83 FR 47548 - Transport Airplane Fuel Tank and System Lightning Protection
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration Federal Register Volume 83, Issue 183 (September 20, 2018)
Federal Aviation Administration
Federal Register Volume 83, Issue 183 (September 20, 2018)
| Page Range | 47548-47557 | |
| FR Document | 2018-20174 |
[Federal Register Volume 83, Number 183 (Thursday, September 20, 2018)] [Rules and Regulations] [Pages 47548-47557] From the Federal Register Online [www.thefederalregister.org] [FR Doc No: 2018-20174] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No.: FAA-2014-1027; Amdt. No. 25-146] RIN 2120-AK24 Transport Airplane Fuel Tank and System Lightning Protection AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. ----------------------------------------------------------------------- SUMMARY: The FAA is amending certain airworthiness regulations for transport category airplanes regarding lightning protection of fuel systems. This action is relieving in several ways. It removes the requirement for manufacturers to provide triple-redundant fault tolerance in lightning protection. It removes regulatory inconsistency by establishing a single standard for lightning protection of both fuel tank structure and fuel tank systems. It establishes a performance- based standard that the design and installation of fuel systems prevent catastrophic fuel vapor ignition caused by lightning and its effects. This performance-based standard allows applicants to choose how to provide the required level of safety. This action requires airworthiness limitations to preclude the degradation of design features that prevent catastrophic fuel vapor ignition caused by lightning. Its intended effects are to align airworthiness standards with industry's and the FAA's understanding of lightning, and to address issues of inconsistency and impracticality that applicants experienced with previous lightning protection regulations. DATES: Effective November 19, 2018. ADDRESSES: For information on where to obtain copies of rulemaking documents and other information related to this final rule, see ``How To Obtain Additional Information'' in the SUPPLEMENTARY INFORMATION section of this document. FOR FURTHER INFORMATION CONTACT: For questions concerning this action, contact Stephen Slotte, Airplane and Flight Crew Interface Section, AIR-671, Transport Standards Branch, Policy and Innovation Division, Aircraft Certification Service, Federal Aviation Administration, 2200 South 216th Street, Des Moines, WA 98198; telephone and fax (206) 231- 3163; email [email protected]. SUPPLEMENTARY INFORMATION: Authority for This Rulemaking The FAA's authority to issue rules on aviation safety is found in Title 49 of the United States Code. 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. This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, ``General Requirements.'' Under that section, the FAA is charged with promoting safe flight of civil aircraft in air commerce by prescribing regulations and minimum standards for the design and performance of aircraft that the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority. It prescribes revised safety standards for the design and operation of transport category airplanes. I. Overview of Final Rule The FAA is amending the airworthiness regulations in title 14, Code of Federal Regulations (14 CFR) part 25 related to the lightning protection of fuel systems \1\ (including fuel tank structure \2\ and fuel tank systems \3\). This amendment removes the requirement for prevention of lightning ignition sources from Sec. 25.981(a)(3), ``Fuel tank ignition prevention,'' at amendment 25-102 and modifies Sec. 25.954, ``Fuel system lightning protection.'' The modification to Sec. 25.954 creates a performance-based standard that provides definitions for ``critical lightning strike'' and ``fuel systems;'' requires catastrophic fuel vapor ignition due to lightning and its effects to be extremely improbable; and requires applicants to add airworthiness limitations to the airplane's Instructions for Continued Airworthiness (ICA) to prevent catastrophic fuel vapor ignition caused by lightning. These changes align the rule with the current understanding of lightning-related risk, fuel tank flammability exposure, and current airplane design practices. It also revises the title of Sec. 25.981 to ``Fuel tank explosion prevention.'' --------------------------------------------------------------------------- \1\ Fuel system, in the context of this final rule, includes any component within either the fuel tank structure or the fuel tank systems and any airplane structure or system components that penetrate, connect to, or are located within a fuel tank. \2\ Fuel tank structure, in the context of this final rule, includes structural members of the fuel tank such as airplane skins, access panels, joints, ribs, spars, stringers, and associated fasteners, brackets, coatings, and sealant. \3\ Fuel tank systems, or systems, in the context of this final rule, include tubing, components, and wiring that penetrate, connect to, or are located within a fuel tank. --------------------------------------------------------------------------- This amendment removes lightning from the ignition sources regulated by Sec. 25.981(a)(3). Inclusion of lightning in that section has resulted in applicants showing that compliance was impractical, leading them to seek exemptions to compliance with Sec. 25.981 for fuel tank structure and systems. The FAA has granted several exemptions for fuel tank structure and systems. The FAA agrees, however, with the Large Airplane Fuel System Lightning Protection Aviation Rulemaking Committee (Lightning ARC) \4\ that common regulatory treatment of structure- and systems-related lightning protection in the fuel system is appropriate. Applicants have also requested that the FAA develop special conditions to allow the consideration of fuel tank flammability and the probability of lightning strikes when meeting the requirement that a fuel tank explosion caused by lightning be extremely