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Proposed Rule

Airworthiness Directives; Lockheed Model L-1011 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Lockheed Model L-1011 series airplanes. This proposed AD would require revising the FAA-approved maintenance program by incorporating new airworthiness limitations for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. This proposed AD would also require the accomplishment of certain fuel system modifications, the initial inspections of certain repetitive fuel system limitations to phase in those inspections, and repair if necessary. This proposed AD results from a design review of the fuel tank systems. We are proposing 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.

DATES:

We must receive comments on this proposed AD by March 21, 2008.

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 AD, contact Lockheed Continued Airworthiness Project Office, Attention: Airworthiness, 86 South Cobb Drive, Marietta, Georgia 30063-0567.

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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Robert A. Bosak, Aerospace Engineer, Propulsion and Services Branch, ACE-118A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30349; telephone (770) 703-6094; fax (770) 703-6097.

End Further Info End Preamble Start Supplemental Information

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-2008-0181; Directorate Identifier 2007-NM-180-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

The FAA has examined the underlying safety issues involved in fuel tank explosions on several large transport airplanes, including the adequacy of existing regulations, the service history of airplanes subject to those regulations, and existing maintenance practices for fuel tank systems. As a result of those findings, we issued a regulation titled “Transport Airplane Fuel Tank System Design Review, Flammability Reduction and Maintenance and Inspection Requirements” (66 FR 23086, May 7, 2001). In addition to new airworthiness standards for transport airplanes and new maintenance requirements, this rule included Special Federal Aviation Regulation No. 88 (“SFAR 88,” Amendment 21-78, and subsequent Amendments 21-82 and 21-83).

Among other actions, SFAR 88 requires certain type design (i.e., type certificate (TC) and supplemental type certificate (STC)) holders to substantiate that their fuel tank systems can prevent ignition sources in the fuel tanks. This requirement applies to type design holders for large turbine-powered transport airplanes and for subsequent modifications to those airplanes. It requires them to perform design reviews and to develop design changes and maintenance procedures if their designs do not meet the new fuel tank safety standards. As explained in the preamble to the rule, we intended to adopt airworthiness directives to mandate any changes found necessary to address unsafe conditions identified as a result of these reviews.

In evaluating these design reviews, we have established four criteria intended to define the unsafe conditions associated with fuel tank systems that require corrective actions. The percentage of operating time during which fuel tanks are exposed to flammable conditions is one of these criteria. The other three criteria address the failure types under evaluation: Single failures, single failures in combination with a latent condition(s), and in-service failure experience. For all four criteria, the evaluations included consideration of previous actions taken that may mitigate the need for further action. Start Printed Page 9236

We have determined that the actions identified in this proposed AD are necessary to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Relevant Service Information

We have reviewed Lockheed Service Bulletin 093-28-098, Revision 1, dated January 22, 2008. The service bulletin describes procedures for incorporating new airworthiness limitations for fuel tank systems into the operator's FAA-approved maintenance program. The airworthiness limitations for fuel tank systems include fuel system limitations (FSLs) and critical design configuration control limitations (CDCCLs). FSLs are modifications, design features, and periodic inspections of certain features for latent failures that could contribute to an ignition source. CDCCLs are limitation requirements to preserve a critical ignition source prevention feature of the fuel tank system design that is necessary to prevent the occurrence of an unsafe condition. The purpose of a CDCCL is to provide instruction to retain the critical ignition source prevention feature during configuration change that may be caused by alterations, repairs, or maintenance actions. A CDCCL is not a periodic inspection.

Lockheed Service Bulletin 093-28-098 refers to the following service information for doing certain CDCCLs:

