Par 3-5 Page 13 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 operators job/work cards so that the person performing the task knows the safety significance of the task.
c. Types of Airworthiness Limitations. This paragraph includes the airworthiness limitations. Some DAH have separated fuel system airworthiness limitations into two sub-categories: 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 FAA Oversight Office-approved. Any changes to these references in the AMM or the SWPM must be FAA Oversight Office-approved before being used.
d. Work Instructions/Procedures. As stated in subparagraph 3-5c. above, AMM and SWPM references in the airworthiness limitations are FAA Oversight Office-approved. The following paragraphs should be used as guidance when complying with airworthiness limitations that contain references to AMMs or SWPMs:
(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 FAA Oversight Office approval before they are used. Proposed changes must be submitted through the PI, who may add comments and forward them to the FAA Oversight Office for approval.
(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 FAA Oversight Office approval is not required for this action. This does not preclude the PI from coordinating with the FAA Oversight Office before concurring with the revision.
(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 FAA Oversight Office, and those that can be changed by the operator without prior FAA Oversight Office approval.
e. 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 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 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
Page 14 Par 3-5 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 1 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 2 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.
(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.
(2) The FAA Oversight 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 FAA Oversight Office must approve any operator changes to the airworthiness limitations or the manual following the process described in subparagraph 3-5d.
(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 FAA Oversight Office must be submitted by the operator through the PI, who may add comments and then send them to the appropriate FAA Oversight Office.
3-6. OPERATOR COMPLIANCE WITH AIRWORTHINESS LIMITATIONS.
a. ALS Approved Under § 25.981. Section H25.4 (a)(2), Amendment 25-102, requires “Each mandatory replacement time, inspection interval, related inspection procedure, and all
Par 3-6 Page 15 critical design configuration control limitations approved under §25.981 for the fuel tank system” must be contained in a section of the ICA titled Airworthiness Limitations. The ALS is FAA Oversight Office-approved and specifies maintenance required under §§ 43.16 and 91.403.
Simply stated, each operator must incorporate the ALS approved under § 25.981 for the fuel tank system into its maintenance or inspection program. As stated in § H25.4(a)(2), the fuel tank system must include the following under § 25.981 for fuel tank system:
• Mandatory replacement times,
• Inspection intervals,
• Related inspection instruction/procedures, and
• All CDCCLs.
b. 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 FAA Oversight 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 FAA Oversight 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 FAA Oversight Office will approve certain CMMs and certain parts of CMMs in accordance with the requirement in § 25.981(d) in establishing certain CDCCLs.
a. CMM Example. An example is the CMM for overhauling or repairing fuel pumps.
In certain CDCCLs, the entire manual is FAA Oversight Office-approved and a statement is contained in the manual to that effect. The FAA Oversight Office must approve any operator changes to the CMM.
b. CDCCL Example. Another example is a CDCCL where the entire CMM is not FAA Oversight 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.
c. 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 FAA Oversight 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.
a. 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 FAA Oversight Office approval. The FAA Oversight Office-approved ALS includes a statement explaining that the exceptional short-term
Page 16 Par 3-8 extensions of fuel tank system airworthiness limitations, subject to the procedures in the document, are FAA Oversight 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.)
b. 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 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.
c. Airworthiness Limitation Extension Requests. The extension request must be submitted to the PI, who will forward the request along with comments to the FAA Oversight Office for approval. Any such request must include substantiating data. If approved by the FAA Oversight Office, the PI will then approve the change to the maintenance program. (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 § 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.
a. Major Alterations. The only alterations for which fuel tank system ICA will be developed are those for which compliance with either SFAR 88 or § 25.1529 must be shown.
These are major alterations approved under STCs or amended TCs.
b. 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.
a. New Philosophical Approach. To fully realize the objectives of fuel tank system ignition prevention, the operators need to rethink their current philosophical approach to
Par 3-9 Page 17 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.
b. 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 must have procedures in place that ensure maintenance record entries for complying with a CDCCL are consistent with §§ 43.9 and 43.11, or in accordance with the applicable provisions of part 121 or part 129 and the operators’ manual.
c. 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.
