Airworthiness Directives; The Boeing Company 737-200, -200C, -300, -400, and -500 Series Airplanes, 12619-12624 [2011-5159]
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Federal Register / Vol. 76, No. 45 / Tuesday, March 8, 2011 / Proposed Rules
Issued in Renton, Washington on February
22, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane
Directorate, Aircraft Certification Service.
[FR Doc. 2011–5158 Filed 3–7–11; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2011–0155; Directorate
Identifier 2009–NM–141–AD]
RIN 2120–AA64
Airworthiness Directives; The Boeing
Company 737–200, –200C, –300, –400,
and –500 Series Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
AGENCY:
The FAA proposes to
supersede an existing airworthiness
directive (AD) that applies to certain
Boeing Model 737–200, –200C, –300,
–400, and –500 series airplanes. The
existing AD currently requires repetitive
inspections to find fatigue cracking of
certain upper and lower skin panels of
the fuselage, and follow-on and
corrective actions if necessary. The
existing AD also includes a terminating
action for the repetitive inspections of
certain modified or repaired areas only.
This proposed AD would add new
inspections for cracking of the fuselage
skin along certain chem-milled lines,
and corrective actions if necessary. This
proposed AD would also reduce certain
thresholds and intervals required by the
existing AD. This proposed AD results
from reports of new findings of vertical
cracks in the fuselage skin along the
chem-milled steps adjacent to the butt
joints. We are proposing this AD to
detect and correct fatigue cracking of the
skin panels, which could result in
sudden fracture and failure of the skin
panels of the fuselage, and consequent
rapid decompression of the airplane.
DATES: We must receive comments on
this proposed AD by April 22, 2011.
ADDRESSES: You may send comments by
any of the following methods:
• Federal eRulemaking Portal: Go to
https://www.regulations.gov. Follow the
instructions for submitting comments.
• Fax: 202–493–2251.
• Mail: U.S. Department of
Transportation, Docket Operations,
M–30, West Building Ground Floor,
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SUMMARY:
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Room W12–140, 1200 New Jersey
Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of
Transportation, Docket Operations,
M–30, West Building Ground Floor,
Room W12–140, 1200 New Jersey
Avenue, SE., Washington, DC 20590,
between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
For service information identified in
this proposed AD, contact Boeing
Commercial Airplanes, Attention: Data
& Services Management, P.O. Box 3707,
MC 2H–65, Seattle, Washington 98124–
2207; telephone 206–544–5000,
extension 1; fax 206–766–5680; e-mail
me.boecom@boeing.com; Internet
https://www.myboeingfleet.com. You
may review copies of the referenced
service information at the FAA,
Transport Airplane Directorate, 1601
Lind Avenue, SW., Renton, Washington.
For information on the availability of
this material at the FAA, call 425–227–
1221.
Examining the AD Docket
You may examine the AD docket on
the Internet at https://
www.regulations.gov; or in person at the
Docket Management Facility between
9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays. The AD
docket contains this proposed AD, the
regulatory evaluation, any comments
received, and other information. The
street address for the Docket Office
(telephone 800–647–5527) is in the
ADDRESSES section. Comments will be
available in the AD docket shortly after
receipt.
FOR FURTHER INFORMATION CONTACT:
Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM–120S, FAA,
Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton,
Washington 98057–3356; telephone
(425) 917–6447; fax (425) 917–6590;
e-mail: wayne.lockett@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written
relevant data, views, or arguments about
this proposed AD. Send your comments
to an address listed under the
ADDRESSES section. Include ‘‘Docket No.
FAA–2011–0155; Directorate Identifier
2009–NM–141–AD’’ at the beginning of
your comments. We specifically invite
comments on the overall regulatory,
economic, environmental, and energy
aspects of this proposed AD. We will
consider all comments received by the
closing date and may amend this
proposed AD because of those
comments.
We will post all comments we
receive, without change, to https://
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12619
www.regulations.gov, including any
personal information you provide. We
will also post a report summarizing each
substantive verbal contact we receive
about this proposed AD.
Discussion
On August 26, 2004, we issued AD
2004–18–06, Amendment 39–13784 (69
FR 54206, September 8, 2004), for
certain Model 737–200, –200C, –300,
–400, and –500 series airplanes. That
AD requires repetitive inspections to
find fatigue cracking of certain upper
and lower skin panels of the fuselage,
and follow-on and corrective actions if
necessary. That AD also includes a
terminating action for the repetitive
inspections of certain modified or
repaired areas only. That AD resulted
from reports indicating new findings of
cracks were found along the edges of the
chem-milled pockets in the upper skin
at certain stringers. We issued that AD
to find and fix fatigue cracking of the
skin panels, which could result in
sudden fracture and failure of the skin
panels of the fuselage, and consequent
rapid decompression of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 2004–18–06, we
have received reports of new findings of
vertical cracks in the fuselage skin along
the chem-milled steps adjacent to the
butt joints and at certain body stations
on airplanes with between 45,100 flight
cycles (65,200 flight hours) and 67,400
flight cycles (70,800 flight hours).
A decompression event connected to
chem-milled steps occurred in July 2009
(after issuance of Boeing Alert Service
Bulletin 737–53A1210, Revision 3,
dated July 16, 2009) and resulted in reevaluation of the inspection thresholds
and repetitive intervals. The new data
and analysis require the repetitive
intervals be reduced from those
currently specified in Boeing Alert
Service Bulletin 737–53A1210, Revision
3, dated July 16, 2009. These new
repetitive intervals are defined in the
differences section of the NPRM.
Explanation of Relevant Service
Information
We have reviewed Boeing Alert
Service Bulletin 737–53A1210, Revision
2, dated March 3, 2009; and Boeing
Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009. Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001, was
referred to as the appropriate source of
service information for accomplishing
the actions in the existing AD.
Boeing Alert Service Bulletin 737–
53A1210, Revision 2, describes
procedures for, among other things,
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repetitive external detailed and eddy
current inspections for cracking of the
fuselage skin along certain chem-milled
lines, and corrective actions if
necessary. The corrective actions
include doing a time-limited repair or a
permanent repair, as applicable. After
installation of a time-limited repair, an
external detailed inspection is done of
the repaired area for cracks and loose or
missing fasteners. For airplanes on
which cracks are found, this service
bulletin recommends contacting Boeing
for repair instructions and repairing;
and, for airplanes on which loose or
damaged fasteners are found this service
bulletin specifies replacing any
damaged or loose fasteners. This service
bulletin adds an optional preventive
modification for Groups 3, 5, 6, and 8
at body station (BS) 500D through BS
520 on Model 737–300 airplanes, and
BS 482B through BS 520, stringer 12, on
Model 737–500 airplanes. This service
bulletin also reduces the effectivity
specified in Revision 1, and contains
editorial changes.
Boeing Alert Service Bulletin 737–
53A1210, Revision 3, clarifies certain
work instructions. This service bulletin
also specifies that more work is
necessary for airplanes on which the
actions in Boeing Alert Service Bulletin
737–53A1210, dated December 14,
2000; or Revision 1, dated October 25,
2001; were done. In addition, Revision
3 of this service bulletin adds the
airplanes that were incorrectly removed
from the effectivity in Revision 2 of this
service bulletin, which were not
identified until after Revision 2 of this
service bulletin was issued. Therefore,
the effectivity in Revision 3 of this
service bulletin is the same as the
effectivity in Revision 1 of this service
bulletin.
Boeing Alert Service Bulletin 737–
53A1210, Revision 3, specifies that the
repetitive inspection interval is 4,500
flight cycles.
certain actions in AD 2004–18–06; this
proposed AD specifies a compliance
time of 35,000 total flight cycles in
paragraph (s) of this AD.
Differences Between the Proposed AD
and Service Information
Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16,
2009, specifies to contact the
manufacturer for disposition of certain
repair conditions, but this proposed AD
would require repairing those
conditions in one of the following ways:
• In accordance with a method that
we approve; or
• Using data that meet the
certification basis of the airplane, and
that have been approved by the Boeing
Commercial Airplanes Organization
Designation Authorization (ODA) that
we have authorized to make those
findings.
Boeing Alert Service Bulletin 737–
53A1210, Revision 2, dated March 3,
2009, specifies that no airplanes were
added or removed from the effectivity;
however, the manufacturer has
informed us that there were airplanes
incorrectly removed in the
‘‘Identification by Customer, Customer
Code, Group and Variable Number’’
section in Paragraph 1.A.1 of Revision 2
of this service bulletin. In light of the
fact that Revision 3 of this service
bulletin includes those airplanes in its
effectivity, and includes all the actions
specified in Revision 2 of this service
bulletin, this proposed AD would
require that the new actions be done in
accordance with Revision 3 of this
service bulletin.