improbable. This amendment removes the necessity for such special conditions by incorporating such considerations into the rule. --------------------------------------------------------------------------- \4\ See the ``Large Airplane Fuel System Lightning Protection Rulemaking Recommendations'' report, May 2011, available in the docket. --------------------------------------------------------------------------- To maintain the integrity of lightning protection features of airplanes, this amendment adds a new paragraph (d) to Sec. 25.954 and amends part 25, appendix H, section H25.4(a) to require applicants to establish airworthiness limitations to protect the continued function of the lightning protection features of fuel tank structure and fuel systems. This rule applies to applications for new type certificates, and applications for amended or supplemental type certificates on significant product-level change projects in which Sec. 25.954, ``Fuel system lightning protection,'' is applicable to the changed area. II. Background A. Statement of the Problem Section 25.954, adopted in 1967, required protection of the airplane from the effects of lightning, regardless of the likelihood that lightning would strike the airplane. The regulation did not acknowledge that lightning protection [[Page 47549]] features, or other features, could fail or become ineffective. The regulation also did not require evaluation of probabilities of failures affecting lightning protection features, nor did it require maintenance actions to ensure the continued effectiveness of design features that prevent catastrophic fuel vapor ignition. Compliance with Sec. 25.981(a)(3), at amendment 25-102,\5\ required the assumption that lightning would strike the airplane (i.e., that the probability of lightning was one) and that the design provide fail-safe ignition prevention means to preclude ignition sources from being present in fuel tanks when component failures, malfunctions, or lightning strikes occur. This typically resulted in the need for triple-redundant lightning ignition protection features because some structural failures may have long latency periods.\6\ The FAA found, however, that for lightning protection, providing triple-redundant features is not always practical. This impracticality has led applicants to apply for exemptions and special conditions to ensure the design and maintenance actions provide for, and maintain, an acceptable level of safety. However, the processing and issuance of these exemptions and special conditions has created an administrative burden on industry and the FAA. --------------------------------------------------------------------------- \5\ See 66 FR 23086 (May 7, 2001), ``Transport Airplane Fuel Tank System Design Review, Flammability Reduction, and Maintenance and Inspection Requirements.'' \6\ In this context, latency period means the time interval between a failure and the discovery of that failure. --------------------------------------------------------------------------- B. Related Actions On May 26, 2009, the FAA issued a policy memorandum to standardize the process for granting exemptions and issuing special conditions for fuel tank structure lightning protection. FAA Policy Memorandum ANM- 112-08-002, ``Policy on Issuance of Special Conditions and Exemptions Related to Lightning Protection of Fuel Tank Structure,'' defined alternative methods that could be applied through special conditions or exemptions to some areas of structural designs where compliance with Sec. 25.981(a)(3) was impractical. This policy allowed the applicant's risk assessment to account for the reduced likelihood of the simultaneous occurrence of a critical lightning strike and a fuel tank being flammable. The policy explained the level of safety intended by Sec. 25.981(a)(3) for fuel tank structure, and provided guidance for alternatives to compliance that still achieve that level of safety. On June 24, 2014, the FAA superseded that policy memorandum with Policy Statement PS-ANM-25.981-02, ``Policy on Issuance of Special Conditions and Exemptions Related to Lightning Protection of Fuel Tank Structure and Systems,'' expanding the scope of the policy to include systems. The policy statement provided guidance for approval of special conditions and exemptions for lightning protection features in fuel tank structure and fuel systems with respect to Sec. 25.981(a)(3). The revisions to Sec. 25.981(a)(3) in this amendment should eliminate the need to issue such special conditions and exemptions. However, some of the information in that policy statement will remain in Advisory Circular (AC) 25.981-1D, ``Fuel Tank Ignition Source Prevention Guidelines,'' \7\ for this rule because the FAA expects that the information will continue to be useful in ensuring the level of safety required by the amended Sec. 25.954 for fuel tank structure and systems. --------------------------------------------------------------------------- \7\ AC 25.981-1D is available in the docket and on the internet at http://www.faa.gov/regulations_policies/advisory_circulars/. --------------------------------------------------------------------------- The final rule will maintain the level of safety established by these policies. It codifies these policies into a performance-based rule that allows the applicant to choose the means of compliance. C. Summary of the NPRM On December 9, 2014, the FAA issued a notice of proposed rulemaking (NPRM) to amend Sec. Sec. 25.954 and 25.981 and appendix H to part 25. The Federal Register published NPRM Notice No. 14-09, Docket No. FAA- 2014-1027, on December 18, 2014. In the NPRM, the FAA proposed the following changes: 1. ``Fuel System Lightning Protection,'' (Sec. 25.954)Consolidate the requirements for the prevention of fuel vapor ignition due to lightning, currently in Sec. Sec. 25.954 and 25.981, into Sec. 25.954; Retain and renumber the existing rule text; Add lightning-induced or conducted electrical transients \8\ to the lightning effects that applicants must consider; --------------------------------------------------------------------------- \8\ As used in this discussion, a transient is a brief electrical disturbance on wiring and equipment caused by the intense voltage, current, and electromagnetic fields associate with lightning. --------------------------------------------------------------------------- Add a new performance-based standard to require that a catastrophic fuel tank explosion be extremely improbable when taking into account the risk of failures, probability of a critical lightning strike, and fuel tank flammability exposure; Add maintenance requirements to maintain the integrity of lightning protection features during the airplane service life; and Define critical lightning strike and fuel system. 