[Federal Register Volume 70, Number 63 (Monday, April 4, 2005)]
[Proposed Rules]
[Pages 16979-16981]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-6577]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20799; Directorate Identifier 2004-NM-264-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 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 727 airplanes. This proposed AD would require 
determining whether any float switches are installed in the fuel tanks, 
and corrective actions if necessary. This proposed AD is prompted by 
reports of contamination of the fueling float switch by moisture or 
fuel, and chafing of the float switch wiring against the fuel tank 
conduit. We are proposing this AD to prevent such contamination and 
chafing, which could present an ignition source inside the fuel tank 
that could cause a fire or explosion.

DATES: We must receive comments on this proposed AD by May 19, 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.
     By 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 service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, 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 in person 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. This docket 
number is FAA-2005-20799; the directorate identifier for this docket is 
2004-NM-264-AD.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6501; 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 under ADDRESSES. Include ``Docket No. FAA-2005-20799; 
Directorate Identifier 2004-NM-264-AD'' in the subject line 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 submitted 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 can review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or 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 located 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

    Boeing has performed a quality analysis on float switches removed 
from Model 737-200 series airplanes. Investigation revealed cracked 
potting material, which permitted moisture and fuel to enter the switch 
cavity. Fuel and moisture contamination inside the float switch reed 
cavity could provide an electrical path between the switch and the 
airplane structure that could result in electrical arcing that could 
lead to a fuel tank explosion. Also, Boeing reported worn float switch 
wiring insulation in the center fuel tank due to chafing of the wires 
against the walls of the conduit housing the wires. Wire chafing 
against the conduit could present an ignition source inside the fuel 
tank that could cause a fire or explosion.
    The float switch wiring installation is similar on Model 727 and 
737-200 series airplanes. Therefore, the unsafe condition could exist 
on Model 727 airplanes equipped with the same float switch model found 
on the 737-200 series airplanes.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 727-28A0127, dated 
August 26, 2004. The service bulletin describes procedures for 
replacing Ametek Model F8300-146 float switches with new switches and 
installing a liner system inside the electrical cable conduit in the 
main and auxiliary fuel tanks.

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

[[Page 16980]]

develop on other airplanes of this same type design. Therefore, we are 
proposing this AD, which would require accomplishing the actions 
specified in the service information described previously, except as 
discussed under ``Differences Between the Proposed AD and the Service 
Bulletin.''

Differences Between the Proposed AD and the Service Bulletin

    The service bulletin affects Model 727 airplanes ``with active 
Boeing fueling float switch shutoff systems installed'' and requires 
replacing the float switches and installing a liner system. However, 
this proposed AD would apply to all Model 727 airplanes and would 
require first determining whether any fuel float switches are installed 
in the fuel tanks. For those airplanes with float switches, this 
proposed AD would then require identifying the float switches, 
replacing Ametek Model F8300-146 float switches with new switches, and 
installing the liner system. We have determined that the effectivity in 
the service bulletin may not encompass all possible scenarios involving 
the subject float switches. Because the auxiliary fuel tanks have been 
moved from airplane to airplane--via field approval or supplemental 
type certificate, the proposed applicability and requirements would 
ensure that all subject float switch designs are replaced.
    These differences have been coordinated with Boeing and are 
intended to adequately address the unsafe condition.

Costs of Compliance

    There are about 1,300 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 800 airplanes of 
U.S. registry.
    The proposed inspections (for presence and model of float switch) 
would take about 1 work hour, at an average labor rate of $65 per hour. 
Based on these figures, the estimated cost of the proposed inspections 
for U.S. operators is $52,000, or $65 per airplane.
    The following table provides the estimated costs for U.S. operators 
to replace the float switches, if necessary. We estimate that about 162 
airplanes may require parts replacement.

                                                 Estimated Costs
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                                                                                    Average
                                                   Airplane    Number of    Work     hourly             Cost per
                    Airplane                         model     auxiliary    hours    labor     Parts    airplane
                                                               fuel tanks             rate
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1...............................................     727-200            0      27        $65   $4,174     $5,929
2...............................................     727-200            1       9         65    1,542      2,127
3...............................................     727-200            2      14         65    3,108      4,018
4...............................................     727-200            3      18         65    4,626      5,796
5...............................................     727-200            4      23         65    6,168      7,663
6...............................................     727-100            2      14         65    3,079      3,989
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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. 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 adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20799; Directorate Identifier 2004-NM-
264-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by May 19, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 727 airplanes, 
certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of contamination of the 
fueling float switch by moisture or fuel, and chafing of the float 
switch wiring against the fuel tank conduit. We are issuing this AD 
to prevent such contamination and chafing, which could present an 
ignition source inside the fuel tank that could cause a fire or 
explosion.

[[Page 16981]]

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 for Float Switches

    (f) Within 48 months after the effective date of this AD, 
inspect the wing and auxiliary fuel tanks to determine if any float 
switches are present. Instead of an inspection of the fuel tanks, a 
review of airplane maintenance records is acceptable if the presence 
of any float switch can be conclusively determined from that review.
    (1) If no float switches are present: No further work is 
required by this paragraph.
    (2) If any float switch is present: Before further flight, 
inspect to identify the float switch models. Instead of an 
inspection of the fuel tanks, a review of airplane maintenance 
records is acceptable if the identity of the float switch can be 
conclusively determined from that review.
    (i) If a float switch other than an Ametek Model F8300-146 float 
switch is installed: Before further flight, install a liner system 
inside the float switch electrical cable conduit in the fuel tanks 
by doing all applicable actions specified in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 727-28A0127, dated 
August 26, 2004.
    (ii) If any Ametek Model F8300-146 float switch is installed: 
Before further flight, replace it with a new switch and install a 
liner system inside the float switch electrical cable conduit in the 
fuel tanks, by doing all applicable actions specified in the 
Accomplishment Instructions of Boeing Alert Service Bulletin 727-
28A0127, dated August 26, 2004.

    Note 1: Boeing Alert Service Bulletin 727-28A0127 segregates the 
work into nine work packages for the six fuel tank configurations 
identified in the service bulletin. The work packages do not have to 
be completed sequentially. Each work package can be done 
independently or simultaneously. However, all work packages, as 
applicable for each fuel tank configuration, must be done to 
complete the requirements of this AD.

Parts Installation

    (g) As of the effective date of this AD, no person may install 
an Ametek Model F8300-146 float switch in a fuel tank on any 
airplane.

Alternative Methods of Compliance (AMOCs)

    (h) 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.

    Issued in Renton, Washington, on March 28, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-6577 Filed 4-1-05; 8:45 am]
BILLING CODE 4910-13-P