00-32765. Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 767 series airplanes. For certain airplanes this proposal would require rework of the bonding jumper assemblies. For certain other airplanes, this proposal would require repetitive inspections of the drain tube assemblies of the slat track housing of the wings to find discrepancies, and corrective actions, if necessary. This proposal also provides for terminating action for the repetitive inspections. This action is necessary to find and fix discrepancies of the bonding jumper assemblies, which could result in electrostatic discharge and an in-tank ignition source. This action also is necessary to find and fix discrepancies of the fuel drain tubes, which could result in fuel migrating into the tubes and leaking onto an engine or exhaust nozzle, and consequent risk of a fire when the airplane is stationary or during low speed taxiing. This action is intended to address the identified unsafe conditions.

DATES:

Comments must be received by February 5, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-309-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-309-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Dennis Kammers, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-309-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-309-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports on certain Boeing Model 767 series airplanes that a new drain tube assembly was installed during production, and the manufacturer determined that the bonding jumper assembly on the installation did not meet the current bonding specifications. Such discrepancies of the bonding jumper assemblies could result in electrostatic discharge and an intank ignition source.

For certain other airplanes, the FAA has received reports of the detection of fuel leaks from the number 5 and number 8 drain locations of the slat track housing near the engine exhaust nozzles of the wings. One report showed that the fuel leak originated from a drain tube fitting that had loosened over time. The other reports showed that the fuel leaks originated from a crack in each of the drain tubes due to improper installation. Such discrepancies of the fuel drain tubes could result in fuel migrating into the tubes and leaking onto an engine or exhaust nozzle, and consequent risk of a fire when the airplane is stationary or during low speed taxiing.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 767-57A0060, Revision 1, dated December 31, 1998, which describes procedures for repetitive visual inspections of the drain tube assemblies of the slat track housing of the wings to find discrepancies (loose fittings and/or cracking of the fuel drain tubes); rework of the drain tube assemblies if any discrepancies are found; and eventual replacement of the drain tube assemblies, which would constitute terminating action for the repetitive inspections.

The FAA also has reviewed and approved Boeing Service Bulletin 767-57-0068, dated September 16, 1999, which describes procedures for rework of the bonding jumper assembly of the number 5 and number 8 drain tube assemblies of the inboard slat track that were installed before per a production change (PRRB12900-133) that was incorporated at the manufacturer's facility. The rework includes, but is not limited to, replacement of the fasteners common to the drain doubler assembly; installation of bonding jumper brackets to the rib stiffeners, and installation of bonding jumpers between the drain tube assemblies and the brackets installed on the rib panels.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe conditions.

Explanation of Requirements of Proposed Rule

Since two unsafe conditions have been identified that are likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletins described before, except as discussed below.

Differences Between Boeing Service Bulletin 767-57A0060, Revision 1, and This Proposed Rule

Operators should note that the service bulletin does not direct operators to do the initial and repeat visual inspections of the drain tube assemblies of the slat track housing of the wings to find leakage, if the inspection recommended in the Boeing 767 Maintenance Planning Document (MPD), Section 57-59-00-A, has been accomplished. This proposed rule would require accomplishment of the initial and repeat visual inspections regardless of earlier accomplishment of the inspection specified in the MPD.

Operators also should note that this AD proposes to mandate, within 6,000 flight hours or 18 months, whichever occurs first, the replacement of the drain tube assemblies of the slat track housing of the wings described in the service bulletin as terminating action for the repetitive inspections. (The service bulletin states that incorporation of the terminating action specified is optional.) The FAA has determined that long-term continued operational safety will be better assured by design changes to remove the source of the problem, rather than by repetitive inspections. Long-term inspections may not be providing the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous continual inspections, has led the FAA to consider placing less emphasis on inspections and more emphasis on design improvements. The proposed replacement is consistent with these conditions.

