[Federal Register: September 21, 2004 (Volume 69, Number 182)]
[Proposed Rules]
[Page 56375-56377]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21se04-11]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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[[Page 56375]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-19140; Directorate Identifier 2004-NM-84-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 Series Airplanes
Powered by Pratt & Whitney Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Boeing Model 757 series airplanes. This proposed AD would
require repetitive inspections for corrosion and cracking of the
midspar fittings in the nacelle struts, and corrective actions if
necessary. This action also provides an optional terminating action for
the repetitive inspections. This proposed AD is prompted by reports of
corrosion and cracking on midspar fittings on the nacelle struts of
several Boeing Model 757 series airplanes. We are proposing this AD to
detect and correct cracking in the midspar fittings of the nacelle
struts, consequent reduced structural integrity of the struts, and
possible separation of an engine and strut from the airplane.
DATES: We must receive comments on this proposed AD by November 5,
2004.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility, U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590.
By fax: (202) 493-2251.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
You can get the service information identified in this proposed AD
from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington
98124-2207.
You may examine the contents of this AD docket on the Internet at
http://dms.dot.gov, or at the Docket Management Facility, U.S.
Department of Transportation, 400 Seventh Street, SW., Room PL-401, on
the plaza level of the Nassif Building, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6450; fax (425) 914-6590.
SUPPLEMENTARY INFORMATION:
Docket Management System (DMS)
The FAA has implemented new procedures for maintaining AD dockets
electronically. As of May 17, 2004, new AD actions are posted on DMS
and assigned a docket number. We track each action and assign a
corresponding directorate identifier. The DMS AD docket number is in
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier
(``Old Docket Number'') as a cross-reference for searching purposes.
Comments Invited
We invite you to submit any written relevant data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2004-19140;
Directorate Identifier 2004-NM-84-AD'' in the subject line of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments submitted by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov
, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
We are reviewing the writing style we currently use in regulatory
documents. We are interested in your comments on whether the style of
this document is clear, and your suggestions to improve the clarity of
our communications that affect you. You can get more information about
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.Examining
the Docket
You may examine the AD docket 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 DOT street address stated in the ADDRESSES section.
Comments will be available in the AD docket shortly after the DMS
receives them.
Discussion
We have received reports of corrosion and cracking on midspar
fittings on the nacelle struts of several Boeing Model 757 series
airplanes. Investigation revealed that the fittings were made from
4330M material. Corrosion may cause pits that result in cracking of the
midspar fittings. This condition, if not corrected, could result in
reduced structural integrity of the struts, and possible separation of
an engine and strut from the airplane.
Other Related Rulemaking
On August 29, 2003, we issued AD 2003-18-05, amendment 39-13296 (68
FR 53496, September 11, 2003), applicable to certain Boeing Model 757
series airplanes powered by Pratt & Whitney engines. That AD requires
[[Page 56376]]
modifying the nacelle strut and wing structure at a threshold of 37,500
total flight cycles or 20 years, whichever is first. That AD is part of
the manufacturer's nacelle strut improvement program. The newly
reported cracking of the midspar fittings that prompted this proposed
AD occurred at approximately 29,700 total flight cycles and 18 years--
below the compliance time threshold for the modifications required by
AD 2003-18-05. If the modifications required by AD 2003-18-05 have been
accomplished, operators do not need to do the inspections required by
this proposed AD. The nacelle strut modification required by AD 2003-
18-05 includes replacing the midspar fittings. This proposed AD does
not affect the requirements of AD 2003-18-05.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 757-54-
0042, dated May 13, 1999, which describes various procedures for
repetitive visual and detail visual inspections of the midspar fittings
located in the nacelle struts for evidence of corrosion and cracking,
and corrective actions. Evidence of corrosion includes rust stains
around the cap seals; along the edge of the fittings; and on the skins,
spars, and bulkheads.
The service bulletin effectivity is divided into two groups of
airplanes, depending on the material used to make the midspar fittings.
Group 1 airplanes have midspar fittings made exclusively of 4330M
material, while Group 2 airplanes have fittings made of both 4330M
material and 15-5PH CRES material. For both Group 1 and Group 2
airplanes, the procedures and corrective actions include:
Doing visual and detail visual inspections of the midspar
fittings.
