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3.4.2.2 These CDCCLs must be incorporated and adhered to as written. Any proposed operator changes to the CDCCL must be approved by the responsible Aircraft Certification Service office.
3.4.3 Inspection in a Hangar Environment. Traditionally structural airworthiness limitations have a specific task and interval and are performed as part of a scheduled inspection in a hangar environment. Most fuel system airworthiness limitations will also involve access requirements that are generally only available in a hangar environment during a scheduled maintenance visit.
3.4.4 Critical Design Feature Maintenance. For example, there will also be times when a fuel system CDCCL will involve unscheduled maintenance such as a fuel pump change due to pump failure at a line station overnight. The CDCCL requires that the critical design feature identified in paragraph 3.4.2.1 above must be maintained during the fuel pump change.
3.4.5 Fuel System Airworthiness Limitations that Include CDCCLs. Accomplishment of fuel system airworthiness limitations that include CDCCLs relates directly to safety of flight similar to the Required Inspection Item (RII) requirement in the 14 CFR part 121 rule.
Operators must consider CDCCLs with the same safety consideration and emphasis, whether the work occurs during scheduled or unscheduled maintenance, or it arises at an inconvenient time or location.
3.4.5.1 Operators must have procedures in their maintenance program that ensure that any airworthiness limitation critical design feature that is affected is maintained whether it’s during scheduled or unscheduled maintenance.
3.4.5.2 CDCCLs are intended to identify only critical features of a design that must be maintained. For example, certain components of a fuel pump (or all components) may include critical features that are identified as CDCCLs.
These critical features would be identified in the ALS of the ICA and in the component maintenance manual (CMM) as CDCCLs.
3.4.5.3 Although not intended by the introduction of CDCCLs and other fuel system airworthiness limitations, there are also DAH that have created certain airworthiness limitations CDCCLs that include both the critical design feature as well as the tasks associated with maintaining the CDCCL. Typically these airworthiness limitations require adhering to a specific CMM at a specific revision level when repairing or overhauling fuel system components. In this case, operators are required to adhere to all elements of the CMM specified in the CDCCL. Any deviations from CMMs specified in the CDCCL, including using later revisions of those CMMs, must be approved by the responsible Aircraft Certification Service office. The operator should submit its proposed changes through the PI, who may add comments and forward them to the responsible Aircraft Certification Service office for approval. Deviations from CMMs specified in the CDCCL may also involve an AMOC to an AD. (See the CMM deviation definition in Appendix C, Definitions.)
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3.5 AD Requirements. The AD requires the operator to incorporate fuel tank system airworthiness limitations into their maintenance or inspection program.
3.5.1 Fuel Systems Airworthiness Limitations. The information in this paragraph and the following paragraphs 3.5.2 and 3.5.3 is based on a transport airplane Maintenance Planning Data (MPD) ALS. Not all airplane manufacturers use the term MPD. It includes explanatory language, which is also referred to as the program rules/front matter, about what the fuel system airworthiness limitations are, their regulatory basis, and what they contain. It explains the difference between an ALI and a CDCCL. Operators must incorporate this explanatory language into their maintenance or inspection program. This includes appropriate manuals used in the administration of the operator’s maintenance or inspection program. Any changes to these program rules must be approved by the responsible Aircraft Certification Service office and may also involve an AMOC to an AD. The operator should submit any changes through the PI, who may add comments and forward them to the responsible Aircraft Certification Service office for approval.
3.5.2 Format of Airworthiness Limitations. This paragraph includes a format in terms of airworthiness limitation number, task, interval, airplane applicability, and description.
This is the format used by the DAH and included in the ALS of its maintenance manual.
The operator can use its own format but it must include the airworthiness limitation number, task, interval, airplane applicability, and description in its maintenance or inspection program. This includes appropriate manuals and documents such as Engineering Orders (EO) and job/work cards used in the administration of the operator’s maintenance or inspection program. It is especially important that this information be included on the operator’s job/work cards so that the person performing the task knows the safety significance of the task.
