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[Federal Register Volume 75, Number 39 (Monday, March 1, 2010)]
[Proposed Rules]
[Pages 9137-9140]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-4167]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0173; Directorate Identifier 2009-NM-076-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Model 737-100, -200, 
-200C, -300, -400, and -500 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 Model 737-100, -200, -200C, -300, -
400, and -500 series airplanes. The existing AD currently requires 
repetitive inspections to find cracks, fractures, or corrosion of each 
carriage spindle of the left and right outboard mid-flaps, and 
corrective action if necessary. The existing AD also currently requires 
repetitive gap checks of the inboard and outboard carriage of the 
outboard mid-flaps to detect fractured carriage spindles, and 
corrective actions if necessary. This proposed AD would require any new 
or serviceable carriage spindle installed per the requirements of the 
existing AD to meet minimum allowable diameter measurements taken at 
three locations. This proposed AD also would require new repetitive 
inspections, measurements, and overhaul of the carriage spindles, and 
applicable corrective actions. In addition, this proposed AD would 
require replacing any carriage spindle when it has reached its maximum 
life limit. This proposed AD results from reports of fractures that 
resulted from stress corrosion and pitting along the length of the 
spindle and spindle diameter, and additional reports of corrosion on 
the outboard flap carriage spindles. We are proposing this AD to detect 
and correct cracked, corroded, or fractured carriage spindles, and to 
prevent severe flap asymmetry, which could result in reduced control or 
loss of controllability of the airplane.

DATES: We must receive comments on this proposed AD by April 15, 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 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: 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-2010-0173; 
Directorate Identifier 2009-NM-076-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 November 24, 2003, we issued AD 2003-24-08, Amendment 39-13377 
(68 FR 67027, December 1, 2003), for all Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes. That

[[Page 9138]]

AD currently requires repetitive inspections to find cracks, fractures, 
or corrosion of each carriage spindle of the left and right outboard 
mid-flaps, and corrective action if necessary. That AD also currently 
requires repetitive gap checks of the inboard and outboard carriage of 
the outboard mid-flaps to detect fractured carriage spindles, and 
corrective actions if necessary. That AD resulted from a report 
indicating that the inboard and outboard carriage spindles (number 7 
and 8 carriage spindles) were fractured on the right outboard flap 
during approach to landing. We issued that AD to detect and correct 
cracked, corroded, or fractured carriage spindles, and to prevent 
severe flap asymmetry, which could result in reduced control or loss of 
controllability of the airplane.

Actions Since Existing AD Was Issued

    The preamble to AD 2003-24-08 explains that we considered the 
requirements ``interim action'' and were considering further 
rulemaking. We now have determined that further rulemaking is indeed 
necessary, and this proposed AD follows from that determination.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-57A1218, 
Revision 5, dated February 9, 2009. The service bulletin describes 
procedures for repetitive detailed and magnetic particle inspections to 
detect discrepancies (including corrosion, pitting, and cracks) of the 
carriage spindle, repetitive measurements to determine the diameter of 
certain areas of the carriage spindle, and applicable corrective 
actions. The corrective actions include repairing any corrosion or 
pitting, or replacement with a new or serviceable carriage. The service 
bulletin also describes procedures for repetitive overhauls of the 
carriage. In addition, the service bulletin describes procedures for 
repetitive replacements of any carriage when it has reached its maximum 
life limit.

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 2003-24-08 and would retain certain requirements of 
the existing AD. This proposed AD would require any new or serviceable 
carriage spindle installed per the requirements of the existing AD to 
meet minimum allowable diameter measurements taken at three locations 
of the spindle. This proposed AD also would require accomplishing the 
actions specified in the service bulletin described previously.

