
[Federal Register: May 29, 2008 (Volume 73, Number 104)]
[Rules and Regulations]               
[Page 30760-30763]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29my08-10]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0263; Directorate Identifier 2007-NM-207-AD; 
Amendment 39-15530; AD 2008-11-08]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all 
Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes. This AD requires repetitive inspections for any cracking of 
or damage to the left side and right side flight deck No. 2, No. 4, and 
No. 5 windows, as necessary, and corrective actions if necessary. This 
AD results from reports of in-flight departure and separation of the 
flight deck windows. We are issuing this AD to detect and correct 
cracking in the vinyl interlayer or damage to the structural inner 
glass panes of the flight deck No. 2, No. 4, and No. 5 windows, which 
could result in loss of a window and rapid loss of cabin pressure. Loss 
of cabin pressure could cause crew communication difficulties or crew 
incapacitation.

DATES: This AD is effective July 3, 2008.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of July 3, 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,

[[Page 30761]]

1200 New Jersey Avenue, SE., Washington, DC 20590.

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.

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 
all Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. 
That NPRM was published in the Federal Register on December 3, 2007 (72 
FR 67864). That NPRM proposed to require repetitive inspections for any 
cracking of or damage to the left side and right side flight deck No. 
2, No. 4, and No. 5 windows, as necessary, and corrective actions if 
necessary.

Changes Made to This AD

    We have revised the applicability of this AD to clearly identify 
that Boeing Model 737-900ER series airplanes are also subject to the 
requirements of this AD. These airplanes were not previously identified 
in the applicability of the NPRM because they were type certificated 
after issuance of Boeing Alert Service Bulletin 737-56A1022, dated July 
18, 2007, which we referenced for the applicability of the NPRM. 
Although these airplanes are not explicitly identified in the 
effectivity of the service bulletin, they are included as Group 2 
airplanes in the service bulletin.
    We have deleted paragraph (h)(4) of the NPRM and added a new 
paragraph (h) to this AD specifying that installation of metallic 
window blanks at cockpit eyebrow windows No. 4 and No. 5 in accordance 
with Supplemental Type Certificate (STC) ST01630SE terminates the 
initial and repetitive inspections for the flight deck No. 4 and No. 5 
windows required by paragraph (f) of this AD. Incorporation of STC 
ST01630SE is considered a terminating action, not an alternative method 
of compliance (AMOC), since an AMOC can be issued only after an AD has 
been issued. We also have reidentified the AMOC paragraph of the NPRM 
as paragraph (j) in this AD.

Comments

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

Support for the NPRM

    Boeing and AirTran Airways agree with the NPRM.

Request To Add Terminating Action

    AirTran Airways and Continental Airlines (CAL) request that we 
revise the NPRM to specify that installing structural plugs at cockpit 
eyebrow windows No. 4 and No. 5 in accordance with Boeing Service 
Bulletin 737-56-1017, dated May 17, 2006; or Revision 1, dated February 
15, 2007; terminates the initial and repetitive inspections for the 
flight deck No. 4 and No. 5 windows. CAL notes that a similar statement 
is found in Tables 2 and 3 of Boeing Alert Service Bulletin 737-
56A1022, dated July 18, 2007. (We referred to Boeing Alert Service 
Bulletin 737-56A1022 as the appropriate source of service information 
for accomplishing the proposed requirements of the NPRM.)
    We agree with the commenters and have added a new paragraph (i) to 
this AD accordingly.

Request To Revise the Applicability

    CAL requests that we limit the applicability of the NPRM to 
airplanes delivered before line number 2589. As justification, CAL 
states that new production airplanes do not include the flight deck No. 
4 and No. 5 windows, and that Boeing is in the final stages of 
approving a new, improved flight deck No. 2 window, part numbers 5-
89355-87 and -88. According to CAL, the new, improved No. 2 window, 
which is manufactured by PPG Aerospace, is designed specifically to 
address the unsafe condition of the NPRM. CAL also states that Boeing 
plans to install the new, improved No. 2 windows on new production 
airplanes this year.
    We do not agree to exclude any airplanes from the applicability of 
this AD. The affected flight deck No. 2 windows are interchangeable 
with the new, improved windows manufactured by PPG Aerospace; 
therefore, the unsafe condition could be introduced on a new production 
airplane if an affected No. 2 window is installed after airplane 
delivery. We have not changed this AD in this regard.