Paragraph 1.E of Boeing Alert Service
Bulletin 737–53A1210, Revision 3,
specifies a repetitive inspection interval
of 4,500 flight cycles; that interval is
expected to be reduced when this
service bulletin is revised. The
manufacturer has informed us that it has
re-evaluated the inspection interval
because it would not address the
FAA’s Determination and Requirements identified unsafe condition soon enough
of the Proposed AD
to ensure an acceptable level of safety
We have evaluated all pertinent
for the affected fleet. In light of this fact,
information and identified an unsafe
we find that a repetitive inspection
condition that is likely to develop on
interval of 1,800 flight cycles, for the
other airplanes of the same type design. actions specified in Tables 1 through 5,
For this reason, we are proposing this
represents an appropriate interval of
AD, which would supersede AD 2004–
time for affected airplanes to continue to
18–06 and would retain certain
operate without compromising safety.
Part 8 of the Accomplishment
requirements of the existing AD. This
Instructions of Boeing Alert Service
proposed AD would also require
Bulletin 737–53A1210, Revision 3,
accomplishing the actions specified in
specifies a post-repair inspection of the
the service information described
skin chem-milled crack repair at stringer
previously, except as discussed under
12; that inspection is not required by
‘‘Differences Between the Proposed AD
and Service Information.’’ This proposed this proposed AD. The damage tolerance
AD also reduces the compliance time of inspections specified in Table 7 of
Boeing Alert Service Bulletin 737–
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53A1210, Revision 3, dated July 16,
2009, may be used in support of
compliance with section 121.1109(c)(2)
or 129.109(c)(2) of the Federal Aviation
Regulations (14 CFR 121.1109(c)(2) or
14 CFR 129.109(c)(2)).
Explanation of Change to This Proposed
AD
Boeing Commercial Airplanes has
received an Organization Delegation
Authority (ODA), which replaces their
previous designation as a Designated
Engineering Representative (DER). We
have revised paragraphs (j) and (l)(2) of
this proposed AD to delegate the
authority to approve an alternative
method of compliance for any repair
required by this AD to the Boeing
Commercial Airplanes ODA.
Change to Existing AD
This proposed AD would retain
certain requirements of AD 2004–18–06.
Since AD 2004–18–06 was issued, the
AD format has been revised, and certain
paragraphs have been rearranged. As a
result, the corresponding paragraph
identifiers have changed in this
proposed AD, as listed in the following
table:
REVISED PARAGRAPH IDENTIFIERS
Requirement in AD
2004–18–06
Corresponding
requirement in this
proposed AD
paragraph (a)
paragraph (b)
paragraph (c)
paragraph (d)
paragraph (e)
paragraph (f)
paragraph (g)
paragraph (h)
paragraph (i)
paragraph (g)
paragraph (h)
paragraph (i)
paragraph (j)
paragraph (k)
paragraph (l)
paragraph (m)
paragraph (n)
paragraph (o)
We have revised paragraph (m) of this
proposed AD to specify that doing
paragraph (b) or (c), as applicable, of AD
2003–14–06, Amendment 39–13225,
after the effective date of this proposed
AD does not terminate any of the
actions required by paragraph (g) of this
proposed AD. Recent reports of cracking
have shown that a detailed inspection
alone is not sufficient to find cracks in
the fuselage skin. The cracking begins
on the internal surface of the skin and
grows outward, not becoming visible on
the external surface until the crack is at
least three inches in length. Actions
accomplished before the effective date
of this AD in accordance with AD 2003–
14–06, which terminate certain
requirements of paragraph (g) of this
proposed AD, are reinstated with the
new requirements specified in
paragraph (p) of this proposed AD.
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Costs of Compliance
There are about 903 airplanes of U.S.
registry affected by AD 2004–18–06.
The inspections of the crown area that
are required by AD 2004–18–06 take
about 94 work hours per airplane to
accomplish, at an average labor rate of
$85 per work hour. Based on these
figures, the estimated cost of the
currently required inspections is $7,990
per airplane, per inspection cycle.
The inspections of the lower lobe area
that are required by AD 2004–18–06
take about 96 work hours per airplane
to accomplish, at an average labor rate
of $85 per work hour. Based on these
figures, the estimated cost of the
currently required inspections is $8,160
per airplane, per inspection cycle.
Should an operator elect to install the
preventive modification specified in AD
2004–18–06 it will take about 108 work
hours per airplane to accomplish, at an
average labor rate of $85 per work hour.
Based on these figures, the estimated
cost of the modification is $9,180 per
airplane.
The new proposed inspections would
affect about 701 airplanes of U.S.
registry.
The new proposed inspections would
take about 27 work hours per airplane,
at an average labor rate of $85 per work
hour. Based on these figures, the
estimated cost of the new actions
specified in this proposed AD for U.S.
operators is $1,608,795, or $2,295 per
airplane, per inspection cycle.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation
safety, Incorporation by reference,
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.
Authority for This Rulemaking
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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.
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),
(3) Will not affect intrastate aviation
in Alaska, and
(4) 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.
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.
§ 39.13
[Amended]
2. The FAA amends § 39.13 by
removing amendment 39–13784 (69 FR
54206, September 8, 2004) and adding
the following new AD:
The Boeing Company: Docket No. FAA–
2011–0155; Directorate Identifier 2009–
NM–141–AD.
Comments Due Date
(a) The FAA must receive comments on
this AD action by April 22, 2011.
Affected ADs
(b) This AD supersedes AD 2004–18–06,
Amendment 39–13784. AD 2002–07–08,
Amendment 39–12702; and AD 2003–14–06,
Amendment 39–13225; affect this AD.
Regulatory Findings
Applicability
(c) This AD applies to The Boeing
Company Model 737–200, –200C, –300,
–400, and –500 series airplanes, certificated
in any category, as listed in Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009.
We have determined that this
proposed AD would not have federalism
implications under Executive Order
Subject
(d) Air Transport Association (ATA) of
America Code 53: Fuselage.
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Unsafe Condition
(e) This AD results from new findings of
vertical cracks along chem-milled steps
adjacent to the butt joints. The Federal
Aviation Administration is issuing this AD to
detect and correct fatigue cracking of the skin
panels, which could result in sudden fracture
and failure of the skin panels of the fuselage,
and consequent rapid decompression of the
airplane.
Compliance
(f) You are responsible for having the
actions required by this AD performed within
the compliance times specified, unless the
actions have already been done.
Restatement of Certain Requirements of AD
2004–18–06, Amendment 39–13784
External Detailed and Eddy Current
Inspections
(g) For Groups 1 through 5 airplanes
identified in Boeing Alert Service Bulletin
737–53A1210, Revision 1, dated October 25,
2001: Before the accumulation of 35,000 total
flight cycles, or within 4,500 flight cycles
after October 13, 2004 (the effective date of
AD 2004–18–06), whichever is later, do
external detailed and eddy current
inspections of the crown area and other
known areas of fuselage skin cracking, per
Part 1 and Figure 1 of the Work Instructions
of Boeing Alert Service Bulletin 737–
53A1210, Revision 1, dated October 25, 2001;
or in accordance with Part 1 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. As of the effective date
of this AD, use only Boeing Alert Service
Bulletin 737–53A1210, Revision 3, dated July
16, 2009. Repeat the external detailed and
eddy current inspections at intervals not to
exceed 4,500 flight cycles until paragraph (i),
(j)(1)(ii), (k), (l), or (m) of this AD has been
done, as applicable. Although paragraph 1.D.
of Boeing Alert Service Bulletin 737–
53A1210, Revision 1, dated October 25, 2001,
references a reporting requirement, such
reporting is not required by this AD.
Accomplishing the actions required by
paragraph (p) or (q) of this AD ends the
repetitive requirements in this paragraph.
Note 1: 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.’’
(h) For all airplanes identified in Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001, do an
external detailed inspection of the lower lobe
area and section 41 of the fuselage for
cracking, per Part 2 and Figure 2 of the Work
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 1, dated October 25,
2001; or in accordance with Part 4 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
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dated July 16, 2009. As of the effective date
of this AD, use only Boeing Alert Service
Bulletin 737–53A1210, Revision 3, dated July
16, 2009. At the earlier of the times specified
in paragraphs (h)(1) and (h)(2) of this AD, do
the inspection specified in this paragraph
and repeat the inspection thereafter at
intervals not to exceed 4,500 flight cycles
until paragraph (j)(2) or (k) of this AD has
been done, as applicable. Accomplishing the
actions required by paragraph (s) of this AD
ends the requirements in this paragraph.
