E7-5928. Airworthiness Directives; Boeing Model 747 and 767 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 certain Boeing Model 747 and 767 airplanes. The original NPRM would have required 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. The original NPRM would also have required related investigative actions and corrective actions if necessary. The original NPRM resulted from fuel system reviews conducted by the manufacturer. This action revises the original NPRM by adding an inspection requirement for certain Model 747 airplanes, and by specifying cold-working the fastener holes for certain other Model 747 airplanes. We are proposing this supplemental NPRM 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 supplemental NPRM by April 24, 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: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: [phone].
• 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.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Philip Sheridan, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, 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-2005-21701; Directorate Identifier 2005-NM-086-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 Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level in the Nassif Building at the DOT street address stated in ADDRESSES. 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) (the “original NPRM”) for an AD for certain Boeing Model 747 and 767 airplanes. The original NPRM was published in the Federal Register on June 29, 2005 (70 FR 37293). The original NPRM proposed to 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. The original NPRM also proposed to require related investigative actions and corrective actions if necessary.

Actions Since Original NPRM Was Issued

Since we issued the original NPRM, Boeing has issued Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, dated October 5, 2006 (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). The original NPRM referred to Boeing Special Attention Service Bulletin 747-28-2259, dated November 4, 2004, as the appropriate source of service information for accomplishing certain actions.

Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, adds, for Group 1 airplanes, a high frequency eddy current (HFEC) inspection for cracks, corrosion, and damage of the fastener holes. Revision 1 also indicates reaming to repair those conditions, and gives an additional structural repair manual reference for doing the repair; but also specifies contacting Boeing if the repair does not eliminate cracks, corrosion, or damage when reamed to 0.2942- to 0.2962-inch in diameter. Revision 1 also adds a step that specifies cold-working the fastener holes for Group 2 airplanes; adds and revises certain part numbers for certain rivets; removes the step that specifies emptying fuel from the outboard main fuel tanks; clarifies an illustration of the new bonding rivets; and clarifies the measurements of the bonding resistance.

Comments

We have considered the following comments on the original NPRM.

Support for the Original NPRM

US Airways supports the original NPRM.

Request To Use New Revision of Service Bulletin

Japan Airlines (JAL) requests that we refer to Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, rather than the original issue of the service bulletin (Boeing Special Attention Service Bulletin 747-28-2259, dated November 4, 2004, was referred to as the appropriate source of service information for accomplishing the required actions). JAL also would like to confirm that it is acceptable to use the original issue of the service bulletin for compliance with the original NPRM, if the actions are done before the effective date of the AD.

We agree with JAL's requests. We have revised this supplemental NPRM to refer to Revision 1 of the service bulletin. We have also added a new paragraph (g) to this supplemental NPRM to give operators credit for accomplishing the applicable actions before the effective date of the AD in accordance with the original issue of the service bulletin. We have also re-identified subsequent paragraphs accordingly.

Requests To Extend Compliance Time

Boeing, British Airways, Royal Dutch Airlines (KLM), and the Air Transport Association (ATA) on behalf of one of its members, Delta Airlines, all request that we extend the 60-month compliance time for reworking the electrical bonding, as described below.

Boeing, British Airways, and KLM request a 72-month compliance time because it is the threshold that the manufacturer recommends. British Airways and KLM discussed this issue with Boeing and advise that the 60-month compliance time pre-dates Boeing's latest risk management guidelines for Special Federal Aviation Regulation (SFAR) 88 issues and is, therefore, out of step with current Boeing analyses. Boeing confirms that it initially recommended a 60-month compliance time before the completion of a formal compliance recommendation process. As such, the 60-month compliance time does not reflect current analyses. Boeing subsequently submitted a letter to the FAA that proposes a 72-month compliance time for all SFAR 88 design changes, with the exception of those associated with fuel pump inlet protection.

British Airways supports its request to extend the compliance time from 60 months to 72 months by asking us to consider an interim action. The proposed interim action would be any fuel pump housing replacement that is mounted and electrically bonded to the AD-affected under-wing housing. British Airways proposes an alternate ground path through the fasteners of the pump housing. If this bond can be verified, British Airways states that it justifies a 12-month extension to the compliance time.

Delta Airlines requests an 84-month compliance time because it would allow operators to accomplish the proposed actions during scheduled substantial aircraft maintenance visits due to complete de-fueling requirements. Delta states that an 84-month compliance time would also prevent undue financial and scheduling burdens.

We disagree with the requests to change the compliance time from 60 months to 72 or 84 months. In establishing the proposed compliance time, we considered not only the manufacturer's recommendation, but also the labor required to accomplish the actions, and the risks to the airplane if these actions are not done in a timely manner. We also considered that the alternate ground path proposed by British Airways does not have sufficient current-carrying capability (as stated in Boeing Special Attention Service Bulletin 747-28-2259); and we have taken into account the fact that there is a primary bond path. We determined that a 60-month compliance time is adequate for operators to schedule the task during heavy maintenance visits, and that it will provide an adequate level of safety. In further discussions, Boeing agrees with the 60-month compliance time for this supplemental NPRM.

