[Federal Register: March 17, 2005 (Volume 70, Number 51)]
[Proposed Rules]
[Page 12982-12986]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17mr05-9]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-20627; Directorate Identifier 2004-NM-39-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Boeing Model 737-100, -200, -200C, -300, -400, and -500
series airplanes. This proposed AD would require the following:
Repetitive eddy current inspections for cracks of the countersunk rivet
holes in the lower lobe, adjacent to the radio altimeter cutouts;
additional inspections, for certain airplanes, for cracks and/or
corrosion; and further investigative and corrective action if any crack
is found. This proposed AD also would provide an optional terminating
action for the repetitive inspections. This proposed AD was prompted by
reports of cracks in the fuselage skin of the lower lobe. We are
proposing this AD to detect and correct fatigue cracks of the
countersunk rivet holes, which could result in cracks of the fuselage
skin of the lower lobe, and consequent rapid depressurization of the
cabin.
DATES: We must receive comments on this proposed AD by May 2, 2005.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility, U.S. Department of
Transportation, 400 Seventh Street SW., Nassif Building, room PL-401,
Washington, DC 20590.
[[Page 12983]]
By fax: (202) 493-2251.
Hand Delivery: room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m.
and 5 p.m., Monday through Friday, except Federal holidays.
You can get the service information identified in this proposed AD
from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington
98124-2207.
You can examine the contents of this AD docket on the Internet at
http://dms.dot.gov, or in person at the Docket Management Facility,
U.S. Department of Transportation, 400 Seventh Street SW., room PL-401,
on the plaza level of the Nassif Building, Washington, DC. This docket
number is FAA-2005-20627; the directorate identifier for this docket is
2004-NM-39-AD.
FOR FURTHER INFORMATION CONTACT: Sue Lucier, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6438; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any written relevant data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2005-20627;
Directorate Identifier 2004-NM-39-AD'' in the subject line of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments submitted by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov
, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
Examining the Docket
You can examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Management Facility office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT
street address stated in the ADDRESSES section. Comments will be
available in the AD docket shortly after the DMS receives them.
Discussion
We have received a report indicating that five operators have found
seven cracks in the lower lobe fuselage skin on Boeing Model 737-200
series airplanes. All cracks originated at the countersunk rivet holes
adjacent to the radio altimeter cutouts at body stations (BSs) 430 and
450, and were located at buttock line (BL) 0. The cracks were from
0.375 inch to 5.25 inches in length. One operator reported two cracks
on the same airplane: a 2-inch crack running aft of BS 431, and a
2.125-inch crack running forward of BS 449. The two cracks were growing
toward each other from two adjacent cutouts. The cracks propagate by
normal fatigue due to operating loads (pressure). Cracking of the
countersunk rivet holes, if not detected and corrected, could result in
cracks in the lower lobe fuselage skin reaching critical length for
residual strength, and consequent rapid depressurization of the cabin.
The fuselage skin configuration on certain Model 737-200 series
airplanes is almost identical to that on certain Model 737-100, -200C,
-300, -400, and -500 series airplanes. Therefore, all of these models
may be subject to the same unsafe condition.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 737-53-
1230, dated June 13, 2002. This service bulletin describes procedures
for doing an eddy current inspection for cracks of the surface area
around the countersunk rivet holes in the lower lobe, adjacent to the
radio altimeter cutouts at BL 0, between BS 390 and BS 450. This
inspection is done with the fasteners installed.
If no crack is found during the eddy current inspection, the
service bulletin describes options for repeating the eddy current
inspection (with fasteners installed), or for doing a preventive
modification that would eliminate the need for the repetitive
inspections.
For operators that choose to do the optional preventive
modification, the service bulletin describes procedures for an
additional eddy current inspection for cracks of the satellite holes
with the fasteners removed.
If no crack is found during the additional eddy current inspection,
the service bulletin gives procedures for fabricating and installing
the preventive modification doublers. The service bulletin states that
a preventive modification doubler is not needed at BS 390 if the
doubler has been previously installed in accordance with Boeing Service
Bulletin 737-53-1117, Revision 1, dated April 6, 1989. For these
airplanes, the preventive modification is removing the ten fasteners
around the altimeter cutout at BS 390, doing an eddy current inspection
of the satellite holes, and installing oversize fasteners.
If any crack is found during the additional eddy current
inspection, the service bulletin specifies to discontinue the
preventive modification and repair the affected area, as described
below. Repair of the affected area eliminates the need for the
repetitive inspections.
If any crack is found during any eddy current inspection, the
service bulletin describes procedures for repair, which includes
further investigative and corrective actions. The corrective actions
included in the repair are cutting out the crack if it is within the
allowable cutout repair zone, and fabricating and installing a repair
doubler and spacer ring. The further investigative actions included in
the repair are an eddy current inspection of the edge of the cutout
area, an eddy current inspection of the satellite holes (with fasteners
removed) for additional cracking, and a visual inspection for corrosion
of the area under the previously repaired area. If any crack is outside
the allowable cutout repair zone, or if any corrosion is detected, the
service bulletin specifies to contact Boeing for repair instructions.
