917-6590.
SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39
with an AD for certain Boeing Model 747 airplanes. That action,
published in the Federal Register on February 14, 2005 (70 FR 7446),
proposed to require repetitive inspections of the dual side braces
(DSBs), underwing midspar fittings, and associated parts; other
specified actions; and corrective actions
[[Page 54613]]
if necessary. That action also provides an optional terminating action
for the inspections and other specified actions.
Comments
We provided the public the opportunity to participate in the
development of this AD. We have considered the comments that have been
submitted on the proposed AD.
Support for the Proposed AD
One commenter concurs with the content of the proposed AD.
Requests to Refer to Revised Service Bulletin and Give Credit for Prior
Issue
One commenter asks that the proposed AD reference Boeing Service
Bulletin 747-54A2218, Revision 1, dated February 24, 2005. Boeing Alert
Service Bulletin 747-54A2218, dated June 17, 2004, was referenced in
the proposed AD as the appropriate source of service information for
accomplishing the specified actions. The commenter states that Revision
1 specifies that no more work is necessary on airplanes changed per the
original issue of the service bulletin. The commenter also asks that we
give credit for actions done in accordance with the original issue of
the service bulletin. The commenter notes that this will prevent
additional work for the Civil Aviation Authorities that would
necessitate approving Revision 1 as an alternative method of
compliance. The commenter adds that the revised information specified
in Revision 1 may be helpful for operators in accomplishing the actions
required by the proposed AD. A second commenter asks that credit be
given for the initial inspection done in accordance with the original
issue of the service bulletin.
We agree with the commenters. We have reviewed Boeing Service
Bulletin 747-54A2218, Revision 1, dated February 24, 2005. The
instructions in Revision 1 are essentially the same as those in the
original issue of the service bulletin. Accordingly, we have revised
this AD to refer to Revision 1 of the service bulletin in the
applicability section and as the applicable source of service
information for accomplishing the actions required by this AD. We have
also added a new paragraph (i) (and re-identified subsequent paragraphs
accordingly) to give credit for actions accomplished before the
effective date of this AD in accordance with the original issue of the
service bulletin.
Requests to Remove/Delay Check for an Insufficient Gap/Delay Corrective
Actions
One commenter questions why the check for an insufficient gap
between the underwing midspar fitting and the strut midspar fitting is
necessary if no discrepancies are found during the proposed inspections
of the dual side brace (DSB) bearings. The commenter states that it was
both surprising and disappointing to learn of reported interference
between the underwing midspar fitting and the adjacent strut midspar
fitting. The commenter states that, while recognizing that corrective
actions should be accomplished only if conditions warrant such actions,
any future adopted rule should consider the inclusion of options that
will enable corrective actions to occur during planned D-check visits
to minimize unplanned out-of-service situations. The commenter notes
that the proposed AD includes a check for an insufficient gap between
those fittings within 24 months. The commenter concludes that the check
for an insufficient gap between those fittings should only be required
if discrepancies are found during the inspection of the DSB bearings
per Parts 1 and 2 of the referenced service bulletin.
A second commenter asks that paragraph (f) of the proposed AD be
changed to postpone the requirement for accomplishing the corrective
actions per Parts 3, 5, and 6 of the referenced service bulletin, if an
insufficient gap is found per Part 4. The commenter states that those
actions can be performed at its first FD-check, and until the actions
are performed, the spring beam/wing fitting joint and DSB fitting can
be inspected per the baseline inspection task specified in Boeing
Service Bulletin 747-54A2182, Revision 1, dated January 8, 2004, but at
a 3A interval. That service bulletin describes procedures for certain
baseline inspections of the strut-to-wing attachment structure. The
commenter adds that it has performed wing pylon modifications on more
than 50 airplanes per Boeing Alert Service Bulletins 747-54A2156
(referenced in AD 95-13-06, amendment 39-9286, as the appropriate
source of service information for modification of the nacelle strut and
wing) and 747-54A2158 (referenced in AD 95-13-07, amendment 39-9287, as
the appropriate source of service information for modification of the
nacelle strut and wing), concurrently with Boeing Service Bulletin 747-
57-2246, Revision 5, dated July 17, 1997. Boeing Service Bulletin 747-
57-2246 describes procedures for modification of the nacelle strut
attachment fittings. The commenter notes that Service Bulletin 747-57-
2246 also describes procedures for checking the surface wear on the
underwing fittings of the outboard pylon midspar that were caused by
interference with the spring beam flanged bushings, and removal of any
damage by spotfacing. The commenter states that only four of its
airplanes required the spotfaces to be larger than what was allowed in
the service bulletin, and the larger spotfaces were approved by the
FAA. The commenter adds that cracks were never found in the wear/
spotface area; however, several of the 50 airplanes must have had the
insufficient gap condition for many years. The commenter concludes that
if additional surface damage occurs on the underwing midspar fittings,
it would be detected in a timely manner when performing the proposed
inspections.