3.5.3 Types of Airworthiness Limitations. This paragraph includes the airworthiness limitations. Some DAH have separated fuel system airworthiness limitations into two subcategories: ALIs and CDCCLs. In this case, ALIs include only fuel tank airworthiness limitation inspections and procedures. The description of the CDCCLs in some cases contains references to the DAH AMM and the SWPM or equivalent. Unless otherwise noted, these manuals’ references are incorporated by reference (IBR) and therefore are Aircraft Certification Service office-approved. Any changes to these references in the AMM or the SWPM must be Aircraft Certification Service office-approved before being used.
3.5.4 Work Instructions/Procedures. As stated in paragraph 3.5.3, AMM and SWPM references in the airworthiness limitations are Aircraft Certification Service office-approved. The following paragraphs should be used as guidance when complying with airworthiness limitations that contain references to AMMs or SWPMs:
3.5.4.1 When the words “in accordance with” or “per” are cited in the airworthiness limitations, the procedures in the AMM or SWPM must be followed to ensure that the critical design feature is maintained. Any changes to these procedures require Aircraft Certification Service office approval before they are used.
Proposed changes must be submitted through the PI, who may add comments
3- 6 and forward them to the responsible Aircraft Certification Service office for approval.
3.5.4.2 When the words “refer to” are cited in the airworthiness limitation, the procedures in the AMM or SWPM represent one method of complying with the airworthiness limitation. An accepted alternative procedure may be developed by the operator in accordance with its procedures in its maintenance program/manual. Prior Aircraft Certification Service office approval is not required for this action. This does not preclude the PI from coordinating with the responsible Aircraft Certification Service office before concurring with the revision.
3.5.4.3 Operators must include specific procedures in its maintenance program/manual that identify fuel system airworthiness limitations that have AMM and SWPM procedures that are FAA-approved and can only be changed by the responsible Aircraft Certification Service office, and those that can be changed by the operator without prior Aircraft Certification Service office approval.
3.5.5 Example Airworthiness Limitation Identification Tables. The following tables are examples of how two fuel tank system airworthiness limitations are identified; one as an ALI, and the other a CDCCL. Table 3-1 identifies a portion of an airworthiness limitation in ATA Chapter 28 for the fuel tank system. The task is identified as an ALI with an assigned interval, airplane applicability, and a description of the airworthiness limitation task to be performed (not shown). Table 3-2 identifies a portion of an airworthiness limitation with the task being a CDCCL (the task is not shown). There is no assigned interval because a CDCCL is not an inspection or procedure. It refers to information for maintenance personnel to follow when performing maintenance and alteration to protect the critical design features of the fuel tank system.
Table 3-1. Airworthiness Limitation Table Example 1—ALI AWL Number Task Interval Applicability Description 28-AWL 01 ALI 12 Yrs/ 36000 Hrs All Models External wires over center fuel tank.
Concern: Potential for chaffing and arcing to center fuel tank upper panel.
Table 3-2. Airworthiness Limitation Table Example 2—CDCCL AWL Number Task Interval Applicability Description 28-AWL 02 CDCCL N/A All Models External wires over center fuel tank.
Concern: Potential for chaffing and arcing to center fuel tank upper panel.
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3.5.5.1 An example of a CDCCL for current designs would be maintaining wire separation between FQIS wiring and other high power electrical circuits. The original DAH defined a method to ensure that this essential information will be evident to those who may perform and approve repairs and alterations. The DAH provided visual means to alert maintenance personnel of areas in the airplane where inappropriate actions may degrade the integrity of the design configuration.
3.5.5.2 The responsible Aircraft Certification Service office approved the airworthiness limitations and the information is communicated by statements in appropriate manuals such as Wiring Diagram Manuals (WDM), AMMs, SWPMs, or the CMM. The responsible Aircraft Certification Service office must approve any operator changes to the airworthiness limitations or the manual following the process described in paragraph 3.5.4.
3.5.5.3 Operators must incorporate these CDCCLs in their maintenance or inspection program; CDCCL instructions should be included in the operator’s manual and in the job/work cards. Any changes that require approval by the Aircraft Certification Service office must be submitted by the operator through the PI, who may add comments and then send them to the responsible Aircraft Certification Service office.
