[Federal Register Volume 69, Number 230 (Wednesday, December 1, 2004)]
[Proposed Rules]
[Pages 69832-69834]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-26497]



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DEPARTMENT OF TRANSPORTATION (DOT)

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19750; Directorate Identifier 2003-NM-192-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), 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. That AD currently requires either 
determining exposure to runway deicing fluids containing potassium 
formate, or performing repetitive inspections of certain electrical 
connectors in the wheel well of the main landing gear (MLG) for 
corrosion, and follow-on actions. This proposed AD would add a new 
inspection requirement and related corrective actions. This proposed AD 
is prompted by additional reports indicating that significant corrosion 
of the electrical connectors in the wheel well of the MLG has also been 
found on airplanes that land on runways treated with deicing fluids 
containing potassium acetate. We are proposing this AD to prevent 
corrosion and subsequent moisture ingress into the electrical 
connectors, which could result in an electrical short and consequent 
incorrect functioning of critical airplane systems essential to safe 
flight and landing of the airplane, including fire warning systems.

DATES: We must receive comments on this proposed AD by January 18, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    For the service information identified in this proposed AD contact 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Technical Information: Binh Tran, 
Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 917-6485; fax (425) 917-6590.
    Plain language information: Marcia Walters, [email protected].

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-19750; 
Directorate Identifier 2003-NM-192-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of our 
docket Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is on the plaza level of the Nassif Building 
at the DOT street address stated in the ADDRESSES section. Comments 
will be available in the AD docket shortly after the DMS receives them.

Discussion

    On July 29, 2002, we issued AD 2002-16-03, amendment 39-12842 (67 
FR 52396, August 12, 2002), for all Boeing Model 737-600, -700, -700C, 
-800, and -900 series airplanes. That AD requires either determining 
exposure to runway deicing fluids containing potassium formate or 
performing repetitive inspections of certain electrical connectors in 
the wheel well of the main landing gear (MLG) for corrosion, and 
follow-on actions. That AD was prompted by reports of significant 
corrosion of the electrical connectors in the main wheel well. We 
issued that AD to prevent such corrosion, which could result in 
incorrect functioning of critical airplane systems essential to safe 
flight and landing of the airplane, including fire warning systems.

Actions Since Existing AD was Issued

    Since we issued AD 2002-16-03, we have received reports of 
significant corrosion of the electrical connectors located in the wheel 
well of the MLG on Model 737 series airplanes that land on runways 
treated with deicing fluids containing potassium acetate. Investigation 
revealed that the corrosive effects of potassium acetate on the 
electrical connectors are similar to those of potassium formate, and 
the

[[Page 69833]]

requirements in the existing AD do not account for exposure to deicing 
fluids containing potassium acetate. Significant corrosion can lead to 
loss of the cadmium plating of the electrical connectors and subsequent 
moisture ingress into the connectors, which could result in an 
electrical short and consequent incorrect functioning of critical 
airplane systems essential to safe flight and landing of the airplane, 
including fire warning systems.

Revised Service Information

    We have reviewed Boeing Alert Service Bulletin 737-24A1148, 
Revision 1, dated July 10, 2003 (the original issue was referenced in 
the existing AD as the appropriate source of service information for 
accomplishment of the actions). The service bulletin describes 
procedures for inspecting electrical connectors (including the contacts 
and backshells) of the line replaceable unit (LRU) in the wheel well of 
the MLG for corrosion, and related corrective actions if necessary. 
Signs of corrosion are the presence of moisture, corrosion pits, or 
white-colored material buildup on the connectors; black or reddish 
discoloration on the contacts; or loss of the olive-drab conversion 
coating on the backshells. The related corrective actions include 
cleaning the LRU connectors and applying corrosion inhibiting compound 
(CIC) if no corrosion is found, and replacing the LRU with a new LRU 
and applying CIC if corrosion is found. The service bulletin also 
recommends an operational test of the affected systems after doing the 
applicable actions. Accomplishing the actions specified in the revised 
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 exist or develop on other products 
of this same type design. Therefore, we are proposing this AD, which 
would supersede AD 2002-16-03. This proposed AD would require either 
determining exposure to runway deicing fluids containing potassium 
formate and/or potassium acetate, or performing repetitive inspections 
of certain electrical connectors in the wheel well of the main landing 
gear for corrosion, and significant/corrective actions if necessary. 
This proposed AD would require you to use the service information 
described previously to perform these actions, except as discussed 
under ``Difference Between the Proposed AD and Service Information.''