A third commenter, the airplane manufacturer, states that it is
concerned with the comments regarding a no-gap condition that may exist
during inspection, and the actions specified in paragraph (f) of the
proposed AD per Parts 4, 5, and 6 of the referenced service bulletin.
The commenter adds that a deferral for these actions may be justified
for a no-gap condition, provided that no damage is found during the
Part 4 inspection. The commenter's position is based on fleet history
data with similar conditions, as provided by other commenters. The
commenter may consider a change to the referenced service bulletin upon
a recommended course of action, and will advise us accordingly. The
commenter adds that we may choose to approve an alternative method of
compliance (AMOC) on a case-by-case basis, at our discretion.
We acknowledge the new information provided by the commenters. The
airplane manufacturer has informed us that it is planning to revise the
service bulletin to reflect this new information by the end of 2005.
Delaying this action until after the release and approval of the
manufacturer's planned service bulletin is not warranted. We have
determined that the inspections must be conducted to ensure continued
operational safety. When a new revision of the service bulletin has
been developed, we will review that revision and consider approving it
as an alternative method of compliance with the requirements of this
AD. In light of this, we have determined that all the actions required
by this AD are appropriate and warranted. No change is made to the AD
in this regard.
Additionally, insufficient technical justification was provided by
the
[[Page 54614]]
commenters to justify delaying issuance of the AD; however, if
sufficient technical justification is provided, we may approve an AMOC,
in accordance with paragraph (j)(1) of the AD.
Requests to Change Costs of Compliance Section/Extend Compliance Time
One commenter states that we should revise the Costs of Compliance
section that is specified in the preamble of the proposed AD. The
language in that section states, ``The following table provides the
estimated costs for U.S. operators to comply with this proposed AD.''
The commenter notes that the table provides the cost impact of the
required inspections, but offers no estimate of the cost impact should
an inspection detect the specific discrepancy that is the basis for the
proposal. The commenter states that it is well aware that the FAA's
policy for estimating the impact of proposed ADs does not include
publishing the impact of aircraft re-routing, preparation, access,
correction of discrepancies found, aircraft close-up, or return-to-
flight tests and procedures, often categorizing them as ``incidental''
impacts. The commenter does not support that policy. The commenter
states that, in this particular proposal, the impact of the man hours
necessary for accomplishing the corrective action alone can be an
order-of-magnitude greater than the per airplane cost published for
comment. The commenter asks us to consider adopting a policy for
proposed ADs that consistently states the per airplane impact of the
prescribed corrective action in cases where that action is found
necessary.
A second commenter states that it will be subjected to a huge
economic impact when accomplishing the actions specified in the
proposed AD, per the referenced service bulletin, due to the mandatory
status of the follow-up inspections and modification after an
insufficient gap is found. The commenter adds that the follow-up
inspections require engine and pylon removal. The commenter lists, and
we respond to, the following factors that will make the economic impact
of the proposed AD even greater:
1. Experience with the modification specified in Part 3 of the
referenced service bulletin shows that one of the DSB underwing fitting
bolts may interfere with the modification tool. If a bolt interferes,
it will have to be removed. Removal of a bolt requires removal of the
WS 1140 rib to gain access to the DSB underwing fitting bolt for
modification, which is a very time-consuming job.