(Refer to subparagraphs 3-4 b, c, d, and e for further guidance on this subject.)
d. 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.
e. 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 §§ 121.1113 AND 129.113. Parts 121 and 129 operator will be issued OpSpec D097, Aging Aircraft Programs, to implement FTS requirements. The operators must submit its fuel tank system maintenance program changes that include ICA (inspections, procedures and limitations) to the PI, who will review and approve operator incorporation with OpSpec D097. Operator-proposed changes must be submitted to the PI for review and approval. Any changes to the operators’ FAA Oversight Office-approved ICA will be handled as stated in this AC.
3-12. OPERATOR’S INSPECTION PROGRAM APPROVAL UNDER § 125.507. Part 125 operators will be issued Letter of Authorization (LOA) Aging Aircraft Programs to implement FTS requirements. The operator must submit its fuel tank system inspection program changes that include ICA (inspections, procedures and limitations) to the PI, who will review and approve operator incorporation with the LOA. Operator-proposed changes must be submitted to the PI for review and approval. Any changes to the operators’ FAA Oversight Office-approved ICA will be handled as stated in this AC.
Page 18 Par 3-13
3-13. OPERATOR INSPECTION PROGRAM APPROVAL UNDER § 91.1507. Part 91 and part 91K operators will be issued LOA/Management Specification (MSpec) MD097, Aging Aircraft Programs, to implement FTS requirements. The operator must submit its fuel tank system inspection program changes that include ICA (inspections, procedures and limitations) to the PI, who will review and approve operator incorporation with LOA/ MSpec MD097.
Operator-proposed changes must be submitted to the PI for review and approval. Any changes to the FAA Oversight Office-approved ICA will be handled as stated in this AC.
a. PI Action.The PI will approve incorporation into the maintenance/inspection program by issuing OpSpec/MSpec D097. The free text area of the OpSpec/MSpec D097 is used to:
• Identify and record the document(s)— by document number, revision number, and date—used as the source of the FAA Oversight Office-approved EWIS/FTS ICA, or
• If this information is contained in the operator’s manual system, a reference to that location in their manual system can be recorded in the free text area.
b. Operator Action. The operator must have procedures in its manual that track any changes and approvals made to the FAA Oversight Office-approved EWIS/FTS ICA.
Appendix 1 6B6BAPPENDIX 1. ACRONYMS 14 CFR Title 14 of the Code of Federal Regulations AC Advisory Circular ACO Aircraft Certification Office AD Airworthiness Directive AEG Aircraft Evaluation Group AFS Flight Standards Service 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 ATA Air Transport Association of America 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 EAPAS Enhanced Airworthiness Program for Airplane Systems EWIS Electrical Wiring Interconnection System EZAP Enhanced Zonal Analysis Procedure ESPM Electrical Standard Practices Manual FAA Federal Aviation Administration FEC Failure Effects Category FQIS Fuel Quantity Indicating System FR Federal Register FSU Fuel System Unit FTS Fuel Tank Safety HQ Headquarters IBR Incorporated by Reference ICA Instructions for Continued Airworthiness LOA Letter of Authorization 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 MWG Maintenance Working Group NAA National Aviation Authority NTSB National Transportation Safety Board OEM Original Equipment Manufacturer OpSpec Operations Specification PI Principal Inspector RGL Regulatory and Guidance Library
Appendix 1 RII Required Inspection Items SFAR Special Federal Aviation Regulation STC Supplemental Type Certificate SWPM Standard Wring Practice Manual TC Type Certificate TSO Technical Standard Order TWA Trans World Airlines VTO Volumeric Top-off WDM Wiring Diagram Manual
Appendix 2 Page 1 (and 2) 7B7BAPPENDIX 2. LIST OF APPLICABLE SUPPLEMENTAL TYPE CERTIFICATES 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) part 91, § 91.1507; part 121, § 121.1113; part 125, § 125.507; and part 129, § 129.113. Other STCs may be addressed via Airworthiness Directives (AD).