Difference Between the Proposed AD and Service Information

    The service bulletin specifies an ``examination'' for corrosion of 
the electrical connectors in the MLG wheel well. For the purposes of 
this AD, we have determined that the procedures in the service bulletin 
constitute a ``detailed inspection.'' Note 1 of this proposed AD 
defines that inspection.

Work Hour Rate Increase

    We have reviewed the figures we have used over the past several 
years to calculate AD costs to operators. To account for various 
inflationary costs in the airline industry, we find it necessary to 
increase the labor rate used in these calculations from $60 per work 
hour to $65 per work hour. The cost impact information, below, reflects 
this increase in the specified hourly labor rate.

Costs of Compliance

    This proposed AD would affect about 587 airplanes of U.S. registry. 
The new determination of airplane exposure would take about 1 work hour 
per airplane, at an average labor rate of $65 per work hour. Based on 
these figures, the estimated cost of the actions specified in this 
proposed AD for U.S. operators is $38,155, or $65 per airplane, per 
cycle.

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. 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, 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 removing amendment 39-12842 (67 FR 
52396, August 12, 2002) and adding the following new airworthiness 
directive (AD):

Boeing: Docket No. FAA-2004-19750; Directorate Identifier 2003-NM-
192-AD.

Comments Due Date

    (a) The Federal Aviation Administration must receive comments on 
this airworthiness directive (AD) action by January 18, 2005.

Affected ADs

    (b) This AD supersedes AD 2002-16-03, amendment 39-12842.

Applicability

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

Unsafe Condition

    (d) This AD was prompted by additional reports indicating that 
significant corrosion of the electrical connectors in the wheel well 
of the MLG has also been found on airplanes that land on runways 
treated with deicing fluids containing potassium acetate. We are 
issuing this AD to prevent corrosion and subsequent moisture ingress 
into the electrical connectors, which could result in an electrical 
short and consequent incorrect functioning of critical airplane 
systems essential to safe flight and landing of the airplane, 
including fire warning systems.

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.

Determine Airplane Exposure/Significant & Corrective Actions

    (f) Except as required by paragraph (f)(1)(ii) of this AD: 
Within 12 months after the effective date of this AD, do the actions 
required by either paragraph (f)(1) or (f)(2) of this AD.
    (1) Determine airplane exposure to runway deicing fluids 
containing potassium formate or potassium acetate by reviewing 
airport data on the type of components in the deicing fluid used at 
airports that support airplane operations.

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    (i) For airplanes that have not been exposed to potassium 
formate or potassium acetate: Repeat the requirements in paragraph 
(f) of this AD thereafter at intervals not to exceed 12 months.
    (ii) For airplanes that have been exposed to potassium formate 
or potassium acetate: Before further flight, do the inspection 
required by paragraph (f)(2) of this AD.
    (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 by doing all the 
actions in accordance with the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-24A1148, Revision 1, dated July 10, 2003. 
Do any significant/corrective actions before further flight in 
accordance with the service bulletin. Repeat the actions required by 
paragraph (f)(1) of this AD thereafter at intervals not to exceed 12 
months.

    Note 1: 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.''

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) AMOCs approved previously in accordance with AD 2002-16-03, 
amendment 39-12842, are not approved as AMOCs with this AD.

    Issued in Renton, Washington, on November 17, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-26497 Filed 11-30-04; 8:45 am]
BILLING CODE 4910-13-P