Since we issued the proposed AD, this condition has not been
reported by any other operators. In addition, accomplishing the
modification is only necessary if damage or cracking is found, thus
making it an on-condition action and not part of the inspections
required by the AD.
2. The tooling kit specified in the referenced service bulletin
limits the operator to modifying only one fitting on one pylon at a
time, and not two or more pylons simultaneously. This results in
additional downtime when more than one pylon must be modified.
As we stated previously, accomplishing the modification is an on-
condition action. Obtaining the tooling kits necessary for
accomplishing the modification should be addressed by operators on a
case-by-case basis.
3. The airplane manufacturer does not seem ready to support so many
modifications with tooling and material kits. Currently, the airplane
manufacturer does not have enough tooling and material kits available
to support all operators in the 24-month timeframe allowed for the
modification.
We have no way of estimating how many operators will be
accomplishing the on-condition modifications. The airplane manufacturer
has confirmed that it will have the necessary tooling and material kits
available to complete the on-condition actions required by the AD.
A third commenter states that the maintenance and economic impact
of the proposed AD could be significantly greater than that specified
in the ``Costs of Compliance'' section. The commenter notes that a
review of labor estimates in the referenced service bulletin revealed
that over 500 labor hours per airplane may be required to perform the
necessary corrective actions if problems exist at all four engine strut
to wing attachment locations. The commenter adds that this would raise
the labor cost for compliance to over $30K per airplane; additionally,
material costs total over $21K per airplane, plus tooling rental
charges in excess of $1K per day are expected.
We do not agree with the commenters that request changing the work
hours in this AD, because the AD reflects only the direct costs of the
specific required actions based on the best data available from the
manufacturer. We recognize that operators may incur incidental costs
(such as the time for planning and associated administrative actions)
in addition to the direct costs. The cost analysis in ADs, however,
typically does not include incidental costs.
The 24-month compliance time for the initial inspection required by
this AD should allow ample time for the majority of affected operators
to do the required actions at the same time as scheduled major airplane
inspection and maintenance activities, which would reduce the
additional time and costs associated with special scheduling. We note
that the 24-month compliance time is consistent with the compliance
time specified in the referenced service bulletin. However, operators
may submit a request for approval of an AMOC, as specified in paragraph
(j)(1) of this AD. The request must include data substantiating that an
acceptable level of safety would be maintained by extending the
compliance time. No change is made to the AD in this regard.
Conclusion
We have carefully reviewed the available data, including the
comments that have been submitted, and determined that air safety and
the public interest require adopting the AD with the changes described
previously. These changes will neither increase the economic burden on
any operator nor increase the scope of the AD.
Costs of Compliance
There are about 1,091 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs for
U.S. operators to comply with this AD.
Estimated Costs
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Number of
Work Average Cost per U.S.-
Action hours labor rate Parts airplane registered Fleet cost
per hour airplanes
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Part 1 Inspections, per inspection 8 $65 None.......................... $520 229 $119,080, per inspection
cycle. cycle.
[[Page 54615]]
Part 2 Inspections, per inspection 48 65 None.......................... 3,120 229 714,480, per inspection
cycle. cycle.
Part 4 Inspections, per inspection 4 65 None.......................... 260 229 59,540, per inspection
cycle. cycle.
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
subtitle VII, part A, subpart III, section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will 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.
For the reasons discussed above, I certify that this AD:
(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.
We prepared a regulatory evaluation of the estimated costs to
comply with this AD. See the ADDRESSES section for a location to
examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
2005-19-09 Boeing: Amendment 39-14274. Docket No. FAA-2005-20364;
Directorate Identifier 2004-NM-186-AD.
Effective Date
(a) This AD becomes effective October 21, 2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-
400F, 747SR, and 747SP series airplanes; certificated in any
category; as identified in Boeing Service Bulletin 747-54A2218,
Revision 1, dated February 24, 2005.