2. ``Fuel Tank Ignition Prevention,'' (Sec. 25.981) Remove the requirement to prevent lightning ignition sources and instead refer applicants to Sec. 25.954 for lightning protection requirements; Clarify that the applicant must provide critical design control configuration limitations (CDCCLs) to identify critical design features in addition to inspections or other procedures; and Change the title to ``Fuel tank explosion prevention.'' 3. ``Instructions for Continued Airworthiness,'' Appendix H to Part 25 Add a new paragraph to make mandatory any inspection and test procedures that are needed to sustain the integrity of the lightning protection design features used to show compliance with Sec. 25.954; and Add a new section to require applicants to develop ICA that protect the lightning protection features required by Sec. 25.954. The FAA proposed these changes based on recommendations from the Lightning ARC. The comment period closed on March 18, 2015. III. Discussion of the Final Rule and Public Comments The FAA received comments from eight (8) manufacturers and one (1) industry group. All of the commenters generally supported the proposed amendments. Some of the comments suggested changes. In the discussion below, some comments identify paragraph designations of the rules as proposed in the NPRM. In this final rule, the FAA is revising and reorganizing some of those paragraphs, so paragraph references in the comments may be different from their designation in the final rule. This section references each paragraph according to its designation in this final rule, with the NPRM paragraph designation noted in brackets when there has been a change. A. ``Fuel System Lightning Protection'' (Sec. 25.954) With some differences from what the FAA proposed in the NPRM, this amendment requires that the design and installation of the airplane fuel system [[Page 47550]] prevent catastrophic fuel vapor ignition due to lightning and its effects. This final rule removes ``corona and streamering at fuel vent outlets'' as a lightning effect that applicants must consider, and adds ``lightning-induced or conducted electrical transients'' to the non- exclusive list of lightning effects against which the fuel system must be protected. This amendment adds definitions for ``critical lightning strike'' and ``fuel system'' to ensure common understanding and consistent application of those terms. To comply with the revised Sec. 25.954, this amendment requires applicants to show that catastrophic fuel vapor ignition is extremely improbable, taking into account flammability, critical lightning strikes, and failures within the fuel system. To protect those features of the airplane that prevent catastrophic fuel vapor ignition due to lightning, this amendment adds a requirement that the type design include CDCCLs identifying those features and providing information to protect them. To ensure the continued effectiveness of those features, the rule requires that the type design specify necessary inspections and test procedures, intervals between repetitive inspections and tests, and mandatory replacement times. The rule also requires the applicant to include information regarding CDCCLs and methods for ensuring continued effectiveness of lightning protection features in the Airworthiness Limitations section (ALS) of the ICA. The following is a discussion of comments the FAA received on the changes to Sec. 25.954 as they were proposed in the NPRM. 1. Definitions The NPRM proposed adding definitions of ``critical lightning strike'' and ``fuel system'' to Sec. 25.954(d). This final rule revises these definitions and moves them to paragraph (a) of the section. The AE-2 and WG-31 Lightning Committees (SAE Lightning Group) supported the proposed definition of ``fuel system.'' However, the FAA determined that the inclusion of the word ``other'' in the definition, ``A fuel system includes any component within either the fuel tank structure or the fuel tank systems, and any other airplane structure or system components that penetrate, connect to, or are located within a fuel tank,'' could be misinterpreted to exclude basic structure, such as wings, in the context of the definition. Therefore, the definition of fuel system in the final rule does not include ``other.'' The proposed definition of a ``critical lightning strike'' was ``. . . a lightning strike that attaches to the airplane in a location that affects a failed feature or a structural failure, and the amplitude of the strike is sufficient to create an ignition source when combined with that failure.'' The SAE Lightning Group requested changes to this definition for clarity. The commenter requested that the term ``failed feature'' be changed to ``failed protection feature,'' but did not provide a rationale. The commenter also stated that it is unnecessary to list structural failures separately. The commenter further stated that the inclusion of ``a failed [protection] feature'' already includes structural failures, which otherwise could result in an ignition source. The commenter also suggested revising the definition to, ``A critical lightning strike is a lightning strike that attaches to the airplane in a location that affects a failed protection feature with characteristics that could create an ignition source when combined with that failure.'' The FAA partially agrees with the SAE Lightning Group's