E7-14867. Airworthiness Directives; Boeing Model 757 Airplanes

AGENCY:

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

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier proposed airworthiness directive (AD) for all Boeing Model 757 airplanes. The original NPRM would have required revising the Airworthiness Limitations (AWLs) section of the Instructions for Continued Airworthiness by incorporating new limitations for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. The original NPRM also would have required the initial inspection of certain repetitive inspections specified in the AWLs to phase-in those inspections, and repair if necessary. The original NPRM resulted from a design review of the fuel tank systems. This action revises the original NPRM by aligning the compliance time for revising the AWLs section with the compliance date of the special maintenance program requirements, updating the listing of applicable airplane maintenance manuals in Appendix 1, and clarifying certain actions. We are proposing this supplemental NPRM to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs, or maintenance actions, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this supplemental NPRM by August 27, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this supplemental NPRM.

• 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: 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: [phone].
• 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 service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Kathrine Rask, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this supplemental NPRM. Send your comments to an address listed in the ADDRESSES section. Include the docket number “Docket No. FAA-2006-26710; Directorate Identifier 2006-NM-147-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this supplemental NPRM. We will consider all comments received by the closing date and may amend this supplemental NPRM in light of those comments.

We will post all comments submitted, 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 supplemental NPRM. 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 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.

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 [phone]) is located on the ground level 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 proposed to amend 14 CFR part 39 with a notice of proposed rulemaking (NPRM) for an AD (the “original NPRM”) for all Boeing Model 757 airplanes. The original NPRM was published in the Federal Register on January 3, 2007 (72 FR 50). The original NPRM proposed to require revising the Airworthiness Limitations (AWLs) section of the Instructions for Continued Airworthiness by incorporating new limitations for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 (SFAR 88) requirements. The original NPRM also proposed to require the initial inspection of certain repetitive inspections specified in the AWLs to phase-in those inspections, and repair if necessary.

Explanation of Change in Compliance Time

In most ADs, we adopt a compliance time allowing a specified amount of time after the AD's effective date. In this case, however, we have already issued regulations that require operators to revise their maintenance/inspection programs to address fuel tank safety issues. The compliance date for these regulations is December 16, 2008. To provide for efficient and coordinated implementation of these regulations and this supplemental NPRM, we are using this same compliance date in this supplemental NPRM, instead of the 18-month compliance time recommended by Boeing. Therefore, we have revised the compliance time in paragraph (g) from “within 18 months after the effective date of this AD” to a compliance date of “no later than December 16, 2008.”

Comments

We have considered the following comments on the original NPRM.

Request To Revise Note 1

Boeing requests that the Note 1 of the original NPRM be revised from “* * * the operator must request approval for revision * * *” to “* * * the operator must request approval for deviation from * * * .” Boeing states that, as written, Note 1 would result in modifications, alternations, or repairs being incorporated into the Boeing 757 Maintenance Planning Data (MPD) Document D622N001-9, Revision March 2006 (referred to in the original NPRM as the appropriate source of service information) that are outside of its configuration definition data and responsibility. Boeing also states that the MPD document is intended to reflect the Boeing 757 type design as defined only by Boeing data.

We partially agree. We do not agree with Boeing's suggested change. We find that Boeing is misinterpreting the intent of Note 1, and that clarification is necessary. The sentence in question states, “In this situation, * * * the operator must request approval for revision to the airworthiness limitations (AWLs) in the Boeing 757 Maintenance Planning Data (MPD) Document D622N001-9 * * * .” The term “revision” refers to the “airworthiness limitations,” not to the MPD document. The modification, alteration, or repair would affect only a few airplanes, so a revision to the MPD document, which would affect the whole fleet, would not be appropriate. However, we do agree with Boeing that a revision to the MPD document may not be necessary. We have determined that operators also can request approval for revision to the AWLs in the MPD document according to paragraph (i) of this supplemental NPRM. Therefore, we have revised Note 1 accordingly.

Request To Add Procedures of Boeing 757 MPD Document

Boeing requests that the original NPRM be revised to contain the procedures specified in Section 9 of Boeing 757 MPD Document D622N001-9 or an approved equivalent AWL/Certification Maintenance Requirement (CMR) document, rather than referring to the MPD document as the source for the procedures. Boeing states that it may move Section 9 (airworthiness limitation section) out of the Boeing 757 MPD document, and thus the AD may need to be revised.

