[Federal Register Volume 76, Number 170 (Thursday, September 1, 2011)]
[Proposed Rules]
[Pages 54399-54403]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-22370]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2011-0914; Directorate Identifier 2010-NM-166-AD]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Model 737-200, -
200C, -300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: We propose to supersede an existing airworthiness directive
(AD) that applies to certain Model 737-300,
[[Page 54400]]
-400, and -500 series airplanes. The existing AD currently requires
repetitive external non-destructive inspections to detect cracks in the
fuselage skin along the chem-mill step at stringers S-1 and S-2 right,
between station (STA) 827 and STA 847, and repair if necessary. Since
we issued that AD, we have received reports of additional crack
findings of the fuselage crown skin at the chem-milled steps. This
proposed AD would add inspections for cracking in additional fuselage
crown skin locations, and repair if necessary. This proposed AD would
also reduce the inspection thresholds for certain airplanes, extend
certain repetitive inspection intervals, and add airplanes to the
applicability of the existing AD. We are proposing this AD to detect
and correct fatigue cracking of the fuselage skin panels at the chem-
milled steps, which could result in sudden fracture and failure of the
fuselage skin panels, and consequent rapid decompression of the
airplane.
DATES: We must receive comments on this proposed AD by October 17,
2011.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http://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: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this 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 [email protected]; 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 http://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 (phone: 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; phone: 425-917-
6447; fax: 425-917-6590; e-mail: [email protected].
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-2011-0914;
Directorate Identifier 2010-NM-166-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 http://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 December 21, 2009, we issued AD 2010-01-09, Amendment 39-16167
(75 FR 1527, January 12, 2010), for certain Model 737-300, -400, and -
500 series airplanes. That AD requires repetitive external non-
destructive inspections to detect cracks in the fuselage skin along the
chem-mill step at stringers S-1 and S-2 right, between STA 827 and STA
847, and repair if necessary. That AD resulted from a report of a hole
in the fuselage skin common to stringers S-1 and S-2 left, between STA
827 and STA 847, on an airplane that diverted to an alternate airport
due to cabin depressurization and subsequent deployment of the oxygen
masks. We issued that AD to detect and correct fatigue cracking of the
fuselage skin panels at the chem-milled steps, which could result in
sudden fracture and failure of the fuselage skin panels, and consequent
rapid decompression of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 2010-01-09, we have received reports of new
findings of cracking in the fuselage crown skin at the horizontal chem-
milled steps at locations between body stations 259.5 and 1016 and
between stringers S-10L and S-10R. The cause of the cracking is under
investigation.
Relevant Service Information
We reviewed Boeing Alert Service Bulletin 737-53A1301, Revision 2,
dated April 25, 2011. Boeing Alert Service Bulletin 737-53A1301, dated
September 3, 2009, was referred to for accomplishing the actions in the
existing AD. We also reviewed Boeing Alert Service Bulletin 737-
53A1301, Revision 1, dated June 7, 2010. Revision 1 of this service
bulletin adds inspections for cracking in additional fuselage crown
skin locations, and repair if necessary; it reduces the inspection
threshold for certain airplanes; extends certain repetitive inspection
intervals; and adds airplanes to the effectivity (Model 737-200 and -
200C series airplanes, and Model 737-300, -400, and -500 series without
ELT antenna provisions). The new inspection types specified in Revision
1 of this service bulletin are detailed inspections, and optional
external nondestructive: ultrasonic phased array inspections. Revision
1 of this service bulletin also recommends contacting Boeing for
inspection instructions for Group 26 airplanes. Revision 2 of this
service bulletin specifies that no more work is necessary on airplanes
changed as specified in Revision 1 of this service bulletin. Revision 2
of this service bulletin only includes minor editorial changes.