requests. The FAA modified the definition of critical lightning strike by deleting ``the amplitude of the strike is sufficient,'' but did not replace that text with ``characteristics that could,'' as the commenter recommended. The definition is clear without either of those phrases. The FAA also did not replace ``failed feature'' with ``failed protection feature,'' or delete the phrase ``structural failure.'' To address the comments, we have revised the definition by removing the phrase ``failed feature'' and stating instead that, ``A critical lightning strike is a lightning strike that attaches to the airplane in a location that, when combined with the failure of any design feature or structure, could create an ignition source.'' In this revised definition, a ``design feature'' means any feature specifically designed for lightning protection or any other design feature whose failure, when combined with a lightning strike, could cause ignition. An example of a design feature that is specifically designed for lightning protection is a metal foil layer installed between the laminate layers of a composite wing. An example of a design feature that is not specifically designed for lightning protection but whose failure, when combined with a lightning strike, could cause ignition is a swaged fitting on a hydraulic tube located within the fuel tank. Structural failures that could create an ignition source in the event of a lightning strike must also be addressed and, therefore, the final definition includes ``any design feature or structure.'' Related to the definition of critical lightning strike, the NPRM stated that a critical lightning strike occurs ``on the order of once every 100,000 hours of airplane operation.'' The SAE Lightning Group commented that the location of the lightning's attachment to the airplane, whether the strike's amplitude is sufficient to create an ignition source, and the effect of a failed feature or structural failure are all design-dependent. The SAE Lightning Group also commented that compliance with Sec. 25.954 would require use of a strike rate of 1 in 100,000 hours. The commenter suggested that the FAA should allow applicants to identify how often a critical lightning strike might occur relative to their designs. The intent of the statement in the NPRM that a critical lightning strike occurs once per 100,000 hours was to provide a general understanding of their average rate of occurrence. It was not intended as a rate to be used in demonstrating compliance. The FAA agrees with the SAE Lightning Group that the actual rate of a critical strike would be based on an applicant's analysis of the specific airplane design features, which include additional factors such as location of the strike, characteristics of the lightning strike, failure of design features and structure, and specific ignition source thresholds for each feature failure and failure mode. Related to this same discussion in the NPRM, Parker Aerospace (``Parker'') requested that the FAA add a paragraph to Sec. 25.954 that describes all of the conditions and guidance regarding probabilities that the applicant must consider, such as flammability exposure and failure latency of inerting systems. The FAA disagrees with Parker's request. Rather than make such conditions and guidance on probabilities mandatory via a new paragraph in Sec. 25.954, such guidance is included in AC 25.954-1, ``Transport Airplane Fuel System Lightning Protection.'' \9\ The AC discusses the probability for different airplane composite tank structures and threat levels. --------------------------------------------------------------------------- \9\ AC 25.954-1 is available in the docket and on the internet at http://www.faa.gov/regulations_policies/advisory_circulars/. --------------------------------------------------------------------------- 2. Relationship of Sec. 25.954 to Sec. Sec. 25.901 and 25.1309 The SAE Lightning Group suggested that the FAA clearly state that the revised Sec. 25.954 takes precedence over the general requirements of Sec. Sec. 25.901, [[Page 47551]] ``Installation'' (``Subpart E--Powerplant''), and 25.1309, ``Equipment, systems, and installations.'' The FAA disagrees. Section 25.954 does not supersede the requirements of Sec. 25.901 or Sec. 25.1309. However, compliance with Sec. 25.954 may assist applicants in showing compliance with other regulations. 3. Lightning Effects The NPRM proposed adding ``lightning-induced or conducted electrical transients'' to the lightning effects in Sec. 25.954(b) [paragraph (a) in the NPRM] that applicants must ensure will not cause ignition of fuel vapor within the fuel system. The SAE Lightning Group recommended that, rather than adding to the existing list of lightning threats in the rule, the FAA delete the list of lightning effects. Instead, the SAE Lightning Group recommended that the rule include a more general and inclusive reference to lightning that requires that the airplane be protected against catastrophic effects from lightning. The SAE Lightning Group suggested that the list may not be complete and may be inconsistent with lightning environments defined in the industry documents accepted by the FAA in AC 20-155A, ``Industry Documents to Support Aircraft Lightning Protection Certification.'' In contrast, Parker supported keeping the text as proposed, including ``lightning- induced or conducted electrical transients.'' The FAA disagrees with the SAE Lightning Group's suggestion to include only a general lightning requirement. Relying on guidance material to detail the lightning effects that applicants must consider could result in some applicants not addressing all effects. However, the FAA recognizes that the list of effects, as proposed, could be misinterpreted as an exhaustive list. Therefore, the FAA added ``including'' to the text that introduces the list to clarify that the list is not exhaustive. The FAA agrees to limit, in Sec. 25.954(b), the type of fuel vapor ignition that must be prevented to ``catastrophic'' events. This change will make the requirement consistent with Policy