We do not agree. We have confirmed with Boeing that it has no immediate plans to change the Boeing 757 MPD document. Therefore, until the Boeing 757 MPD Document D622N001-9 is revised, we consider it appropriate that this supplemental NPRM refer to it as the appropriate source of service information for accomplishing the proposed actions. We might consider issuing additional rulemaking or approving alternative methods of compliance to address that concern in the future. We have not changed the supplemental NPRM regarding this issue.

Request To Extend Compliance Time

United Parcel Service (UPS) requests that, for low cycle operators (less than 800 flight cycles per year), the compliance time for the initial inspections in paragraph (h) of the original NPRM be extended from “10 years or 36,000 flight cycles” to “16 years (8C) or 36,000 flight cycles, whichever occurs first.” UPS states that this will not penalize low-utilization operators. UPS states that it has tank entries approximately every 8 years, and that 16 years lines up better with its maintenance program. UPS also states that a compliance time of 10 years would significantly increase its financial burden. UPS did not submit any data with its comment.

We do not agree. In developing the compliance time for the original NPRM, we considered not only the risk of creating an ignition source in the tank, but we also considered the practical aspect of accomplishing the proposed inspections within a period of time that corresponds to the major structural inspections or fuel tank entries to limit the impact on operators. With UPS's tank entries occurring approximately every 8 years, the 36,000 total flight cycles or 120-month proposed compliance time would allow UPS's entire fleet to be inspected during scheduled maintenance with an additional 2 years to allow for some scheduling flexibility. However, paragraph (i) of the supplemental NPRM provides operators the opportunity to request an extension of the compliance time if data are presented to justify such an extension.

Request To Include an Additional Airworthiness Limitation

Boeing requests that we revise paragraph (h) of the original NPRM for completeness to include Airworthiness Limitation 28-AWL-25 (Lightning and Fault Current Protection—Motor Operated Valve Actuator). Boeing notes this AWL was added to Section 9 of the Boeing 757 MPD Document D622N001-9 in October 2006.

We agree with Boeing's intent; however, we do not agree with including Airworthiness Limitation 28-AWL-25 in this supplemental NPRM. We are considering issuing a separate rulemaking action that would propose to require installation of a new actuator and inspections in accordance with Airworthiness Limitation 28-AWL-25.

Request To Revise Numbering of Notes

Boeing requests that Notes 2 and 3 of the original NPRM be renumbered. Boeing believes that there are only two notes as part of Table 1 of the original NPRM, and that the notes were incorrectly numbered.

We understand Boeing's concern; however, we do not agree that the notes need to be renumbered. There are total of three notes in the supplemental NPRM. All three notes are correctly numbered. In all ADs, notes are numbered sequentially in the regulatory text.

Request To Revise Appendix 1

Boeing requests that Appendix 1 of the original NPRM be revised to include missing task titles and numbers. Boeing provided no justification.

We partially agree. Since we issued the original NPRM, the modifications of the motor operated valve actuator have been approved, and the associated airplane maintenance manual (AMM) changes have been released. Therefore, we agree with Boeing to revise columns “Task Title” and “Task #,” as applicable, of Appendix 1 of the supplemental NPRM to include the latest information specified in the AMM that is associated with design changes of the fuel tank system changes. However, we do not agree with Boeing to add task titles for the component maintenance manuals (CMM), because the AWLs cover the entire CMM, not just specific tasks.

Explanation of Other Changes to Original NPRM

We have revised paragraph (g) of this supplemental NPRM to clarify that the exception refers to the “initial inspections” specified in Table 1 of this AD rather than the “inspections.”

We have revised paragraph (h) of this supplemental NPRM to allow the use of later revisions of the MPD.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

Some of the changes discussed above expand the scope of the original NPRM; therefore, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment on this supplemental NPRM.

Costs of Compliance

There are about 990 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

Action	Work hours	Average labor rate per hour	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Revision of AWLs section of the Instructions for Continued Airworthiness	8	$80	$640	639	$408,960
Detailed and special detailed inspections	8	80	640	639	408,960

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 supplemental NPRM 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.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-26710; Directorate Identifier 2006-NM-147-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by August 27, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new inspections and maintenance actions. Compliance with these limitations is required by 14 CFR 43.16 and 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these limitations, the operator may not be able to accomplish the actions described in the revisions. In this situation, to comply with 14 CFR 43.16 and 91.403(c), the operator must request approval for revision to the airworthiness limitations (AWLs) in the Boeing 757 Maintenance Planning Data (MPD) Document D622N001-9 according to paragraph (g) or (i) of this AD.