Request To Track Compliance Time by Flight Cycles

    AirTran Airways requests that we add an option to this AD to allow 
operators to track the inspections by airplane flight cycles instead of 
window flight hours, provided that any used window is inspected before 
it is installed. AirTran Airways states that tracking compliance by a 
component rather than by airplane is more difficult due to the extra 
work and documentation generated for the removal and installation of a 
component. According to AirTran Airways, tracking compliance by 
component also increases the opportunity for human factor errors. 
AirTran Airways also states that tracking inspections by airplane 
flight cycles will accomplish the inspections within the same timeframe 
as proposed in the NPRM and be less of a burden.
    We disagree with allowing operators to track compliance by airplane 
flight cycles because the unsafe condition is primarily related to 
window flight hours. The utilization of airplanes within the fleet 
varies from short to long flight hours per flight cycle. Therefore, we 
have not changed this AD in this regard.

Request To Revise the Compliance Time for the No. 2 Window

    CAL requests that we revise the compliance time for the initial 
inspection of the flight deck No. 2 window to within 36 months or 7,500 
flight hours, whichever occurs first, after the window installation; or 
to within 24 months, for windows installed more than 36 months ago or 
for windows where the number of flight hours is unknown. CAL states 
that the NPRM, which proposes to require the initial inspection within 
24 months after the effective date of this AD regardless of the age or 
flight time of the window, unnecessarily penalizes operators who 
proactively inspect and replace the No. 2 window before the AD is 
issued. CAL also states that, according to the wording in the NPRM, a 
window replaced one day before the effective date of the AD would need 
to be re-inspected within 24 months, but a window inspected and 
replaced one day after the effective date of the AD would not need to 
be re-inspected until 36 months or 7,500 window flight hours.
    We do not agree to revise the compliance time for the initial 
inspection of the flight deck No. 2 window. According to paragraph (e) 
of this AD, an operator is responsible for having the actions required 
by this AD performed within the compliance times specified, unless the 
actions have already been done. If the initial inspection of the No. 2 
window was done before the effective date of this AD in accordance with 
Boeing Alert Service Bulletin 737-56A1022, dated July 18, 2007, then 
the initial inspection does not need to be accomplished again; only the 
repetitive inspections would need to be accomplished in accordance with 
the service bulletin at the applicable interval specified in the 
service bulletin.

[[Page 30762]]

If the initial and repetitive inspections of the No. 2 window are done 
before the effective date of this AD, but are not done in accordance 
with the service bulletin, then those inspections are not acceptable 
for compliance with this AD unless an AMOC is issued for those prior 
inspections. Under the provisions of paragraph (j) of this AD, we will 
consider requests for approval of an AMOC if sufficient data are 
submitted to substantiate that prior inspections incorporate similar 
criteria to what is provided for in the service bulletin. Therefore, no 
change to this AD is necessary in this regard.

Request for an AMOC for a Parts Manufacturer Approval (PMA) Equivalent 
Part

    CAL states that the FAA has approved a new, improved flight deck 
No. 2 window designed by GKN Aerospace Transparency Systems, under PMA 
Holder No. PQ1250NM, Supplement 10, dated September 17, 2007. CAL also 
states that the new, improved No. 2 window was designed to prevent the 
premature failure of the window, and that the new, improved window 
addresses the unsafe condition of the NPRM. CAL, therefore, requests 
that we add a new AMOC paragraph to this AD, which would exempt the 
new, improved No. 2 window from the required inspections.
    We do not agree to allow the PMA equivalent No. 2 window as an AMOC 
to the required inspections. Although the window has been approved as a 
PMA equivalent part, the commenter has not provided data showing that 
the PMA equivalent window is not susceptible to the same vinyl 
interlayer cracking. However, under the provisions of paragraph (j) of 
this AD, we will consider requests for approval of an AMOC if 
sufficient data are submitted to substantiate that the design change 
would provide an acceptable level of safety. No change to this AD is 
necessary in this regard.

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 2,127 airplanes of the affected design in the 
worldwide fleet. This AD affects about 737 airplanes of U.S. registry. 
The required actions take about 2 work hours per airplane, at an 
average labor rate of $80 per work hour. Based on these figures, the 
estimated cost of the AD for U.S. operators is $117,920, or $160 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

    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:

2008-11-08 Boeing: Amendment 39-15530. Docket No. FAA-2007-0263; 
Directorate Identifier 2007-NM-207-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective July 3, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes, certificated in any 
category.

Unsafe Condition

    (d) This AD results from reports of in-flight departure and 
separation of the flight deck windows. We are issuing this AD to 
detect and correct cracking in the vinyl interlayer or damage to the 
structural inner glass panes of the flight deck No. 2, No. 4, and 
No. 5 windows, which could result in loss of a window and rapid loss 
of cabin pressure. Loss of cabin pressure could cause crew 
communication difficulties or crew incapacitation.

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 and Replacement

    (f) At the applicable times specified in Tables 1, 2, and 3 of 
paragraph 1.E. of Boeing Alert Service Bulletin 737-56A1022, dated 
July 18, 2007, except as provided by paragraph (g) of this AD: Do 
the internal and external detailed inspections for any cracking of 
or damage to the left side and right side flight deck No. 2, No. 4, 
and No. 5 windows, as applicable, and do the applicable corrective 
actions before further flight, by accomplishing all of the 
applicable actions specified in the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-56A1022, dated July 18, 2007. 
Repeat the inspections thereafter at the applicable interval 
specified in paragraph 1.E. of Boeing Alert Service Bulletin 737-
56A1022, dated July 18, 2007.

Exception to Compliance Times

    (g) Where Tables 1, 2, and 3 of paragraph 1.E. of Boeing Alert 
Service Bulletin 737-56A1022, dated July 18, 2007, specify counting 
the compliance time from `` * * * the date on this service 
bulletin,'' this AD requires counting the compliance time from the 
effective date of this AD.

[[Page 30763]]

Optional Terminating Actions

    (h) Installation of metallic window blanks at cockpit eyebrow 
windows No. 4 and No. 5 in accordance with Supplemental Type 
Certificate ST01630SE terminates the initial and repetitive 
inspections for the flight deck No. 4 and No. 5 windows required by 
paragraph (f) of this AD. All other applicable actions required by 
paragraph (f) of this AD must be fully complied with.
    (i) Installation of structural plugs at cockpit eyebrow windows 
No. 4 and No. 5 in accordance with Boeing Service Bulletin 737-56-
1017, dated May 17, 2006; or Revision 1, dated February 15, 2007, 
terminates the initial and repetitive inspections for the flight 
deck No. 4 and No. 5 windows required by paragraph (f) of this AD. 
All other applicable actions required by paragraph (f) of this AD 
must be fully complied with.

Alternative Methods of Compliance (AMOCs)

    (j)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) 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 737-56A1022, 
dated July 18, 2007, to do the actions required by this AD, unless 
the AD specifies otherwise. If you do the optional actions specified 
in this AD, you must use Boeing Service Bulletin 737-56-1017, dated 
May 17, 2006; or Boeing Service Bulletin 737-56-1017, Revision 1, 
dated February 15, 2007, 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 May 10, 2008.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-11336 Filed 5-28-08; 8:45 am]

BILLING CODE 4910-13-P
