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**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2010–1160; Directorate Identifier 2010–NM–148–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; The Boeing Company Model 767 Series Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), Department of Transportation (DOT).

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Model 767 airplanes. The existing AD currently requires repetitive inspections to detect discrepancies of the wiring and surrounding Teflon sleeves of the fuel tank boost pumps and override/jettison pumps; replacement of the sleeves with new sleeves, for certain airplanes; and repair or replacement of the wiring and sleeves with new parts, as necessary. This proposed AD would reduce the initial compliance time and repetitive inspection interval in the existing AD. This proposed AD results from fleet information indicating that the repetitive inspection interval in the existing AD is too long because excessive chafing of the sleeving
continues to occur much earlier than expected between scheduled inspections. We are proposing this AD to detect and correct chafing of the fuel pump wire insulation and consequent exposure of the electrical conductor, which could result in electrical arcing
between the wires and conduit and consequent fire or explosion of the fuel
tank.

**DATES :**  We must receive comments on this proposed AD by January 28, 2011.

**ADDRESSES :**  You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://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: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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, Attention: Data & Services Management, P. O. Box 3707, MC 2H–65, Seattle, Washington 98124– 2207; telephone 206–544–5000, extension 1; fax 206–766–5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425–227–

1221.
Examining the AD Docket

You may examine the AD docket on
the Internet at http:// www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The
street address for the Docket Office (telephone 800–647–5527) is in the

**ADDRESSES** section. Comments will be available in the AD docket shortly after receipt.

**FOR FURTHER INFORMATION CONTACT :**  Douglas Bryant, Aerospace Engineer, Propulsion Branch, ANM–140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 917–6505; fax (425) 917–6590.

**SUPPLEMENTARY INFORMATION :** 

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments
to an address listed under the

**ADDRESSES** section. Include ‘‘Docket No. FAA–2010–1160; Directorate Identifier

2010–NM–148–AD ’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those

comments.

We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each
substantive verbal contact we receive about this proposed AD.

Discussion

On May 23, 2000, we issued AD 2000–11–06, amendment 39–11754 (65 FR 34928, June 1, 2000), for all Model 767 airplanes. (A correction of the rule was published in the Federal Register on August 1, 2000 (65 FR 46862).) That AD requires repetitive inspections to detect discrepancies of the wiring and surrounding Teflon sleeves of the fuel tank boost pumps and override/jettison pumps; replacement of the sleeves with new sleeves, for certain airplanes; and repair or replacement of the wiring and sleeves with new parts, as necessary. That AD resulted from reports of chafing
of Teflon sleeves that surround and protect electrical wires inside conduits
installed in the fuel tanks. We issued that AD to ensure adequate protection to the fuel pump wire insulation. Such chafing of the wire insulation could eventually result in exposure of the electrical conductor, permit arcing from the wire to the conduit, and create a potential for a fuel tank fire or explosion.

Actions Since Existing AD Was Issued

Since we issued AD 2000–11–06, we
received fleet information from the manufacturer indicating that excessive chafing of the sleeving continues to occur much earlier than expected between scheduled inspections. Due to that fact, the manufacturer has revised
the service information to reduce the initial and repetitive inspection
intervals.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010. Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999, was referred to as the appropriate source of service information for accomplishing the actions in the existing AD. Revision 2 of
this service bulletin reduces the initial compliance time and repetitive inspection interval for the repetitive inspections required by the existing AD.

FAA’s Determination and Requirements of the Proposed AD

We have evaluated all pertinent
information and identified an unsafe condition that is likely to develop on other products of the same type design. For this reason, we are proposing this AD, which would supersede AD 2000–
11–06 and would retain the requirements of the existing AD at reduced compliance times.

Change to Existing AD

This proposed AD would retain all requirements of AD 2000–11–06. Since that AD was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers


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have changed in this proposed AD, as listed in the following table:



### R EVISED 

### P ARAGRAPH 

### I DENTIFIERS

Requirement in AD 2000–11–06 Corresponding requirement in this proposed AD

paragraph (a) ..................... paragraph (g). paragraph (b) ..................... paragraph (h). paragraph (c) ..................... paragraph (i). paragraph (d) ..................... paragraph (j). paragraph (e) ..................... paragraph (k).