Boeing Alert Service Bulletin 737-53A1301, Revision 2, dated April
25, 2011; and Boeing Alert Service Bulletin 737-53A1301, Revision 1,
dated June 7, 2010; specify that the compliance times for the initial
inspections for Groups 2, 8, and 10 airplanes at the ELT antenna
provision at stringers S-1 and S-2R between BS 827 and BS 847, are at
the latest of the following: Prior to the accumulation of 35,000 total
flight cycles, or, depending on inspection locations, within 1,800
flight cycles after the issue date of the original issue or Revision 1
of this service bulletin, or within 1,800 flight cycles after the most
recent inspection done in accordance with Boeing Alert Service Bulletin
737-53A1301, dated September 3, 2009. For Groups 1 through 12
airplanes, at the new inspection locations, the compliance times are
prior to the accumulation of 35,000 total flight
[[Page 54401]]
cycles, or within 1,800 flight cycles after the issue date of Revision
1 of this service bulletin. For groups 1 through 12, the repetitive
inspection interval is 1,800 flight cycles (for Option 1 inspections)
and 2,400 flight cycles (for Option 2 inspections). For airplanes on
which the inspection procedure is changed from Option 2 to Option 1,
the first Option 1 inspection must be done within 2,400 flight cycles
after doing the Option 2 inspection. For airplanes on which the
inspection procedure is changed from Option 1 to Option 2, the first
two Option 2 inspections must be done within 1,800 flight cycles.
Boeing Alert Service Bulletin 737-53A1301, Revision 2, dated April
25, 2011; specifies that the compliance times for the initial
inspections for Groups 13 through 18 and 21 through 25 airplanes at the
ELT antenna provision at stringers S-1 and S-2R, between BS 827 and BS
847, are as follows:
For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1301, dated September 3, 2009; or
Revision 1, dated June 7, 2010; have been done: At the latest of the
following, prior to the accumulation of 33,000 total flight cycles, or
within 500 flight cycles after the most recent inspection done in
accordance with Boeing Alert Service Bulletin 737-53A1301, dated
September 3, 2009; or Revision 1, dated June 7, 2010.
For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1301, dated September 3, 2009; or
Revision 1, dated June 7, 2010; have not been done: Prior to the
accumulation of 33,000 total flight cycles, or within 500 flight cycles
after the issue date of Revision 2 of this service bulletin, whichever
occurs later.
For Groups 13 through 25, Boeing Alert Service Bulletin 737-
53A1301, Revision 2, dated April 25, 2011; specifies that the
compliance times for the initial inspections for Groups 13 through 25
airplanes at the new inspection locations are as follows: Prior to the
accumulation of 33,000 total flight cycles, or within 500 flight cycles
after the issue date of Revision 1 of Boeing Alert Service Bulletin
737-53A1301, whichever occurs later.
For Groups 13 through 25, Boeing Alert Service Bulletin 737-
53A1301, Revision 2, dated April 25, 2011; specifies that the
repetitive inspection interval is 500 flight cycles (for Option 1) and
1,000 flight cycles (for Option 2). For airplanes on which the
inspection procedure is changed from Option 2 to Option 1, the first
Option 1 inspection must be done within 1,000 flight cycles after doing
the Option 2 inspection. For airplanes on which the inspection
procedure is changed from Option 1 to Option 2, the first two Option 2
inspections must be done within 500 flight cycles.
For Group 26 airplanes, Boeing Alert Service Bulletin 737-53A1301,
Revision 2, dated April 25, 2011, specifies contacting Boeing to obtain
engineering and accomplishment instructions for certain inspections.
FAA's Determination
We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Proposed AD Requirements
This proposed AD would retain the requirements of AD 2010-01-09,
and would add inspections for cracking in additional fuselage crown
skin locations, and repair if necessary. This proposed AD would also
reduce the inspection thresholds for certain airplanes, extend certain
repetitive inspection intervals, and add airplanes to the applicability
of AD 2010-01-09. This proposed AD would require accomplishing the
actions specified in the service information described previously.
Interim Action
We consider this proposed AD interim action. If final action is
later identified, we might consider further rulemaking then.
Costs of Compliance
We estimate that this proposed AD affects 654 airplanes of U.S.
registry.
We estimate the following costs to comply with this proposed AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Number of U.S.-
Action Work hours Average labor Cost per registered Fleet cost
rate per hour product airplanes
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Inspection in AD 2010-01-09.. 2.............. $85 $170 per 135 $22,950 per
inspection inspection
cycle. cycle.
New inspection in this Between 2 and 85 Between $170 654 Between
proposed AD. 30. and $2,550 per $111,180 and
inspection $1,667,700 per
cycle. inspection
cycle.
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We have received no definitive data that would enable us to provide
a cost estimate for the on-condition actions specified in this proposed
AD.