(1) Within 9,000 flight cycles after doing
the most recent internal detailed inspection.
(2) Within 4,500 flight cycles after October
13, 2004, or before the accumulation of
40,000 total flight cycles, whichever occurs
later.
Preventive Modification
(i) For Groups 3 and 5 airplanes identified
in Boeing Alert Service Bulletin 737–
53A1210, Revision 1, dated October 25, 2001:
If no cracking is found during any inspection
required by paragraph (g) of this AD, doing
the preventive modification of the chemmilled pockets in the upper skin as specified
in Part 5 of the Work Instructions of Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001; or as
specified in Part 7 of the Work Instructions
of Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16, 2009,
except as required by paragraph (x) of this
AD; ends the repetitive external detailed and
eddy current inspections required by
paragraph (g) of this AD for the modified area
only. As of the effective date of this AD, use
only Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16, 2009.
Corrective Actions
(j) If any cracking is found during any
inspection required by paragraph (g), (h), (p),
(q), or (s) of this AD, before further flight, do
the actions specified in paragraphs (j)(1) and
(j)(2) of this AD, as applicable, in accordance
with the Work Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 1,
dated October 25, 2001; or Revision 3, dated
July 16, 2009. As of the effective date of this
AD, use only Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009. Where Boeing Alert Service Bulletin
737–53A1210, Revision 1, dated October 25,
2001; or Revision 3, dated July 16, 2009;
specify to contact Boeing for repair
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 if it is approved by the Boeing
Commercial Airplanes Organization
Designation Authorization (ODA) or any
other person 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.
(1) Except as provided by paragraph (k) of
this AD, for cracking of the crown area, do
the repair specified in either paragraph
(j)(1)(i) or (j)(1)(ii) of this AD.
(i) Do a time-limited repair per Part 4 of the
Work Instructions of Boeing Alert Service
Bulletin 737–53A1210, Revision 1, dated
October 25, 2001; or in accordance with Part
6 of the Work Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009, except as required by
paragraph (x) of this AD, then do the actions
required by paragraph (l) of this AD at the
times specified in that paragraph.
(ii) Do a permanent repair per Part 3 of the
Work Instructions of Boeing Alert Service
Bulletin 737–53A1210, Revision 1, dated
October 25, 2001; or in accordance with Part
5 of the Work Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. Installation of a
permanent repair ends the repetitive
inspections required by paragraph (g) of this
AD for the repaired area only. Installation of
the lap joint repair specified in paragraph (g)
of AD 2002–07–08, Amendment 39–12702, is
considered acceptable for compliance with
the corresponding permanent repair specified
in this paragraph for the repaired areas only.
(2) Except as provided by paragraph (k) of
this AD, for cracking of the lower lobe area
and Section 41, repair per Part 2 of the Work
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 1, dated October 25,
2001; or in accordance with paragraph
(j)(2)(i) or (j)(2)(ii) of this AD.
Accomplishment of this repair ends the
repetitive inspections required by paragraph
(h) of this AD for the repaired area only. As
of the effective date of this, do the repair
specified in paragraph (j)(2)(i) or (j)(2)(ii) of
this AD.
(i) Do a time-limited repair in accordance
with Part 6 of the Work Instructions of
Boeing Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009, except as
required by paragraph (x) of this AD, then do
the actions required by paragraph (l) of this
AD at the times specified in that paragraph.
(ii) Do a permanent repair in accordance
with Part 5 of the Accomplishment
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009.
Optional Repair Method
(k) For cracking in any area specified in
paragraphs (j)(1) and (j)(2) of this AD within
the limitations of the applicable structural
repair manual (SRM) specified in table 1 of
this AD, repair any cracks per the applicable
SRM specified in table 1 of this AD.
Accomplishment of the applicable repair
terminates the repetitive inspections required
by paragraphs (g) and (h) of this AD for the
repaired area only.
TABLE 1—SRM REFERENCES
Model
Subject/figure
737–100, –200 series airplanes ...........
53–30–3, Figure 48 .......
102
737–300 series airplanes .....................
737–400 series airplanes .....................
737–500 series airplanes .....................
53–00–01, Figure 229 ...
53–00–01, Figure 231 ...
53–00–01, Figure 229 ...
92
75
70
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Follow-on and Corrective Actions
(l) If a time-limited repair is done, as
specified in paragraph (j)(1)(i) or (j)(2)(i) of
this AD: Do the actions specified in
paragraphs (l)(1), (l)(2), and (l)(3) of this AD,
at the times specified in paragraphs (l)(1),
(l)(2), and (l)(3) of this AD, per the Work
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 1, dated October 25,
2001; or Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16, 2009.
(1) Within 3,000 flight cycles after doing
the repair: Do the actions specified in
paragraph (l)(1)(i) or (l)(1)(ii) of this AD.
Then repeat the applicable inspection
specified in paragraph (l)(1)(i) or (l)(1)(ii) of
this AD at intervals not to exceed 3,000 flight
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Revision
Date
September 10, 2010
November 10, 2010 ..
November 10, 2010 ..
November 10, 2010 ..
cycles until permanent rivets are installed in
the repaired area, which ends the repetitive
inspections for this paragraph. As of the
effective date of this AD, do only the
inspections specified in paragraph (l)(1)(ii) of
this AD.
(i) For repairs done before the effective
date of this AD: Do a detailed inspection of
the repaired area for loose fasteners per Part
4 of the Work Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 1,
dated October 25, 2001, or do the actions
specified in paragraph (l)(1)(ii) of this AD. If
any loose fastener is found, before further
flight, replace with a new fastener per Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001.
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SRM
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Boeing 737–100/–200 SRM, D6–
15565.
Boeing 737–300 SRM D6–37635.
Boeing 737–400 SRM, D6–38246.
Boeing 737–500 SRM, D6–38441.
(ii) For repairs done after the effective date
of this AD: Do a detailed inspection of the
repaired area for loose, damaged, and missing
fasteners in accordance with Part 6 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. If any loose, missing, or
damaged fastener is found, before further
flight, replace with a new fastener in
accordance with Boeing Alert Service
Bulletin 737–53A1210, Revision 3, dated July
16, 2009.
(2) At the applicable time specified in
paragraph (l)(2)(i) and (l)(2)(ii) of this AD: Do
inspections of the repaired area for cracking
per Part 4 of the Work Instructions of Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001; or in
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accordance with Part 6 of the Work
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009. If any cracking is found, before further
flight, repair per a method approved by the
Manager, Seattle ACO, or per data meeting
the type certification basis of the airplane if
it is approved by the Boeing Commercial
Airplanes ODA or any other person
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.
(i) For repairs done before the effective
date of this AD: Within 4,000 flight cycles
after doing the repair, do the inspections.
(ii) For repairs done on or after the
effective date of this AD: Within 3,000 flight
cycles after doing the repair, do the
inspections.
(3) At the earlier of the times specified in
paragraphs (l)(3)(i) and (l)(3)(ii) of this AD:
Make the repair permanent per Part 4 and
Figure 20 of the Work Instructions of Boeing
Alert Service Bulletin 737–53A1210,
Revision 1, dated October 25, 2001, or do the
permanent repair in accordance with Part 5
of the Work Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009, which ends the
repetitive inspections for the repaired area
only. As of the effective date of this AD,
make the repair permanent in accordance
with Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16, 2009.
(i) Within 10,000 flight cycles after doing
the repair in accordance with Boeing Alert
Service Bulletin 737–53A1210, Revision 1,
dated October 25, 2001.
(ii) At the later of the times specified in
paragraphs (l)(3)(ii)(A) and (l)(3)(ii)(B) of this
AD.
(A) Within 6,000 flight cycles after doing
the repair.
(B) Within 1,000 flight cycles after the
effective date of this AD.
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Optional Terminating Action for Repetitive
Eddy Current Inspections if Done Before the
Effective Date of This AD
(m) Accomplishment of paragraph (b) or
(c), as applicable, of AD 2003–14–06,
Amendment 39–13225, before the effective
date of this AD ends the repetitive eddy
current inspections required by paragraph (g)
of this AD for that skin panel only; however,
the repetitive external detailed inspections
required by paragraph (g) of this AD are still
required for all areas. As of the effective date
of this AD, accomplishing paragraph (b) or
(c), as applicable, of AD 2003–14–06,
Amendment 39–13225, does not end the
repetitive eddy current inspections required
by paragraph (g) of this AD.
Credit for Actions Done per Previous Service
Bulletin
(n) Inspections, repairs, and preventive
modifications done before October 13, 2004,
in accordance with Boeing Alert Service
Bulletin 737–53A1210, dated December 14,
2000, are acceptable for compliance with the
corresponding actions required by
paragraphs (g), (h), (i), (j), (k), and (l) of this
AD.