Costs of Compliance

There are about 932 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 410 airplanes of U.S. registry. The new requirements of this proposed AD add
no additional economic burden. The current costs for this proposed AD are repeated below for the convenience of affected operators.

The actions that are required by AD
2000–11–06 and retained in this proposed AD take about 5 work-hours per airplane (for airplanes with jettison pumps) or 3 work-hours per airplane (for airplanes without jettison pumps),at an average labor rate of $85 per workhour. Required parts cost about $336 per airplane. Based on these figures, the estimated cost of the currently required actions is either $761 or $591 per airplane, per inspection cycle.

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, 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**

1. The authority citation for part 39
continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

**§ 39.13 [Amended]**

2. The FAA amends § 39.13 by removing Amendment 39–11754 (65 FR 34928, June 1, 2000) and adding the following new AD:

The Boeing Company: Docket No. FAA– 2010–1160; Directorate Identifier 2010–

NM–148–AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 28, 2011.

Affected ADs

(b) This AD supersedes AD 2000–11–06,
Amendment 39–11754.

Applicability

(c) This AD applies to all The Boeing Company Model 767–200, –300, –300F, and –400ER series airplanes, certificated in any category.

Subject

(d) Air Transport Association (ATA) of
America Code 28: Fuel.

Unsafe Condition

(e) This AD results from fleet information indicating that the repetitive inspection interval in the existing AD is too long because excessive chafing of the sleeving
continues to occur much earlier than expected between scheduled inspections.
The Federal Aviation Administration is issuing this AD to detect and correct chafing of the fuel pump wire insulation and consequent exposure of the electrical conductor, which could result in electrical arcing between the wires and conduit and consequent fire or explosion of the fuel tank.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Restatement of Requirements of AD 2000– 11–06, Amendment 39–11754

Inspections

(g) Perform a detailed visual inspection to detect discrepancies—including the presence of splices, cuts, splits, holes, worn areas, and lacing ties installed on the outside of the sleeves (except at the sleeve ends)—of the Teflon sleeves surrounding the wiring of the fuel tank boost pumps and override/jettison pumps, at the earlier of the times specified in paragraphs (g)(1) and (g)(2) of this AD, in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767– 28A0053, Revision 2, dated June 24, 2010; as applicable. Repeat the inspection thereafter at intervals not to exceed 60,000 flight hours or 30,000 flight cycles, whichever occurs first. After the effective date of this AD, only Revision 2 of Boeing Alert Service Bulletin 767–28A0053 may be used.

(1) Prior to the accumulation of 50,000 total flight hours, or within 90 days after July 6, 2000 (the effective date of AD 2000–11– 06), whichever occurs later.

(2) Within 18 months after July 6, 2000.

Note 1: For the purposes of this AD, a detailed visual 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. ’’

Corrective Actions

(h) If any discrepancy is detected during any inspection required by paragraph (g) of this AD: Prior to further flight, remove the Teflon sleeves and perform a detailed visual inspection to detect damage of the wiring, in accordance with paragraph D. of the Accomplishment Instructions of Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010; as applicable. After the effective date of this AD, only Revision 2 of Boeing Alert Service Bulletin 767–28A0053 may be used.

(1) If no damage to the wiring is detected, prior to further flight, install new Teflon sleeves in accordance with Boeing Service


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Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010.

(2) If any damage to the wiring is detected, prior to further flight, accomplish the requirements of paragraph (i) of this AD.

(i) If any damage to the wiring is detected during any inspection required by paragraph (h) of this AD: Prior to further flight, perform a detailed visual inspection to determine if the wiring damage was caused by arcing, in accordance with paragraph D. of the Accomplishment Instructions of Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010, as applicable. After the effective date of this AD, only Revision 2 of Boeing Alert Service Bulletin 767–28A0053 may be used.

(1) If the wire damage was not caused by arcing: Prior to further flight, repair any damaged wires or replace the wires with new or serviceable wires, as applicable, and install new Teflon sleeves; in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010.