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
[[Page 54402]]
(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 airworthiness directive
(AD) 2010-01-09, Amendment 39-16167 (75 FR 1527, January 12, 2010), and
adding the following new AD:
The Boeing Company: Docket No. FAA-2011-0914; Directorate Identifier
2010-NM-166-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by October
17, 2011.
Affected ADs
(b) This AD supersedes AD 2010-01-09, Amendment 39-16167.
Applicability
(c) This AD applies to all The Boeing Company Model 737-200, -
200C, -300, -400, and -500 series airplanes, certificated in any
category.
Subject
(d) Joint Aircraft System Component (JASC)/Air Transport
Association (ATA) of America Code 53, Fuselage.
Unsafe Condition
(e) This AD was prompted by reports of additional crack findings
of the fuselage crown skin at the chem-milled steps. We are issuing
this AD to detect and correct fatigue cracking of the fuselage skin
panels at the chem-milled steps, which could result in sudden
fracture and failure of the fuselage skin panels, and consequent
rapid decompression of the airplane.
Compliance
(f) Comply with this AD within the compliance times specified,
unless already done.
Restatement of Requirements of AD 2010-01-09, Amendment 39-16167
Initial and Repetitive Inspections
(g) For airplanes identified in Boeing Alert Service Bulletin
737-53A1301, dated September 3, 2009: Before the accumulation of
35,000 total flight cycles, or within 500 flight cycles after
February 16, 2010 (the effective date of AD 2010-01-09), whichever
occurs later, except as provided by paragraph (i) of this AD, do an
external non-destructive inspection (NDI) to detect cracks in the
fuselage skin along the chem-mill steps at stringers S-1 and S-2
right, between station (STA) 827 and STA 847, in accordance with the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1301, dated September 3, 2009; or Boeing Alert Service Bulletin
737-53A1301, Revision 2, dated April 25, 2011. If no cracking is
found, repeat the inspection thereafter at intervals not to exceed
500 flight cycles; except as provided by paragraphs (i) and (n) of
this AD. Accomplishing the inspections required by paragraph (j) of
this AD terminates the inspections required by this paragraph.
Repair
(h) If any crack is found during any inspection required by
paragraph (g) of this AD, and Boeing Alert Service Bulletin 737-
53A1301, dated September 3, 2009; or Boeing Alert Service Bulletin
737-53A1301, Revision 2, dated April 25, 2011; specifies to contact
Boeing for repair instructions: Before further flight, repair the
crack using a method approved in accordance with the procedures
specified in paragraph (q) of this AD.
Optional Terminating Action for Repetitive Inspections in Paragraph (g)
of This AD
(i) Installing an external repair doubler along the chem-milled
steps at stringers S-1 and S-2 right, between STA 827 and STA 847,
constitutes terminating action for the repetitive inspections
required by paragraph (g) of this AD for the repaired area only,
provided all of the conditions specified in paragraphs (i)(1),
(i)(2), and (i)(3) of this AD are met.
(1) The repair is installed after September 3, 2009;
(2) The repair was approved by the FAA or by a Boeing Company
Authorized Representative or the Boeing Commercial Airplanes
Organization Designation Authorization (ODA) that has been
authorized by the Manager, Seattle Aircraft Certification Office
(ACO) to make such findings; and
(3) The repair extends a minimum of three rows of fasteners on
each side of the chem-mill line in the circumferential direction.
New Inspections Including Additional Locations and Reduced Inspection
Intervals
Groups 1 Through 25: Initial and Repetitive Inspections
(j) For Groups 1 through 25 airplanes identified in Boeing Alert
Service Bulletin 737-53A1301, Revision 2, dated April 25, 2011:
Except as provided by paragraph (k) of this AD, at the applicable
time specified in paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1301, Revision 2, dated April 25, 2011, do
the applicable inspections required by paragraphs (j)(1) and (j)(2)
of this AD, in accordance with paragraphs 3.B.1 through 3.B.25 of
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1301, Revision 2, dated April 25, 2011. If no cracking is
found, repeat the applicable inspections thereafter at the
applicable intervals specified in paragraph 1.E., ``Compliance,'' of
Boeing Alert Service Bulletin 737-53A1301, Revision 2, dated April
25, 2011; except as provided by paragraphs (m) and (n) of this AD.
Doing the inspections required by this paragraph terminates the
inspections required by paragraph (g) of this AD.
(1) For Groups 2, 8, 10, 13 through 18, and 21 through 25
airplanes: Do a detailed inspection and an external non-destructive
inspection (NDI) (medium frequency eddy current inspection, magneto
optical imaging inspection, c-scan inspection, or ultrasonic phased
array inspection) for cracking in the fuselage skin at the chem-mill
steps at S-1 and S-2R between STA 827 and STA 847, as identified in
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1301, Revision 2, dated April 25, 2011.
(2) For Groups 1 through 25 airplanes: Do a detailed inspection
and an external NDI (medium frequency eddy current inspection;
magneto optical imaging inspection, c-scan inspection, or ultrasonic
phased array inspection) for cracking in the fuselage skin at the
chem-mill steps at the specified locations other than at S-1 and S-
2R between STA 827 and STA 847, as identified in the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1301, Revision
2, dated April 25, 2011.
Note 1: Option 1 of Boeing Alert Service Bulletin 737-53A1301,
Revision 2, dated April 25, 2011, specifies a detailed inspection,
and one additional inspection (external NDI, medium frequency eddy
current inspection, magneto optical imaging inspection, or c-scan
inspection). Option 2 specifies a detailed inspection and an
external ultrasonic phased array inspection. These options have
different compliance times after the initial inspection.
(k) Where Boeing Alert Service Bulletin 737-53A1301, Revision 2,
dated April 25, 2011, specifies a compliance time after ``the date
of Revision 1,'' or ``the date of Revision 2'' of that service
bulletin, this AD requires compliance within the specified time
after the effective date of this AD.
Repair
(l) If any crack is found during any inspection required by
paragraph (j) of this AD: Before further flight, repair the crack
using a method approved in accordance with the procedures specified
in paragraph (q) of this AD. Doing the repair ends the repetitive
inspections required by paragraph (j) for the repaired area only.
Optional Terminating Action for Repetitive Inspections
(m) Installing an external repair doubler along the chem-milled
steps at any location identified in Boeing Alert Service Bulletin
737-53A1301, Revision 2, dated April 25, 2011, constitutes
terminating action for the repetitive inspections required by
paragraph (j) of this AD for the repaired area only, provided all of
the conditions specified in
[[Page 54403]]
paragraphs (m)(1), (m)(2), and (m)(3) of this AD are met.
(1) The repair is installed after the applicable date specified
in paragraph (m)(1)(i) and (m)(1)(ii) of this AD.
(i) For repairs at S-1 and S-2R between STA 827 and STA 847:
Installed after September 3, 2009.
(ii) For repairs at locations other than at S-1 and S-2R between
STA 827 and STA 847: Installed after June 7, 2010.
(2) The repair was approved by the FAA or by a Boeing Company
Authorized Representative or the Boeing Commercial Airplanes
Organization Designation Authorization (ODA) that has been
authorized by the Manager, Seattle Aircraft Certification Office
(ACO) to make such findings; and
(3) The repair extends a minimum of three rows of fasteners on
each side of the chem-mill line in the circumferential direction.
(n) Accomplishing a modification of the chem-milled steps at any
location identified in Boeing Alert Service Bulletin 737-53A1301,
Revision 2, dated April 25, 2011, using a method approved in
accordance with the procedures specified in paragraph (q)(1) of this
AD, terminates the repetitive inspections required by paragraphs (g)
and (j) of this AD for the modified area only.
Group 26 Airplanes
(o) For Group 26 airplanes identified in Boeing Alert Service
Bulletin 737-53A1301, Revision 2, dated April 25, 2011: Within 1,800
flight cycles after the effective date of this AD, accomplish
applicable inspections and corrective action, as identified in the
service bulletin, using a method approved in accordance with the
procedures specified in paragraph (q)(1) of this AD.
Credit for Actions Accomplished in Accordance With Previous Service
Information
(p) Actions done before the effective date of this AD in
accordance with Boeing Alert Service Bulletin 737-53A1301, Revision
1, dated June 7, 2010, are acceptable for compliance with the
corresponding requirements of this AD.
Alternative Methods of Compliance (AMOCs)
(q)(1) The Manager, Seattle 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: [email protected].
(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.
Related Information
(r) 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; phone: 425-917-6447; fax: 425-917-6590; e-mail:
[email protected].
(s) For service information identified in this 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
[email protected]; 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.
Issued in Renton, Washington, on August 25, 2011.
Ali Bahrami,
Manager Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011-22370 Filed 8-31-11; 8:45 am]
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