Change to Existing AD

    This proposed AD would retain certain requirements of AD 2003-24-
08. Since AD 2003-24-08 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 this
    Requirement in AD 2003-24-08                 proposed AD
------------------------------------------------------------------------
             paragraph (c)                        paragraph (g)
             paragraph (d)                        paragraph (h)
             paragraph (e)                        paragraph (i)
             paragraph (f)                        paragraph (j)
             paragraph (g)                        paragraph (k)
             paragraph (h)                        paragraph (l)
             paragraph (i)                        paragraph (m)
             paragraph (j)                        paragraph (n)
------------------------------------------------------------------------

Costs of Compliance

    There are about 2,852 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                    Number of
                                                      Average                                                         U.S.-
                Action                  Work hours   labor rate           Parts              Cost per airplane      registered         Fleet cost
                                                      per hour                                                      airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspections (required by AD 2003-24-            12          $85  None..................  $1,020 per inspection             652  $665,040 per inspection
 08).                                                                                     cycle.                                 cycle.
Inspections and measurements (new                2           85  None..................  $170 per inspection and           652  $110,840 per inspection
 proposed actions).                                                                       measurement cycle.                     and measurement cycle.
Overhauls (new proposed actions).....           16           85  $28,000 \1\...........  $29,360 per overhaul              652  $19,142,720 per overhaul
                                                                                          cycle.                                 cycle.
Replacements (new proposed actions)..           16           85  $60,000 \2\...........  $61,360 per replacement           652  $40,006,720 per
                                                                                          cycle.                                 replacement cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ $7,000 per spindle; 4 spindles per airplane.
\2\ $15,000 per spindle; 4 spindles per airplane.

    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the actions required by 
this AD, and that no operator would accomplish those actions in the 
future if this AD were not adopted. However, we have been advised that 
the carriages are already being overhauled and replaced on some 
affected airplanes. In addition, the replacement cycle is approximately 
every 20 years. Therefore, the future economic cost impact of this 
proposed rule on U.S. operators is expected to be less than the cost 
impact figures indicated above.

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

[[Page 9139]]

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.
    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 39-13377 (68 FR 67027, December 1, 2003) and adding 
the following new airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2010-0173; Directorate Identifier 
2009-NM-076-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by April 15, 
2010.

Affected ADs

    (b) This AD supersedes AD 2003-24-08, Amendment 39-13377.

Applicability

    (c) This AD applies to all The Boeing Company Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes, certificated in 
any category.

Subject

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

Unsafe Condition

    (e) This AD results from a report indicating that the inboard 
and outboard carriage spindles were fractured on the right outboard 
flap during approach to landing. We are issuing this AD to detect 
and correct cracked, corroded, or fractured carriage spindles and to 
prevent severe flap asymmetry, which could result in reduced control 
or loss of controllability of the airplane.

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.

Restatement of Certain Requirements of AD 2003-24-08, With Updated 
Service Information

Compliance Times

    (g) The tables in paragraph 1.E., ``Compliance'' of Boeing Alert 
Service Bulletin 737-57A1277, Revision 1, dated November 25, 2003, 
specify the compliance times for paragraphs (g) through (k) of this 
AD. For carriage spindles that have accumulated the number of flight 
cycles or years in service specified in the ``Threshold'' column of 
the tables, accomplish the gap check and nondestructive test (NDT) 
and general visual inspections specified in paragraphs (h) and (j) 
of this AD within the corresponding interval after December 4, 2003 
(the effective date AD 2003-24-08), as specified in the ``Interval'' 
column. Repeat the gap check and NDT and general visual inspections 
at the same intervals, except:
    (1) The gap check does not have to be done at the same time as 
an NDT inspection; after doing an NDT inspection, the interval for 
doing the next gap check can be measured from the NDT inspection; 
and
    (2) As carriage spindles gain flight cycles or years in service 
and move from one category in the ``Threshold'' column to another, 
they are subject to the repetitive inspection intervals 
corresponding to the new threshold category.

Work Package 2: Gap Check

    (h) Perform a gap check of the inboard and outboard carriage of 
the left and right outboard mid-flaps to determine if there is a 
positive indication of a severed carriage spindle, in accordance 
with Work Package 2 of paragraph 3.B., ``Work Instructions'' of 
Boeing Alert Service Bulletin 737-57A1277, Revision 1, dated 
November 25, 2003.

Work Package 2: Corrective Actions

    (i) If there is a positive indication of a severed carriage 
spindle during the gap check required by paragraph (h) of this AD, 
before further flight, remove the carriage spindle and install a new 
or serviceable carriage spindle in accordance with the ``Work 
Instructions'' of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003; or Boeing Alert Service 
Bulletin 737-57A1218, Revision 5, dated February 9, 2009. If, as a 
result of the detailed inspection described in paragraph 4.b. of 
Work Package 2 of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003, a carriage spindle is found not 
to be severed and no corrosion and no cracking is present, it can be 
reinstalled on the mid-flap in accordance with Boeing Alert Service 
Bulletin 737-57A1277, Revision 1, dated November 25, 2003; or Boeing 
Alert Service Bulletin 737-57A1218, Revision 5, dated February 9, 
2009. After the effective date of this AD, use only Boeing Alert 
Service Bulletin 737-57A1218, Revision 5, dated February 9, 2009.

Work Package 1: Inspections

    (j) Perform a NDT inspection and general visual inspection for 
each carriage spindle of the left and right outboard mid-flaps to 
detect cracks, corrosion, or severed carriage spindles, in 
accordance with the ``Work Instructions'' of Boeing Alert Service 
Bulletin 737-57A1277, Revision 1, dated November 25, 2003.

Work Package 1: Corrective Actions

    (k) If any corroded, cracked, or severed carriage spindle is 
found during any inspection required by paragraph (j) of this AD, 
before further flight, remove the carriage spindle and install a new 
or serviceable carriage spindle in accordance with the ``Work 
Instructions'' of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003; or Boeing Alert Service 
Bulletin 737-57A1218, Revision 5, dated February 9, 2009. After the 
effective date of this AD, use only Boeing Alert Service Bulletin 
737-57A1218, Revision 5, dated February 9, 2009.

Parts Installation

    (l) Except as provided in paragraph (i) of this AD: As of 
December 4, 2003, no person may install on any airplane a carriage 
spindle that has been removed as required by paragraph (i) or (k) of 
this AD, unless it has been overhauled in accordance with the ``Work 
Instructions'' of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003; or Boeing Alert Service 
Bulletin 737-57A1218, Revision 5, dated February 9, 2009. After the 
effective date of this AD, use only Boeing Alert Service Bulletin 
737-57A1218, Revision 5, dated February 9, 2009. To be eligible for 
installation under this paragraph, the carriage spindle must have 
been overhauled in accordance with the requirements of paragraph (m) 
of this AD.
    (m) During accomplishment of any overhaul specified in paragraph 
(l) of this AD, use the procedures specified in paragraphs (m)(1) 
and (m)(2) of this AD during application of the nickel plating to 
the carriage spindle in addition to those specified in Boeing 737 
Standard Overhaul Practices Manual, Chapter 20-42-09, Revision 25, 
dated July 1, 2009.

[[Page 9140]]

    (1) The maximum deposition rate of the nickel plating in any one 
plating/baking cycle must not exceed 0.002-inches-per-hour.
    (2) Begin the hydrogen embrittlement relief bake within 10 hours 
after application of the plating, or less than 24 hours after the 
current was first applied to the part, whichever is first.

Exception to Reporting Recommendations in Certain Service Bulletins

    (n) Although Boeing Alert Service Bulletin 737-57A1277, Revision 
1, dated November 25, 2003, recommends that operators report 
inspection findings to the manufacturer, this AD does not contain 
such a reporting requirement.