Unsafe Condition
(d) This AD was prompted by reports of corroded, migrated, and
rotated bearings for the dual side braces (DSB) in the inboard and
outboard struts, a report of a fractured retainer for the eccentric
bushing for one of the side links of a DSB, and reports of wear and
damage to the underwing midspar fitting on the outboard strut. We
are issuing this AD to prevent the loss of a DSB or underwing
midspar fitting load path, which could result in the transfer of
loads and motion to other areas of a strut, and possible separation
of a strut and engine from the airplane during flight.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Inspections and Other Specified Actions
(f) At the times specified in Figure 1 of Boeing Service
Bulletin 747-54A2218, Revision 1, dated February 24, 2005, except as
provided by paragraph (g) of this AD: Do the various inspections and
other specified actions in the figure to detect discrepancies of the
DSBs, underwing midspar fittings, and associated parts, by doing all
of the actions specified in Parts 1, 2, and 4; and the applicable
corrective actions specified in Parts 3, 5, 6, and 7; of the
Accomplishment Instructions of the service bulletin, except as
provided by paragraph (h) of this AD. Repeat the inspections and
other specified actions thereafter at the intervals specified in
Figure 1 of the service bulletin. Accomplishment of any terminating
action specified in Figure 1 of the service bulletin terminates the
inspections and other specified actions for the affected strut.
(g) Where Boeing Service Bulletin 747-54A2218, Revision 1, dated
February 24, 2005, recommends an initial compliance threshold of
``within 24 months after the original issue date on this service
bulletin'' for Parts 1 and 4 of the service bulletin, and of
``within 72 months after the original issue date on this service
bulletin'' for Part 2 of the service bulletin, this AD requires an
initial compliance threshold of ``within 24 months after the
effective date of this AD'' for Parts 1 and 4 of the service
bulletin and of ``within 72 months after the effective date of this
AD'' for Part 2 of the service bulletin.
Corrective Actions
(h) If any damage or crack is found during any inspection or
corrective action required by this AD, before further flight, repair
in accordance with the Accomplishment Instructions of Boeing Service
Bulletin 747-54A2218, Revision 1, dated February 24, 2005; except,
where the service bulletin specifies to contact Boeing, before
further flight, repair according to a method approved by the
Manager, Seattle Aircraft Certification Office (ACO), FAA; or
according to data meeting the certification basis of the airplane
approved by an Authorized Representative for the Boeing Delegation
Option Authorization Organization who has been authorized by the
Manager, Seattle ACO, to make those findings. For a repair method to
be approved, the repair must meet the certification basis of the
airplane, and the approval must specifically refer to this AD.
Actions Accomplished According to Previous Issue of Service Bulletin
(i) Inspections and other specified and corrective actions
accomplished before the effective date of this AD in accordance with
[[Page 54616]]
Boeing Alert Service Bulletin 747-54A2218, dated June 17, 2004, are
considered acceptable for compliance with the corresponding actions
specified in paragraph (f) of this AD.
Alternative Methods of Compliance (AMOCs)
(j)(1) The Manager, Seattle ACO, has the authority to approve
AMOCs for this AD, if requested in accordance with the procedures
found in 14 CFR 39.19.
(2) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by an
Authorized Representative for the Boeing Delegation Option
Authorization Organization who has been authorized by the Manager,
Seattle ACO, to make those findings. For a repair method to be
approved, the repair must meet the certification basis of the
airplane, and the approval must specifically refer to this AD.
Material Incorporated by Reference
(k) You must use Boeing Service Bulletin 747-54A2218, Revision
1, dated February 24, 2005, to perform the actions that are required
by this AD, unless the AD specifies otherwise. The Director of the
Federal Register approves the incorporation by reference of this
document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To
get copies of the service information, contact Boeing Commercial
Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view
the AD docket, go to the Docket Management Facility, U.S. Department
of Transportation, 400 Seventh Street SW., room PL-401, Nassif
Building, Washington, DC. To review copies of the service
information, go to the National Archives and Records Administration
(NARA). For information on the availability of this material at the
NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html
.
Issued in Renton, Washington, on September 8, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-18313 Filed 9-15-05; 8:45 am]
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