FR Doc E8-18812

[Federal Register: August 19, 2008 (Volume 73, Number 161)]
[Rules and Regulations]
[Page 48288-48290]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19au08-3]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29174; Directorate Identifier 2007-NM-125-AD;
Amendment 39-15641; AD 2008-17-03]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. This AD requires repetitive inspections to detect cracking
of the body station 303.9 frame, and corrective action if necessary.
This AD also provides for optional terminating action for the
repetitive inspections. This AD results from reports of cracks found at
the cutout in the web of body station frame 303.9 inboard of stringer
16L. We are issuing this AD to detect and correct such cracking, which
could prevent the left forward entry door from sealing correctly, and
could cause in-flight decompression of the airplane.

DATES: This AD is effective September 23, 2008.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of September 23,
2008.

ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.

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 AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (telephone 800-647-5527) is the Document Management
Facility, U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Howard Hall, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6430; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. That NPRM was published in the Federal Register on September
13, 2007 (72 FR 52314). That NPRM proposed to require repetitive
inspections to detect cracking of the body station 303.9 frame, and
corrective action if necessary. That NPRM also proposed optional
terminating action for the repetitive inspections.

Comments

We gave the public the opportunity to participate in developing
this AD. We considered the comments received.

Support for the NPRM

Boeing concurs with the NPRM.

Request To Delay Final Rule

The Air Transport Association (ATA), on behalf of its member United
Airlines, requests that we delay issuing the final rule until kits (to
repair cracks or to terminate the repetitive inspections) are readily
available from Boeing. Only Boeing kits are specified; Boeing kit
65C37763-8 is under parts management control by Boeing.
We disagree with the request to delay issuing the final rule. To
delay this action would be inappropriate, since we have determined that
an unsafe condition exists, and that inspections must be conducted in a
timely manner to ensure continued safety. Boeing is aware of the
pending AD. We have been advised that kits are currently available from
Boeing Spares, and that Boeing has already made forecasts to ensure
continued kit availability. Operators that order out-of-stock kits from
Boeing can request permission from Boeing Spares to manufacture the
kits. We have been advised that Boeing Spares will provide the drawings
and specifications required to make kits. The kits related to this AD
are made up of simple parts that should be easy for operators to
fabricate. We have not changed the final rule regarding this issue.

Request To Allow Existing Repairs as Terminating Action

Continental requests that we revise the NPRM to allow existing FAA-
approved repairs (in the inspection area specified in the NPRM) as
terminating action for the proposed repetitive inspections. The
commenter notes that the service bulletin has no provisions for
inspecting existing FAA-approved repairs.
While certain previously installed repairs might be acceptable as a
terminating action for the AD inspections, we cannot classify all
previously installed repairs--even ones approved by the FAA--as
terminating action unless the repair is properly evaluated in light of
the requirements of this AD. Paragraph (j) of the final rule provides
operators the opportunity to request approval of specific repair
configurations as terminating action. Such a request should include
data/rationale to show that the repair configuration provides an
acceptable level of safety without continued inspections. We have not
changed the final rule regarding this issue.

Request To Extend Grace Period

Continental Airlines requests that we revise the NPRM to extend the
grace period for the initial inspection (for airplanes that have
exceeded the specified flight-cycle threshold). The commenter requests
an extension from 2,250 flight cycles to 4,500 flight cycles to
coincide with a scheduled heavy maintenance check. The commenter
asserts that the proposed grace period would not give operators
adequate time to comply with the AD without added financial and
logistical burden on the airlines. The commenter refers to AD 2005-20-
03, amendment 39-14296 (70 FR 56361, September 27, 2005). That AD also
applies to Boeing Model 737-100, -200, -200C, -300, -400, and -500
series airplanes. That AD requires repetitive inspections of the
intercostal webs, attachment clips, and stringer splice channels for
cracks; and corrective action if necessary. The commenter states that
the inspection area is the same for AD 2005-20-03 and the subject NPRM.
The grace period for that AD is 4,500 flight cycles, so extending the
grace period in the NPRM to 4,500 flight cycles will provide an
acceptable safety level in this AD.
We agree with the commenter's request and rationale. We have
revised paragraph (h) in this final rule accordingly. We have
coordinated this change with Boeing.