  • Hamilton Sundstrand Overhaul Manual 28-24-03, Revision 14, dated May 15, 2000, or later, for overhauling and repairing the electrically-operated fuel boost pumps.
  • Lockheed L-1011 Service Information Letter 28-12 for keeping the electrical conduit for the electrically-operated fuel boost pumps open and unplugged at the wing rear spar.
  • Lockheed Drawing 1527514 for installing the fuel tank valves, auxiliary power unit pump, sight gages, fuel quantity indicating system tank units, over wing filler cap adapter ring, boost pump mounting plate, and access doors for the boost pump, vent box, vent valve, and fuel level control switch.
  • Lockheed Service Bulletin 093-28-098 also refers to the following service bulletins as additional sources of service information for doing the FSLs:
  • Lockheed Service Bulletin 093-28-062, Revision 7, dated December 9, 1983, for Model L-1011 series airplanes, which describes procedures for inspecting and modifying the plug-in valve assemblies of the fuel shutoff system.
  • Lockheed Service Bulletin 093-28-089, Revision 3, dated October 4, 2006, for Model L-1011-385-3 series airplanes, which describes procedures for removing auxiliary fuel tank No. 4.
  • Lockheed Service Bulletin 093-28-093, Revision 1, dated February 8, 1999, for Model L-1011 series airplanes, which describes procedures for installing and inspecting fuel boost pumps and modifying the centrifugal pump and motor.
  • Lockheed Service Bulletin 093-28-094, Revision 1, dated June 23, 2006, for Model L-1011 series airplanes. This service bulletin describes procedures for (1) modifying the wiring harnesses of the fuel level control switch, (2) repetitively inspecting the fuel level control switch, wiring harnesses, and harness conduit for any visible damage, wear or chafing, broken or missing O-rings, or indications of electrical arcing, (3) replacing the fuel level control switch assembly with a new assembly if any damage, wear or chafing, or indications of electrical arcing to the wiring is found or any broken or missing O-rings are found, (4) notifying Lockheed of any discrepancies found during the inspection, and (5) revising the airplane records and maintenance planning documents to require the repetitive inspections. The modification involves replacing the braided fiberglass sleeving with PVC electrical sleeving over each wiring harness and replacing the smaller inside diameter conduit with the larger inside diameter conduit, if applicable. (Although AD 2001-08-21, amendment 39-12198 (66 FR 21072, April 27, 2001) mandated accomplishment of Lockheed Service Bulletin 093-28-094, dated March 3, 2000, more work is necessary for Revision 1 of Lockheed Service Bulletin 093-28-094.)
  • Lockheed Service Bulletin 093-28-095, dated September 13, 2006, for Model L-1011 series airplanes. This service bulletin describes procedures for (1) repetitively inspecting the airplane fuel tanks and vent boxes for cleanliness and evidence of deteriorated or damaged fuel/vent tubes and components, (2) repetitively inspecting bonding jumpers on the fuel/vent tubes and components for proper installation, corrosion, frayed or broken strands, and the condition of the environmental sealing or bonding clamps and hardware, (3) correcting any discrepant conditions, (4) notifying Lockheed of any discrepancies found during the inspection, (5) adding about 444 bonding jumpers across the fuel/vent tube fittings located in fuel tanks 1, 2L, 2R, and 3, (6) repetitively inspecting the bonding jumpers on the fuel/vent tube fittings, and (7) revising the airplane records and maintenance planning documents to require the repetitive inspections.
  • Lockheed Service Bulletin 093-28-096, Revision 2, dated June 23, 2006, for Model L-1011 series airplanes. This service bulletin describes procedures for (1) repetitively inspecting the wiring harnesses of the No. 1 and No. 3 engine tank valves for evidence of damage and fuel contamination, (2) replacing any damaged wire with new wire, (3) repairing or replacing any contaminated wires as applicable, (4) reporting any evidence of damage or wire replacement to Lockheed, and (5) revising the airplane records and maintenance planning documents to require the repetitive inspections.
  • Lockheed Service Bulletin 093-28-097, dated August 3, 2006, for Model L-1011 series airplanes. This service bulletin describes procedures for (1) installing identification markers or sleeving on the wiring harnesses of the fuel quantity indicating system (FQIS), (2) repetitively inspecting the FQIS wiring harnesses for any visible damage, wear, chafing, or indications of electrical arcing, (3) replacing or repairing any damaged wires, (4) notifying Lockheed of any discrepancies found during the inspection, and (5) revising the airplane records and maintenance planning documents to require the repetitive inspection.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Findings

During the SFAR 88 safety assessment, Lockheed concluded that no operator had installed auxiliary fuel tank No. 4, in accordance with Lockheed Service Bulletin 093-28-089, on Model L-1011-385-3 series airplanes. Thus, safety assessments for the auxiliary fuel tank, including the electrical equipment involved with the modification, did not need to be analyzed to show compliance with SFAR 88. Since Lockheed has not provided the service information required under SFAR 88 that could lead the FAA to make a finding of compliance, and there is a possibility that there may be unreported installations of the modification, we must mandate the removal of auxiliary fuel tank.

