[Federal Register Volume 85, Number 7 (Friday, January 10, 2020)]
[Proposed Rules]
[Pages 1290-1292]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-28469]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1071; Product Identifier 2019-NM-165-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: The FAA proposes to adopt a new airworthiness directive (AD) 
for all The Boeing Company Model 737-900ER series airplanes. This 
proposed AD was prompted by reports of significant corrosion of 
electrical connectors located in the main landing gear (MLG) wheel 
well. This proposed AD would require repetitive records checks to 
determine exposure to certain deicing fluids or repetitive inspections 
for corrosion of the electrical connectors, and corrective actions if 
necessary. The FAA is proposing this AD to address the unsafe condition 
on these products.

DATES: The FAA must receive comments on this proposed AD by February 
24, 2020.

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 https://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 NPRM, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; internet https://www.myboeingfleet.com. You may 
view this service information at the FAA, Transport Standards Branch, 
2200 South 216th St., Des Moines, WA. For information on the 
availability of this material at the FAA, call 206-231-3195. It is also 
available on the internet at https://www.regulations.gov by searching 
for and locating Docket No. FAA-2019-1071.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
1071; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this NPRM, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations is listed above. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Julio C. Alvarez, Aerospace Engineer, 
Systems and Equipment Section, FAA, Seattle ACO Branch, 2200 South 
216th St., Des Moines, WA 98198; phone and fax: 206-231-3657; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites 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-2019-1071; 
Product Identifier 2019-NM-165-AD'' at the beginning of your comments. 
The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. The FAA will 
consider all comments received by the closing date and may amend this 
NPRM because of those comments.
    The FAA will post all comments we receive, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The FAA will also post a report summarizing each substantive 
verbal contact received about this NPRM.

Discussion

    The FAA has received reports indicating the presence of significant 
corrosion of electrical connectors located in the MLG wheel well of 
airplanes that land on runways treated with deicing fluids containing 
potassium formate or potassium acetate. Corrosion and subsequent 
moisture ingress may lead to electrical shorting of the connectors. 
This condition, if not addressed, can cause incorrect function of 
critical systems necessary for safe flight and landing.

Related Rulemaking

    AD 2005-18-23, Amendment 39-14264 (70 FR 54253, September 14, 2005) 
(``AD 2005-18-23''), applies to Boeing Model 737-600, -700, -700C, -
800, and -900 series airplanes, and addresses the same unsafe condition 
identified in this NPRM. Model 737-900ER series airplanes were not type 
certificated at the time AD 2005-18-23 was issued. The FAA has 
therefore determined that this NPRM is necessary to mandate the same 
requirements on Model 737-900ER series airplanes.

Related Service Information Under 1 CFR Part 51

    This proposed AD would require Boeing Alert Service Bulletin 737-
24A1148, Revision 1, dated July 10, 2003, which the Director of the 
Federal Register approved for incorporation by reference as of October 
19, 2005 (70 FR 54253, September 14, 2005). This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

FAA's Determination

    The FAA is proposing this AD because the agency 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 repetitive records checks to 
determine exposure to certain deicing fluids or repetitive inspections 
for corrosion of electrical connectors, and applicable corrective 
actions.
    The phrase ``corrective actions'' is used in this proposed AD. 
Corrective actions correct or address any condition found. Corrective 
actions in an AD could include, for example, repairs.

Differences Between This Proposed AD and the Service Information

    The effectivity of Boeing Alert Service Bulletin 737-24A1148, 
Revision 1, dated July 10, 2003, does not specifically identify Model 
737-900ER series airplanes; that airplane model was not type 
certificated at the time the service information was issued. The 
service information does, however, identify the line numbers for Model 
737-900ER series airplanes, all of which are in Group 3, so the actions 
of that service bulletin are appropriate and can be accomplished on 
those airplanes.
    Boeing Alert Service Bulletin 737-24A1148, Revision 1, dated July 
10, 2003, differs from this proposed AD in the cumulative areas of 
backshell corrosion that need corrective action,

[[Page 1291]]

and in the compliance time for the respective corrective actions, which 
are specified in paragraphs (g)(2)(i) through (ii) of this proposed AD. 
These differences have been coordinated with Boeing. The proposed 
requirements correspond to three alternative methods of compliance 
approved for AD 2005-18-23 and reflect the relief provided for AD 2005-
18-23.
    Boeing Alert Service Bulletin 737-24A1148, Revision 1, dated July 
10, 2003, specifies that airplanes exposed to affected runway deicing 
fluids be inspected for corroded electrical connectors within 12 
months. AD 2005-18-23 instead requires initially determining the 
airplane's exposure to affected runway deicing fluids within 12 months, 
and allows an additional 90 days to inspect for corrosion. For AD 2005-
18-23, the FAA had determined that the additional 90 days for the 
inspection represented an acceptable interval of time for affected 
airplanes to operate without jeopardizing safety. Therefore, since the 
unsafe condition and airplane design are the same in AD 2005-18-23 and 
this NPRM, the FAA has determined that 90 days is an appropriate 
compliance time for the initial inspection in this proposed AD.
    Boeing Alert Service Bulletin 737-24A1148, Revision 1, dated July 
10, 2003, and AD 2005-18-23 specify repeating the inspection at 12-
month intervals. However, the FAA determined that a longer interval 
would provide an acceptable level of safety. The FAA therefore issued 
alternative methods of compliance (AMOCs) for AD 2005-18-23 allowing 
this inspection interval to be increased to 24 months. Therefore, this 
proposed AD specifies a repetitive inspection interval of 24 months.

