
[Federal Register: October 30, 2008 (Volume 73, Number 211)]
[Proposed Rules]               
[Page 64568-64571]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30oc08-17]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1118; Directorate Identifier 2007-NM-318-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) that applies to all Boeing Model 737-600, -700, -700C, -
800, and -900 series airplanes. The existing AD currently requires 
reviewing the airplane maintenance records to determine whether an 
engine has been removed from the airplane since the airplane was 
manufactured. For airplanes on which an engine has been removed, the 
existing AD also requires an inspection of the aft engine mount to 
determine if the center link assembly is correctly installed, and 
follow-on actions if necessary. This proposed AD would require the same 
actions for airplanes on which the engine has not been previously 
removed. This proposed AD results from reports indicating that 
operators found that the center link assembly for the aft engine mount 
was reversed on several airplanes that had not had an engine removed 
since delivery. We are proposing this AD to prevent increased 
structural loads on the aft engine mount, which could result in failure 
of the aft engine mount and consequent separation of the engine from 
the airplane.

DATES: We must receive comments on this proposed AD by December 15, 
2008.

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 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 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: Allen Rauschendorfer, Aerospace 
Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6432; 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-2008-1118; 
Directorate Identifier 2007-NM-318-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

    On January 21, 2003, we issued AD 2003-03-01, amendment 39-13025 
(68 FR 4367, January 29, 2003), for all Boeing Model 737-600, -700, -
700C, -800, and -900 series airplanes. That AD requires reviewing the 
airplane maintenance records to determine whether an engine has been 
removed from the airplane since the airplane was manufactured. For 
airplanes on which an engine has been removed, that AD requires an 
inspection of the aft engine mount to determine if the center link 
assembly is correctly installed, and follow-on actions if necessary. 
That AD resulted from reports indicating that operators found that the 
center link assembly for the aft engine mount was reversed on several 
airplanes. We issued that AD to prevent increased structural loads on 
the aft engine mount, which could result in failure of the aft engine 
mount and consequent separation of the engine from the airplane.

Actions Since Existing AD Was Issued

    Since we issued AD 2003-03-01, the manufacturer informed us that it 
is possible that some center links were incorrectly installed in an aft 
engine mount before the airplane was delivered. In AD 2003-03-01 
inspection of the aft engine mounts was required only for airplanes 
that had an engine change after the airplane was delivered to the 
operator. The inspection is now necessary for all airplanes, line 
numbers 1 through 1277 inclusive.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-71A1462, 
Revision 3, dated May 20, 2004. The procedures in Revision 3 of the 
service bulletin are essentially the same as those in Boeing Alert 
Service Bulletin 737-71A1462, Revision 1, dated November 7, 2002. We 
referred to Revision 1 of the service bulletin as the appropriate 
source of service information for accomplishing the actions required by 
AD 2003-03-01. However, Revision 3 of the service bulletin also 
specifies inspecting to determine if the center link assembly is 
installed correctly on any installed engine that has not been removed 
from

[[Page 64569]]

the airplane since the airplane's delivery. Revision 3 of the service 
bulletin also specifies repeating the inspection during each subsequent 
engine change for each aft engine mount. Finally, Revision 3 also 
specifies that adding permanent part marks on the center link assembly 
and the hanger fitting ends the need for the repetitive inspections. 
Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2003-03-01 and would retain the requirements of the 
existing AD. This proposed AD would also require the same actions for 
airplanes on which the engine has not been previously removed. This 
proposed AD would also require accomplishing the actions specified in 
the service bulletin described previously, except as discussed under 
``Difference Between the Proposed AD and the Service Bulletin.''

Difference Between the Proposed AD and the Service Bulletin

    Boeing Alert Service Bulletin 737-71A1462, Revision 3 specifies 
contacting the part manufacturer (CFMI) for more instructions if damage 
is found to the engine mounting lugs and the adjacent engine turbine 
rear frame. (Damage includes cracking, yielding, buckling, and wear.) 
However, 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 an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
(DOA) Organization whom we have authorized to make those findings.

