Document ID: FAA-2007-0004-0060
Agency: faa
Document Type: Notice
Title: Airworthiness Directives; Boeing Model 737-600, -700, -700C, - 800, and -900 Series Airplanes
Posted Date: 2007-09-06T04:00Z

[Federal Register: September 6, 2007 (Volume 72, Number 172)]
[Proposed Rules]               
[Page 51201-51203]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06se07-24]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29116; Directorate Identifier 2007-NM-064-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 adopt a new airworthiness directive (AD) 
for all Boeing Model 737-600, -700, -700C, -800, and -900 series 
airplanes. This proposed AD would require a one-time inspection to 
determine the material of the forward and aft gray water drain masts. 
For airplanes having composite gray water drain masts, this proposed AD 
would also require installation of a copper bonding jumper between a 
ground and the clamp on the tube of the forward and aft gray water 
composite drain masts. This proposed AD results from a report of 
charred insulation blankets and burned wires around the forward gray 
water composite drain mast found during an inspection of the forward 
cargo compartment on a Model 767-300F airplane. We are proposing this 
AD to prevent a fire near a composite drain mast and possible 
disruption of the electrical power system caused by a lightning strike 
on a composite drain mast, which could result in the loss of several 
functions essential for safe flight.

DATES: We must receive comments on this proposed AD by October 22, 
2007.

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.
     U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, 
SE., Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room W12-140 on the ground floor of the 
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Marcia Smith, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6484; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
29116; Directorate Identifier 2007-NM-064-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 
that 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 may review 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.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Operations office between 9 

a.m. and 5 p.m., Monday through Friday, except Federal holidays. The 
Docket Operations office (telephone (800) 647-5527) is located on the 
ground floor of the West Building at the DOT street address stated in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after the Docket Management System receives them.

Discussion

    We have received a report indicating that, during an inspection of 
the forward cargo compartment on a Model 767-300F airplane, an operator 
found charred insulation blankets and burned wires around the forward 
gray water composite drain mast. Additional charring on the insulation 
blankets was noticed several feet away along the routing of the drain 
mast's ground wire and power wires. Analysis of the

[[Page 51202]]

damaged parts revealed that a lightning strike on the composite drain 
mast caused the damage to the wires and insulation blankets. This 
condition, if not corrected, could cause disruption of electrical power 
and fire and heat damage to equipment in the event of a lightning 
strike on the composite drain mast, which could result in the potential 
loss of several functions essential for safe flight.
    A design review of the gray water composite drain mast installation 
on Model 737, 757, 767, and 777 airplanes revealed that the 
installation of a heavier bonding jumper is necessary to provide 
adequate lightning protection to the gray water composite drain mast 
installation. The subject area on Model 737-600, -700, -700C, -800, and 
-900 airplanes is almost identical to that on the affected Model 767-
300F airplane. Therefore, Model 737-600, -700, -700C, -800, and -900 
series airplanes might be subject to the unsafe condition revealed on 
the Model 767-300F airplane. We are currently considering additional 
rulemaking to address the identified unsafe condition on Model 757, 
767, and 777 airplanes.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-30-
1056, dated February 28, 2007. The service bulletin describes 
procedures for installing a 135-ampere copper bonding jumper between a 
ground and the clamp on the tube of the forward and aft gray water 
composite drain mast.

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 airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    There are about 1,540 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 U.S.-
             Action                    Work hours       Average labor         Parts          Cost per airplane        registered          Fleet cost
                                                        rate per hour                                                 airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection to determine gray      1..................             $80  None...............  $80................  420................  $33,600.
 water drain mast material.
Installation of bonding jumper..  Between 2 and 4                 $80  Between $7 and $15,  Between $167 and     Up to 420..........  Between $70,140
                                   (depending on                        depending on kit.    $335.                                     and $140,700.
                                   airplane
                                   configuration).
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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.
    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, 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 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-29116; Directorate Identifier 2007-NM-
064-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by October 
22, 2007.

Affected ADs

    (b) None.

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 a report of charred insulation blankets 
and burned wires around the forward gray water composite drain mast 
found during an inspection of the forward cargo compartment on a 
Model 767-300F airplane. We are issuing this AD to prevent a fire 
near a composite drain mast and possible disruption of the 
electrical power

[[Page 51203]]

system caused by a lightning strike on a composite drain mast, which 
could result in the loss of several functions essential for safe 
flight.

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.

Inspection To Determine Material of Gray Water Drain Masts

    (f) Within 60 months after the effective date of this AD, 
inspect the forward and aft gray water drain masts to determine 
whether the drain masts are made of aluminum or composite. A review 
of airplane maintenance records is acceptable in lieu of this 
inspection if the material of the forward and aft gray water drain 
masts can be conclusively determined from that review.
    (1) For any aluminum gray water drain mast identified during the 
inspection or records check required by paragraph (f) of this AD, no 
further action is required by this paragraph for that drain mast 
only.
    (2) For any composite gray water drain mast identified during 
the inspection or records check required by paragraph (f) of this 
AD, do the actions specified in paragraph (g) of this AD.

Installation of Bonding Jumper

    (g) For any composite gray water drain mast identified during 
the inspection or records check required by paragraph (f) of this 
AD: Within 60 months after the effective date of this AD, install a 
135-ampere copper bonding jumper between a ground and the clamp on 
the tube of the gray water composite drain mast, in accordance with 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-30-1056, dated February 28, 2007.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with 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.

    Issued in Renton, Washington, on August 28, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-17586 Filed 9-5-07; 8:45 am]

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