Appendix 3 3B3BAPPENDIX 3. DEFINITIONS
a. Aircraft Evaluation Group (AEG). AFS representatives who know the operational and maintenance aspects of the certification project and are responsible for determining the operational acceptability and continuing airworthiness requirements of newly certified or modified aircraft, engines, and propellers intended to be operated under the provisions of the 14 CFR. This function includes providing the cognizant ACO support in the review and approval of the initial and subsequent changes to the type design.
b. Aircraft Maintenance Manual (AMM). A manual developed by the manufacturer of a particular airplane that contains information necessary for the continued airworthiness of that airplane.
c. Airworthy. An aircraft, aircraft engine, or component that conforms to its type design and is safe to operate.
d. Fuel System Airworthiness Limitation. An airworthiness limitation that contains “each mandatory replacement time, inspection interval, related inspection procedure, and all CDCCL approved under 14 CFR part 25, § 25.981 for the fuel tank system.”
e. Airworthiness Limitation. Mandatory maintenance of the fuel system that includes CDCCL, inspections, or other procedures determined necessary to ensure that fuel tank ignition sources do not occur and are not introduced into the fuel system as a result of maintenance actions, repairs, or alterations throughout the operational life of the airplane.
f. Airworthiness Limitation Item (ALI). A term used by some DAH to group maintenance/inspection type fuel tank airworthiness limitations separately from CDCCL type fuel tank ALs.
g. Airworthiness Limitations Section (ALS). “Airworthiness Limitations” is the title required by part 25 appendix H, § H25.4(a) and (a)(2) for the section of the ICA that contains “each mandatory replacement time, inspection interval, related inspection procedure, and all critical design configuration control limitations approved under Sec. 25.981 for the fuel tank system.”
h. Auxiliary Tanks. Fuel tanks installed which make additional fuel available to increase the flight range of that airplane and are secondary to the airplane’s main fuel tanks.
Auxiliary tanks have been installed in various locations including center wing structure, horizontal stabilizers, wings, and cargo compartments.
i. AMOC. Alternative method of compliance.
j. Component Maintenance Manual (CMM). A manual developed by a manufacturer that contains information necessary for the continued airworthiness of a particular component.
Appendix 3
k. CMM Deviation.
(1) Term used for approval of changes to CMMs that are the subject of CDCCLs adopted by a type design change.
(2) Term used for the approval of changes to CMMs referenced in CDCCLs that are mandated by ADs, provided the CDCCL includes wording that allows use of “later approved” CMMs. Otherwise, approval is granted as an AMOC to the AD. As with AMOC approvals, a CMM deviation approval is by a letter from the FAA Oversight Office.
l. Continued Airworthiness. Certified aircraft, engines, propellers, and appliances are safe to operate for the intended purpose; they are maintained safely throughout their service life;
the product meets its type design; and is in a condition for safe operation.
m. Critical Design Configuration Control Limitation (CDCCL). A CDCCL is an airworthiness limitation required by §§ 25.981 and H25.4 that defines those parameters of the design that must be maintained to ensure that ignition sources will not develop within the fuel tank. CDCCLs include any information necessary to maintain those design features that have been determined by analysis of the fuel tank system as needed to preclude development of ignition sources. This information is essential to ensure that maintenance, repairs, or alterations do not unintentionally violate the integrity of the original type design of the fuel tank system.
n. Design Approval Holder (DAH). The holder of any design approval, including TC, amended TC, STC, amended STC, parts manufacturer approval, TSO authorization, letter of TSO design approval, and field approvals (refer to FAA Form 337).
o. Exceptional Short-Term Extension. An increase in a fuel system ALI interval that may be used by the operator to cover an uncontrollable or unexpected situation where the ALI cannot be performed within the ALI timeframe.
p. Electrical Arc or Spark. The transfer of electrons across a gap.
q. Enhanced Zonal Analysis Procedure (EZAP). An analytical process for developing maintenance and inspection instructions for the EWIS.
r. Electrical Wiring Interconnection System (EWIS). Any wire, wiring device, or combination of these, including termination devices, installed in the airplane for transmitting electrical energy between two or more termination points.
s. FAA Oversight Office. The ACO or the office of the Transport Airplane Directorate having oversight responsibility for the relevant TC or STC as determined by the Administrator.
(Refer to Appendix 4 FAA Oversight Offices by Airplane Manufacturer, for a list of FAA Oversight Offices for certain transport airplane TC holders.)
t. Flammable. With respect to a fluid or gas, flammable means susceptible to igniting readily or to exploding (refer to 14 CFR part 1, Definitions and Abbreviations).