Clarification of Certain Actions

    Revision 3 of the service bulletin specifies repeating the 
inspection during each subsequent engine change for each aft engine 
mount. This proposed AD does not specify a repetitive inspection but 
instead specifies in paragraph (n), ``Parts Installation,'' that no 
person may install an engine on any airplane unless the center link 
assembly of the aft engine mount is found to be installed correctly.
    Revision 3 of the service bulletin also specifies that adding 
permanent part marks on the center link assembly and the hanger fitting 
ends the need for the repetitive inspections. As noted above, this 
proposed AD would not include a repetitive inspection requirement. In 
addition, because the affected parts are rotable, the repetitive 
inspections referred to in the service bulletin would be terminated 
only as long as the engine stays on the airplane.

Changes to Existing AD

    This proposed AD would retain the requirements of AD 2003-03-01. 
Since AD 2003-03-01 was issued, the AD format has been revised, and 
certain paragraphs have been rearranged. As a result, the corresponding 
paragraph identifiers have changed in this proposed AD, as listed in 
the following table:

                      Revised Paragraph Identifiers
------------------------------------------------------------------------
                                          Corresponding  requirement  in
      Requirement in AD  2003-03-01              this  proposed AD
------------------------------------------------------------------------
Paragraph (a)...........................  Paragraph (f).
Paragraph (b)...........................  Paragraph (g).
Paragraph (c)...........................  Paragraph (h).
Paragraph (d)...........................  Paragraph (i).
Paragraph (e)...........................  Paragraph (m).
Paragraph (f)...........................  Paragraph (n).
------------------------------------------------------------------------

    We have also removed Note 1 of the existing AD and re-numbered 
subsequent notes accordingly. We have also revised Note 2 and Note 3 of 
the existing AD (Note 1 and Note 2 of this proposed AD) to provide a 
more up-to-date definition of a general visual inspection and a 
detailed inspection.
    Boeing Commercial Airplanes has received a DOA. We have revised 
paragraph (i) of this AD (paragraph (d) of AD 2003-03-01) to delegate 
the authority to approve an alternative method of compliance for any 
repair required by this proposed AD to an Authorized Representative for 
the Boeing Commercial Airplanes DOA rather than a Designated 
Engineering Representative (DER). We have also simplified paragraph (i) 
of this AD by referring to the ``Alternative Methods of Compliance 
(AMOCs)'' paragraph (o) of this proposed AD for repair methods, which 
includes a reference to the DOA.

Costs of Compliance

    There are about 1,277 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 500 airplanes of 
U.S. registry. The average labor rate is $80 per work hour. The 
following table provides the estimated costs for U.S. operators to 
comply with this proposed AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                          Cost per
                           Action                              Work hours     Parts       airplane    Fleet cost
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Maintenance records review (required by AD 2003-03-01)......            1           $0          $80      $40,000
Inspection for correct installation of center link assembly             1            0           80       40,000
 (new proposed action)......................................
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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 have 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.

[[Page 64570]]

    For the reasons discussed above, I certify that the 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-13025 (68 FR 4367, January 29, 2003) and adding 
the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2008-1118; Directorate Identifier 2007-NM-
318-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by December 
15, 2008.

Affected ADs

    (b) This AD supersedes AD 2003-03-01.

Applicability

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

Unsafe Condition

    (d) This AD results from reports indicating that operators found 
that the center link assembly for the aft engine mount was reversed 
on several airplanes that had not had an engine removed since 
delivery. We are issuing this AD to prevent increased structural 
loads on the aft engine mount, which could result in failure of the 
aft engine mount and consequent separation of the engine from 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.

Restatement of the Requirements of AD 2003-03-01

Review of Maintenance Records

    (f) Within 90 days after February 13, 2003 (the effective date 
of AD 2003-03-01), review the airplane maintenance records to 
determine whether either engine has been removed since the 
airplane's date of manufacture. If neither engine has been removed 
since the airplane's date of manufacture, no further action is 
required by this paragraph; however paragraph (n) of this AD 
continues to apply.

Inspection To Determine if Center Link Assembly Is Installed Correctly

    (g) For any installed engine that is found to have been removed 
from the airplane since the airplane's date of manufacture: Within 
90 days after February 13, 2003, do a one-time general visual 
inspection to determine if the center link assembly of the aft 
engine mount is installed correctly, per the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-71A1462, Revision 
1, dated November 7, 2002; or Revision 3, dated May 20, 2004. If the 
center link assembly is installed correctly, as specified in the 
service bulletin, no further action is required by paragraph (g), 
(h), or (i) of this AD for that engine; however paragraph (n) of 
this AD continues to apply.