Statement PS-ANM-25.981-02, which states that ``the fuel tank structure and systems must be designed and installed to prevent catastrophic fuel vapor ignition due to lightning.'' This change also makes Sec. 25.954(b) consistent with Sec. 25.581, which requires that the airplane be protected against ``catastrophic'' effects from lightning. Thus, Sec. 25.954(b) now states, ``The design and installation of a fuel system must prevent catastrophic fuel vapor ignition due to lightning and its effects, including . . . .'' The SAE Lightning Group recommended the removal of ``corona and streamering at fuel vent outlets'' from the list of lightning effects because that term is inconsistent with the terminology in the industry guidance material recommended by AC 20-155A. The FAA agrees and has removed this term from the final rule. 4. Fault-Tolerant Design Regarding Sec. 25.954(c) [paragraph (b) in the NPRM], the SAE Lightning Group requested that the FAA require that catastrophic fuel vapor ignition due to lightning be prevented by demonstrating that the fuel system ignition source protection design is fault tolerant, or for designs that are not fault tolerant, by showing catastrophic fuel vapor ignition to be extremely improbable, taking into account flammability, critical lightning strikes, and failures in the fuel system. The SAE Lightning Group argued that the proposed broader requirement to show that catastrophic ignition is extremely improbable, without requiring a fault tolerant design, would be costly and would negate the savings to industry stated in the regulatory evaluation. In a related comment, Bombardier S.A. (Bombardier) requested that ``fault tolerant'' be defined to clarify if it is equivalent to single fault tolerance and the type of compliance that the FAA would expect, numerical analysis or qualitative. Although the term was not used in the proposed rule (and is not in the final rule), Bombardier suggested more clarity was needed in the rule and supporting guidance. The FAA agrees that fuel systems designed with reliable fault- tolerant ignition source protection features should comply with the requirement that catastrophic fuel vapor ignition be extremely improbable. As used in this context, a fault-tolerant fuel system design is a design that precludes ignition sources in the fuel system even when a fault is present; ``reliable'' means the ability to maintain the effectiveness of the protection features over the service life of the individual airplane. However, the FAA disagrees that fault tolerance should be required because fault tolerance is only one possible means of compliance with the requirement that catastrophic fuel vapor ignition be extremely improbable. The use of a full-time flammability control system (e.g., fuel system inerting) exceeding the current part 25 flammability reduction means (FRM) performance standard could be another means of compliance. If the FAA limited the requirement to fault tolerance as requested by the SAE Lightning Group, such a design approach, or others as technology progresses, would not be allowed. Regardless of the design approach chosen by the applicant to prevent lightning-induced catastrophic fuel vapor ignition, a safety analysis will be necessary to demonstrate extreme improbability. The complexity of the analysis can range from a relatively simple assessment to establish any maintenance requirements for reliable fault-tolerant ignition protection features, to a more in-depth analysis if non-fault-tolerant design features are used. For reliable fault-tolerant features, this analysis would be substantially less costly than traditional methods for showing that catastrophic failures are extremely improbable. The supporting AC 25.954-1 provides guidance on methods for both fault-tolerant and FRM compliance approaches, including the necessary safety assessment, which could be numerical, qualitative, or a combination of the two. The FAA disagrees with Bombardier's request to define fault- tolerant in Sec. 25.954. Since a fault-tolerant design is not a requirement for compliance with this rule, there is no need to provide a regulatory definition. However, the supporting AC 25.954-1 includes the definition for fault-tolerant design noted earlier in this section (4. Fault-Tolerant Design), ``A fault-tolerant fuel system design is a design that precludes ignition sources in the fuel system even when a fault is present.'' Therefore, this amendment retains the requirement in Sec. 25.954(c) that catastrophic fuel vapor ignition be extremely improbable, and clarifies its relationship with paragraph (b). The revised Sec. 25.954(c) states, ``To comply with paragraph (b) of this section, catastrophic fuel vapor ignition must be extremely improbable, taking into account flammability, critical lightning strikes, and failures within the fuel system.'' The SAE Lightning Group also commented that the FAA should revise the regulatory evaluation if the FAA does not adopt the SAE Lightning Group's recommendation to replace the requirement of extreme improbability with fault tolerance. The commenter argued that the requirement to show that fuel tank ignition is extremely improbable would be costly and negate the savings to industry shown in the regulatory evaluation. The SAE Lightning Group did not submit any supporting financial data. The FAA does not agree that the requirement to show that fuel tank [[Page 47552]] ignition is extremely improbable would be costly and negate the savings to industry. In general, an applicant that can show its design is reliably fault-tolerant will not need to conduct an extensive safety analysis. The requirement to develop airworthiness limitations for critical lightning protection features will result in the need for the applicant to assess the reliability of the features and provide appropriate maintenance tasks to achieve an acceptable level of reliability. In addition, this rule allows both fault-tolerant and non-fault- tolerant design approaches. Under the rule, the fuel system must prevent catastrophic fuel vapor ignition due to lightning. To comply with this requirement, catastrophic fuel vapor ignition must be extremely improbable. If an applicant's design achieves this requirement through the use of fault-tolerant design, the safety analysis (Sec. 25.1309) to support the design will not have to be as extensive as one that would be necessary to support a non-fault- tolerant design. As a result, the rule allows industry the flexibility to select the means of compliance based on design approach, safety analysis, and costs. Therefore, the FAA determined that the regulatory evaluation did not need to be revised as a result of this comment. 