Costs of Compliance

    The FAA estimates that this proposed AD affects 346 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per  product       operators
----------------------------------------------------------------------------------------------------------------
Repetitive records check.......  1 work-hour x $85 per                $0  $85 per inspection  Up to $29,410 per
                                  hour = $85 per                           cycle.              inspection cycle.
                                  inspection cycle.
Repetitive detailed inspection.  3 work-hours x $85 per                0  $255 per            Up to $88,230 per
                                  hour = $255 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary repairs 
or replacements that would be required based on the results of the 
proposed inspection. The FAA has no way of determining the number of 
aircraft that might need these repairs or replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
               Action                         Labor cost                Parts cost           Cost per product
----------------------------------------------------------------------------------------------------------------
Cleaning or replacement............  Up to 5 work-hours x $85     Up to $831............  Up to $1,256.
                                      per hour = Up to $425.
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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.
    The FAA is 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.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes and associated appliances to the 
Director of the System Oversight Division.

Regulatory Findings

    The FAA 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) Will not affect intrastate aviation in Alaska, 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.

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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

The Boeing Company: Docket No. FAA-2019-1071; Product Identifier 
2019-NM-165-AD.

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(a) Comments Due Date

    The FAA must receive comments by February 24, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-900ER series 
airplanes, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 24, Electrical 
power.

(e) Unsafe Condition

    This AD was prompted by reports of significant corrosion of 
electrical connectors located in the main landing gear (MLG) wheel 
well. The FAA is issuing this AD to address corrosion and subsequent 
moisture ingress that may lead to electrical shorting of the 
connectors and incorrect functioning of critical systems necessary 
for safe flight and landing.

(f) Compliance

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

(g) Required Actions

    Within 12 months after the effective date of this AD: Do the 
actions required by paragraph (g)(1) or (2) of this AD.
    (1) Determine airplane exposure to runway deicing fluids 
containing potassium formate or potassium acetate by reviewing 
airport data on the types of components in the deicing fluid used at 
airports that support airplane operations.
    (i) If the airplane has not been exposed: Repeat the 
requirements specified in paragraph (g)(1) of this AD thereafter at 
intervals not to exceed 24 months.
    (ii) If the airplane has been exposed: Within 90 days after that 
determination is made, do the inspection required by paragraph 
(g)(2) of this AD. Repeat the inspection thereafter at intervals not 
to exceed 24 months.
    (2) Do a detailed inspection of the electrical connectors, 
including the contacts and backshells of the line replaceable unit 
(LRU) in the wheel well of the MLG, for corrosion in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-24A1148, Revision 1, dated July 10, 2003. Perform applicable 
corrective actions at the applicable times, as specified in 
paragraphs (g)(2)(i) through (iii) of this AD, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-24A1148, Revision 1, dated July 10, 2003. Repeat the inspection 
thereafter at intervals not to exceed 24 months. For the purposes of 
this AD, a detailed inspection is defined as an intensive visual 
examination of a specific structural area, system, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at intensity deemed appropriate by the inspector. 
Inspection aids such as mirror, magnifying lenses, etc., may be 
used. Surface cleaning and elaborate access procedures may be 
required.
    (i) If the total backshell surface area corrosion is 10 percent 
or less, clean the backshell(s) before further flight.
    (ii) If the total backshell surface area corrosion is greater 
than 10 percent but less than 20 percent, replace the connectors and 
backshells within 30 days after the detailed inspection.
    (iii) If the total backshell surface area corrosion is 20 
percent or more, replace the connectors and backshells before 
further flight.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, 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 certification office, send it to the attention of the 
person identified in paragraph (i)(1) of this AD. Information may be 
emailed to: [email protected].
    (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, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO Branch, FAA, to make those findings. To be approved, the repair 
method, modification deviation, or alteration deviation must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.
    (4) AMOCs approved previously for AD 2005-18-23, Amendment 39-
14264 (70 FR 54253, September 14, 2005) (``AD 2005-18-23''), are 
approved as AMOCs for the corresponding provisions of this AD.

(i) Related Information

    (1) For more information about this AD, contact Julio C. 
Alvarez, Aerospace Engineer, Systems and Equipment Section, FAA, 
Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3657; email: [email protected].
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. You may view this service information at the 
FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, 
WA. For information on the availability of this material at the FAA, 
call 206-231-3195.

    Issued on December 26, 2019.
Jeffrey E. Duven,
Director, System Oversight Division, Aircraft Certification Service.
[FR Doc. 2019-28469 Filed 1-9-20; 8:45 am]
BILLING CODE 4910-13-P