    Note 1: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normally available lighting 
conditions such as daylight, hangar lighting, flashlight, or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

Follow-on and Corrective Actions

    (h) For any center link assembly that is found installed 
incorrectly during the inspection required by paragraph (g) of this 
AD: Before further flight, do the actions in paragraphs (h)(1), 
(h)(2), and (h)(3) of this AD, per the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-71A1462, Revision 1, dated 
November 7, 2002; or Revision 3, dated May 20, 2004; except that it 
is not necessary to submit a report of findings to the airplane 
manufacturer.
    (1) Remove the center link assembly and install it correctly.
    (2) Perform a detailed inspection of the engine mounting lugs 
and engine turbine rear frame for cracking, yielding, buckling, or 
wear damage.
    (3) Perform a detailed inspection of the hardware for the aft 
engine mount; including the center link assembly, right link 
assembly, aft mount hanger assembly, and link pins; for cracking, 
yielding, buckling, or wear damage.

    Note 2: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Repair

    (i) If any cracking, yielding, buckling, or wear damage is found 
during the inspections required by paragraphs (h)(2) and (h)(3) of 
this AD: Before further flight, replace the discrepant part with a 
new or serviceable part, or repair in accordance with a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA; or using a method approved in accordance with the 
procedures specified in paragraph (o) of this AD.

New Requirements of This AD

Inspection of Engines That Have Not Been Removed

    (j) For all airplanes identified in Boeing Alert Service 
Bulletin 737-71A1462, Revision 3, dated May 20, 2004: For any 
installed engine that has not been removed from the airplane since 
the airplane's date of manufacture, within 90 days after the 
effective date of this AD, do a detailed inspection to determine if 
the center link assembly of the aft engine mount is installed 
correctly, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 
2004.

Follow-on and Corrective Actions

    (k) For any center link assembly that is found installed 
incorrectly during any inspection required by paragraph (j) of this 
AD: Before further flight, do the actions required by paragraphs 
(k)(1), (k)(2), and (k)(3) of this AD, per the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-71A1462, Revision 
3, dated May 20, 2004, except that it is not necessary to submit a 
report of findings to the airplane manufacturer.
    (1) Remove the center link assembly and install it correctly.
    (2) Perform a detailed inspection of the engine mounting lugs 
and engine turbine rear frame for cracking, yielding, buckling, or 
wear damage.
    (3) Perform a detailed inspection of the hardware for the aft 
engine mount; including the center link assembly, right link 
assembly, aft mount hanger assembly, and link pins; for cracking, 
yielding, buckling, or wear damage.

Repair

    (l) If any cracking, yielding, buckling, or wear damage is found 
during the inspections required by paragraphs (k)(2) and (k)(3) of 
this AD, and Boeing Alert Service Bulletin 737-71A1462, Revision 3, 
dated May 20, 2004, specifies to contact Boeing or the part

[[Page 64571]]

manufacturer: Before further flight, replace the discrepant part 
(e.g., parts with cracking, yielding, buckling, and wear damage) 
with a new or serviceable part, or repair using a method approved in 
accordance with the procedures specified in paragraph (o) of this 
AD.

Credit for Actions Done Using Previous Service Information

    (m) Inspections and corrective actions done before the effective 
date of this AD in accordance with a service bulletin listed in 
Table 1 of this AD are acceptable for compliance with the 
corresponding requirements of this AD.

                   Table 1--Previous Service Bulletins
------------------------------------------------------------------------
 Boeing Alert Service  Bulletin       Revision              Date
------------------------------------------------------------------------
737-71A1462.....................  Original.......  Aug. 29, 2002.
737-71A1462.....................  1..............  Nov. 7, 2002.
737-71A1462.....................  2..............  May 29, 2003.
------------------------------------------------------------------------

Parts Installation

    (n) As of the effective date of this AD, no person may install 
an engine on any airplane unless the inspections specified in 
paragraph (g) or (j) of this AD are accomplished and the center link 
assembly of the aft engine mount is found to be installed correctly.

Alternative Methods of Compliance (AMOCs)

    (o)(1) The Manager, Seattle Aircraft Certification Office (ACO) 
FAA, ATTN: Allen Rauschendorfer, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 
Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6432; 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.

    Issued in Renton, Washington, on October 10, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-25903 Filed 10-29-08; 8:45 am]

BILLING CODE 4910-13-P