Unsafe Condition

(d) This AD results from a design review of the fuel tank systems. We are issuing this AD to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs, or maintenance actions, which, in combination with flammable fuel vapors, could result in a fuel tank explosion 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.

Service Information

(f) The term “Revision March 2006 of the MPD” as used in this AD, means Section 9 of Boeing 757 MPD Document D622N001-9, Revision March 2006.

Revision of AWLs Section

(g) No later than December 16, 2008, revise the AWLs section of the Instructions for Continued Airworthiness by incorporating the information in the sections specified in paragraphs (g)(1) through (g)(3) of this AD into the MPD, except that the initial inspections specified in Table 1 of this AD must be done at the compliance times specified in Table 1. Accomplishing the revision in accordance with a later revision of the MPD is an acceptable method of compliance if the revision is approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA.

(1) Section E., “AIRWORTHINESS LIMITATIONS—FUEL SYSTEMS,” of Revision March 2006 of the MPD.

(2) Section F., “PAGE FORMAT: SYSTEMS AIRWORTHINESS LIMITATIONS,” of Revision March 2006 of the MPD.

(3) Section G., “AIRWORTHINESS LIMITATIONS—FUEL SYSTEM AWLs” of Revision March 2006 of the MPD.

Initial Inspections and Repair

(h) Do the inspections specified in Table 1 of this AD and repair any discrepancy, in accordance with Section G., “AIRWORTHINESS LIMITATIONS—FUEL SYSTEM AWLs,” of Revision March 2006 of the MPD. The repair must be done before further flight. Accomplishing the actions in accordance with a later revision of the MPD is an acceptable method of compliance if the revision is approved by the Manager, Seattle ACO, FAA.

Table 1.—Initial Inspections

Airworthiness limitations	Description	Compliance time (whichever occurs later)
		Threshold	Grace period
(1) 28-AWL-01	A detailed inspection of external wires over the center fuel tank for damaged clamps, wire chafing, and wire bundles in contact with the surface of the center fuel tank	Before the accumulation of 36,000 total flight cycles, or within 120 months since the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness, whichever occurs first	Within 72 months after the effective date of this AD.
(2) 28-AWL-03	A special detailed inspection of the lightning shield to ground termination on the out-of-tank fuel quantity indicating system to verify functional integrity	Before the accumulation of 36,000 total flight cycles, or within 120 months since the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness, whichever occurs first	Within 24 months after the effective date of this AD.
(3) 28-AWL-14	A special detailed inspection of the fault current bond of the fueling shutoff valve actuator of the center wing tank to verify electrical bond	Before the accumulation of 36,000 total flight cycles, or within 120 months since the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness, whichever occurs first	Within 60 months after the effective date of this AD.

Note 2:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Note 3:

For the purposes of this AD, a special detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. The examination is likely to make extensive use of specialized inspection techniques and/or equipment. Intricate cleaning and substantial access or disassembly procedure may be required.”

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Seattle ACO 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.

Appendix 1. Fuel Tank System Airworthiness Limitations—Applicable Maintenance Manuals