If an operator does not wish to remove the auxiliary fuel tank, we will consider requests for alternative methods of compliance (AMOCs). The most likely requests would be to allow continued use of the tank by showing compliance Start Printed Page 9237with SFAR 88. This would involve obtaining STCs and developing design and maintenance procedures to address all identified safety issues.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require revising the FAA-approved maintenance program to incorporate the FSLs and CDCCLs specified in Lockheed Service Bulletin 093-28-098. This proposed AD would also require the accomplishment of certain fuel system modifications, the initial inspections of certain repetitive FSLs to phase in those inspections, and repair if necessary.

Differences Between the Proposed AD and Service Bulletin

Lockheed Service Bulletin 093-28-098 specifies to revise the operator's maintenance program to incorporate Revision 7 of Lockheed Service Bulletin 093-28-062 and Revision 1 of Lockheed Service Bulletin 093-28-093. However, this proposed AD would not require those actions, since Lockheed Service Bulletins 093-28-062 and 093-28-093 are mandated by other ADs. AD 99-24-12, amendment 39-11436 (64 FR 66756, November 30, 1999), mandated Revision 1 of Lockheed Service Bulletin 093-28-093. AD 80-25-04, amendment 39-3983 (45 FR 79011, November 28, 1980), mandated Revision 1 of Lockheed Service Bulletin 093-28-062, but this proposed AD would not require accomplishing Revision 7 of the service bulletin since both Revisions 1 and 7 adequately address the unsafe condition.

Where Lockheed Service Bulletin 093-28-098 specifies to inspect, this proposed AD would require a general visual inspection. We have included Note 2 in this proposed AD to define this type of inspection.

Although Lockheed Service Bulletins 093-28-094, 093-28-095, 093-28-096, and 093-28-097 describe procedures for notifying Lockheed of any discrepancies found during inspection or any evidence of damage or wire replacement, this proposed AD would not require those actions.

Explanation of 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, the FAA has 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 proposed AD, we are using that same compliance date in this proposed AD.

Costs of Compliance

There are about 108 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs, at an average labor rate of $80 per hour, for U.S. operators to comply with this proposed AD.

Estimated Costs

ActionWork hoursPartsCost per airplaneNumber of U.S.-registered airplanesFleet cost
Maintenance program revision to incorporate FSLs and CDCCLs4None$32063$20,160
Removal of auxiliary fuel tank No. 4, if applicable40None3,200825,600
Modification and inspection of the wiring harnesses of the fuel level control switch19$9742,49463157,122
Inspection of the airplane fuel tanks, vent boxes, and bonding jumpers, and the addition of bonding jumpers to the fuel/vent tube fittings370$18,49148,091633,029,733
Inspection of the wiring harnesses of the No. 1 and No. 3 engine tank valves2$41,78541,945632,642,535
Identification and inspection of the FQIS wiring harnesses4$3366566341,328

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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PART 39—AIRWORTHINESS DIRECTIVES

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

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Start Printed Page 9238 Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

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

Lockheed: Docket No. FAA-2008-0181; Directorate Identifier 2007-NM-180-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by March 21, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Lockheed Model L-1011 series airplanes, certificated in any category.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these inspections is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these inspections, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance (AMOC) in accordance with paragraph (k) of this AD. The request should include a description of changes to the required inspections that will ensure the continued operational safety of the airplane.

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 Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Lockheed Service Bulletin 093-28-098, Revision 1, dated January 22, 2008.

Maintenance Program Revision

(g) Before December 16, 2008, revise the FAA-approved maintenance program to incorporate the fuel system limitations (FSLs) specified in paragraph 2.B. of the service bulletin and the critical design configuration control limitations (CDCCLs) specified in paragraph 2.C. of the service bulletin; except as provided by paragraphs (g)(1) and (g)(2) of this AD.

(1) Where the FSLs specify to inspect, this AD would require doing a general visual inspection.

Note 2:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight 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.”

(2) For the CDCCLs specified in paragraphs 2.C.(2)(c), 2.C.(2)(d), and 2.C.(15)(a) of the service bulletin, do the applicable actions using a method approved in accordance with the procedures specified in paragraph (k) of this AD. The applicable service information listed in Table 1 of this AD is one approved method.