5. Flammability Reduction Means (FRM) as a Means of Compliance The SAE Lightning Group, Bombardier, and Parker all commented on the discussion of fuel tank flammability reduction in the NPRM and asked for clarification of how flammability reduction could be used as a means of compliance with Sec. 25.954. Boeing stated that the majority of the NPRM discussion of fuel tank FRM was unnecessary because applicants could infer that the FAA would relax the requirement for providing fault tolerance if the FAA allowed FRM as a sole means of compliance. Boeing did not agree that the FAA should accept controlling fuel tank flammability as the primary means for preventing a fuel tank explosion without providing fault-tolerant lightning protection features. As discussed in the previous section (4. Fault-Tolerant Design), the FAA does not agree that the lightning protection requirement in Sec. 25.954 should dictate the use of fault-tolerant ignition protection features in the design without allowing the use of flammability control means. As explained in the NPRM, the intent of the amendment to Sec. 25.954 is to require the design to take into account the likelihood of a critical lightning strike, the fuel tank being flammable, and the creation of an ignition source due to the failure of fuel system or structural lightning protection features. If designers develop a full-time fuel tank flammability control system that prevents the fuel tanks from being flammable during all foreseeable operating conditions and all phases of airplane operation (including descent), resulting in the probability of a fuel tank explosion being extremely improbable, this could achieve the level of safety that Sec. 25.954 requires, and could be used as a means of compliance without the need for fault-tolerant lightning protection features. While fuel tank flammability control system technology has not evolved to a state where flammability control can replace the need for fault-tolerant ignition prevention, the FAA's goal is to develop rules that are performance- based, and in this case, to allow designers to comply via the use of flammability control when the technology is adequately developed. Allowing the use of fuel tank FRM for demonstrating compliance with the rule could offer designers the opportunity to reduce the number of fault-tolerant features and mandatory maintenance actions. 6. CDCCLs Section 25.954(d) [paragraph (c) in the NPRM] requires that the type design include CDCCLs identifying those design features that prevent catastrophic fuel vapor ignition caused by lightning and providing information to protect them. To ensure the continued effectiveness of those features, paragraph (d) also requires that the type design include inspections and test procedures, intervals between repetitive inspections and tests, and mandatory replacement times. This paragraph also requires applicants to place all this information in the ALS of the ICA. The SAE Lightning Group proposed that CDCCLs be included as cautions \10\ in the airplane maintenance manual, not as airworthiness limitations in the ALS of the ICA. The SAE Lightning Group suggested that, as proposed, the requirement would create a burden on the airlines because the ALS documents are not used by the airline mechanics, and therefore the CDCCL information must be duplicated and links created for the information in both the ALS documents and the maintenance documents used by the mechanics. The commenter stated that if the FAA does not agree with this approach, then only critical information necessary to demonstrate compliance, along with CDCCLs, should be included as airworthiness limitations, and proposed that the regulatory text be amended to reflect this request. The SAE Lightning Group did not define what it considered critical information. --------------------------------------------------------------------------- \10\ Cautions in an airplane maintenance manual call attention to methods and procedures that must be followed to avoid damage to equipment (ATA iSpec 2200, Information Standards for Aviation Maintenance, published by Airlines for America, 2014). --------------------------------------------------------------------------- The FAA disagrees with the SAE Lightning Group's request to move the CDCCLs from the ALS of the ICA to the Cautions section of the maintenance manual. CDCCLs provide information that is essential for protecting the design features that are critical for preventing fuel tank explosions. The Caution section of the maintenance manual is not mandatory for U.S. operators, and therefore CDCCLs need to be included in the ALS of the ICA, which is mandatory. The SAE Lightning Group commented that, since the Lightning ARC study and report in 2011, the use of Air Transport Association (ATA) Maintenance Steering Group (MSG)-3 \11\ processes has not been effective in establishing maintenance requirements for lightning protection features and does not take into consideration the many factors that are critical for certification. This can create conflicting or duplicate fuel tank entry requirements. To eliminate this potential duplication, the SAE Lightning Group stated that industry now recommends that maintenance practices for both fault- tolerant and non-fault-tolerant protection features be established via the type certification process only, and that the ATA MSG-3 process should not be used for this purpose. --------------------------------------------------------------------------- \11\ ATA MSG-3 is a maintenance steering group composed of regulatory authorities, operators, and manufacturers that, through a process, develop documents that present a methodology for developing scheduled maintenance tasks and intervals for aircraft structure, systems, and components. --------------------------------------------------------------------------- Airbus and Airlines for America disagreed with the request to establish maintenance practices for both fault-tolerant and non-fault- tolerant protection features via the type certification process. Both commenters proposed that the FAA require airworthiness limitations and CDCCLs for only non-fault-tolerant design features. Both commenters stated that an airworthiness limitation requirement for fault-tolerant design features could be a disincentive to develop fault-tolerant designs and may increase the burden on operators unnecessarily. As an alternative, they proposed reliance on the current ATA MSG-3 process for establishing maintenance programs for [[Page 47553]] fault-tolerant design features. Airbus also suggested that operational rules and guidance could be established to prevent tasks identified through the ATA MSG-3 process from being deleted in service. The FAA agrees with the SAE Lightning Group that all maintenance practices for both fault-tolerant and non-fault-tolerant protection features be established via the type certification process and not through the ATA MSG-3 process. Using the certification process will ensure that applicants develop necessary maintenance actions to maintain the integrity of lightning ignition source protection features. As all maintenance actions necessary to ensure the integrity of lightning ignition source protection features will be addressed by compliance with section H25.4(a)(5), the ICA requirement in the proposed section H25.X is not necessary and has been deleted from the final rule. This is discussed further in the discussion regarding appendix H. The FAA disagrees with Airbus' and Airlines for America's proposal to rely on the ATA MSG-3 process for development of maintenance actions for fault-tolerant design features. U.S. operators are not required to adopt the ATA MSG-3 developed maintenance program, but they are required to include all airworthiness limitations in their maintenance program.\12\ Therefore, airworthiness limitations are needed to ensure an operator's maintenance program includes all tasks determined by the safety analysis, performed as part of the system's certification activity, to be critical. The safety analysis may show that some fault- tolerant features are life-limited or require periodic inspection, so mandatory maintenance tasks established through engineering review and approval would be needed. Therefore, the FAA did not change this rule as a result of these comments. --------------------------------------------------------------------------- \12\ Section H25.4(a) and 14 CFR 91.403(c). --------------------------------------------------------------------------- The SAE Lightning Group also stated that the reference to Sec. 25.1729 in Sec. 25.954(d) is not within the scope of this rule and requested that it be removed. The FAA agrees and removed that reference from the final rule. Embraer suggested that Sec. 25.954(d) include the same requirement that is in Sec. 25.981(d). Section 25.981(d) requires the type design to include visible means for identifying critical features in areas where foreseeable maintenance actions, repairs, or alterations may compromise the CDCCLs. Embraer stated that this would harmonize both requirements. The FAA does not agree. Because of the large number and multiple types of bonding features used for fuel tank and system lightning protection, it is not practical to require installation of visible means of identification for all lightning-related CDCCLs. However, all critical lightning protection features identified as CDCCLs must be included in the ALS of the ICA. Although the FAA made minor editorial changes \13\ to the final Sec. 25.954(d), the requirement that the type design include CDCCLs is adopted as proposed. --------------------------------------------------------------------------- \13\ The FAA deleted ``on how'' in the first sentence of the paragraph, ``. . . (CDCCLs) identifying those features and providing information on how to protect them,'' and added ``used in demonstrating compliance to paragraph (b) of this section'' in the second sentence, ``. . . and mandatory replacement times for those design features used in demonstrating compliance to paragraph (b) of this section.'' --------------------------------------------------------------------------- B. ``Fuel Tank Explosion Protection'' (Sec. 25.981) Section 25.981 requires that the airplane design protect the fuel tank and fuel tank system against ignition from all sources. This amendment adds an exception to Sec. 25.981(a)(3) to remove lightning as an ignition source from the scope of this section and refers applicants to Sec. 25.954 for lightning protection requirements. Paragraph (d) of Sec. 25.981 requires applicants to establish CDCCLs, inspections, or other procedures to ensure fuel tank safety. This amendment revises paragraph (d) to clarify that applicants must provide CDCCLs to identify critical design features, in addition to inspections or other procedures. The FAA received the following comments on the proposed changes to this section. 1. Consistency of Language Boeing suggested that the FAA expand the applicability of Sec. 25.981(d) to include the fuel tank system, in addition to the fuel tank, to be consistent with Sec. 25.981(a). Paragraph (a) of Sec. 25.981 requires ignition source prevention in the ``fuel tank or fuel tank system.'' The FAA agrees and revised the final rule to add, ``. . . or fuel tank system according to paragraph (a) of this section. . . .'' This addition makes it consistent with Sec. 25.981(a). Boeing proposed that Sec. 25.981(d) refer to paragraph (b) of that section in addition to the references to paragraphs (a) and (c) of that section because mandatory maintenance required by paragraph (d) should also apply to flammability reduction means. The FAA agrees, and this amendment includes a reference to paragraph (b) in Sec. 25.981(d). 