If no corrosion is found, applying corrosion inhibitor and
repeating the inspections at the times specified in the service
bulletin.
If corrosion is found and the fitting is not replaced
before further flight, removing the clip from the affected strut and
repeating the inspections at the times specified.
If corrosion is found and the fitting is replaced before
further flight, either modifying only the strut, or the wing and strut
together, in accordance with the Accomplishment Instructions in Boeing
Service Bulletin 757-54-0034, Revision 1, dated October 11, 2001.
If no cracking is found, doing repetitive visual
inspections of the upper and lower tangs of the midspar fittings at the
intervals specified.
If any cracking is found, replacing the fitting before
further flight by either modifying only the strut, or the wing and
strut together, in accordance with the Accomplishment Instructions in
Boeing Service Bulletin 757-54-0034.
For Group 2 airplanes, there is an additional procedure for
identifying the material used to make each fitting.
Accomplishment of the actions specified in Boeing Special Attention
Service Bulletin 757-54-0042 is intended to adequately address the
identified unsafe condition.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. Therefore, we are proposing this AD, which
would require repetitive inspections for corrosion and cracking of the
midspar fittings in the nacelle struts, and corrective actions if
necessary. The proposed AD would require you to use the service
information described previously to perform these actions, except as
discussed under ``Differences Between the Proposed AD and Service
Information.'' The proposed AD also provides an optional terminating
action for the repetitive inspections.
Differences Between the Proposed AD and Service Information
The service bulletin states that airplanes with any corroded
midspar fitting may continue to fly for up to 18 months before
replacing an affected fitting, if repetitive inspections are done at
intervals of 300 flight cycles. Neither the referenced service
bulletin, Boeing Special Attention Service Bulletin 757-54-0042, nor
the Boeing 757 Structural Repair Manual, provide instructions for
removing corrosion from these midspar fittings. Operators are allowed
to make specific proposals for an alternative method of compliance
through the provisions of paragraph (l) of this proposed AD. In the
absence of established or acceptable methods of removing corrosion on
midspar fittings, this proposed AD would require replacing any corroded
midspar fitting before further flight. Continued operation with
untreated corrosion can lead to cracking that emanates from a corrosion
pit. This is especially true for a high strength steel like 4330M.
For Group 2 airplanes, the service bulletin states that, if there
is a mixture of midspar fittings made of 15-5PH CRES material and 4330M
material, regular zonal inspections may be done for airplanes less than
ten years old. This proposed AD would require repetitive detailed
inspections for all fittings made of 4330M material at 18-month
intervals since all affected airplanes are at least ten years old.
The manufacturer is aware of these differences and concurs.
Clarification of Inspection Terminology
Boeing Special Attention Service Bulletin 757-54-0042 specifies
visual and detail visual inspections of the midspar fittings. This
proposed AD requires general visual and detailed inspections of the
midspar fittings. Notes 1 and 2 have been included in this proposed
rule to define these types of inspections.
Costs of Compliance
This proposed AD would affect about 410 airplanes worldwide. The
following table provides the estimated costs for U.S. operators to
comply with this proposed AD.
Estimated Costs
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Number of U.S.-
Action Work hours Average labor Parts Cost per airplane registered Fleet cost
rate per hour airplanes
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Inspection, per inspection 3 $65 None............. $195, per inspection 338 $65,910, per inspection
cycle. cycle. cycle
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Regulatory Findings
We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD 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.
[[Page 56377]]
For the reasons discussed above, I certify that the 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. 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 proposed 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, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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. The FAA amends Sec. 39.13 by adding the following new
airworthiness directive (AD):
Boeing: Docket No. FAA-2004-19140; Directorate Identifier 2004-NM-
84-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by November 5, 2004.
Affected ADs
(b) This AD is related to AD 2003-18-05, amendment 39-13296.
Applicability
(c) This AD applies to Boeing Model 757 series airplanes, line
numbers 1 through 639 inclusive, powered by Pratt & Whitney engines;
certificated in any category.