Table 1.—Approved Methods for Certain CDCCLs

For the CDCCL identified in the service bulletin in paragraph—One approved method is—For—
2.C.(2)(c)Hamilton Sundstrand Overhaul Manual 28-24-03, Revision 14, dated May 15, 2000Overhauling and repairing the electrically-operated fuel boost pumps.
2.C.(2)(d)Lockheed L-1011 Service Information Letter 28-12, dated March 17, 1998Keeping the electrical conduit for the electrically-operated fuel boost pumps open and unplugged at the wing rear spar.
2.C.(15)(a)Lockheed Drawing 1527514, Revision D, dated November 11, 1981Installing the fuel tank valves, auxiliary power unit pump, sight gages, fuel quantity indicating system tank units, over wing filler cap adapter ring, boost pump mounting plate, and access doors for the boost pump, vent box, vent valve, and fuel level control switch.

Initial Accomplishment of FSLs and Repair if Necessary

(h) Before December 16, 2008, do the applicable FSLs specified in paragraphs 2.B.(1)(b), 2.B.(1)(d), 2.B.(1)(e), 2.B.(1)(f), and 2.B.(1)(g) of the service bulletin and repair any discrepancy, in accordance with the service bulletin. Any repair must be done before further flight.

Note 3:

The service bulletin refers to the service information listed in Table 2 of this AD as additional sources of service information for doing the FSLs and repair.

Table 2.—Additional Sources of Service Information for Certain FSLs

The FSL identified in the service bulletin in paragraph—Refers to Lockheed Service Bulletin—For—
2.B.(1)(b)093-28-089, Revision 3, dated October 4, 2006 (or later)Removing auxiliary fuel tank No. 4, if applicable.
2.B.(1)(d)093-28-094, Revision 1, dated June 23, 2006 (or later)Modifying the wiring harnesses of the fuel level control switch; repetitively inspecting the fuel level control switch, wiring harness, and harness conduit for any visible damage, wear or chafing, broken or missing O-rings, or indications of electrical arcing; and replacing the fuel level control switch assembly with a new assembly if any damage or evidence of chafing to the wiring is found.
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2.B.(1)(e)093-28-095, dated September 13, 2006 (or later)Repetitively inspecting the airplane fuel tanks and vent boxes for cleanliness and evidence of deteriorated or damaged fuel/vent tubes and components; repetitively inspecting bonding jumpers for proper installation, corrosion, frayed or broken strands, and the condition of the environmental sealing or bonding clamps and hardware; correcting any discrepant conditions; adding bonding jumpers to the fuel/vent tube fittings; and repetitively inspecting the bonding jumpers on the fuel/vent tube fittings.
2.B.(1)(f)093-28-096, Revision 2, dated June 23, 2006 (or later)Repetitively inspecting the wiring harnesses of the No. 1 and No. 3 engine tank valves for evidence of damage and fuel contamination; replacing any damaged wire with new wire; and repairing or replacing any contaminated wires as applicable.
2.B.(1)(g)093-28-097, dated August 3, 2006 (or later)Identifying the wiring harnesses for the fuel quantity indicator system (FQIS); repetitively inspecting the FQIS wiring harnesses for any visible damage, wear, chafing, or indications of electrical arcing; and replacing or repairing any damaged wires as applicable.

No Reporting Requirement

(i) Although Lockheed Service Bulletin 093-28-094, Revision 1, dated June 23, 2006; Lockheed Service Bulletin 093-28-095, dated September 13, 2006; Lockheed Service Bulletin 093-28-096, Revision 2, dated June 23, 2006; and Lockheed Service Bulletin 093-28-097, dated August 3, 2006; specify to notify Lockheed of any discrepancies found during inspection or any evidence of damage or wire replacement, this AD does not require that action.

No Alternative Inspections, Inspection Intervals, or CDCCLs

(j) After accomplishing the actions specified in paragraphs (g) and (h) of this AD, no alternative inspections, inspection intervals, or CDCCLs may be used unless the inspections, intervals, or CDCCLs are part of a later revision of the service bulletin that is approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA; or unless the inspections, intervals, or CDCCLs are approved as an AMOC in accordance with the procedures specified in paragraph (k) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Atlanta 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) 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.

Start Signature

Issued in Renton, Washington, on February 11, 2008.

Stephen P. Boyd,

Assistant Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. E8-2996 Filed 2-19-08; 8:45 am]

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