DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION
14 CFR Part 39
[Docket No. FAA-2010-0764; Directorate Identifier 2009-NM-260-AD]
RIN 2120-AA64
AIRWORTHINESS DIRECTIVES; The Boeing Company Model 737-900ER
Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Model 737-900ER series airplanes. This proposed AD would require
doing a one-time general visual inspection for a keyway in two fuel tank
access door cutouts, and related investigative and corrective actions if
necessary. This proposed AD results from reports of cracks emanating from
the keyway of the fuel tank access hole. We are proposing this AD to
detect and correct such cracking, which could result in the loss of the
lower wing skin load path and consequent structural failure of the wing.
DATES: We must receive comments on this proposed AD by September 24, 2010.
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: 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 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 (telephone 800-647-5527) is in the ADDRESSES section.
Comments will be available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, Airframe
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6440; fax
(425) 917-6590.
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-2010-0764; Directorate
Identifier 2009-NM-260-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
We have received reports of cracks, ranging from 0.02 to 0.380 inch in
length emanating from the keyway of the fuel tank access hole on the wing
lower skin between wing rib numbers 8 and 9 on Model 777-200LR and 777
-300ER series airplanes. The fuel tank access door at this location has a
fuel measuring stick installed, and the keyway is used to ensure that the
fuel measuring stick is oriented correctly when the fuel tank access door
is installed. The crack is believed to be the result of fatigue due to the
position of the keyway. The lower wing skins on Model 737-900ER series
airplanes have fuel tank access holes with the same configuration as that
of the affected fuel tank access holes on Model 777-300ER series
airplanes. The affected fuel tank access holes on the Model 737-900ER
series airplanes are located between ribs 4 and 5, between wing stations
180 and 204.25. These fuel tank access holes are for fuel tank access
doors 531BB and 631BB. Although cracks have not yet been reported on any
Model 737-900ER series airplanes, damage tolerance analysis shows
potential for Model 737-900ER series airplanes lower wing skins to crack
at the noted locations. This condition, if not corrected, could result in
the loss of the lower wing skin load path and consequent structural
failure of the wing.
RELEVANT SERVICE INFORMATION
We have reviewed Boeing Alert Service Bulletin 737-57A1308, Revision 1,
dated October 1, 2009. The service bulletin describes procedures for a
general visual inspection for a keyway in the fuel tank access door cutout
on the left and right wings, and related investigative and corrective
actions if necessary. The related investigative action is a high frequency
eddy current inspection for cracking of the keyway. The corrective actions
include changing the profile of the keyway for the fuel tank access door
cutout, repairing any cracking of the keyway of the access door cutout,
and contacting Boeing for certain repair instructions and doing the
repair.
FAA'S DETERMINATION AND REQUIREMENTS OF THIS PROPOSED AD
We are proposing this AD because we evaluated all relevant information and
determined the unsafe condition described previously is likely to exist or
develop in other products of the same type design. This proposed AD would
require accomplishing the actions specified in the service information
described previously, except as discussed under "Difference Between the
Proposed AD and Service Bulletin."
DIFFERENCE BETWEEN THE PROPOSED AD AND SERVICE BULLETIN
Boeing Alert Service Bulletin 737-57A1308, Revision 1, dated October 1,
2009, specifies to contact the manufacturer for instructions on how to
repair certain conditions, but this proposed AD would require repairing
those conditions in one of the following ways:
Using 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), whom we have authorized to make those
findings.
OTHER RELEVANT RULEMAKING
The lower wing skins on Model 777-200LR and 777-300ER series airplanes
have fuel tank access holes with the same configuration as those of the
affected fuel tank access holes on the Model 737-900ER airplanes.
Therefore, Model 777-200LR and 777-300ER series airplanes may be subject
to the identified unsafe condition. We are considering similar rulemaking
related to the identified unsafe condition for certain Model 777-200LR and
777-300ER series airplanes.
COSTS OF COMPLIANCE
We estimate that this proposed AD would affect 30 airplanes of U.S.
registry. We also estimate that it would take 3 work-hours per product to
comply with this proposed AD. The average labor rate is $85 per work-hour.
Based on these figures, we estimate the cost of this proposed AD to the
U.S. operators to be $7,650, or $255 per product.
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 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 this 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.
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.
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 adding the following new AD: