
[Federal Register: October 8, 2008 (Volume 73, Number 196)]
[Proposed Rules]               
[Page 58906-58908]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08oc08-27]                         

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1070; Directorate Identifier 2008-NM-087-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. For all airplanes, this proposed AD would require repetitive 
overhaul of the retract actuator beam of the main landing gear (MLG). 
For certain airplanes, this proposed AD would require repetitive 
inspections for damage of the retract actuator beam, and related 
investigative and corrective actions if necessary. This proposed AD 
results from reports of broken retract actuator beams of the MLG and 
the subsequent failure of the MLG to fully retract. We are proposing 
this AD to detect and correct broken retract actuator beams of the MLG, 
which could cause damage to the beam arm, hydraulic tubing, and flight 
control cables. Damage to the flight control cables could result in 
loss of control of the airplane.

DATES: We must receive comments on this proposed AD by November 24, 
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: 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-2008-1070; 
Directorate Identifier 2008-NM-087-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 broken retract actuator beams of the 
main landing gear (MLG) and the subsequent failure of the MLG to fully 
retract. In one incident, hydraulic system A became unserviceable. In 
another incident, the flightcrew declared an emergency and made an air 
turn-back. For all the reports of MLG retract actuator beams that broke 
in service, the MLG fell to the down-and-locked position, and landings 
were normal. Investigation revealed that proper procedures were not 
followed during overhaul, resulting in stress corrosion cracking 
initiating from small corrosion pits that were not entirely removed. In 
one incident, cracking initiated in an area of heat damage/burning 
caused by incorrect stylus cadmium plating. Broken retract actuator 
beams of the MLG, if not corrected, could cause damage to the beam arm, 
hydraulic tubing, and flight control cables. Damage to the flight 
control cables could result in loss of control of the airplane.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 737-32A1355, Revision 2, 
dated March 5, 2008. The service bulletin describes the procedures and 
compliance times specified in the following service information table.

[[Page 58907]]



                                               Service Information
----------------------------------------------------------------------------------------------------------------
    Applicability description                      Actions                            Compliance time
----------------------------------------------------------------------------------------------------------------
All airplanes....................  An overhaul of the beam is performed    Within 180 days after the date of
                                    and improved finishes are applied.      this service bulletin, or within 10
                                    New fittings, bushings and bearings     years from the date of the most
                                    are installed. The lubrication          recent overhaul of the beam,
                                    passages must be cleared. The related   whichever occurs later. Repeat
                                    investigative and corrective actions,   interval is not to exceed 10 years
                                    if necessary, include a special         after the last overhaul.
                                    detailed inspection for corrosion
                                    pits or damage of the beam, and
                                    repair before further flight.
Group 1, Configuration 3           A general visual inspection (GVI) of    Within 2 years after the date of this
 airplanes with a MLG retract       the beam is performed for damage,       service bulletin. Repeat interval is
 actuator beam having part number   finish degradation, and corrosion.      not to exceed 2 years after the last
 (P/N) 65-46108-14 and previous     The related investigative and           inspection.
 dash numbers that have not         corrective actions, if necessary,
 incorporated the original issue,   include a special detailed inspection
 Revision 1, or Revision 2 of the   for corrosion pits or damage of the
 service bulletin.                  beam, and repair before further
                                    flight.
----------------------------------------------------------------------------------------------------------------

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed AD and Service Information.''

Differences Between the Proposed AD and Service Information

    Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 
2008, does not specify a compliance time for repairing the retract 
actuator beam if damage, finish degradation, or corrosion is found. 
This proposed AD would require that those repairs be done before 
further flight after accomplishing the applicable inspections.
    Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 
2008, specifies that the actions are for airplanes with new MLG retract 
actuator beams having P/N 65-46108-15 and subsequent dash numbers that 
have not been overhauled, and new or overhauled MLG retract actuator 
beams having P/N 65-46108-14 and previous dash numbers. However, MLG 
retract actuator beams which are not new or overhauled may also exhibit 
the identified unsafe condition. For this reason, this proposed AD is 
not limited to new or overhauled beams; the proposed AD would require 
that the actions be done on airplanes having any MLG retract actuator 
beam having one of those P/Ns. This correction will be included in the 
next revision of the service bulletin.
    We have coordinated these differences with the manufacturer.

Costs of Compliance

    We estimate that this proposed AD would affect 652 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Number of U.S.-
        Action/airplane group            Work hours     Average labor         Parts cost             Cost per product       registered      Fleet cost
                                                        rate per hour                                                        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Overhaul for Group 1; Configurations               64             $80  None....................  $5,120, per overhaul                652      $3,338,240
 1, 2, and 3.                                                                                     cycle.
Inspection for Group 1, Configuration               1              80  None....................  $80, per inspection                 525          42,000
 3.                                                                                               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), and
    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

[[Page 58908]]

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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:

Boeing: Docket No. FAA-2008-1070; Directorate Identifier 2008-NM-
087-AD.

Comments Due Date

    (a) We must receive comments by November 24, 2008.

Affected ADs

    (b) None.

Applicability

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

Unsafe Condition

    (d) This AD results from reports of broken retract actuator 
beams of the main landing gear (MLG) and the subsequent failure of 
the MLG to fully retract. We are issuing this AD to detect and 
correct broken retract actuator beams of the MLG, which could result 
in damage to the beam arm, hydraulic tubing, and flight control 
cables. Damage to the flight control cables could result in loss of 
control of the airplane.

Compliance

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

Inspection and Related Investigative and Corrective Actions/Overhaul

    (f) Except as provided by paragraphs (g) and (h) of this AD: At 
the applicable times specified in paragraph 1.E. of Boeing Service 
Bulletin 737-32A1355, Revision 2, dated March 5, 2008; inspect for 
damage of the retract actuator beam of the MLG and overhaul the 
retract actuator beam, as applicable, by doing all the applicable 
actions specified in the Accomplishment Instructions of the service 
bulletin. Do all applicable related investigative and corrective 
actions before further flight. Repeat the applicable inspection or 
overhaul thereafter at the applicable time specified in paragraph 
1.E. of the service bulletin.

Exceptions to Service Information

    (g) Where Boeing Service Bulletin 737-32A1355, Revision 2, dated 
March 5, 2008, specifies a compliance time after ``* * * the date on 
this service bulletin,'' this AD requires compliance within the 
specified compliance time after the effective date of this AD.
    (h) Boeing Service Bulletin 737-32A1355, Revision 2, dated March 
5, 2008, specifies that the actions are for airplanes with new MLG 
retract actuator beams that have not been overhauled having P/N 65-
46108-15 and subsequent dash numbers, and new or overhauled MLG 
retract actuator beams having P/N 65-46108-14 and previous dash 
numbers; however, this AD is not limited to new or overhauled beams. 
This AD requires that the actions required by paragraph (f) of this 
AD be done on airplanes with any MLG retract actuator beam having 
those P/Ns.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, 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; 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 September 26, 2008.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-23828 Filed 10-7-08; 8:45 am]

BILLING CODE 4910-13-P