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19:07 Mar 07, 2011
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Exception to Service Bulletin Procedures
(o) For airplanes subject to the
requirements of paragraphs (g), (h), (p), and
(q) of this AD: Inspections are not required
in areas that are spanned by an FAAapproved repair that has a minimum of 3
rows of fasteners above and below the chemmilled step. If an external doubler covers the
chem-milled step, but does not span it by a
minimum of 3 rows of fasteners above and
below, in lieu of requesting approval for an
alternative method of compliance (AMOC),
one option to comply with the inspection
requirement of paragraphs (g) and (h) of this
AD is to inspect all chem-milled steps
covered by the repair using internal
nondestructive test (NDT) methods in
accordance with Part 6 of the Boeing 737
Non-Destructive Test NDT Manual. As of the
effective date of this AD, inspect in
accordance with Boeing Alert Service
Bulletin 737–53A1210, Revision 3, dated July
16, 2009.
New Requirements of This AD
Repetitive Inspections and Corrective Actions
if Necessary
(p) For Groups 1 through 5 and 9 through
21 airplanes identified in Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009, on which the inspections
required by paragraph (g) of this AD have
been done before the effective date of this
AD: At the applicable time specified in
paragraph (p)(1) or (p)(2) of this AD, do
external detailed and eddy current
inspections of the crown area and other
known areas of fuselage skin cracking in
accordance with Part 1 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009; except as provided by
paragraph (o) of this AD. Repeat the external
detailed and eddy current inspections
thereafter at intervals not to exceed 1,800
flight cycles. Accomplishing the inspections
required by this paragraph ends the repetitive
inspections required by paragraph (g) of this
AD. Before further flight, do all applicable
corrective actions as specified in paragraph
(j) of this AD.
(1) For airplanes on which any action
specified in paragraph (i), (j)(1)(ii), (k), (l), or
(m) of this AD has been done: Within 1,800
flight cycles after the effective date of this
AD.
(2) For airplanes on which actions
specified in paragraphs (i), (j)(1)(ii), (k), (l),
and (m) of this AD have not been done:
Within 4,500 flight cycles after doing the
most recent inspection required by paragraph
(g) of this AD, or within 1,800 flight cycles
after the effective date of this AD, whichever
is later.
(q) For Groups 1 through 5 and 9 through
21 airplanes identified in Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009; on which the inspections
required by paragraph (g) of this AD have not
been done before the effective date of this
AD: Before the accumulation of 35,000 total
flight cycles, or within 1,800 flight cycles
after the effective date of this AD, whichever
is later, do external detailed and eddy current
inspections of the crown area and other
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12623
known areas of fuselage skin cracking in
accordance with Part 1 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. Repeat the external
detailed and eddy current inspections
thereafter at intervals not to exceed 1,800
flight cycles. Before further flight, do all
applicable corrective actions as specified in
paragraph (j) of this AD.
(r) For Group 1 through 5 and 9 through
21 airplanes identified in Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009: At the later of the times
specified in paragraphs (r)(1) and (r)(2) of this
AD, do external detailed and eddy current
inspections for vertical cracks in the fuselage
skin along the chem-milled steps of the butt
joints, in accordance with Part 3 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. Repeat the inspections
thereafter at intervals not to exceed 1,800
flight cycles or 1,800 flight hours, whichever
occurs first. If any cracking is found, before
further flight, repair in accordance with Part
5 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009. Doing the
repair terminates the repetitive inspections
specified in this paragraph for the repaired
area only.
(1) Before the accumulation of 55,000 total
flight cycles or 55,000 total flight hours,
whichever occurs first.
(2) Within 1,800 flight cycles or 1,800
flight hours after the effective date of this AD,
whichever occurs first.
(s) For Groups 1 through 21 airplanes
identified in Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009: Before the accumulation of 35,000 total
flight cycles or within 4,500 flight cycles
after the effective date of this AD, whichever
is later, do external detailed and eddy current
inspections for horizontal cracks along the
chem-milled lines of the fuselage skin of the
lower lobe area and section 41, in accordance
with Part 4 of the Accomplishment
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009; except as required by paragraph (u) of
this AD. Repeat the inspections thereafter at
intervals not to exceed 4,500 flight cycles.
Accomplishing the inspections required by
this paragraph ends the repetitive inspections
required by paragraph (h) of this AD. Before
further flight, do all applicable corrective
actions as specified in paragraph (j) of this
AD.
(t) For Groups 4, 11, and 16 airplanes
identified in Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009: Before the accumulation of 25,000 total
flight cycles or within 4,500 flight cycles
after the effective date of this AD, whichever
is later, do external detailed and eddy current
inspections for horizontal cracks along the
chem-milled lines of the fuselage skin of the
fuselage window belt area in accordance with
Part 2 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009. Repeat the
inspections thereafter at intervals not to
exceed 4,500 flight cycles. If any cracking is
found, before further flight, repair using a
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method approved in accordance with
paragraph (y) of this AD.
(u) For Groups 3, 5, 9, 10, 12, 14, 15, 17,
18, 19, 20, and 21 airplanes identified in
Boeing Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009: Do the
actions specified in paragraph (u)(1) or (u)(2)
of this AD, as applicable.
(1) For airplanes on which the inspections
required by paragraph (g) of this AD have
been done before the effective date of this
AD: Within 4,500 flight cycles after doing the
most recent inspection required by paragraph
(g) of this AD, do external detailed and eddy
current inspections for horizontal cracks
along the chem-milled lines of the fuselage
skin of the fuselage window belt area in
accordance with Part 2 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009. Repeat the inspections
thereafter at intervals not to exceed 4,500
flight cycles. If any cracking is found, before
further flight, repair in accordance with Part
8 of Boeing Alert Service Bulletin 737–
53A1210, Revision 3, dated July 16, 2009,
except as required by paragraph (x) of this
AD.
(2) For airplanes on which the inspections
required by paragraph (g) of this AD have not
been done before the effective date of this
AD: Before the accumulation of 25,000 total
flight cycles or within 4,500 flight cycles
after the effective date of this AD, whichever
is later, do external detailed and eddy current
inspections for horizontal cracks along the
chem-milled lines of the fuselage skin of the
fuselage window belt area in accordance with
Part 2 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737–53A1210,
Revision 3, dated July 16, 2009. Repeat the
inspections thereafter at intervals not to
exceed 4,500 flight cycles. If any cracking is
found, before further flight, repair in
accordance with Part 8 of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009, except as required by
paragraph (x) of this AD.
Repair and Preventive Modification
(v) For airplanes on which cracking is
found during any inspection required by
paragraph (p), (q), (r), or (s) of this AD, as
applicable, doing the repair of the chemmilled area in the skin, as specified in Part
5 or Part 6 of the Accomplishment
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009, ends the repetitive external detailed
and eddy current inspections required by
paragraph (p), (q), (r), or (s) of this AD, as
applicable, for the repaired area only.
Note 2: Part 8 of the Accomplishment
Instructions of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009, specifies a post-repair inspection of the
skin chem-milled crack repair at stringer 12;
that inspection is not required by this AD.
The damage tolerance inspections specified
in Table 7 of Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009, may be used in support of compliance
with section 121.1109(c)(2) or 129.109(c)(2)
of the Code of Federal Regulations (14 CFR
121.1109(c)(2) or 14 CFR 129.109(c)(2)).
(w) For airplanes on which no cracking is
found during any inspection required by
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paragraph (p) or (q) of this AD, as applicable,
doing the preventive modification of the
chem-milled areas in the skin at stringer
S–12, as specified in Part 7 of the
Accomplishment Instructions of Boeing Alert
Service Bulletin 737–53A1210, Revision 3,
dated July 16, 2009, except as required by
paragraph (x) of this AD, ends the repetitive
external detailed and eddy current
inspections required by paragraph (p) or (q)
of this AD, as applicable, for the modified
area only.
DEPARTMENT OF TRANSPORTATION
Exception to Boeing Alert Service Bulletin
737–53A1210, Revision 3
AGENCY:
(x) Where Boeing Alert Service Bulletin
737–53A1210, Revision 3, dated July 16,
2009, specifies to contact Boeing for repair
instructions, before further flight, repair
using a method approved in accordance with
paragraph (y) of this AD.
Alternative Methods of Compliance
(AMOCs)
(y)(1) The Manager, Seattle Aircraft
Certification Office (ACO), FAA, has the
authority to approve AMOCs for this AD, if
requested using the procedures found in 14
CFR 39.19. In accordance with 14 CFR 39.19,
send your request to your principal inspector
or local Flight Standards District Office, as
appropriate. If sending information directly
to the manager of the ACO, send it to the
attention of the person identified in the
Related Information section of this AD.