[[Page 48289]]

Request To Relax Dimensional Tolerances

Continental requests that the dimensional requirements be specified
to a maximum of two decimal places with a tolerance of
0.03 inch. Figure 11, detail A, of Boeing Alert Service Bulletin 737-
53A1188, Revision 2, dated May 9, 2007, specifies enlarging the slotted
hole to dimensions of three decimal places. (Boeing Alert Service
Bulletin 737-53A1197, dated August 25, 2006, contains similar
specifications.) The commenter asserts that a tight (three-decimal-
place) tolerance is virtually impossible to attain with this particular
modification.
We agree that the noted dimension in the service bulletin is shown
to three decimal places. But we disagree that the actual ``build to''
or ``measure to'' dimensions must be controlled to three decimal
places. According to paragraph 3.A. of the Accomplishment Instructions
of the service bulletin, the tolerance for linear dimensions is 0.03 inch. Given the two-decimal-place accuracy of this
tolerance, the corresponding final dimension will require only two-
decimal-place accuracy. So, for example, for a specified dimension of
1.29900 0.03, the final ``build to'' and ``measure to''
dimensions, when appropriately rounded to the 2-decimal-place tolerance
accuracy, are 1.27-1.33. We have not changed the final rule regarding
this issue.

Clarification of Required Service Information

We have revised the final rule to clarify that Revision 2 of Boeing
Alert Service Bulletin 737-53A1188 must be used for the requirements of
paragraph (f) of this AD.

Conclusion

We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD with the changes described previously. We also determined that
these changes will not increase the economic burden on any operator or
increase the scope of the AD.

Costs of Compliance

There are about 2,765 airplanes of the affected design in the
worldwide fleet. The following table provides the estimated costs,
depending on airplane configuration, for U.S. operators to comply with
this AD.

Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of U.S.-
Action Work hours Average labor Parts Cost per airplane registered Fleet cost
rate per hour airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection...................... 1 to 4.............. $80 None............... $80 to $320, per 1,154.............. $92,320 to
inspection cycle. $369,280, per
inspection cycle.
Repair/preventive change, if 12 to 30............ 80 $564 to $2,236..... $1,524 to $4,636.. Up to 1,154........ Up to $5,349,944.
done.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

This AD will not have federalism implications under Executive Order
13132. This AD will 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under 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.
You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec. 39.13 by adding the following new AD:

2008-17-03 Boeing: Amendment 39-15641. Docket No. FAA-2007-29174;
Directorate Identifier 2007-NM-125-AD.

Effective Date

(a) This airworthiness directive (AD) is effective September 23,
2008.

Affected ADs

(b) None.

Applicability

[[Page 48290]]

Table 1--Applicability
------------------------------------------------------------------------
As identified in Boeing Alert
Boeing model-- Service Bulletin--
------------------------------------------------------------------------
737-100, -200, and -200C series 737-53A1197, dated August 25,
airplanes. 2006.
737-300, -400, and -500 series 737-53A1188, Revision 2, dated
airplanes. May 9, 2007, or 737-53A1197,
dated August 25, 2006.
------------------------------------------------------------------------

Unsafe Condition

(d) This AD results from reports of cracks found at the cutout
in the web of body station frame 303.9 inboard of stringer 16L. We
are issuing this AD to detect and correct such cracking, which could
prevent the left forward entry door from sealing correctly, and
could cause in-flight decompression of the airplane.

Compliance

(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.

