[Federal Register Volume 77, Number 12 (Thursday, January 19, 2012)]
[Proposed Rules]
[Pages 2664-2666]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-858]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1415; Directorate Identifier 2011-NM-145-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 
The Boeing Company Model 717-200 airplanes. This proposed AD was 
prompted by reports of cracks found on the center section ribs of the 
horizontal stabilizers. This proposed AD would require repetitive 
inspections for cracking of the aft face of the left and right rib 
hinge bearing lugs of the center section of the horizontal stabilizer; 
and crack measurement, repairs, and installation of a new center 
section rib if necessary. We are proposing this AD to detect and 
correct cracks in the left and right bearing lugs of the rib hinge 
spreading at the same time, which could result in failure of both hinge 
bearing lugs. Failure of the hinge bearing lugs could result in the 
inability of the horizontal stabilizer to sustain flight loads and 
therefore reduce the controllability of the airplane.

DATES: We must receive comments on this proposed AD by March 5, 2012.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, 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: Deliver to Mail address above 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; phone: (206) 544-5000, extension 2; fax: (206) 766-5683; email: 
[email protected]; 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 (phone: (800) 647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: George Garrido, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712-
4137; phone: (562) 627-5357; fax: (562) 627-5210; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-1415; 
Directorate Identifier 2011-NM-145-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

[[Page 2665]]

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 found on the left, right, or, in 
several instances, both of the center section ribs of the horizontal 
stabilizer on Model MD-80 and MD-90 series airplanes. Two cracks were 
reported on Model MD-80 series airplanes having accumulated between 
23,700 and 41,963 total flight hours and between 23,300 and 35,294 
total flight cycles. Nine cracks were reported on Model MD-90 series 
airplanes having accumulated between 9,051 and 26,053 total flight 
hours and between 8,939 and 25,260 total flight cycles. These cracks 
were found on the aft face of the hinge bearing lugs of the horizontal 
stabilizer. Undetected cracks in the left and right bearing lugs of the 
rib hinge, if not corrected, could spread at the same time, which could 
result in failure of both hinge bearing lugs, the inability of the 
horizontal stabilizer to sustain flight loads, and consequent reduced 
controllability of the airplane.
    The design of the horizontal rib on Model 717-200 airplanes is the 
same rib design used on Model MD-80 and MD-90 series airplanes, and is 
susceptible to the same failure mode. Therefore, Model 717-200 
airplanes may also be subject to the identified unsafe condition.

Related Rulemaking

    We have issued similar rulemaking in AD 2011-01-11, Amendment 39-
16565 (76 FR 430, January 5, 2011), for The Boeing Company Model MD-90 
airplanes, that requires repetitive high frequency eddy current (HFEC) 
inspections for cracking on the hinge bearing lugs of the left and 
right sides of the center section ribs of the horizontal stabilizer, 
and related investigative and corrective actions if necessary.
    We have also issued NPRM 2011-NM-027-AD (76 FR 53346, August 26, 
2011), for The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), 
DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. That NPRM 
proposes to require repetitive HFEC inspections for cracking of the 
left and right rib hinge bearing lugs of the aft face of the center 
section of the horizontal stabilizer; measuring crack length and 
blending out cracks; and replacing the horizontal stabilizer center 
section rib, if necessary.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 717-55A0011, dated May 
17, 2011. This service information describes procedures for repetitive 
eddy current high frequency (ETHF) inspections for cracks on the aft 
face on the left and right rib hinge bearing lugs of the center section 
of the horizontal stabilizer; and crack measurement, repairs, post-
repair repetitive inspections, and installation of a new center section 
rib if necessary.

FAA's Determination

    We are proposing this AD because we evaluated all the 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

    Operators should note that, although the Accomplishment 
Instructions of Boeing Alert Service Bulletin 717-55A0011, dated May 
17, 2011, describe procedures for submitting inspection results, this 
proposed AD would not require those actions.