Accomplishing the actions specified in Special Attention Service
Bulletin 737-53-1230 will address the identified unsafe condition
adequately.
This special attention service bulletin refers to Boeing Service
Bulletin 737-53-1117, Revision 1, dated April 6, 1989, as an additional
source of service information for repairing certain affected airplanes.
Concurrent Service Bulletin for Certain Airplanes
Boeing Service Bulletin 737-53-1117, Revision 1, dated April 6,
1989, must be accomplished before or at the same time as the repair
procedures in Boeing Special Attention Service Bulletin 737-53-1230 for
any airplane that meets all three of the following conditions:
[[Page 12984]]
1. The airplane is specified as belonging in Group 1, 2, 3, 4, or 5
as listed in Boeing Special Attention Service Bulletin 737-53-1230;
2. The airplane has a skin crack at the cutout at BS 390; and
3. The airplane has not had an external repair doubler installed
previously in accordance with Boeing Service Bulletin 737-53-1117. The
repair in Service Bulletin 737-53-1117 includes further investigative
and corrective actions, which are an additional inspection and repair
of any crack by stop-drilling the cracks and installing an external
repair doubler.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. Therefore, we are proposing this AD, which
would require you to accomplish the actions specified in Special
Attention Service Bulletin 737-53-1230, except as discussed under
``Differences Between the Proposed AD and the Service Bulletins.'' This
proposed AD also would provide for optional terminating action for the
repetitive inspections.
This proposed AD would allow repetitive inspections to continue in
lieu of the terminating action. In making this determination, we
considered that long-term continued operational safety in this case
would be adequately ensured by repetitive inspections to detect cracks
before they represent a hazard to the airplane.
Differences Between the Proposed AD and the Service Bulletins
For airplanes designated as Groups 1, 2, 3, 4, and 5 that have a
skin crack at BS 390, Part III of the Accomplishment Instructions of
Boeing Special Attention Service Bulletin 737-53-1230 specifies
additional actions in accordance with Boeing Service Bulletin 737-53-
1117. These additional actions are a detailed inspection and repair, if
necessary, of an adjacent equipment cooling duct cutout just forward of
BS 390. The repair in Boeing Service Bulletin 737-53-1117 allows for
repair of any crack by stop-drilling and installing an external repair
doubler. This repair doubler reinforces the equipment cooling duct
cutout and the BS 390 cutout. This proposed AD also would allow
operators the option to do an eddy current inspection and repair in
accordance with Figure 17 of Boeing Special Attention Service Bulletin
737-53-1230.
Special Attention Service Bulletin 737-53-1230 specifies that you
may contact the manufacturer for instructions for certain repair
instructions. However, rather than contacting the manufacturer, and for
instructions for repairing any crack that is 3 inches in length or
greater that is found during the inspection specified in Service
Bulletin 737-53-1117, this proposed AD would require you to do these
repairs in one of the ways listed in the bullets below.
Using a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Delegation Option Authorization Organization who has
been authorized by the FAA to make those findings.
Clarification of Inspection Language
Both Boeing Service bulletins request that operators ``visually
inspect'' for certain conditions. This proposed AD defines this
inspection in Boeing Service Bulletin 737-53-1117 as a ``detailed
inspection,'' and in Boeing Special Attention Service Bulletin 737-53-
1230 as a ``general visual inspection.'' These inspections are defined
in Note 1 and Note 2 of this proposed AD.
Costs of Compliance
This proposed AD would affect about 3,132 airplanes worldwide. The
following table provides the estimated costs for U.S. operators to
comply with this proposed AD.
Estimated Costs
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Number of
Work Average Cost per U.S.-
Action hours labor rate Parts airplane registered Fleet cost
per hour airplanes
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Inspection.................... 3 $65 No parts $195 1,004 $195,780
required.
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
subtitle VII, part A, subpart III, section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
We have determined that this 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); and
3. Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
We prepared a regulatory evaluation of the estimated costs to
comply with this proposed AD. See the ADDRESSES section for a location
to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:
[[Page 12985]]
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new
airworthiness directive (AD):
Boeing: Docket No. FAA-2005-20627; Directorate Identifier 2004-NM-
39-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by May 2, 2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-100, -200, -200C, -300,
-400, and -500 series airplanes, certificated in any category; as
identified in Boeing Special Attention Service Bulletin 737-53-1230,
dated June 13, 2002.
Unsafe Condition
(d) This AD was prompted by reports of cracks in the lower lobe
fuselage skin of the affected airplanes. We are issuing this AD to
detect and correct fatigue cracks of the countersunk rivet holes,
which could result in cracks of the fuselage skin of the lower lobe,
and consequent rapid depressurization of the cabin.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Service Bulletin Reference
(f) The term ``special attention service bulletin,'' as used in
this AD, means the Accomplishment Instructions of Boeing Special
Attention Service Bulletin 737-53-1230, dated June 13, 2002.