3.6 Operator Compliance with Airworthiness Limitations.
3.6.1 ALS Approved Under 14 CFR § 25.981. Title 14 CFR § H25.4(a)(2), Amendment 25-102, requires “Each mandatory replacement time, inspection interval, related inspection procedure, and all critical design configuration control limitations approved under 14 CFR § 25.981 for the fuel tank system” must be contained in a section of the ICA titled Airworthiness Limitations. The ALS is Aircraft Certification Service office-approved and specifies maintenance required under 14 CFR §§ 43.16 and 91.403.
Simply stated, each operator must incorporate the ALS approved under 14 CFR § 25.981 for the fuel tank system into its maintenance or inspection program. As stated in 14 CFR § H25.4(a)(2), the fuel tank system must include the following under 14 CFR § 25.981 for fuel tank system:
• Mandatory replacement times,
• Inspection intervals,
• Related inspection instruction/procedures, and
• All CDCCLs.
3.6.2 Compliance with CDCCLs. All fuel tank system CMMs as specified in the CDCCLs are FAA-approved. Any changes must be submitted through the PI, who may add comments and forward them to the responsible Aircraft Certification Service office for approval. An example is provided as follows: If required by CDCCLs, repair and overhaul of certain fuel system components must be “per” or “in accordance with” the manufacturers’ CMM, or later revisions of these CMMs that have been approved by the responsible Aircraft
3-8 Certification Service office. The operator must comply with the CMMs if required by CDCCLs.
3.7 Operator-Developed Shop Instructions. In the past, CMMs were accepted by the FAA, not approved. The responsible Aircraft Certification Service office will approve certain CMMs and certain parts of CMMs in accordance with the requirement in 14 CFR § 25.981(d) in establishing certain CDCCLs.
3.7.1 CMM Example. An example is the CMM for overhauling or repairing fuel pumps. In certain CDCCLs, the entire manual is Aircraft Certification Service office-approved and a statement is contained in the manual to that effect. The responsible Aircraft Certification Service office must approve any operator changes to the CMM.
3.7.2 CDCCL Example. Another example is a CDCCL where the entire CMM is not Aircraft Certification Service office-approved, but the CDCCL requires following specific FAA-approved data such as maintenance instructions, inspections, and procedures in the CMM. This data will be flagged as FAA-approved data in the CDCCL and CMM.
3.7.3 Identify FAA-Approved Data. Operators who develop their own shop manuals and instructions need to ensure that the FAA-approved data used in their manuals and instructions are identified as FAA-approved data. The responsible Aircraft Certification Service office must approve any changes to the FAA-approved data in the operators’ shop manuals or instructions.
3.8 Exceptional Short-Term Extension of Fuel Tank System Airworthiness Limitations.
3.8.1 Extension Without Approval. The FAA has determined that an operator may extend certain fuel system airworthiness limitations by up to the maximum number of days specified in the applicable ALS for a specific airplane without Aircraft Certification Service office approval. The Aircraft Certification Service office-approved ALS includes a statement explaining that the exceptional short-term extensions of fuel tank system airworthiness limitations, subject to the procedures in the document, are Aircraft Certification Service office-approved. The FAA defines an exceptional short-term extension as an increase in a fuel system ALI interval that may be used by the operator to cover an uncontrollable or unexpected situation where the airworthiness limitation cannot be performed within the ALI timeframe. For example, an operator’s airplane is scheduled for an airworthiness limitation inspection but cannot enter the hangar bay because it is still occupied by another airplane. In this case, the operator, in accordance with the procedures in the ALS must request and have advance approval from the PI for the exceptional short-term extension. (For the purposes of the FTS requirements and this AC, short-term escalation procedures authorized by air carrier OpSpecs cannot be used for exceptional short-term extension of fuel tank system airworthiness limitations.)