 Costs of Compliance

    We estimate that this proposed AD affects 129 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
ETHF Inspection                    6 work-hours x $85               $0  $510 per inspection  $65,790 per
                                    per hour = $510                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

     We have received no definitive data that would enable us to 
provide cost estimates for the on-condition labor costs specified in 
this proposed AD. The estimated parts cost for a replacement rib is 
$16,387.

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.

[[Page 2666]]

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 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2011-1415; Directorate Identifier 
2011-NM-145-AD.

(a) Comments Due Date

    We must receive comments by March 5, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 717-200 
airplanes, certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 5510, Horizontal Stabilizer Structure.

(e) Unsafe Condition

    This AD was prompted by reports of cracks found on the center 
section ribs of the horizontal stabilizers. We are issuing this AD 
to detect and correct cracks in the left and right bearing lugs of 
the rib hinge spreading at the same time, which could result in 
failure of both hinge bearing lugs. Failure of the hinge bearing 
lugs could result in the inability of the horizontal stabilizer to 
sustain flight loads and therefore reduce the controllability of the 
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Repetitive Eddy Current High Frequency (ETHF) Inspections

    Before the accumulation of 35,000 total flight cycles, or within 
8,275 flight cycles after the effective date of this AD, whichever 
occurs later: Do an ETHF inspection for cracks of the aft face on 
the left and right rib hinge bearing lugs of the center section of 
the horizontal stabilizer, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 717-55A0011, dated May 
17, 2011. If no crack is found, repeat the inspection thereafter at 
intervals not to exceed 10,500 flight cycles.

 (h) Crack Measurement

    If any crack is found during any inspection required by 
paragraph (g) of this AD: Before further flight, measure the length 
of the crack, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 717-55A0011, dated May 17, 2011.

(i) Blend Out Repair, ETHF Inspections, and Corrective Action for 
Certain Crack Lengths

    For any crack that meets ``Condition 2A'' of Table 1 of 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 717-55A0011, dated 
May 17, 2011: Do the actions in paragraphs (i)(1) and (i)(2) of this 
AD.
    (1) Before further flight, do a blend out repair, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 717-55A0011, dated May 17, 2011.
    (2) Within 14,200 flight cycles after accomplishing the blend 
out repair required by paragraph (i)(1) of this AD: Do an ETHF 
inspection of the blend out repair area for cracking, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 717-55A0011, dated May 17, 2011. If no cracking is found, 
repeat the inspection thereafter at intervals not to exceed 5,400 
flight cycles.
    (i) If any crack is found during the ETHF inspection required by 
paragraph (i)(2) of this AD: Before further flight, remove the 
cracked center section rib of the horizontal stabilizer and install 
a new center section rib, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 717-55A0011, dated May 
17, 2011.
    (ii) Within 35,000 flight cycles after the installation of the 
new center section rib, do the actions in paragraph (g) of this AD.

(j) Corrective Action for Certain Crack Lengths

    For any crack that meets ``Condition 2D'' of Table 1 of 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 717-55A0011, dated 
May 17, 2011: Before further flight, remove the cracked center 
section rib of the horizontal stabilizer and install a new center 
section rib, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 717-55A0011, dated May 17, 2011. 
Within 35,000 flight cycles after the installation of the new rib, 
do the actions in paragraph (g) of this AD.

(k) No Reporting Requirement

    Although Boeing Alert Service Bulletin 717-55A0011, dated May 
17, 2011, specifies to submit certain information to the 
manufacturer, this AD does not include that requirement.

 (l) Alternative Methods of Compliance (AMOCs)

    (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 the approval 
must specifically refer to this AD.

(m) Related Information

    (1) For more information about this AD, contact George Garrido, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office (ACO), 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; phone: (562) 627-5357; fax: (562) 
627-5210; email: [email protected].
    (2) For service information identified in this AD, Boeing 
Commercial Airplanes, Attention: Data & Services Management, 3855 
Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; 
phone: (206) 544-5000, extension 2; fax: (206) 766-5683; email: 
[email protected]; 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 January 6, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-858 Filed 1-18-12; 8:45 am]
BILLING CODE 4910-13-P