Information may be e-mailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov.
(2) Before using any approved AMOC,
notify your appropriate principal inspector,
or lacking a principal inspector, the manager
of the local flight standards district office/
certificate holding district office.
(3) An AMOC that provides an acceptable
level of safety may be used for any repair
required by this AD if it is approved by the
Boeing Commercial Airplanes ODA that 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.
(4) AMOCs approved previously in
accordance with AD 2004–18–06,
Amendment 39–13784, are approved as
AMOCs for the corresponding provisions of
this AD.
Related Information
(z) For more information about this AD,
contact Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM–120S, FAA, Seattle
Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98057–
3356; telephone (425) 917–6447; fax (425)
917–6590; e-mail: wayne.lockett@faa.gov.
Issued in Renton, Washington on February
22, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane
Directorate, Aircraft Certification Service.
[FR Doc. 2011–5159 Filed 3–7–11; 8:45 am]
BILLING CODE 4910–13–P
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Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2011–0152; Directorate
Identifier 2010–NM–079–AD]
RIN 2120–AA64
Airworthiness Directives; DassaultAviation Model FALCON 7X Airplanes
Federal Aviation
Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking
(NPRM).
We propose to adopt a new
airworthiness directive (AD) for the
products listed above. This proposed
AD results from mandatory continuing
airworthiness information (MCAI)
originated by an aviation authority of
another country to identify and correct
an unsafe condition on an aviation
product. The MCAI describes the unsafe
condition as:
SUMMARY:
On some Falcon 7X aeroplanes, it has been
determined potential low clearance between
electrical wiring or hydraulic pipe and
nearby structure. Although no in service
incident has been reported, there is no
certainty that the minimum clearances would
be maintained over time. In the worst case,
interference or contact with structure might
occur and lead to electrical short circuits or
fluid leakage, potentially resulting in loss of
several functions essential for safe flight.
*
*
*
*
*
The proposed AD would require
actions that are intended to address the
unsafe condition described in the MCAI.
DATES: We must receive comments on
this proposed AD by April 22, 2011.
ADDRESSES: You may send comments by
any of the following methods:
• Federal eRulemaking Portal: Go to
https://www.regulations.gov. Follow the
instructions for submitting comments.
• Fax: (202) 493–2251.
• Mail: U.S. Department of
Transportation, Docket Operations,
M–30, West Building Ground Floor,
Room W12–140, 1200 New Jersey
Avenue SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of
Transportation, Docket Operations,
M–30, West Building Ground Floor,
Room W12–40, 1200 New Jersey
Avenue SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through
Friday, except Federal holidays.
For service information identified in
this proposed AD, contact Dassault
Falcon Jet, P.O. Box 2000, South
Hackensack, New Jersey 07606;
telephone 201–440–6700; Internet
https://www.dassaultfalcon.com. You
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]]>Agencies
[Federal Register Volume 76, Number 45 (Tuesday, March 8, 2011)]
[Proposed Rules]
[Pages 12619-12624]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-5159]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2011-0155; Directorate Identifier 2009-NM-141-AD]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company 737-200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to supersede an existing airworthiness
directive (AD) that applies to certain Boeing Model 737-200, -200C, -
300, -400, and -500 series airplanes. The existing AD currently
requires repetitive inspections to find fatigue cracking of certain
upper and lower skin panels of the fuselage, and follow-on and
corrective actions if necessary. The existing AD also includes a
terminating action for the repetitive inspections of certain modified
or repaired areas only. This proposed AD would add new inspections for
cracking of the fuselage skin along certain chem-milled lines, and
corrective actions if necessary. This proposed AD would also reduce
certain thresholds and intervals required by the existing AD. This
proposed AD results from reports of new findings of vertical cracks in
the fuselage skin along the chem-milled steps adjacent to the butt
joints. We are proposing this AD to detect and correct fatigue cracking
of the skin panels, which could result in sudden fracture and failure
of the skin panels of the fuselage, and consequent rapid decompression
of the airplane.
DATES: We must receive comments on this proposed AD by April 22, 2011.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this proposed AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com;
Internet https://www.myboeingfleet.com. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information
on the availability of this material at the FAA, call 425-227-1221.
Examining the AD Docket
You may examine the AD docket on the Internet at https://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6447; fax (425) 917-6590; e-mail: wayne.lockett@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2011-0155;
Directorate Identifier 2009-NM-141-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to https://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
On August 26, 2004, we issued AD 2004-18-06, Amendment 39-13784 (69
FR 54206, September 8, 2004), for certain Model 737-200, -200C, -300, -
400, and -500 series airplanes. That AD requires repetitive inspections
to find fatigue cracking of certain upper and lower skin panels of the
fuselage, and follow-on and corrective actions if necessary. That AD
also includes a terminating action for the repetitive inspections of
certain modified or repaired areas only. That AD resulted from reports
indicating new findings of cracks were found along the edges of the
chem-milled pockets in the upper skin at certain stringers. We issued
that AD to find and fix fatigue cracking of the skin panels, which
could result in sudden fracture and failure of the skin panels of the
fuselage, and consequent rapid decompression of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 2004-18-06, we have received reports of new
findings of vertical cracks in the fuselage skin along the chem-milled
steps adjacent to the butt joints and at certain body stations on
airplanes with between 45,100 flight cycles (65,200 flight hours) and
67,400 flight cycles (70,800 flight hours).
A decompression event connected to chem-milled steps occurred in
July 2009 (after issuance of Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009) and resulted in re-evaluation of the
inspection thresholds and repetitive intervals. The new data and
analysis require the repetitive intervals be reduced from those
currently specified in Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009. These new repetitive intervals are
defined in the differences section of the NPRM.
Explanation of Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-53A1210,
Revision 2, dated March 3, 2009; and Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. Boeing Alert Service Bulletin
737-53A1210, Revision 1, dated October 25, 2001, was referred to as the
appropriate source of service information for accomplishing the actions
in the existing AD.
Boeing Alert Service Bulletin 737-53A1210, Revision 2, describes
procedures for, among other things,
[[Page 12620]]
repetitive external detailed and eddy current inspections for cracking
of the fuselage skin along certain chem-milled lines, and corrective
actions if necessary. The corrective actions include doing a time-
limited repair or a permanent repair, as applicable. After installation
of a time-limited repair, an external detailed inspection is done of
the repaired area for cracks and loose or missing fasteners. For
airplanes on which cracks are found, this service bulletin recommends
contacting Boeing for repair instructions and repairing; and, for
airplanes on which loose or damaged fasteners are found this service
bulletin specifies replacing any damaged or loose fasteners. This
service bulletin adds an optional preventive modification for Groups 3,
5, 6, and 8 at body station (BS) 500D through BS 520 on Model 737-300
airplanes, and BS 482B through BS 520, stringer 12, on Model 737-500
airplanes. This service bulletin also reduces the effectivity specified
in Revision 1, and contains editorial changes.
Boeing Alert Service Bulletin 737-53A1210, Revision 3, clarifies
certain work instructions. This service bulletin also specifies that
more work is necessary for airplanes on which the actions in Boeing
Alert Service Bulletin 737-53A1210, dated December 14, 2000; or
Revision 1, dated October 25, 2001; were done. In addition, Revision 3
of this service bulletin adds the airplanes that were incorrectly
removed from the effectivity in Revision 2 of this service bulletin,
which were not identified until after Revision 2 of this service
bulletin was issued. Therefore, the effectivity in Revision 3 of this
service bulletin is the same as the effectivity in Revision 1 of this
service bulletin.
Boeing Alert Service Bulletin 737-53A1210, Revision 3, specifies
that the repetitive inspection interval is 4,500 flight cycles.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to develop on other airplanes of the
same type design. For this reason, we are proposing this AD, which
would supersede AD 2004-18-06 and would retain certain requirements of
the existing AD. This proposed AD would also require accomplishing the
actions specified in the service information described previously,
except as discussed under ``Differences Between the Proposed AD and
Service Information.'' This proposed AD also reduces the compliance
time of 40,000 total flight cycles for doing certain actions in AD
2004-18-06; this proposed AD specifies a compliance time of 35,000
total flight cycles in paragraph (s) of this AD.
Differences Between the Proposed AD and Service Information
Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009, specifies to contact the manufacturer for disposition of
certain repair conditions, but this proposed AD would require repairing
those conditions in one of the following ways:
In accordance with a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) that we have
authorized to make those findings.