Unsafe Condition
(d) This AD was prompted by reports of corrosion and cracking on
midspar fittings on the nacelle struts of several Boeing Model 757
series airplanes. We are issuing this AD to detect and correct
cracking in the midspar fittings of the nacelle struts, consequent
reduced structural integrity of the struts, and possible separation
of an engine and strut from the airplane.
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 for Group 1 Airplanes
(f) For airplanes identified as Group 1 in Boeing Special
Attention Service Bulletin 757-54-0042, dated May 13, 1999: Within
18 months after the effective date of this AD, do general visual and
detailed inspections for evidence of corrosion and/or cracking of
the midspar fittings located in the nacelle struts, in accordance
with the Accomplishment Instructions of Boeing Special Attention
Service Bulletin 757-54-0042, dated May 13, 1999. Repeat the
inspections thereafter at intervals not to exceed 18 months until
the requirements of paragraph (j) are accomplished.
Note 1: For the purposes of this AD, a general visual inspection
is defined as: ``A visual examination of an interior or exterior
area, installation, or assembly to detect obvious damage, failure,
or irregularity. This level of inspection is made from within
touching distance unless otherwise specified. A mirror may be
necessary to enhance visual access to all exposed surfaces in the
inspection area. This level of inspection is made under normally
available lighting conditions such as daylight, hangar lighting,
flashlight, or droplight and may require removal or opening of
access panels or doors. Stands, ladders, or platforms may be
required to gain proximity to the area being checked.''
Note 2: For the purposes of this AD, a detailed inspection is
defined as: ``An intensive visual examination of a specific
structural area, system, installation, or assembly to detect damage,
failure, or irregularity. Available lighting is normally
supplemented with a direct source of good lighting at intensity
deemed appropriate by the inspector. Inspection aids such as mirror,
magnifying lenses, etc., may be used. Surface cleaning and elaborate
access procedures may be required.''
Inspections for Group 2 Airplanes
(g) For airplanes identified as Group 2 in Boeing Special
Attention Service Bulletin 757-54-0042, dated May 13, 1999: Within
18 months after the effective date of this AD, do a general visual
inspection to identify the type of material the midspar fittings are
made from, in accordance with the Accomplishment Instructions of
Boeing Special Attention Service Bulletin 757-54-0042, dated May 13,
1999.
(1) If all four midspar fittings are made of 15-5PH CRES
material, no further action is required by this AD.
(2) If any midspar fitting is made of 4330M material, do the
inspections required by paragraph (h) of this AD.
(h) For Group 2 airplanes with fittings made of 4330M material:
After the inspection required by paragraph (g) of this AD, but
before further flight: Do a general visual and a detailed inspection
of the 4330M midspar fittings for evidence of corrosion and/or
cracking, in accordance with the Accomplishment Instructions of
Boeing Special Attention Service Bulletin 757-54-0042, dated May 13,
1999. Repeat the inspections for corrosion and/or cracking
thereafter at intervals not to exceed 18 months until the
requirements of paragraph (j) of this AD are accomplished.
Corrective Actions
(i) For Group 1 and Group 2 airplanes: If any corrosion or
cracking is found during any inspection required by paragraph (f) or
(h) of this AD, before further flight, replace the affected midspar
fitting with a new midspar fitting by accomplishing all of the
applicable actions in accordance with the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 757-54-
0042, dated May 13, 1999. Replacement of an affected midspar fitting
terminates the repetitive inspections required by paragraphs (f) and
(h) of this AD for that fitting only.
Optional Terminating Action
(j) Replacement of all of the midspar fittings with new midspar
fittings in accordance with the Accomplishment Instructions of
Boeing Special Attention Service Bulletin 757-54-0042, dated May 13,
1999, terminates the repetitive inspections required by paragraphs
(f) and (h) of this AD.
Actions Accomplished Previously
(k) Accomplishment of the nacelle strut and wing modification
required by AD 2003-18-05, amendment 39-13296, is considered
acceptable for compliance with the requirements of this AD.
Alternative Methods of Compliance (AMOCs)
(l)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, 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 replacement required by this AD, if it is approved by a
Boeing Company Designated Engineering Representative who has been
authorized by the Manager, Seattle ACO, to make those findings.
Issued in Renton, Washington, on September 13, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-21176 Filed 9-20-04; 8:45 am]
BILLING CODE 4910-13-P