
[Federal Register Volume 76, Number 131 (Friday, July 8, 2011)]
[Proposed Rules]
[Pages 40288-40291]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-17267]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0652; Directorate Identifier 2010-NM-045-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model MD-90-30 
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 all 
Model MD-90-30 airplanes. This proposed AD would require repetitive 
eddy current high frequency (ETHF) inspections for cracking on the aft 
side of the left and right wing rear spar lower caps at station Xrs = 
164.000, further ETHF inspections if cracks are found, and repair if 
necessary. This proposed AD would also require repetitive post-repair 
inspections and repair if necessary. This proposed AD was prompted by 
reports of cracks of the wing rear spar lower cap at the outboard flap, 
inboard drive hinge at station Xrs = 164.000. We are proposing this AD 
to detect and correct cracking of the left and right rear spar lower 
caps, which could result in fuel leaks and damage to the wing skin or 
other structure, and consequent loss of the structural integrity of the 
wing.

DATES: We must receive comments on this proposed AD by August 22, 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: 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, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail 
dse.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: Roger Durbin, Airframe Branch, ANM-
120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 
Paramount Boulevard, Lakewood, California 90712-4137; phone (562) 627-
5233; fax (562) 627-5210; e-mail: roger.durbin@faa.gov.

SUPPLEMENTARY INFORMATION:

[[Page 40289]]

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-2011-0652; 
Directorate Identifier 2010-NM-045-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 of the wing rear spar lower cap 
at the outboard flap, inboard drive hinge at station Xrs = 164.000, on 
Model MD-80 airplanes. It has been determined that these cracks are the 
result of material fatigue from normal flap operating loads. This 
condition, if not corrected, could result in fuel leaks and damage to 
the wing skin or other structure, and consequent loss of the structural 
integrity of the wing.
    The subject area on Model MD-90-30 airplanes is almost identical to 
that on Model MD-80 airplanes. Therefore, Model MD-90-30 airplanes may 
be subject to the unsafe condition revealed on Model MD-80 airplanes.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin MD90-57A026, 
Revision 1, dated February 23, 2011. This service bulletin describes 
procedures for repetitive eddy current high frequency (ETHF) 
inspections for cracks on the left and right rear spar lower caps at 
station Xrs=164.000, further ETHF inspections if cracks are found, 
optional and non-optional repairs, and repetitive post-repair 
inspections.

FAA's Determination

    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.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously, except as discussed 
under ``Differences Between the Proposed AD and the Service 
Information.''

Differences Between the Proposed AD and the Service Information

    Boeing Alert Service Bulletin MD90-57A026, Revision 1, dated 
February 23, 2011, does not specify corrective actions if cracking is 
found during any inspection of repaired areas, but this proposed AD 
would require repairing those conditions in one of the following ways:
     In accordance with 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.

Costs of Compliance

    We estimate that this proposed AD would affect 17 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                                     Estimated Costs
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                Action                            Labor cost            Parts cost      Cost per product                Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection............................  4 work-hours x $85 per hour =          N/A  $340 per inspection       $5,780 per inspection cycle.
                                         $340 per inspection cycle.                  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

    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),
    (3) Will not affect intrastate aviation in Alaska, and
    (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 adding the following new AD:


[[Page 40290]]


The Boeing Company: Docket No. FAA-2011-0652; Directorate Identifier 
2010-NM-045-AD.

Comments Due Date

    (a) We must receive comments by August 22, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all The Boeing Company Model MD-90-30 
airplanes, certificated in any category.

Subject

    (d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

    (e) This AD was prompted by reports of cracks of the wing rear 
spar lower cap at the outboard flap, inboard drive hinge at station 
Xrs = 164.000. We are issuing this AD to detect and correct cracking 
of the left and right rear spar lower caps, which could result in 
fuel leaks and damage to the wing skin or other structure, and 
consequent loss of the structural integrity of the wing.

Compliance

    (f) 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, Further Inspections if Cracking Found, Repair, 
and Repetitive Post-Repair Inspections

    (g) Before the accumulation of 30,000 total flight cycles, or 
within 10,000 flight cycles after the effective date of this AD, 
whichever occurs later, do an eddy current high frequency (ETHF) 
inspection for cracking on the aft side of the left and right wing 
rear spar lower caps at station Xrs = 164.000, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
MD90-57A026, Revision 1, dated February 23, 2011. If no cracking is 
found on the left or right wing rear spar lower cap, repeat the 
inspection on the affected wing rear spar lower cap thereafter at 
intervals not to exceed 2,550 flight cycles. Doing a repair of the 
left or right wing rear spar lower cap required by this AD 
terminates the repetitive inspection required by this paragraph for 
that side only.
    (h) If, during any inspection required by paragraph (g) of this 
AD, any crack is found that is two inches or less and not in the 
rear spar lower cap forward horizontal leg radius: Before further 
flight, do an ETHF inspection for cracking on the affected wing rear 
spar upper cap at station Xrs = 164.000, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011.
    (1) If no crack is found in the rear spar upper cap during the 
inspection required in paragraph (h) of this AD, do the actions 
specified in paragraph (h)(1)(i) or (h)(1)(ii) of this AD.
    (i) Option 1: Before further flight, do a doubler repair of the 
rear spar lower cap, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-57A026, Revision 
1, dated February 23, 2011. Within 13,500 flight cycles after doing 
the doubler repair, do an ETHF inspection for any cracking in the 
repaired area of the rear spar lower cap, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Repeat the inspection 
thereafter at intervals not to exceed 8,500 flight cycles. If any 
cracking is found during any inspection required by this paragraph, 
before further flight, repair in accordance with a method approved 
in accordance with the procedures specified in paragraph (k) of this 
AD.
    (ii) Option 2: Before further flight, do a splice repair of the 
rear spar lower cap, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-57A026, Revision 
1, dated February 23, 2011. Within 20,000 flight cycles after doing 
the splice repair, do an eddy current low frequency (ETLF) 
inspection and an ultrasonic (UT) inspection for cracking in the 
repaired area of the rear spar lower cap, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Repeat the inspections 
thereafter at intervals not to exceed 3,000 flight cycles. If any 
cracking is found during any inspection required by this paragraph, 
before further flight, repair in accordance with a method approved 
in accordance with the procedures specified in paragraph (k) of this 
AD.
    (2) If any crack that is two inches or less is found in the rear 
spar upper cap during the inspection required by paragraph (h) of 
this AD, do the actions specified in paragraph (h)(2)(i) or 
(h)(2)(ii) of this AD.
    (i) Option 1: Before further flight, do a doubler repair of the 
rear spar upper and lower caps, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Within 13,500 flight 
cycles after doing the doubler repair, do an ETHF inspection for any 
cracking in the repaired area of the rear spar upper and lower caps, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Repeat the inspection thereafter at intervals not to exceed 8,500 
flight cycles. If any cracking is found during any inspection 
required by this paragraph, before further flight, repair in 
accordance with a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.
    (ii) Option 2: Before further flight, do a splice repair of the 
rear spar upper and lower caps, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Within 20,000 flight 
cycles after doing the splice repair, do an ETLF inspection and a UT 
inspection for any cracking in the repaired area of the rear spar 
lower cap, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-57A026, Revision 1, dated 
February 23, 2011. Repeat the inspections thereafter at intervals 
not to exceed 3,000 flight cycles. If any cracking is found during 
any inspection required by this paragraph, before further flight, 
repair in accordance with a method approved in accordance with the 
procedures specified in paragraph (k) of this AD.
    (3) If any crack that is greater than two inches is found in the 
rear spar upper cap during the inspection required by paragraph (h) 
of this AD, do the actions specified in paragraph (h)(3)(i) or 
(h)(3)(ii) of this AD.
    (i) Option 1: Before further flight, do a splice repair of the 
rear spar upper cap and a doubler repair of the rear spar lower cap, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Within 13,500 flight cycles after doing the doubler repair, do an 
ETHF inspection for any cracking in the repaired area of the rear 
spar lower cap, in accordance with the Accomplishment Instructions 
of Boeing Alert Service Bulletin MD90-57A026, Revision 1, dated 
February 23, 2011. Repeat the inspection thereafter at intervals not 
to exceed 8,500 flight cycles. If any cracking is found during any 
inspection required by this paragraph, before further flight, repair 
in accordance with a method approved in accordance with the 
procedures specified in paragraph (k) of this AD.
    (ii) Option 2: Before further flight, do a splice repair of the 
rear spar upper and lower caps, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Within 20,000 flight 
cycles after doing the splice repair, do an ETLF inspection and a UT 
inspection for any cracking in the repaired area of the rear spar 
lower cap, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-57A026, Revision 1, dated 
February 23, 2011. Repeat the inspections thereafter at intervals 
not to exceed 3,000 flight cycles. If any cracking is found during 
any inspection required by this paragraph, before further flight, 
repair in accordance with a method approved in accordance with the 
procedures specified in paragraph (k) of this AD.
    (i) If any crack is found during any inspection required by 
paragraph (g) of this AD that is greater than two inches or is in 
the rear spar lower cap forward horizontal leg radius, before 
further flight, do an ETHF for cracking on the affected wing rear 
spar upper cap at station Xrs = 164.000, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011.
    (1) If no crack is found in the rear spar upper cap, before 
further flight, do a splice repair of the rear spar lower cap, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Within 20,000 flight cycles after doing the splice repair, do an 
ETLF and a UT inspection for any cracking of the repaired area of 
the lower rear spar cap, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-57A026, Revision 
1, dated February 23, 2011. Repeat the inspection thereafter at 
intervals not to exceed 3,000 flight cycles. If any cracking is 
found during any inspection required by this

[[Page 40291]]

paragraph, before further flight, repair in accordance with a method 
approved in accordance with the procedures specified in paragraph 
(k) of this AD.
    (2) If any crack that is two inches or less is found in the rear 
spar upper cap, do the actions specified in paragraph (i)(2)(i) or 
(i)(2)(ii) of this AD.
    (i) Option 1: Do the actions specified in paragraphs 
(i)(2)(i)(A), (i)(2)(i)(B), and (i)(2)(i)(C) of this AD.
    (A) Before further flight, do a doubler repair of the rear spar 
upper cap and a splice repair of the rear spar lower cap, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011.
    (B) Within 13,500 flight cycles after doing the doubler repair 
required by paragraph (i)(2)(i)(A) of this AD, do an ETHF inspection 
for any cracking in the repaired area of the rear spar upper cap, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Repeat the inspection thereafter at intervals not to exceed 8,500 
flight cycles. If any cracking is found during any inspection 
required by this paragraph, before further flight, repair in 
accordance with a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.
    (C) Within 20,000 flight cycles after doing the splice repair 
required by paragraph (i)(2)(i)(A) of this AD, do an ETLF and a UT 
inspection for cracking in the repaired area of the rear spar lower 
cap, in accordance with the Accomplishment Instructions of Boeing 
Alert Service Bulletin MD90-57A026, Revision 1, dated February 23, 
2011. Repeat the inspections thereafter at intervals not to exceed 
3,000 flight cycles. If any cracking is found during any inspection 
required by this paragraph, before further flight, repair in 
accordance with a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.
    (ii) Option 2: Before further flight, do a splice repair of the 
rear spar upper and lower caps, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Within 20,000 flight 
cycles after doing the splice repair, do an ETLF and a UT inspection 
for cracking in the repaired area of the rear spar lower cap, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Repeat the inspections thereafter at intervals not to exceed 3,000 
flight cycles. If any cracking is found during any inspection 
required by this paragraph, before further flight, repair in 
accordance with a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.
    (3) If any crack that is greater than two inches is found in the 
rear spar upper cap, before further flight, do a splice repair of 
the rear spar upper and lower caps, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
57A026, Revision 1, dated February 23, 2011. Within 20,000 flight 
cycles after doing the splice repair, do an ETLF and a UT inspection 
for cracking in the repaired area of the rear spar lower cap, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A026, Revision 1, dated February 23, 2011. 
Repeat the inspections thereafter at intervals not to exceed 3,000 
flight cycles. If any cracking is found during any inspection 
required by this paragraph, before further flight, repair in 
accordance with a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.

Credit for Actions Accomplished in Accordance With Previous Service 
Information

    (j) Doing an ETHF inspection for cracks, and doing a doubler 
repair to the rear spar upper and lower caps in accordance with 
Boeing Alert Service Bulletin MD90-57A026, dated February 11, 2010, 
before the effective date of this AD, are acceptable for compliance 
with the corresponding actions required by paragraphs (g), (h), and 
(i) of this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Los Angeles Aircraft Certification Office 
(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.
    (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 Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Los Angeles ACO, to 
make those findings. For a repair method to be approved, the repair 
must meet the certification basis of the airplane and 14 CFR 25.571, 
Amendment 45, and the approval must specifically refer to this AD.

Related Information

    (l) For more information about this AD, contact Roger Durbin, 
Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; phone: (562) 627-5233; 
fax: (562) 627-5210; e-mail: roger.durbin@faa.gov.
    (m) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail 
dse.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.

    Issued in Renton, Washington, on June 29, 2011.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-17267 Filed 7-7-11; 8:45 am]
BILLING CODE 4910-13-P