Boeing Alert Service Bulletin 737-53A1210, Revision 2, dated March
3, 2009, specifies that no airplanes were added or removed from the
effectivity; however, the manufacturer has informed us that there were
airplanes incorrectly removed in the ``Identification by Customer,
Customer Code, Group and Variable Number'' section in Paragraph 1.A.1
of Revision 2 of this service bulletin. In light of the fact that
Revision 3 of this service bulletin includes those airplanes in its
effectivity, and includes all the actions specified in Revision 2 of
this service bulletin, this proposed AD would require that the new
actions be done in accordance with Revision 3 of this service bulletin.
Paragraph 1.E of Boeing Alert Service Bulletin 737-53A1210,
Revision 3, specifies a repetitive inspection interval of 4,500 flight
cycles; that interval is expected to be reduced when this service
bulletin is revised. The manufacturer has informed us that it has re-
evaluated the inspection interval because it would not address the
identified unsafe condition soon enough to ensure an acceptable level
of safety for the affected fleet. In light of this fact, we find that a
repetitive inspection interval of 1,800 flight cycles, for the actions
specified in Tables 1 through 5, represents an appropriate interval of
time for affected airplanes to continue to operate without compromising
safety.
Part 8 of the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1210, Revision 3, specifies a post-repair inspection of
the skin chem-milled crack repair at stringer 12; that inspection is
not required by this proposed AD. The damage tolerance inspections
specified in Table 7 of Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009, may be used in support of compliance
with section 121.1109(c)(2) or 129.109(c)(2) of the Federal Aviation
Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(c)(2)).
Explanation of Change to This Proposed AD
Boeing Commercial Airplanes has received an Organization Delegation
Authority (ODA), which replaces their previous designation as a
Designated Engineering Representative (DER). We have revised paragraphs
(j) and (l)(2) of this proposed AD to delegate the authority to approve
an alternative method of compliance for any repair required by this AD
to the Boeing Commercial Airplanes ODA.
Change to Existing AD
This proposed AD would retain certain requirements of AD 2004-18-
06. Since AD 2004-18-06 was issued, the AD format has been revised, and
certain paragraphs have been rearranged. As a result, the corresponding
paragraph identifiers have changed in this proposed AD, as listed in
the following table:
Revised Paragraph Identifiers
------------------------------------------------------------------------
Corresponding requirement in this
Requirement in AD 2004-18-06 proposed AD
------------------------------------------------------------------------
paragraph (a) paragraph (g)
paragraph (b) paragraph (h)
paragraph (c) paragraph (i)
paragraph (d) paragraph (j)
paragraph (e) paragraph (k)
paragraph (f) paragraph (l)
paragraph (g) paragraph (m)
paragraph (h) paragraph (n)
paragraph (i) paragraph (o)
------------------------------------------------------------------------
We have revised paragraph (m) of this proposed AD to specify that
doing paragraph (b) or (c), as applicable, of AD 2003-14-06, Amendment
39-13225, after the effective date of this proposed AD does not
terminate any of the actions required by paragraph (g) of this proposed
AD. Recent reports of cracking have shown that a detailed inspection
alone is not sufficient to find cracks in the fuselage skin. The
cracking begins on the internal surface of the skin and grows outward,
not becoming visible on the external surface until the crack is at
least three inches in length. Actions accomplished before the effective
date of this AD in accordance with AD 2003-14-06, which terminate
certain requirements of paragraph (g) of this proposed AD, are
reinstated with the new requirements specified in paragraph (p) of this
proposed AD.
[[Page 12621]]
Costs of Compliance
There are about 903 airplanes of U.S. registry affected by AD 2004-
18-06.
The inspections of the crown area that are required by AD 2004-18-
06 take about 94 work hours per airplane to accomplish, at an average
labor rate of $85 per work hour. Based on these figures, the estimated
cost of the currently required inspections is $7,990 per airplane, per
inspection cycle.
The inspections of the lower lobe area that are required by AD
2004-18-06 take about 96 work hours per airplane to accomplish, at an
average labor rate of $85 per work hour. Based on these figures, the
estimated cost of the currently required inspections is $8,160 per
airplane, per inspection cycle.
Should an operator elect to install the preventive modification
specified in AD 2004-18-06 it will take about 108 work hours per
airplane to accomplish, at an average labor rate of $85 per work hour.
Based on these figures, the estimated cost of the modification is
$9,180 per airplane.
The new proposed inspections would affect about 701 airplanes of
U.S. registry.
The new proposed inspections would take about 27 work hours per
airplane, at an average labor rate of $85 per work hour. Based on these
figures, the estimated cost of the new actions specified in this
proposed AD for U.S. operators is $1,608,795, or $2,295 per airplane,
per inspection cycle.
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 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.
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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, 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 removing amendment 39-13784 (69 FR
54206, September 8, 2004) and adding the following new AD:
The Boeing Company: Docket No. FAA-2011-0155; Directorate Identifier
2009-NM-141-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by April 22,
2011.
Affected ADs
(b) This AD supersedes AD 2004-18-06, Amendment 39-13784. AD
2002-07-08, Amendment 39-12702; and AD 2003-14-06, Amendment 39-
13225; affect this AD.
Applicability
(c) This AD applies to The Boeing Company Model 737-200, -200C,
-300, -400, and -500 series airplanes, certificated in any category,
as listed in Boeing Alert Service Bulletin 737-53A1210, Revision 3,
dated July 16, 2009.
Subject
(d) Air Transport Association (ATA) of America Code 53:
Fuselage.
Unsafe Condition
(e) This AD results from new findings of vertical cracks along
chem-milled steps adjacent to the butt joints. The Federal Aviation
Administration is issuing this AD to detect and correct fatigue
cracking of the skin panels, which could result in sudden fracture
and failure of the skin panels of the fuselage, and consequent rapid
decompression of the airplane.
Compliance
(f) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Restatement of Certain Requirements of AD 2004-18-06, Amendment 39-
13784
External Detailed and Eddy Current Inspections
(g) For Groups 1 through 5 airplanes identified in Boeing Alert
Service Bulletin 737-53A1210, Revision 1, dated October 25, 2001:
Before the accumulation of 35,000 total flight cycles, or within
4,500 flight cycles after October 13, 2004 (the effective date of AD
2004-18-06), whichever is later, do external detailed and eddy
current inspections of the crown area and other known areas of
fuselage skin cracking, per Part 1 and Figure 1 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
1, dated October 25, 2001; or in accordance with Part 1 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. As of the effective date
of this AD, use only Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009. Repeat the external detailed and
eddy current inspections at intervals not to exceed 4,500 flight
cycles until paragraph (i), (j)(1)(ii), (k), (l), or (m) of this AD
has been done, as applicable. Although paragraph 1.D. of Boeing
Alert Service Bulletin 737-53A1210, Revision 1, dated October 25,
2001, references a reporting requirement, such reporting is not
required by this AD. Accomplishing the actions required by paragraph
(p) or (q) of this AD ends the repetitive requirements in this
paragraph.
Note 1: 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.''
(h) For all airplanes identified in Boeing Alert Service
Bulletin 737-53A1210, Revision 1, dated October 25, 2001, do an
external detailed inspection of the lower lobe area and section 41
of the fuselage for cracking, per Part 2 and Figure 2 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
1, dated October 25, 2001; or in accordance with Part 4 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3,
[[Page 12622]]
dated July 16, 2009. As of the effective date of this AD, use only
Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009. At the earlier of the times specified in paragraphs (h)(1)
and (h)(2) of this AD, do the inspection specified in this paragraph
and repeat the inspection thereafter at intervals not to exceed
4,500 flight cycles until paragraph (j)(2) or (k) of this AD has
been done, as applicable. Accomplishing the actions required by
paragraph (s) of this AD ends the requirements in this paragraph.
(1) Within 9,000 flight cycles after doing the most recent
internal detailed inspection.
(2) Within 4,500 flight cycles after October 13, 2004, or before
the accumulation of 40,000 total flight cycles, whichever occurs
later.
Preventive Modification
(i) For Groups 3 and 5 airplanes identified in Boeing Alert
Service Bulletin 737-53A1210, Revision 1, dated October 25, 2001: If
no cracking is found during any inspection required by paragraph (g)
of this AD, doing the preventive modification of the chem-milled
pockets in the upper skin as specified in Part 5 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
1, dated October 25, 2001; or as specified in Part 7 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009, except as required by paragraph (x) of this
AD; ends the repetitive external detailed and eddy current
inspections required by paragraph (g) of this AD for the modified
area only. As of the effective date of this AD, use only Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009.
Corrective Actions
(j) If any cracking is found during any inspection required by
paragraph (g), (h), (p), (q), or (s) of this AD, before further
flight, do the actions specified in paragraphs (j)(1) and (j)(2) of
this AD, as applicable, in accordance with the Work Instructions of
Boeing Alert Service Bulletin 737-53A1210, Revision 1, dated October
25, 2001; or Revision 3, dated July 16, 2009. As of the effective
date of this AD, use only Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009. Where Boeing Alert Service Bulletin
737-53A1210, Revision 1, dated October 25, 2001; or Revision 3,
dated July 16, 2009; specify to contact Boeing for repair
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 if it
is approved by the Boeing Commercial Airplanes Organization
Designation Authorization (ODA) or any other person 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.
(1) Except as provided by paragraph (k) of this AD, for cracking
of the crown area, do the repair specified in either paragraph
(j)(1)(i) or (j)(1)(ii) of this AD.
(i) Do a time-limited repair per Part 4 of the Work Instructions
of Boeing Alert Service Bulletin 737-53A1210, Revision 1, dated
October 25, 2001; or in accordance with Part 6 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009, except as required by paragraph (x) of this
AD, then do the actions required by paragraph (l) of this AD at the
times specified in that paragraph.
(ii) Do a permanent repair per Part 3 of the Work Instructions
of Boeing Alert Service Bulletin 737-53A1210, Revision 1, dated
October 25, 2001; or in accordance with Part 5 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009. Installation of a permanent repair ends the
repetitive inspections required by paragraph (g) of this AD for the
repaired area only. Installation of the lap joint repair specified
in paragraph (g) of AD 2002-07-08, Amendment 39-12702, is considered
acceptable for compliance with the corresponding permanent repair
specified in this paragraph for the repaired areas only.
(2) Except as provided by paragraph (k) of this AD, for cracking
of the lower lobe area and Section 41, repair per Part 2 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
1, dated October 25, 2001; or in accordance with paragraph (j)(2)(i)
or (j)(2)(ii) of this AD. Accomplishment of this repair ends the
repetitive inspections required by paragraph (h) of this AD for the
repaired area only. As of the effective date of this, do the repair
specified in paragraph (j)(2)(i) or (j)(2)(ii) of this AD.
(i) Do a time-limited repair in accordance with Part 6 of the
Work Instructions of Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009, except as required by paragraph (x)
of this AD, then do the actions required by paragraph (l) of this AD
at the times specified in that paragraph.
(ii) Do a permanent repair in accordance with Part 5 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009.
Optional Repair Method
(k) For cracking in any area specified in paragraphs (j)(1) and
(j)(2) of this AD within the limitations of the applicable
structural repair manual (SRM) specified in table 1 of this AD,
repair any cracks per the applicable SRM specified in table 1 of
this AD. Accomplishment of the applicable repair terminates the
repetitive inspections required by paragraphs (g) and (h) of this AD
for the repaired area only.
Table 1--SRM References
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Subject/figure Revision Date SRM
--------------------------------------------------------------------------------------------------------------------------------------------------------
737-100, -200 series airplanes....... 53-30-3, Figure 48..................... 102 September 10, 2010................. Boeing 737-100/-200 SRM,
D6-15565.
737-300 series airplanes............. 53-00-01, Figure 229................... 92 November 10, 2010.................. Boeing 737-300 SRM D6-
37635.
737-400 series airplanes............. 53-00-01, Figure 231................... 75 November 10, 2010.................. Boeing 737-400 SRM, D6-
38246.
737-500 series airplanes............. 53-00-01, Figure 229................... 70 November 10, 2010.................. Boeing 737-500 SRM, D6-
38441.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Follow-on and Corrective Actions
(l) If a time-limited repair is done, as specified in paragraph
(j)(1)(i) or (j)(2)(i) of this AD: Do the actions specified in
paragraphs (l)(1), (l)(2), and (l)(3) of this AD, at the times
specified in paragraphs (l)(1), (l)(2), and (l)(3) of this AD, per
the Work Instructions of Boeing Alert Service Bulletin 737-53A1210,
Revision 1, dated October 25, 2001; or Boeing Alert Service Bulletin
737-53A1210, Revision 3, dated July 16, 2009.
(1) Within 3,000 flight cycles after doing the repair: Do the
actions specified in paragraph (l)(1)(i) or (l)(1)(ii) of this AD.
Then repeat the applicable inspection specified in paragraph
(l)(1)(i) or (l)(1)(ii) of this AD at intervals not to exceed 3,000
flight cycles until permanent rivets are installed in the repaired
area, which ends the repetitive inspections for this paragraph. As
of the effective date of this AD, do only the inspections specified
in paragraph (l)(1)(ii) of this AD.
(i) For repairs done before the effective date of this AD: Do a
detailed inspection of the repaired area for loose fasteners per
Part 4 of the Work Instructions of Boeing Alert Service Bulletin
737-53A1210, Revision 1, dated October 25, 2001, or do the actions
specified in paragraph (l)(1)(ii) of this AD. If any loose fastener
is found, before further flight, replace with a new fastener per
Boeing Alert Service Bulletin 737-53A1210, Revision 1, dated October
25, 2001.
(ii) For repairs done after the effective date of this AD: Do a
detailed inspection of the repaired area for loose, damaged, and
missing fasteners in accordance with Part 6 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009. If any loose, missing, or damaged fastener
is found, before further flight, replace with a new fastener in
accordance with Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009.
(2) At the applicable time specified in paragraph (l)(2)(i) and
(l)(2)(ii) of this AD: Do inspections of the repaired area for
cracking per Part 4 of the Work Instructions of Boeing Alert Service
Bulletin 737-53A1210, Revision 1, dated October 25, 2001; or in
[[Page 12623]]
accordance with Part 6 of the Work Instructions of Boeing Alert
Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009. If
any cracking is found, before further flight, repair per a method
approved by the Manager, Seattle ACO, or per data meeting the type
certification basis of the airplane if it is approved by the Boeing
Commercial Airplanes ODA or any other person 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.
(i) For repairs done before the effective date of this AD:
Within 4,000 flight cycles after doing the repair, do the
inspections.
(ii) For repairs done on or after the effective date of this AD:
Within 3,000 flight cycles after doing the repair, do the
inspections.
(3) At the earlier of the times specified in paragraphs
(l)(3)(i) and (l)(3)(ii) of this AD: Make the repair permanent per
Part 4 and Figure 20 of the Work Instructions of Boeing Alert
Service Bulletin 737-53A1210, Revision 1, dated October 25, 2001, or
do the permanent repair in accordance with Part 5 of the Work
Instructions of Boeing Alert Service Bulletin 737-53A1210, Revision
3, dated July 16, 2009, which ends the repetitive inspections for
the repaired area only. As of the effective date of this AD, make
the repair permanent in accordance with Boeing Alert Service
Bulletin 737-53A1210, Revision 3, dated July 16, 2009.
(i) Within 10,000 flight cycles after doing the repair in
accordance with Boeing Alert Service Bulletin 737-53A1210, Revision
1, dated October 25, 2001.
(ii) At the later of the times specified in paragraphs
(l)(3)(ii)(A) and (l)(3)(ii)(B) of this AD.
(A) Within 6,000 flight cycles after doing the repair.
(B) Within 1,000 flight cycles after the effective date of this
AD.
Optional Terminating Action for Repetitive Eddy Current Inspections if
Done Before the Effective Date of This AD
(m) Accomplishment of paragraph (b) or (c), as applicable, of AD
2003-14-06, Amendment 39-13225, before the effective date of this AD
ends the repetitive eddy current inspections required by paragraph
(g) of this AD for that skin panel only; however, the repetitive
external detailed inspections required by paragraph (g) of this AD
are still required for all areas. As of the effective date of this
AD, accomplishing paragraph (b) or (c), as applicable, of AD 2003-
14-06, Amendment 39-13225, does not end the repetitive eddy current
inspections required by paragraph (g) of this AD.
Credit for Actions Done per Previous Service Bulletin
(n) Inspections, repairs, and preventive modifications done
before October 13, 2004, in accordance with Boeing Alert Service
Bulletin 737-53A1210, dated December 14, 2000, are acceptable for
compliance with the corresponding actions required by paragraphs
(g), (h), (i), (j), (k), and (l) of this AD.
Exception to Service Bulletin Procedures
(o) For airplanes subject to the requirements of paragraphs (g),
(h), (p), and (q) of this AD: Inspections are not required in areas
that are spanned by an FAA-approved repair that has a minimum of 3
rows of fasteners above and below the chem-milled step. If an
external doubler covers the chem-milled step, but does not span it
by a minimum of 3 rows of fasteners above and below, in lieu of
requesting approval for an alternative method of compliance (AMOC),
one option to comply with the inspection requirement of paragraphs
(g) and (h) of this AD is to inspect all chem-milled steps covered
by the repair using internal nondestructive test (NDT) methods in
accordance with Part 6 of the Boeing 737 Non-Destructive Test NDT
Manual. As of the effective date of this AD, inspect in accordance
with Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated
July 16, 2009.