Repetitive Inspections: Service Bulletin 737-53A1188

(f) For airplanes identified in Boeing Alert Service Bulletin
737-53A1188, Revision 2, dated May 9, 2007, including airplanes
modified by the repair/preventive change specified in the original
version, dated April 9, 1998; or Revision 1, dated March 18, 1999;
of the service bulletin: Do detailed and high frequency eddy current
(HFEC) inspections in the web and doubler around the slotted holes
in the frame web at stringers 15L and 16L, in accordance with the
Accomplishment Instructions of Revision 2 of the service bulletin.
Do the inspections at the applicable time specified in paragraph
1.E. of Revision 2 of the service bulletin, except as provided by
paragraph (h) of this AD. Do all applicable corrective actions
before further flight in accordance with Revision 2 of the service
bulletin, except as provided by paragraph (i) of this AD. Repeat the
inspections at intervals not to exceed 4,500 flight cycles until
accomplishment of the repair/preventive change in accordance with
Revision 2 of the service bulletin, which terminates the repetitive
inspection requirements. A repair/preventive change done in
accordance with the original version or Revision 1 of the service
bulletin does not terminate the repetitive inspections, but the
repetitive inspections may be terminated after the existing kit is
replaced with a new kit in accordance with paragraph 3.B., Part II,
step 3, or Part III, step 3, of Revision 2 of the service bulletin.

Repetitive Inspections: Service Bulletin 737-53A1197

(g) For airplanes identified in Boeing Alert Service Bulletin
737-53A1197, dated August 25, 2006: Do an ultrasound inspection of
the slot-shaped cutout in the web for the door stop strap at
stringer 16L, an HFEC inspection of the web along the upper and
lower edges of the doubler around the doorstop strap at stringer
16L, and a detailed inspection of the web around the doubler for the
cutout at stringer 16L, in accordance with the Accomplishment
Instructions of the service bulletin. Do the inspections at the
applicable time specified in paragraph 1.E. of the service bulletin,
except as provided by paragraph (h) of this AD. Do all applicable
corrective actions before further flight in accordance with the
service bulletin, except as provided by paragraph (i) of this AD.
Repeat the inspections at intervals not to exceed 4,500 flight
cycles, until accomplishment of the repair/preventive change in
accordance with the service bulletin, which terminates the
repetitive inspections.

Exceptions to Service Bulletin Specifications

(h) Where Boeing Alert Service Bulletin 737-53A1188, Revision 2,
dated May 9, 2007, and Boeing Alert Service Bulletin 737-53A1197,
dated August 25, 2006, specify a compliance time after release of
the service bulletin, this AD requires compliance within the
specified time after the effective date of this AD. For the initial
inspection, the grace period for airplanes that have exceeded the
specified threshold is extended to 4,500 flight cycles after the
effective date of this AD.
(i) Where Boeing Alert Service Bulletin 737-53A1188, Revision 2,
dated May 9, 2007, and Boeing Alert Service Bulletin 737-53A1197,
dated August 25, 2006, specify to contact Boeing for appropriate
action, including repair of damage outside the scope of the service
bulletin, repair using a method approved in accordance with the
procedures specified in paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office, FAA,
ATTN: Howard Hall, Aerospace Engineer, Airframe Branch, ANM-120S;
telephone (425) 917-6430; fax (425) 917-6590; has the authority to
approve AMOCs for this AD, if requested using the procedures found
in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.
(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 an
Authorized Representative for the Boeing Commercial Airplanes
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 repair must meet the certification basis
of the airplane, and the approval must specifically refer to this
AD.

Material Incorporated by Reference

(k) You must use Boeing Alert Service Bulletin 737-53A1188,
Revision 2, dated May 9, 2007; or Boeing Alert Service Bulletin 737-
53A1197, dated August 25, 2006; as applicable; to do the actions
required by this AD; unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington
98124-2207.
(3) You may review copies of the service information
incorporated by reference at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the
National Archives and Records Administration (NARA). For information
on the availability of this material at NARA, call 202-741-6030, or
go to http://www.archives.gov/federal_register/code_of_federal_
regulations/ibr_locations.html.

Issued in Renton, Washington, on August 6, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-18812 Filed 8-18-08; 8:45 am]

BILLING CODE 4910-13-P