However, operators may request approval of an alterative method of compliance (AMOC) in accordance with the procedures specified in paragraph (h) of this supplemental NPRM. The AMOC request must contain appropriate rationale to substantiate that the AMOC will maintain an acceptable level of safety. Operators outside the United States must work with the applicable regulatory authority regarding this process.

We have not changed the supplemental NPRM in this regard.

Request To Use Operator's Equivalent Procedures for Certain Repairs

ATA, on behalf of one of its members, Northwest Airlines, is concerned that the requirement to obtain FAA or authorized Boeing representative approval for repairs of crack or corrosion findings could have additional cost and schedule implications. Northwest Airlines states that obtaining this approval is outside the intent of the modification, and should be addressed with existing Northwest Airlines procedures, which may or may not require FAA approval. Northwest Airlines states that it would perform the specified bonding resistance checks to verify that there are still proper ground paths and current-carrying capabilities.

We disagree with changing the supplemental NPRM to remove the requirement to contact the FAA or authorized Boeing representative. Structural repair manual (SRM) repair procedures are spelled out in both Boeing Special Attention Service Bulletin 747-28-2259, dated November 4, 2004; and Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, dated October 5, 2006. Revision 1 also adds an additional SRM reference, and specifies contacting a Boeing representative for the repairs only if the SRM repair is not clean of cracks, corrosion, or damage when reamed to 0.2942- to 0.2962-inch in diameter. Approval of any deviation from the requirements of this supplemental NPRM, such as operator's equivalent or existing procedures, may be requested in accordance with the AMOC procedures specified in paragraph (h) of this supplemental NPRM. The AMOC request must contain appropriate rationale to substantiate that the AMOC will maintain an acceptable level of safety. We have not changed the supplemental NPRM in this regard.

Request To Clarify HFEC Inspection for Group 1 Airplanes

British Airways points out that Boeing Special Attention Service Bulletin 747-28-2259, dated November 4, 2004, specifies an HFEC inspection for defects after rework only for Group 2 airplanes, but for Group 1 airplanes the service bulletin does not state what inspections, if any, are necessary after reworking the holes. British Airways normally would expect, for all airplanes, to oversize the rivet holes, follow the SRM specifications, and progressively remove any damage. If it is the FAA's intent to subject Group 1 airplanes and Group 2 airplanes to the HFEC inspection, British Airways requests that we include a statement indicating that it affects both groups. However, British Airways believes that this statement would be best published in the service bulletin.

We agree that the inspection applies to both Group 1 and Group 2 airplanes. As stated previously, Boeing has issued Revision 1 of Boeing Special Attention Service Bulletin 747-28-2259, which makes the change that British Airways requests. We have changed the supplemental NPRM to refer to Revision 1 of the service bulletin.

Clarification of AMOC Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Explanation of Change to Costs of Compliance

After the original NPRM was issued, we reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $65 per work hour to $80 per work hour. The cost information, below, reflects this increase in the specified hourly labor rate.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

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.

Difference Between the Supplemental NPRM and Boeing Special Attention Service Bulletin 747-28-2259, Revision 1

Although Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, specifies contacting the manufacturer if any crack, corrosion, or damage that exceeds certain limits is found during the open-hole HFEC inspection, this supplemental NPRM would require operators to repair those conditions in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes 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 supplemental NPRM.

Estimated Costs

Action	Work hours	Average labor rate per hour	Cost per airplane	Number of U.S.- registered airplanes	Fleet cost
Rework electrical bonding for Boeing Model 747 airplanes	10	$80	$800	1,115	$892,000
Rework electrical bonding for Boeing Model 767 airplanes	9	80	720	921	663,120

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-2005-21701; Directorate Identifier 2005-NM-086-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by April 24, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the Boeing airplane models identified in Table 1 of this AD, certificated in any category.

Table 1.—Airplanes Affected by This AD

Model—	As identified in Boeing Special Attention Service Bulletin—
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	747-28-2259, Revision 1, dated October 5, 2006.
767-200, -300, and -300F series airplanes	767-57-0092, dated November 4, 2004.
767-400ER series airplanes	767-57-0093, dated November 4, 2004.

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 applicable corrective actions. If any crack, corrosion, or damage is found during the open-hole high-frequency eddy current (HFEC) inspection specified in Boeing Special Attention Service Bulletin 747-28-2259, Revision 1, dated October 5, 2006, and the special attention service bulletin specifies contacting Boeing for repair instructions: 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 Commercial Airplanes 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 repair must meet the certification basis of the airplane, and 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.

Credit for Actions Accomplished Previously

(g) Actions done before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 747-28-2259, dated November 4, 2004, are acceptable for compliance with the corresponding requirements of paragraph (f)(1) of this AD.

Alternative Methods of Compliance (AMOCs)

(h)(1) 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.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on March 23, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.