Part IV of the Accomplishment Instructions of the service bulletin identifies certain rework specified in the “Validation Copy 1” release of the service bulletin as part of the corrective action. The FAA does not recognize work done using a validation copy of the service bulletin because it is not an FAA-approved document and, therefore, Part IV of the service bulletin is not required by this proposed rule.

Cost Impact

There are approximately 745 airplanes of the affected design in the worldwide fleet. The FAA estimates that 275 airplanes of U.S. registry would be affected by this proposed AD.

For airplanes listed in Boeing Service Bulletin 767-57A0060, Revision 1 (228 U.S.-registered airplanes): It would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $13,680, or $60 per airplane, per inspection cycle.

It would take approximately 12 work hours per airplane to accomplish the proposed replacement of the drain tube assemblies specified in Boeing Service Bulletin 767-57A0060, Revision 1, at an average labor rate of $60 per work hour. Required parts would cost approximately $5,236 per airplane. Based on these figures, the cost impact of the proposed replacement on U.S. operators is estimated to be $1,357,968, or $5,956 per airplane.

For airplanes listed in Boeing Service Bulletin 767-57-0068, (47 U.S.-registered airplanes): It would take approximately 4 work hours per airplane to accomplish the proposed rework of the bonding jumper assemblies, at an average labor rate of $60 per work hour. Required parts would cost approximately $322 per airplane. Based on these figures, the cost impact of the proposed rework on U.S. operators is estimated to be $26,414, or $562 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to do the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time needed by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2000-NM-309-AD.

Applicability: Model 767 series airplanes, line numbers 1 through 757 inclusive, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance per paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe conditions addressed by this AD; and, if the unsafe conditions have not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished before.

To find and fix discrepancies (bonding, loose fittings, cracking) of the bonding jumper assemblies, which could result in electrostatic discharge and an in-tank ignition source; and of the fuel drain tubes, which could result in fuel migrating into the tubes and leaking onto an engine or exhaust nozzle, and consequent risk of a fire when the airplane is stationary or during low speed taxiing; accomplish the following:

Repetitive Inspections/Corrective Action

(a) For airplanes listed in Boeing Service Bulletin 767-57A0060, Revision 1, dated December 31, 1998; within 500 flight hours after the effective date of this AD: Do a general visual inspection of the drain tube assemblies of the slat track housings of the wings to find discrepancies (loose fittings, cracked tubes, fuel leaks), per Part I of the Accomplishment Instructions of the service bulletin.

(1) If any discrepancies are found, before further flight, rework the drain tube assembly per Part II of the Accomplishment Instructions of the service bulletin; repeat the inspection at intervals not to exceed 500 flight hours until accomplishment of the requirements in paragraph (b) of this AD.

(2) If no discrepancies are found, repeat the inspection thereafter at intervals not to exceed 500 flight hours, until accomplishment of the requirements in paragraph (b) of this AD.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to find obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Terminating Action for Repetitive Inspections

(b) For airplanes specified in paragraph (a) of this AD; within 6,000 flight hours or 18 months after the effective date of this AD, whichever occurs first: Replace the drain tube assemblies of the slat track housings of the wings (including general visual inspection and repair) per Part III of the Accomplishment Instructions of Boeing Service Bulletin 767-57A0060, Revision 1, dated December 31, 1998. Any applicable repair must be accomplished prior to further flight. Accomplishment of this paragraph terminates the repetitive inspections required by paragraph (a) of this AD.

Rework of Bonding Jumper Assemblies

(c) For airplanes listed in Boeing Service Bulletin 767-57-0068, dated September 16, 1999; within 5,000 flight cycles or 22 months after the effective date of this AD, whichever occurs first: Rework the bonding jumper assembly of the drain tube assemblies of the slat track housing of the wings (including general visual inspection and repair) per the Accomplishment Instructions of the service bulletin. Any applicable repair must be accomplished prior to further flight. Accomplishment of this paragraph terminates the requirements of this AD.

Alternative Methods of Compliance

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall send their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permit

(e) Special flight permits may be issued per sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Issued in Renton, Washington, on December 18, 2000.

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.