Airworthiness limitation (AWL)	Airworthiness limitation instruction (ALI)/critical design configuration control limitation (CDCCL)	ATA section or component maintenance manual (CMM) document	Task title	Task #
28-AWL-01	ALI	Airplane Maintenance Manual (AMM) 28-11-00/601	External Wires Over the Center Tank Inspection	28-11-00-206-221
28-AWL-02	CDCCL	Standard Wiring Practices Manual (SWPM) 20-10-11	Wiring Assembly and Installation Configuration
28-AWL-03	ALI	AMM 20-55-54/601	Fuel Quantity Indicating System (FQIS) Connectors—Inspection/ Check	20-55-54-286-001
28-AWL-04	CDCCL	SWPM 20-10-15	Assembly of Shield Ground Wires
28-AWL-05	CDCCL	SWPM 20-10-11	Wiring Assembly and Installation Configuration
28-AWL-06	CDCCL	CMM 28-41-68 Revision 4 or subsequent revisions
28-AWL-07	CDCCL	CMM 28-40-56, Revision 4; CMM 28-40-62, revision 3; CMM 28-40-59, revision 5; or subsequent revisions
28-AWL-08	CDCCL	SWPM 20-14-12	Repair of FQIS Wire Harness
		AMM 28-41-09/401	Install the Tank Wiring Harness	Varies with configuration
28-AWL-09	CDCCL	AMM 29-11-26/401	Install the Heat Exchanger	29-11-26-404-012
28-AWL-10	CDCCL	AMM 28-22-07/401	Install the Fuel Line and Fittings	28-22-07-404-005
28-AWL-11	CDCCL
28-AWL-12	CDCCL	CMM 28-22-08, revision 3; CMM 28-20-02, revision 9; or subsequent revisions
28-AWL-13	CDCCL	AMM 28-22-03/401	Install the Fuel Boost Pump Assembly or the Fuel Override Pump Assembly	28-22-03-404-007
28-AWL-14	ALI	AMM 28-21-02/401	Fueling Shutoff Valve Resistance Check	28-21-02-764-047
28-AWL-15	CDCCL	AMM 28-21-02/401	Install the Fueling Shutoff Valve	28-21-02-404-019
		AMM 28-21-12/401	Install the Actuator of the Fueling Shutoff Valve	28-21-12-404-015
28-AWL-16	CDCCL	AMM 28-11-01/401	Install the Main Tank Access Door	28-11-01-404-014
		AMM 28-11-02/401	Install the Center Tank Access Door	28-11-02-404-019
		AMM 28-11-03/401	Install the Surge Tank Access Door	28-11-03-404-008
28-AWL-17	CDCCL	AMM 28-11-03/401	Install the Surge Tank Access Door	28-11-03-404-008
		AMM 28-13-04/201	Install the Pressure Relief Valve	28-13-04-402-014
28-AWL-18	CDCCL	AMM 28-11-03/401	Install the Surge Tank Access Door	28-11-03-404-008
		AMM 28-13-05/401	Install the Housing of the Vent Flame Arrestor	28-13-05-404-004
28-AWL-19	CDCCL	Fault Isolation Manual (FIM) 28-22-00/101	Engine Fuel Feed System—Fault Isolation
28-AWL-20	ALI	AMM 28-22-00/501	Center Tank Fuel Override Pump Auto Shutoff Functional Test	28-22-00-725-507
			System Test—Engine Fuel Feed System	Varies with Configuration
28-AWL-21	ALI	AMM 28-22-00/501	System Test—Engine Fuel Feed System	Varies with Configuration
28-AWL-22	CDCCL	AMM 28-41-24/401	Densitometer Hot Short Protector Installation	28-41-24-404-006
28-AWL-23	CDCCL	AMM 28-22-01/401	Install the Adapter Shaft of the Engine Fuel Shutoff Valve (Spar Valve)	28-22-01-404-19
		AMM 28-22-02/401	Install the Engine Fuel Crossfeed Adapter Shaft	28-22-02-404-041
		AMM 28-22-11/401	Install the Actuator of the Engine Fuel Shutoff Valve (Spar Valve)	28-22-11-404-007
		AMM 28-22-12/401	Install the Actuator of the Engine Fuel Crossfeed Valve	28-22-12-404-024
		AMM 28-26-01/401	Install the Adapter Shaft for the Defuel Valve	28-26-01-404-035
		AMM 28-26-02/401	Install the Defueling Valve Actuator	28-26-02-404-015
28-AWL-24	CDCCL	CMM 28-20-21
28-AWL-25	ALI	AMM 28-22-01/401	Install the Adapter Shaft of the Engine Fuel Shutoff Valve (Spar Valve)	28-22-01-404-19
		AMM 28-022-02/401	Install the Engine Fuel Crossfeed Adapter Shaft	28-22-02-404-041
		AMM 28-22-11/401	Install the Actuator of the Engine Fuel Shutoff Valve (Spar Valve)	28-22-11-404-007
		AMM 28-22-12/401	Install the Actuator of the Engine Fuel Crossfeed Valve	28-22-12-404-024
		AMM 28-26-01/401	Install the Adapter Shaft for the Defuel Valve	28-26-01-404-035
		AMM 28-26-02/401	Install the Defueling Valve Actuator	28-26-02-404-015
		AMM 28-25-11/401	Install the Actuator of the APU Fuel Shutoff Valve	28-25-11-404-010
28-AWL-26	ALI	AMM 28-22-00/501	System Test—Engine Fuel Feed System	Varies with Configuration

Issued in Renton, Washington, on July 25, 2007.

Stephen P. Boyd,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.