FR Doc 05-12840

[Federal Register: June 29, 2005 (Volume 70, Number 124)]
[Proposed Rules]
[Page 37293-37296]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29jn05-18]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-21701; Directorate Identifier 2005-NM-086-AD]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 747 and 767 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 certain Boeing Model 747 and 767 airplanes. This proposed AD would
require reworking the electrical bonding between the airplane structure
and the pump housing of the outboard boost pumps in the main fuel tank
of certain Boeing Model 747 airplanes, and between the airplane
structure and the pump housing of the override/jettison pumps in the
left and right wing center auxiliary fuel tanks of certain Boeing Model
767 airplanes. This proposed AD would also require related
investigative actions and corrective actions if necessary. This
proposed AD is prompted by the results of fuel system reviews conducted
by the manufacturer. We are proposing this AD to prevent insufficient
electrical bonding, which could result in a potential of ignition
sources inside the fuel tanks, and which, in combination with flammable
fuel vapors, could result in fuel tank explosions and consequent loss
of the airplane.

DATES: We must receive comments on this proposed AD by August 15, 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-2005-21701; the directorate identifier for this docket is
2005-NM-086-AD.

FOR FURTHER INFORMATION CONTACT: Diane Pagel, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6488; 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-2005-21701;
Directorate Identifier 2005-NM-086-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

[[Page 37294]]

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 Docket Management System
(DMS) receives them.

Discussion

The FAA has examined the underlying safety issues involved in
recent fuel tank explosions on several large transport airplanes,
including the adequacy of existing regulations, the service history of
airplanes subject to those regulations, and existing maintenance
practices for fuel tank systems. As a result of those findings, we
issued a regulation titled ``Transport Airplane Fuel Tank System Design
Review, Flammability Reduction and Maintenance and Inspection
Requirements'' (67 FR 23086, May 7, 2001). In addition to new
airworthiness standards for transport airplanes and new maintenance
requirements, this rule included Special Federal Aviation Regulation
No. 88 (``SFAR 88,'' Amendment 21-78, and subsequent Amendments 21-82
and 21-83).
Among other actions, SFAR 88 requires certain type design (i.e.,
type certificate (TC) and supplemental type certificate (STC)) holders
to substantiate that their fuel tank systems can prevent ignition
sources in the fuel tanks. This requirement applies to type design
holders for large turbine-powered transport airplanes and for
subsequent modifications to those airplanes. It requires them to
perform design reviews and to develop design changes and maintenance
procedures if their designs do not meet the new fuel tank safety
standards. As explained in the preamble to the rule, we intended to
adopt airworthiness directives to mandate any changes found necessary
to address unsafe conditions identified as a result of these reviews.
In evaluating these design reviews, we have established four
criteria intended to define the unsafe conditions associated with fuel
tank systems that require corrective actions. The percentage of
operating time during which fuel tanks are exposed to flammable
conditions is one of these criteria. The other three criteria address
the failure types under evaluation: Single failures, single failures in
combination with another latent condition(s), and in-service failure
experience. For all four criteria, the evaluations included
consideration of previous actions taken that may mitigate the need for
further action.
We have received a report indicating that the outboard boost pumps
in the main fuel tank of certain Boeing Model 747 airplanes, and the
override/jettison pumps in the left and right wing center auxiliary
fuel tanks of certain Boeing Model 767 airplanes, have insufficient
electrical bonding between the pump housing and the airplane structure.
This condition, if not corrected, could result in an ignition source
inside the fuel tanks, which, in combination with flammable fuel
vapors, could result in fuel tank explosions and consequent loss of the
airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 747-28-
2259, dated November 4, 2004 (for Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D,
747-400F, 747SR, and 747SP series airplanes). This service bulletin
describes procedures for reworking the electrical bonding between the
airplane structure and the pump housing of the outboard boost pumps in
the main fuel tank, and related investigative and corrective actions.
The rework consists of replacing the four mounting fasteners on each of
the pump housings with rivets, stenciling each new rivet with the
statement: ``CAUTION--BONDING RIVET,'' and, when the related
investigative actions are completed, sealing the new rivets as
specified in the airplane maintenance manual. The related investigative
actions are measuring the electrical resistance of the new rivets, and
doing an open-hole high-frequency eddy current (HFEC) inspection for
cracks, corrosion, and damage. If the resistance is greater than the
maximum allowable resistance specified in the service bulletin, the
procedures include reworking the bonding as necessary according to the
standard wiring practices manual, until the resistance is within
allowable limits.
We have also reviewed Boeing Special Attention Service Bulletin
767-57-0092, dated November 4, 2004 (for Boeing Model 767-200, -300,
and -300F series airplanes); and Boeing Special Attention Service
Bulletin 767-57-0093, dated November 4, 2004 (for Boeing Model 767-
400ER series airplanes). These service bulletins describe procedures
for reworking the electrical bonding between the airplane structure and
the pump housing of the override/jettison pumps in the left and right
wing center auxiliary fuel tanks, and related investigative actions and
corrective actions. The rework consists of cleaning the wing rib/ground
bracket bonding surface, installing new fasteners for the ground
brackets of the fuel override/jettison pump, using new bonding
processes during the installation, and sealing the ground brackets. The
related investigative actions are measuring the electrical resistance
at specified points in the re-work process. If the electrical
resistance is greater than the maximum allowable resistance specified
in the service bulletin, the corrective action specified in the
procedures includes repeating the applicable corrective actions and the
applicable related investigative actions until the resistance is within
allowable limits.
Accomplishing the actions specified in the 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 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
``Difference Between the Proposed AD and Special Attention Service
Bulletin 747-28-2259.''

Difference Between the Proposed AD and Special Attention Service
Bulletin 747-28-2259

Although Boeing Special Attention Service Bulletin 747-28-2259 does
not specify an action to take if any crack, corrosion, or damage is
found during the open-hole HFEC inspection, this proposed AD would
require operators to repair those conditions in one of the following
ways:
Using a method that we approve; or

[[Page 37295]]

Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Delegation Option Authorization Organization whom we
have authorized to make those findings.

Costs of Compliance

There are about 3,401 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
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Number of U.S.-
Action Work hour Average labor Cost per registered Fleet cost
rate pere hour airplane airplanes
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Rework electrical bonding for 10 $65 $650 1,115 $724,750
Boeing Model 747 airplanes.....
Rework electrical bonding for 9 65 585 921 538,785
Boeing Model 767 airplanes.....
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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-2005-21701; Directorate Identifier 2005-NM-
086-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by August 15, 2005.

Affected ADs

(b) None.

Applicability

Table 1.--Airplanes Affected by This AD
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As identified in Boeing special
Model-- attention service bulletin--
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747-100, 747-100B, 747-100B SUD, 747- 747-28-2259, dated November 4,
200B, 747-200C, 747-200F, 747-300, 747- 2004.
400, 747-400D, 747-400F, 747SR, and
747SP series airplanes.
767-200, -300, and -300F series 767-57-0092, dated November 4,
airplanes. 2004.
767-400ER series airplanes............. 767-57-0093, dated November 4,
2004.
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Unsafe Condition

(d) This AD was prompted by the results of fuel system reviews
conducted by the manufacturer. We are issuing this AD to prevent
insufficient electrical bonding, which could result in a potential
of ignition sources inside the fuel tanks, and which, in combination
with flammable fuel vapors, could result in fuel tank explosions and
consequent loss of the airplane.

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.

Rework Electrical Bonding

(f) Within 60 months after the effective date of this AD: Do the
actions specified in paragraph (f)(1) or (f)(2) of this AD, as
applicable, by accomplishing all the actions specified in the
Accomplishment Instructions of the applicable service bulletin in
Table 1 of this AD. Do any related investigative and corrective
actions before further flight.
(1) For Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B,
747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and
747SP series airplanes: Rework the electrical bonding between the
airplane structure and the pump housing of the outboard boost pumps
in the main fuel tank, and do related investigative and

[[Page 37296]]

applicable corrective actions. If any crack, corrosion, or damage is
found during the open-hole high-frequency eddy current inspection
specified in Boeing Special Attention Service Bulletin 747-28-2259,
dated November 4, 2004: Before further flight, repair in accordance
with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA; or in accordance with data meeting
the certification basis of the airplane approved by an Authorized
Representative for the Boeing 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
approval must specifically reference this AD.
(2) For Boeing Model 767-200, -300, -300F, and -400ER series
airplanes: Rework the electrical bonding between the airplane
structure and the pump housing of the override/jettison pumps in the
left and right wing center auxiliary fuel tanks, and do the related
investigative and applicable corrective actions.

Alternative Methods of Compliance (AMOCs)

(g) The Manager, Seattle ACO, 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 June 21, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-12840 Filed 6-28-05; 8:45 am]

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