3.8.2 Repeated Use Prohibited. After an operator uses an exceptional short-term extension of an FTS airworthiness limitation, that airworthiness limitation interval must revert back to the original interval in the maintenance program. Extensions are only allowed on an
3- 9 individual airplane. Under the procedures in the ALS, repeated use on the same airplane or on similar airplanes in the operator’s fleet is not allowed.
3.8.3 Airworthiness Limitation Extension Requests. The extension request must be submitted to the PI, who will forward the request along with comments to the responsible Aircraft Certification Service office for approval. Any such request must include substantiating data. After Aircraft Certification Service Office approval, the operator will submit to the PI for review the revisions to their maintenance and inspection program incorporating the Aircraft Certification Service office-approved extension. (For the purposes of the FTS requirements and this AC, short-term escalation procedures authorized by air carrier OpSpecs cannot be used for exceptional short-term extension of a fuel tank system airworthiness limitation.)
3.9 Changes in ICA Resulting from Alterations. The EAPAS/FTS Final Rule requires that after December 16, 2008, before returning an aircraft to service after any alteration for which fuel tank ICA are developed under SFAR 88, or 14 CFR § 25.1529 and part 25 appendix H (effective June 6, 2001), the operator must incorporate the fuel tank ICA into its maintenance or inspection program.
3.9.1 Major Alterations. The only alterations for which fuel tank system ICA will be developed are those for which compliance with either SFAR 88 or 14 CFR § 25.1529 must be shown. These are major alterations approved under STCs or amended TCs.
3.9.2 Scheduled Maintenance Visit/Check. These alterations would normally be scheduled by an operator to occur during a period of allocated downtime such as a scheduled maintenance visit/check. Operators should include in their maintenance planning for such modification actions necessary to incorporate fuel tank ICA into their maintenance or inspection program.
3.10 Fuel Tank System Ignition Prevention Training. The EAPAS/FTS introduced new requirements that affect DAH and operators.
3.10.1 New Philosophical Approach. To fully realize the objectives of fuel tank system ignition prevention, the operators need to rethink their current philosophical approach to maintaining, inspecting, and altering aircraft wiring and systems that could affect the fuel tank system ignition prevention features. This approach has begun at the airplane manufacturers with maintenance program enhancements that address fuel tank system ignition prevention. It is incumbent that the operators include these DAH fuel tank system maintenance program enhancements into their respective programs. Furthermore, they should commit to training their maintenance and inspection work force to understand the new philosophical approach to fuel tank system ignition prevention.
3.10.2 New Procedures. In addition to CDCCLs, there will be new maintenance manual and job card procedures, inspection devices, graphical information showing required tasks, or changes in tasks such as wire splicing. Operators should provide training to maintenance, inspection, and engineering personnel, including persons who write and edit job cards and EOs. Heightened awareness of these critical areas is needed. Additionally, operators
3- 10 must have procedures in place that ensure maintenance record entries for complying with a CDCCL are consistent with 14 CFR §§ 43.9 and 43.11, or in accordance with the applicable provisions of 14 CFR part 121 or part 129 and the operators’ manual.
3.10.3 Operator Training Program. The operator training program should emphasize the importance of accomplishing the fuel tank system airworthiness limitations, CDCCLs, inspections, and other procedures while accomplishing scheduled and unscheduled maintenance. (See paragraphs 3.4.2–3.4.5 for further guidance on this subject.)
3.10.4 Critical Design Features. Maintenance and engineering personnel can ensure that the fuel tank system airworthiness limitations are properly performed throughout the operational life of the airplane by having a thorough understanding of the airplane fuel tank system critical design features.
3.10.5 Manufacturer-Developed Training Programs. Operators should take advantage of any airplane manufacturer-developed training programs that address fuel tank ignition prevention.
3.11 Operator’s Maintenance Program Approval Under 14 CFR §§ 121.1113 and 129.113. OpSpec D097, Aging Aircraft Programs, signifies the FAA has reviewed the certificate holder’s (CH) policies and procedures incorporated into their maintenance and/or inspection programs for compliance with the Aging Aircraft Program rules. The operator will submit to the PI for review the revisions to their maintenance and inspection program incorporating the Aircraft Certification Service office-approved ICA changes.
