[Federal Register: June 16, 2004 (Volume 69, Number 115)]
[Proposed Rules]
[Page 33595-33597]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16jn04-28]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2003-NM-214-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 777-200 and -300 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain Boeing Model 777-200 and -
300 series airplanes. This proposal would require modification of the
bolt holes of the lower side of the body splice t-chord common to the
paddle fitting of the lower wing panel. The modification includes
performing a high frequency eddy current inspection of the fastener
hole for cracks, repairing the hole if necessary, and replacing the
fasteners with new inconel bolts. This action is necessary to prevent
fatigue cracks in the lower t-chord at the bolt holes common to the
paddle fittings that could result in fractures of one or more of the t-
chord segments, which could lead to detachment of the lower wing panel
and consequent loss of the wing. This action is intended to address the
identified unsafe condition.
DATES: Comments must be received by August 2, 2004.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2003-NM-214-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9 a.m. and 3 p.m., Monday through Friday, except
Federal holidays. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address:
9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain
[[Page 33596]]
``Docket No. 2003-NM-214-AD'' in the subject line and need not be
submitted in triplicate. Comments sent via the Internet as attached
electronic files must be formatted in Microsoft Word 97 or 2000 or
ASCII text.
The service information referenced in the proposed rule may be
obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Gary Oltman, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6443; fax (425) 917-6590
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this action may be changed in
light of the comments received.
Submit comments using the following format:
Organize comments issue-by-issue. For example, discuss
a request to change the compliance time and a request to change the
service bulletin reference as two separate issues.
For each issue, state what specific change to the
proposed AD is being requested.
Include justification (e.g., reasons or data) for each
request.
Comments are specifically invited on the overall regulatory, economic,
environmental, and energy aspects of the proposed rule. All comments
submitted will be available, both before and after the closing date for
comments, in the Rules Docket for examination by interested persons. A
report summarizing each FAA-public contact concerned with the substance
of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2003-NM-214-AD.'' The postcard will be date stamped
and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 2003-NM-214-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received a report indicating that, during full scale
fatigue testing of a Boeing Model 777 series airplane, fatigue cracks
were found in the lower side of the body splice t-chord common to the
paddle fitting bolt holes. Fatigue cracks were found on both sides of
the airplane between stringers 1 and 14. This condition, if not
prevented, could result in fractures of one or more of the t-chord
segments, which could lead to detachment of the lower wing panel and
consequent loss of the wing.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 777-
57A0040, Revision 1, dated July 10, 2003, which describes procedures
for performing repetitive ultrasonic and high frequency eddy current
(HFEC) inspections of the t-chord for cracks, and modification of the
lower paddle fitting fasteners. The modification includes performing a
high frequency eddy current inspection of the fastener hole for cracks,
repairing the hole if necessary, and replacing the fasteners with new
inconel bolts. The service bulletin also specifies contacting the
manufacturer for certain repair conditions. Accomplishment of the
modification ends the repetitive inspections.
Accomplishment of the actions specified in the service bulletin is
intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed rule would require accomplishment of the actions specified in
the service bulletin described previously, except as discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that the service bulletin specifies doing
repetitive ultrasonic and HFEC inspections until the modification is
accomplished. However, this proposal only specifies performing the
modification of the bolt holes of the lower side of the body splice t-
chord common to the paddle fitting of the lower wing panel (includes
replacing the fasteners with new inconel bolts, performing an HFEC
inspection of the fastener hole for cracks, and repairing the hole as
applicable). We can better ensure long-term continued operational
safety by modifications or design changes to remove the source of the
problem, rather than by repetitive inspections. Long-term inspections
may not provide the degree of safety necessary for the transport
airplane fleet. This, coupled with a better understanding of the human
factors associated with numerous repetitive inspections, has led us to
consider placing less emphasis on special procedures and more emphasis
on design improvements. We also considered that the work hours needed
to do the inspections in Part 1 of the service bulletin are comparable
to the work hours needed to do the modification in Part 2 of the
service bulletin. We were informed that most likely the inspections
would be skipped and only the modification would be accomplished. In
consideration of all of these factors, we determined that performing
the modification best addresses the unsafe condition, while still
maintaining an adequate level of safety.
Operators should also note that, although the service bulletin
specifies that the manufacturer may be contacted for additional
instructions for repair of certain cracks, this proposal would require
the repair to be accomplished per a method approved by the FAA, or per
data meeting the type certification basis of the airplane approved by a
Boeing Company Designated Engineering Representative who has been
authorized by the FAA to make such findings.
Cost Impact
There are approximately 262 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 73 airplanes of U.S. registry
would be affected by this proposed rule, that it would take
approximately 34 work hours per airplane to accomplish the proposed
modification, and that the average labor rate is $65 per work hour.
Required parts would cost between approximately $21,686 and $24,803 per
airplane. Based on these figures, the cost impact of the proposed rule
on U.S. operators is estimated to be between $1,744,408 and $1,971,
949, or between $23,896 and $27,013 per airplane.
The cost impact figure discussed above is based on assumptions that
no
[[Page 33597]]
operator has yet accomplished any of the proposed requirements of this
AD action, and that no operator would accomplish those actions in the
future if this proposed AD were not adopted. The cost impact figures
discussed in AD rulemaking actions represent only the time necessary to
perform the specific actions actually required by the AD. These figures
typically do not include incidental costs, such as the time required to
gain access and close up, planning time, or time necessitated by other
administrative actions.
Regulatory Impact
The regulations proposed herein would 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. Therefore, it
is determined that this proposal would not have federalism implications
under Executive Order 13132.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
Boeing: Docket 2003-NM-214-AD.
Applicability: Model 777-200 and -300 series airplanes, as
listed in Boeing Service Bulletin 777-57A0040, Revision 1, dated
July 10, 2003; certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent fatigue cracks in the lower t-chord at the bolt holes
common to the paddle fittings that could result in fractures of one
or more of the t-chord segments, which could lead to detachment of
the lower wing panel and consequent loss of the wing, accomplish the
following:
Modification of the Lower Paddle Fitting Bolt Holes/Fastener
Replacement
(a) At the later of the times specified in paragraphs (a)(1) and
(a)(2) of this AD, modify the bolt holes of the lower side of the
body splice t-chord common to the paddle fitting of the lower wing
panel (includes performing a high frequency eddy current inspection
of the fastener hole for cracks, repairing the hole if necessary,
and replacing the fasteners with new inconel bolts) by accomplishing
all of the actions specified in ``Part 2--Preventative
Modification'' of the Work Instructions of Boeing Service Bulletin
777-57A0040, Revision 1, dated July 10, 2003, except as provided by
paragraph (b) of this AD. Any applicable repair must be accomplished
before further flight.
(1) Prior to the accumulation of 20,000 total flight cycles or
60,000 total flight hours, whichever is first.
(2) Within 1,500 days or 8,000 flight cycles after the effective
date of this AD, whichever is first.
(b) If any crack is found during the modification required by
paragraph (a) of this AD, the service bulletin specifies to contact
Boeing for additional instructions: Before further flight, repair
per a method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA; or per data meeting the type certification basis
of the airplane approved by a Boeing Company Designated Engineering
Representative who has been authorized by the Manager, Seattle ACO,
to make such findings. For a repair method to be approved, the
approval must specifically reference this AD.
Alternative Methods of Compliance
(c) In accordance with 14 CFR 39.19, the Manager, Seattle ACO,
is authorized to approve alternative methods of compliance for this
AD.
Issued in Renton, Washington, on June 7, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-13561 Filed 6-15-04; 8:45 am]
BILLING CODE 4910-13-U