New Actions Required by This AD

Inspections, Measurements, and Overhauls of the Carriage Spindle

    (o) At the applicable times specified in paragraph (o)(1) or 
(o)(2) of this AD: Do the detailed inspection for corrosion, 
pitting, and cracking of the carriage spindle, the magnetic particle 
inspection for cracking of the carriage spindle, measurements of the 
spindle to determine if it meets the allowable minimum diameter, and 
overhauls, and applicable corrective actions by accomplishing all 
the applicable actions specified in the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-57A1218, Revision 5, dated 
February 9, 2009. The applicable corrective actions must be done 
before further flight. Repeat these actions thereafter at intervals 
not to exceed 12,000 flight cycles on the carriage spindle or 8 
years, whichever comes first.
    (1) For Model 737-100, -200, -200C airplanes, at the later of 
the times specified in paragraph (o)(1)(i) or (o)(1)(ii) of this AD:
    (i) Before the accumulation of 12,000 total flight cycles on the 
carriage spindle since new or overhauled, or within 8 years after 
the installation of the new or overhauled part, whichever comes 
first.
    (ii) Within 1 year after the effective date of this AD.
    (2) For Model -300, -400, and -500 series airplanes, at the 
later of the times specified in paragraph (o)(2)(i) or (o)(2)(ii) of 
this AD:
    (i) Before the accumulation of 12,000 total flight cycles on the 
carriage spindle since new or overhauled, or within 8 years after 
the installation of the new or overhauled part, whichever comes 
first.
    (ii) Within 2 years after the effective date of this AD.

Replacement of the Carriage Spindle

    (p) For Model 737-100, -200, -200C airplanes: Replace the 
carriage spindle with a new or documented (for which the service 
life, in flight cycles, is known) carriage spindle, in accordance 
with Boeing Alert Service Bulletin 737-57A1218, Revision 5, dated 
February 9, 2009, at the later of the times specified in paragraphs 
(p)(1) and (p)(2) of this AD, except as required by paragraph (r) of 
this AD. Overhauling the carriage spindles does not zero-out the 
flight cycles. Total flight cycles accumulate since new.
    (1) Before the accumulation of 48,000 total flight cycles on the 
new or overhauled carriage.
    (2) Within three years or 7,500 flight cycles after the 
effective date of this AD, whichever occurs first.
    (q) For Model 737-300, -400, and -500 series airplanes: Replace 
the carriage spindle with a new or documented (for which the service 
life, in flight cycles, is known) carriage spindle, in accordance 
with Boeing Alert Service Bulletin 737-57A1218, Revision 5, dated 
February 9, 2009, at the later of the times specified in paragraphs 
(q)(1) and (q)(2) of this AD, except as required by paragraph (r) of 
this AD. Overhauling the carriage spindles does not zero-out the 
flight cycles. Total flight cycles accumulate since new.
    (1) Before the accumulation of 48,000 total flight cycles on the 
new or overhauled carriage.
    (2) Within six years or 15,000 flight cycles after the effective 
date of this AD, whichever occurs first.
    (r) For airplanes with an undocumented carriage: Do the 
applicable actions specified in paragraph (p) or (q) of this AD at 
the applicable time specified in paragraph (r)(1) or (r)(2) of this 
AD.
    (1) For Model 737-100, -200, -200C series airplanes: Do the 
actions specified in paragraph (p) of this AD at the time specified 
in paragraph (p)(2) of this AD.
    (2) For Model -300, -400, and -500 series airplanes: Do the 
actions specified in paragraph (q) of this AD at the time specified 
in paragraph (q)(2) of this AD.

Repetitive Replacements of Carriage Spindle

    (s) For all airplanes: Repeat the replacement of the carriage 
spindle specified by paragraph (p) or (q) of this AD, as applicable, 
thereafter at intervals not to exceed 48,000 total flight cycles on 
the new or overhauled carriage spindle.

Alternative Methods of Compliance (AMOCs)

    (t)(1) The Manager, Seattle 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. Send information to 
ATTN: 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. Or, e-mail information to [email protected].
    (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 principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (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, 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 February 17, 2010.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-4167 Filed 2-26-10; 8:45 am]
BILLING CODE 4910-13-P
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