The PI will ensure the operator has incorporated FTS ICA and any subsequent revisions in their maintenance and inspection programs. When the review is complete, the PI will issue or amend OpSpec D097.
3.12 Operator’s Inspection Program Approval Under 14 CFR § 125.507. Certificated 14 CFR part 125 operators will be issued OpSpec D097 and A125 Letter of Deviation Authority (LODA) holders will be issued Letter of Authorization (LOA) D097, which signifies the FAA has reviewed the CH’s policies and procedures incorporated into their maintenance and/or inspection programs for compliance with the Aging Aircraft Program rules. The operator will submit to the PI for review the revisions to their maintenance and inspection program incorporating the Aircraft Certification Service office-approved ICA.
The PI will ensure the operator has incorporated FTS ICA and any subsequent revisions into their maintenance and/or inspection programs. When the review is complete, the PI will issue or amend OpSpec D097 or A125 LOA D097.
3.13 Operator Inspection Program Approval Under 14 CFR § 91.1507. Title 14 CFR part 91 and part 91K operators will be issued LOA/MSpec D097, which signifies the FAA has reviewed the operator’s policies and procedures incorporated into their maintenance and/or inspection programs for compliance with the Aging Aircraft Program rules. The operator will submit to the PI for review the revisions to their maintenance and inspection program incorporating the Aircraft Certification Service office-approved ICA.
The PI will ensure the operator has incorporated FTS ICA and any subsequent revisions
3-11 into their maintenance and/or inspection programs. When the review is complete, the PI will issue or amend LOA/MSpec D097.
3.14 Operators that are Authorized OPSPEC/MSPEC/LOA D097. The issuance of this OpSpec signifies the FAA has reviewed the operator/CH/program manager’s policy and procedures incorporated into their maintenance and/or inspection programs for compliance with the Aging Aircraft Program rules. Table 1 of D097 will consist of three columns that list:
• The Aging Aircraft Program rules;
• The manual and section where the policy and procedures are located for the applicable Aging Aircraft Program; and
• The date of the manual and section where the current policy and procedures are located for the applicable Aging Aircraft Program.
Note: Table 3-3 below illustrates a sample D097 Table 1 that lists the various 14 CFR part rules. The operator/CH/program manager will have a specific OpSpec D097 template for their operation.
Table 3-3. Sample D097 Table 1–Aging Aircraft Maintenance Programs Aging Aircraft Program Rules Operator/CH/Program Manager’s Maintenance and/or Inspection Program Procedures (Manual and Section) Date Repairs Assessment for Pressurized Fuselages — § 91.1505, § 121.1107, § 125.505, § 129.107 Supplemental Inspections — § 121.1109, § 129.109 Electrical Wiring Interconnection Systems (EWIS) Maintenance Program — § 121.1111, § 129.111 Fuel Tank System Maintenance Program — § 121.1113, § 129.113 Flammability Reduction Means — § 121.1117, § 125.509, § 129.117 Fuel Tank System Inspection Program — § 91.1507, § 125.507
3.14.1 Submission to PI for Review. Initial submission and any subsequent revisions to these policy and procedures sections must be submitted to the PI for review for compliance with the Aging Aircraft Program rules.
3.14.2 Aircraft Certification Service Office-Approved ICAs. Any proposed revisions or deletions of Aircraft Certification Service office-approved ICAs must be coordinated
3-12 with the PI for review and concurrence. The PI will then forward the proposed revisions or deletions to the responsible Aircraft Certification Service office for approval prior to implementation or incorporation into the maintenance and/or inspection program.
3.14.3 Operator Action. An operator must have procedures to ensure that ICAs are incorporated into their maintenance and/or inspection program.