(2) If any damage caused by arcing is found: Prior to further flight, perform an inspection for signs of fuel inside the conduit or on the wires, in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010.

(i) If no sign of fuel is found, accomplish the actions specified by paragraphs (i)(2)(i)(A), (i)(2)(i)(B), (i)(2)(i)(C), and (i)(2)(i)(D) of this AD.

(A) Prior to further flight, repair the wires or replace the wires with new or serviceable wires, as applicable, in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010.

(B) Prior to further flight, install new Teflon sleeves, in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010.

(C) Repeat the inspection for signs of fuel
inside the conduit thereafter at intervals not to exceed 500 flight hours, until the requirements of paragraph (h)(2)(i)(D) of this AD have been accomplished. If any fuel is found inside the conduit during any inspection required by this paragraph, prior to further flight, replace the conduit with a
new or serviceable conduit in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010. Thereafter, repeat the inspection specified in paragraph (g) of this AD at intervals not to exceed 60,000 flight hours or 30,000 flight cycles,
whichever occurs first.

(D) Within 6,000 flight hours or 18 months after the initial fuel inspection specified by paragraph (h)(2) of this AD, whichever occurs first, replace the conduit with a new or serviceable conduit, in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010. Such conduit replacement constitutes terminating action for the repetitive fuel inspections required by paragraph (i)(2)(i)(C) of this AD.

(ii) If any fuel is found in the conduit or on any wire: Prior to further flight, replace
the conduit with a new or serviceable conduit, replace damaged wires with new or serviceable wires, and install new Teflon sleeves; in accordance with Boeing Service Bulletin 767–28A0053, Revision 1, dated August 5, 1999; or Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010. Thereafter, repeat the inspection specified in paragraph (a) of this AD at intervals not to exceed 60,000 flight hours or 30,000 flight cycles, whichever
occurs first.

Pump Retest

(j) For any wire bundle removed and reinstalled during any inspection required by this AD: Prior to further flight after such reinstallation, retest the fuel pump in accordance with paragraph G., H., I., or J., as applicable, of the Accomplishment Instructions of Boeing Service Bulletin 767– 28A0053, Revision 1, dated August 5, 1999.

Reporting Requirement

(k) Submit a report of positive inspection findings (findings of discrepancies only), along with any damaged wiring and sleeves, to the Seattle Manufacturing Inspection District Office (MIDO), 2500 East Valley Road, Suite C–2, Renton, Washington 98057– 3356; fax (425) 227–1159; at the applicable time specified in paragraph (k)(1) or (k)(2) of this AD. The report must include the airplane serial number; the number of total flight hours and flight cycles on the airplane; the
location of the electrical cable on the airplane; and a statement indicating, if known, whether any wire has ever been removed and inspected during maintenance, along with the date (if known) of any such inspection. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq. ) and have been assigned OMB Control Number 2120–0056.

(1) For airplanes on which the initial inspection required by paragraph (g) of this AD is accomplished after July 6, 2000: Submit the report within 10 days after performing the initial inspection.

(2) For airplanes on which the initial inspection required by paragraph (g) of this AD has been accomplished prior to July 6, 2000: Submit the report for the initial inspection within 10 days after the effective
date of this AD.

New Reduced Inspection Intervals

Repetitive Inspections

(l) Do the inspection required by paragraph (g) of this AD at the time specified in paragraph (l)(1) or (l)(2) of this AD, as applicable, in accordance with Boeing Alert Service Bulletin 767–28A0053, Revision 2, dated June 24, 2010. Repeat the inspection thereafter at intervals not to exceed 15,000 flight hours. Accomplishing the first inspection in this paragraph ends the repetitive inspection requirements of paragraph (g) of this AD.

(1) For airplanes on which the inspection required by paragraph (g) of this AD has been
done as of the effective date of this AD: Do the inspection within 15,000 flight hours after the most recent inspection or within 6,000 flight hours after the effective date of this AD, whichever occurs later; but not to exceed 60,000 flight hours after the most recent inspection required by paragraph (g) of
this AD.