New Requirements of This AD
Repetitive Inspections and Corrective Actions if Necessary
(p) For Groups 1 through 5 and 9 through 21 airplanes identified
in Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009, on which the inspections required by paragraph (g) of this
AD have been done before the effective date of this AD: At the
applicable time specified in paragraph (p)(1) or (p)(2) of this AD,
do external detailed and eddy current inspections of the crown area
and other known areas of fuselage skin cracking in accordance with
Part 1 of the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1210, Revision 3, dated July 16, 2009; except as
provided by paragraph (o) of this AD. Repeat the external detailed
and eddy current inspections thereafter at intervals not to exceed
1,800 flight cycles. Accomplishing the inspections required by this
paragraph ends the repetitive inspections required by paragraph (g)
of this AD. Before further flight, do all applicable corrective
actions as specified in paragraph (j) of this AD.
(1) For airplanes on which any action specified in paragraph
(i), (j)(1)(ii), (k), (l), or (m) of this AD has been done: Within
1,800 flight cycles after the effective date of this AD.
(2) For airplanes on which actions specified in paragraphs (i),
(j)(1)(ii), (k), (l), and (m) of this AD have not been done: Within
4,500 flight cycles after doing the most recent inspection required
by paragraph (g) of this AD, or within 1,800 flight cycles after the
effective date of this AD, whichever is later.
(q) For Groups 1 through 5 and 9 through 21 airplanes identified
in Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009; on which the inspections required by paragraph (g) of this
AD have not been done before the effective date of this AD: Before
the accumulation of 35,000 total flight cycles, or within 1,800
flight cycles after the effective date of this AD, whichever is
later, do external detailed and eddy current inspections of the
crown area and other known areas of fuselage skin cracking in
accordance with Part 1 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009.
Repeat the external detailed and eddy current inspections thereafter
at intervals not to exceed 1,800 flight cycles. Before further
flight, do all applicable corrective actions as specified in
paragraph (j) of this AD.
(r) For Group 1 through 5 and 9 through 21 airplanes identified
in Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009: At the later of the times specified in paragraphs (r)(1)
and (r)(2) of this AD, do external detailed and eddy current
inspections for vertical cracks in the fuselage skin along the chem-
milled steps of the butt joints, in accordance with Part 3 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. Repeat the inspections
thereafter at intervals not to exceed 1,800 flight cycles or 1,800
flight hours, whichever occurs first. If any cracking is found,
before further flight, repair in accordance with Part 5 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. Doing the repair
terminates the repetitive inspections specified in this paragraph
for the repaired area only.
(1) Before the accumulation of 55,000 total flight cycles or
55,000 total flight hours, whichever occurs first.
(2) Within 1,800 flight cycles or 1,800 flight hours after the
effective date of this AD, whichever occurs first.
(s) For Groups 1 through 21 airplanes identified in Boeing Alert
Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009:
Before the accumulation of 35,000 total flight cycles or within
4,500 flight cycles after the effective date of this AD, whichever
is later, do external detailed and eddy current inspections for
horizontal cracks along the chem-milled lines of the fuselage skin
of the lower lobe area and section 41, in accordance with Part 4 of
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1210, Revision 3, dated July 16, 2009; except as required by
paragraph (u) of this AD. Repeat the inspections thereafter at
intervals not to exceed 4,500 flight cycles. Accomplishing the
inspections required by this paragraph ends the repetitive
inspections required by paragraph (h) of this AD. Before further
flight, do all applicable corrective actions as specified in
paragraph (j) of this AD.
(t) For Groups 4, 11, and 16 airplanes identified in Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009:
Before the accumulation of 25,000 total flight cycles or within
4,500 flight cycles after the effective date of this AD, whichever
is later, do external detailed and eddy current inspections for
horizontal cracks along the chem-milled lines of the fuselage skin
of the fuselage window belt area in accordance with Part 2 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. Repeat the inspections
thereafter at intervals not to exceed 4,500 flight cycles. If any
cracking is found, before further flight, repair using a
[[Page 12624]]
method approved in accordance with paragraph (y) of this AD.
(u) For Groups 3, 5, 9, 10, 12, 14, 15, 17, 18, 19, 20, and 21
airplanes identified in Boeing Alert Service Bulletin 737-53A1210,
Revision 3, dated July 16, 2009: Do the actions specified in
paragraph (u)(1) or (u)(2) of this AD, as applicable.
(1) For airplanes on which the inspections required by paragraph
(g) of this AD have been done before the effective date of this AD:
Within 4,500 flight cycles after doing the most recent inspection
required by paragraph (g) of this AD, do external detailed and eddy
current inspections for horizontal cracks along the chem-milled
lines of the fuselage skin of the fuselage window belt area in
accordance with Part 2 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009.
Repeat the inspections thereafter at intervals not to exceed 4,500
flight cycles. If any cracking is found, before further flight,
repair in accordance with Part 8 of Boeing Alert Service Bulletin
737-53A1210, Revision 3, dated July 16, 2009, except as required by
paragraph (x) of this AD.
(2) For airplanes on which the inspections required by paragraph
(g) of this AD have not been done before the effective date of this
AD: Before the accumulation of 25,000 total flight cycles or within
4,500 flight cycles after the effective date of this AD, whichever
is later, do external detailed and eddy current inspections for
horizontal cracks along the chem-milled lines of the fuselage skin
of the fuselage window belt area in accordance with Part 2 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009. Repeat the inspections
thereafter at intervals not to exceed 4,500 flight cycles. If any
cracking is found, before further flight, repair in accordance with
Part 8 of Boeing Alert Service Bulletin 737-53A1210, Revision 3,
dated July 16, 2009, except as required by paragraph (x) of this AD.
Repair and Preventive Modification
(v) For airplanes on which cracking is found during any
inspection required by paragraph (p), (q), (r), or (s) of this AD,
as applicable, doing the repair of the chem-milled area in the skin,
as specified in Part 5 or Part 6 of the Accomplishment Instructions
of Boeing Alert Service Bulletin 737-53A1210, Revision 3, dated July
16, 2009, ends the repetitive external detailed and eddy current
inspections required by paragraph (p), (q), (r), or (s) of this AD,
as applicable, for the repaired area only.
Note 2: Part 8 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009,
specifies a post-repair inspection of the skin chem-milled crack
repair at stringer 12; that inspection is not required by this AD.
The damage tolerance inspections specified in Table 7 of Boeing
Alert Service Bulletin 737-53A1210, Revision 3, dated July 16, 2009,
may be used in support of compliance with section 121.1109(c)(2) or
129.109(c)(2) of the Code of Federal Regulations (14 CFR
121.1109(c)(2) or 14 CFR 129.109(c)(2)).
(w) For airplanes on which no cracking is found during any
inspection required by paragraph (p) or (q) of this AD, as
applicable, doing the preventive modification of the chem-milled
areas in the skin at stringer S-12, as specified in Part 7 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1210, Revision 3, dated July 16, 2009, except as required by
paragraph (x) of this AD, ends the repetitive external detailed and
eddy current inspections required by paragraph (p) or (q) of this
AD, as applicable, for the modified area only.
Exception to Boeing Alert Service Bulletin 737-53A1210, Revision 3
(x) Where Boeing Alert Service Bulletin 737-53A1210, Revision 3,
dated July 16, 2009, specifies to contact Boeing for repair
instructions, before further flight, repair using a method approved
in accordance with paragraph (y) of this AD.
Alternative Methods of Compliance (AMOCs)
(y)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested
using the procedures found in 14 CFR 39.19. In accordance with 14
CFR 39.19, send your request to your principal inspector or local
Flight Standards District Office, as appropriate. If sending
information directly to the manager of the ACO, send it to the
attention of the person identified in the Related Information
section of this AD. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(3) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD if it is approved by the
Boeing Commercial Airplanes ODA that 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.
(4) AMOCs approved previously in accordance with AD 2004-18-06,
Amendment 39-13784, are approved as AMOCs for the corresponding
provisions of this AD.
Related Information
(z) For more information about this AD, contact Wayne Lockett,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington
98057-3356; telephone (425) 917-6447; fax (425) 917-6590; e-mail:
wayne.lockett@faa.gov.
Issued in Renton, Washington on February 22, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2011-5159 Filed 3-7-11; 8:45 am]
BILLING CODE 4910-13-P