Appendix A A-1 APPENDIX A. ACRONYMS 14 CFR Title 14 of the Code of Federal Regulations A4A Airlines for America AC Advisory Circular AD Airworthiness Directive AED Aircraft Evaluation Division ALI Airworthiness Limitation Item ALS Airworthiness Limitation Section AMC Acceptable Means of Compliance AMM Aircraft Maintenance Manual AMOC Alternative Method of Compliance ASI Aviation Safety Inspector CAMP Continuous Airworthiness Maintenance Program CDCCL Critical Design Configuration Control Limitations CMM Component Maintenance Manual CWT Center Wing Fuel Tank DAH Design Approval Holder DOT Department of Transportation DRS Dynamic Regulatory System EAPAS Enhanced Airworthiness Program for Airplane Systems EO Engineering Order EWIS Electrical Wiring Interconnection System EZAP Enhanced Zonal Analysis Procedure ESPM Electrical Standard Practices Manual FAA Federal Aviation Administration FEC Failure Effect Category FLSS Fuel Level Sensor System FQIS Fuel Quantity Indicating System FR Federal Register FS Flight Standards FSU Fuel System Unit FTS Fuel Tank Safety GFI Ground Fault Interrupter IBR Incorporated by Reference ICA Instructions for Continued Airworthiness LOA Letter of Authorization
Appendix A A-2 LODA Letter of Deviation Authority MPD Maintenance Planning Data MRB Maintenance Review Board MRBR Maintenance Review Board Report MSG Maintenance Steering Group MSI Maintenance Significant Items MSpec Management Specification MWG Maintenance Working Group NAA National Aviation Authority NTSB National Transportation Safety Board OEM Original Equipment Manufacturer OpSpec Operations Specification PI Principal Inspector PMA Parts Manufacturer Approval RII Required Inspection Item SFAR Special Federal Aviation Regulation STC Supplemental Type Certificate SWPM Standard Wiring Practice Manual TC Type Certificate TSO Technical Standard Order TWA Trans World Airlines VTO Volumeric Top-off WDM Wiring Diagram Manual
Appendix B B-1 APPENDIX B. LIST OF APPLICABLE SUPPLEMENTAL TYPE
CERTIFICATES (STC) Supplemental Type Certificate (STC) Number STC Holder Airplane Models Description Operator Actions ST00069BO Goodrich Corporation DC8-62, -62F, -63F, -72, -72F, -73F Fuel quantity indicating system (FQIS) (external to tank) STC amended January 5, 2004.
Operators must incorporate instructions for continued airworthiness (ICA) T3068-0005-01, Initial Issue, dated October 23, 2003 (or later version). (At “D” check interval, inspections of flight deck wiring and connectors.)
ST00020BO Goodrich Corporation B747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, B747SP & B747SR Retrofit of entire Fuel Quantity Gauging System STC amended October 19, 2004.
Operators must incorporate ICA T3070-0005-0101, Initial issue, dated July 2, 2004 (or later version). (At D check interval, inspections of wiring separation, shielding, bonding.)
ST00142BO Goodrich Corporation B737-300 Isolation fuel quantity transmitter system STC amended February 10, 2004.
Operators must incorporate ICA T3072-0005-0101, Revision A, dated January 22, 2004 (or later version).
(Periodic inspections of wiring and bonding) SA298NE Goodrich Corporation B727-100, -200 Computerized FQIS STC amended April 19, 2004.
Operators must incorporate ICA T3066-0005-0101, Revision D, dated March 10, 2004 (or later version).
(Inspections to determine the condition of the wiring and connector interfaces every 16,000 flight hours.)
ST00053BO Goodrich Corporation B727, -100, -100C, -200, -200F, 727C FQIS indicators with Volumetric Top-off (VTO) and optional fuel system unit (FSU), In-tank harnesses.
STC amended April 19, 2004.
Operators must incorporate ICA T3065-0005-0101, Revision D, dated March 10, 2004 (or later version).
(Inspections to determine the condition of the wiring and connector interfaces every 16,000 flight hours) Note: These STCs have mandatory actions associated with them in accordance with Title 14 of the Code of Federal Regulations (14 CFR) §§ 91.1507, 121.1113,
125.507, and 129.113. Other STCs may be addressed via Airworthiness Directives (AD).