(2) For airplanes on which the inspection required by paragraph (g) of this AD has not
been done as of the effective date of this AD: Do the inspection before the accumulation of 15,000 total flight hours or within 6,000 flight hours after the effective date of this AD,
whichever occurs later.

Paperwork Reduction Act Burden Statement

(m) A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction
Act unless that collection of information displays a current valid OMB Control
Number. The OMB Control Number for this
information collection is 2120–0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the
burden should be directed to the FAA at: 800 Independence Ave., SW., Washington, DC

20591, Attn: Information Collection Clearance Officer, AES–200.

Alternative Methods of Compliance (AMOCs)

(n)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14
CFR 39.19. Send information to Attn: Douglas Bryant, Aerospace Engineer, Propulsion Branch, ANM–140S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 917–6505; fax (425) 917–6590. Information may be e-mailed to: 9–ANM–Seattle-ACO– AMOC–Requests@faa.gov

.

(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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(3) AMOCs approved previously in accordance with AD 2000–11–06, Amendment 39–11754, are approved as


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alternative methods of compliance with the corresponding requirements of this AD. Compliance time extensions approved previously in accordance with AD 2000–11– 06 are not approved as alternative methods of compliance for the compliance times required by paragraph (l) of this AD.

Issued in Renton, Washington, on November 15, 2010.
Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2010–31371 Filed 12–13–10; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2010–1158; Directorate Identifier 2010–NM–125–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; The Boeing Company Model 747 Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), Department of Transportation (DOT).

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Model 747 airplanes. The existing AD currently requires repetitive inspections to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, the existing AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. This proposed AD would reduce the initial compliance time and repetitive inspection interval in the existing AD. This proposed AD results from fleet information indicating that the repetitive inspection interval in the existing AD is too long because excessive chafing of the sleeving
continues to occur much earlier than expected between scheduled inspections. We are proposing this AD
to detect and correct abrasion of the Teflon sleeving and wires in the bundles of the fuel boost pumps for the
numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between the wires and aluminum conduit and consequent fire or explosion of the fuel tank.

**DATES :**  We must receive comments on this proposed AD by January 28, 2011.

**ADDRESSES :**  You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://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: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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, Attention: Data & Services Management, P. O. Box 3707, MC 2H–65, Seattle, Washington 98124– 2207; telephone 206–544–5000, extension 1; fax 206–766–5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425–227–

1221.

Examining the AD Docket

You may examine the AD docket on
the Internet at http://www. regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The
street address for the Docket Office (telephone 800–647–5527) is in the

**ADDRESSES** section. Comments will be available in the AD docket shortly after receipt.

**FOR FURTHER INFORMATION CONTACT :**  Jon Regimbal, Aerospace Engineer, Propulsion Branch, ANM–140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 98057–3356; telephone (425) 917–6506; fax (425) 917–6590.

**SUPPLEMENTARY INFORMATION :** 

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the

**ADDRESSES** section. Include ‘‘Docket No. FAA–2010–1158; Directorate Identifier

2010–NM–125–AD ’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those

comments.

We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each
substantive verbal contact we receive about this proposed AD.

Discussion

On December 9, 1997, we issued AD 97–26–07, Amendment 39–10250 (62 FR 65352, December 12, 1997), for all Model 747 airplanes. That AD currently requires repetitive inspections to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, that AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a
serviceable conduit. That AD resulted from reports of chafing of the sleeving.
We issued that AD to detect and correct abrasion of the Teflon sleeving and
wires in the bundles of the fuel boost pumps for the numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between
the wires and the aluminum conduit and consequent fire or explosion of the
fuel tank.

Actions Since Existing AD Was Issued

Since we issued AD 97–26–07, we
received fleet information from the manufacturer indicating that excessive chafing of the sleeving continues to occur much earlier than expected between scheduled inspections. Due to that fact, the manufacturer has revised
the service information to reduce the repetitive inspection intervals.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747–28A2204, Revision 3, dated March 11, 2010. The service
information reduces the initial compliance time and repetitive inspection interval for detecting damage