Repetitive Inspections
(g) Before the airplane accumulates 20,000 total flight cycles,
or within 4,500 flight cycles after the effective date of this AD,
whichever occurs later: Do an eddy current inspection for cracks of
the surface area around the satellite holes of the radio altimeter
cutouts at buttock line 0, between body station (BS) 390 and BS 450.
Do the inspection with the fasteners installed. Repeat the
inspection at intervals not to exceed 4,500 flight cycles. Do all
inspections in accordance with the special attention service
bulletin.
Repair
(h) If any crack is found during any eddy current inspection
required by this AD: Before further flight, repair the area by doing
all applicable corrective and further investigative actions in
accordance with the special attention service bulletin.
Accomplishment of the repair terminates the repetitive inspection
requirements of paragraph (g) of this AD for the repaired area.
Where the special attention service bulletin specifies to contact
Boeing for appropriate action or for instructions about how to
repair certain conditions: Before further flight, repair in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA; or according to data meeting the
certification basis of the airplane approved by an Authorized
Representative for the Boeing Delegation Option Authorization
Organization who has been authorized by the Manager, Seattle ACO, to
make those findings. For a repair method to be approved, the
approval must specifically reference this AD.
Additional Inspection and Repair for Certain Airplanes
(i) For the following airplanes, before or at the same time as
the repair in paragraph (h) of this AD, inspect in accordance with
Table 1 of this AD: Any airplane in Group 1, 2, 3, 4, or 5 of the
special attention service bulletin; any airplane that has a skin
crack at the cutout at BS 390 found during any inspection required
by paragraphs (g) and (h) of this AD; and any airplane that has not
had an external repair doubler installed in accordance with Boeing
Service Bulletin 737-53-1117, Revision 1, dated April 6, 1989.
Table 1.--Service Information
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Inspect in accordance with either--
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The Accomplishment Instructions of
Boeing Service Bulletin 737-53-1117, Figure 17 of the special
Revision 1, dated April 6, 1989-- attention service bulletin--
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A detailed inspection for cracks in the An eddy current inspection for
fuselage lower skin in the area of the cracks of the exhaust port
electronics bay cooling duct cutout. duct cutout edge and the 6
fastener locations;
An eddy current and open-hole
probe inspection for cracks of
the satellite holes; and
A general visual inspection for
corrosion of the area under
the repair.
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(1) If any crack at the equipment cooling duct cutout is found
that is less than 3 inches in length: Before further flight, stop-
drill the crack or cracks and install an external repair doubler in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1117, Revision 1, dated April 6, 1989; or repair in
accordance with Part III of the special attention service bulletin.
Accomplishment of the repair terminates the repetitive inspection
requirements of paragraph (g) of this AD for the repaired area.
(2) If any corrosion is found, or if any crack is found that is
3 inches in length or greater: Before further flight, repair in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA; or in accordance with data meeting
the certification basis of the airplane approved by an Authorized
Representative for the Boeing Delegation Option Authorization
Organization who has been authorized by the Manager, Seattle ACO, to
make those findings. For a repair method to be approved, the
approval must specifically reference this AD.
Note 1: For the purposes of this AD, a general visual inspection
is: ``A visual examination of an interior or exterior area,
installation, or assembly to detect obvious damage, failure, or
irregularity. This level of inspection is made from within touching
distance unless otherwise specified. A mirror may be necessary to
enhance visual access to all exposed surfaces in the inspection
area. This level of inspection is made under normally available
lighting conditions such as daylight, hangar lighting, flashlight,
or droplight and may require removal or opening of access panels or
doors. Stands, ladders, or platforms may be required to gain
proximity to the area being checked.''
Note 2: For the purposes of this AD, a detailed inspection is
``an intensive examination of a specific item, installation, or
assembly to detect damage, failure, or irregularity. Available
lighting is normally supplemented with a direct source of good
lighting at an intensity deemed appropriate. Inspection aids such as
mirrors magnifying lenses, etc. may be necessary. Surface cleaning
and elaborate procedures may be required.''
Optional Terminating Action
(j) Installing preventive modification doublers in accordance
with the special attention service bulletin, including the
additional eddy current inspection with the fasteners removed (with
no crack finding), terminates the repetitive inspection requirements
of paragraph (g) of this AD. If any crack is found during the eddy
current inspection specified by this paragraph: Before further
flight, discontinue the preventive modification and do the
applicable actions in paragraph (h) of this AD.
[[Page 12986]]
Alternative Methods of Compliance
(k)(1) In accordance with 14 CFR 39.19, the Manager, Seattle
Aircraft Certification Office (SACO), is authorized to approve
alternative methods of compliance (AMOCs) for this AD.
(2) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by an
Authorized Representative for the Boeing Delegation Option
Authorization Organization who has been authorized by the Manager,
Seattle ACO, to make those findings.
Issued in Renton, Washington, on March 8, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-5296 Filed 3-16-05; 8:45 am]
BILLING CODE 4910-13-P