2. CDCCL Visible Means Boeing requested that the FAA revise Sec. 25.981(d) to delete the requirement for placement of visible means, limit that placement to areas where the means would be ``practical and meaningful,'' or provide more clear guidance. Boeing stated that, as proposed, the regulation provides no practical way to fully comply with the requirement to provide visible means of identifying CDCCL. Boeing argued that, ``While it may be easy to pick the color of external fuel quantity wiring, much of the fuel tank design for ignition prevention is basic to airplane design, such as bonding, grounding, sealing, etc. There is no practical way to color code or otherwise identify these design features.'' The FAA partially agrees. The intent is not to require markings in all locations--only in those locations where foreseeable errors due to maintenance actions, repairs, or alterations may compromise critical features. This is not a new requirement with this amendment. However, this amendment deletes the example of visible means (color coding of wire to identify separation limitation), and it removes the requirement of identifying visible means as CDCCLs, both of which had been added at amendment 25-125. AC 25.981-1D provides additional guidance. C. ``Instructions for Continued Airworthiness'' (Appendix H to Part 25) With some differences from what the FAA proposed in the NPRM, this amendment adds a new paragraph, (a)(5), to section H25.4 of appendix H to part 25. This paragraph requires any mandatory replacement times, inspection intervals, related inspection and test procedures, and CDCCLs for lightning protection features approved under Sec. 25.954 to be included in the ALS of the ICA. The SAE Lightning Group proposed revisions to the airworthiness limitation requirements of section H25.4(a)(5) by adding the phrases ``critical design configuration control limitations'' and ``fault tolerant and non-fault tolerant.'' The commenter stated that the revisions would align this paragraph with the SAE Lightning Group's requested changes to Sec. 25.954 regarding fault-tolerant and non- fault tolerant designs. The commenter also requested deletion of the proposed section H25.X, stating that the MSG-3 process has been shown to be ineffective for maintenance inspections and procedures that are critical to fuel tank systems lightning protection. [[Page 47554]] Although Airbus was a participant in the SAE Lightning Group, it disagreed with the above comments on section H25.4(a)(5) because it makes reference to the ALS as being the only means to develop the ICA for both fault-tolerant and non-fault tolerant lightning protection features. Airbus suggested instead that the FAA limit the applicability of section H25.4(a)(5) to non-fault-tolerant lightning protection features rather than to all lightning protection features. Airbus also asked that the FAA delete the reference to sampling programs in section H25.X. Airbus stated that sampling programs are typically managed by the type certificate applicant, not the operator of the airplane that uses the ICA to develop their maintenance programs. The FAA partially agrees with the SAE Lightning Group's proposed changes. The FAA does not agree to the proposed changes to section H25.4(a)(5) as the FAA did not adopt the SAE Lightning Group's requested changes to Sec. 25.954, with the exception of deleting reference to Sec. 25.1729. However, the FAA did add the term ``critical design configuration control limitations'' to the final section H25.4(a)(5). Thus, section H25.4(a)(5) now states, ``Each mandatory replacement time, inspection interval, and related inspection and test procedure, and each critical design configuration control limitation for each lightning protection feature approved under Sec. 25.954.'' The FAA agrees with the request to delete the proposed new section H25.X because all necessary maintenance actions for ensuring the integrity of lightning ignition source protection features will be addressed by compliance with section H25.4(a)(5). Therefore, the ICA requirement in the proposed section H25.X is not necessary, so that section is not included in the final rule. This also addresses Airbus's request to delete the reference to sampling programs in section H25.X. The FAA disagrees with Airbus's request to add the phrase ``non-fault- tolerant'' to section H25.4(a)(5) because all necessary maintenance actions, both fault-tolerant and non-fault-tolerant, must be included in the ALS as required by section H25.4(a)(5). D. Miscellaneous Comments 1. Hazards of Electrostatic Charge An individual suggested that the FAA revise Sec. Sec. 25.954 and 25.981 to include a requirement for fuel system design features to mitigate the hazards of electrostatic charge. The commenter stated that these design features would also have a role in lightning protection. Section 25.899 specifically addresses electrostatic charge, and Sec. 25.981 addresses all ignition sources, which would include electrostatic charge. Lightning is the only exception, and it is now addressed by Sec. 25.954. Adding a specific requirement for electrostatic charge to Sec. Sec. 25.954 and 25.981 would be redundant and may cause confusion. Therefore, the FAA did not revise the rules because of this comment. 2. Regulatory Evaluation Boeing requested that the FAA explain the assumption made in paragraph IV.A.3 of the NPRM preamble, ``Regulatory Notices and Analyses, Regulatory Evaluation, Assumptions and Data Sources,'' that computational weights of composite wing airplanes would change from current approximate 15%-25% level linearly increasing to 50% level for a ten-year production cycle. The FAA clarified the information with the major manufacturer that had provided the data during the development of the NPRM regulatory evaluation. The assumption is more correctly stated that the weighted production rate of composite wing airplanes is estimated at 15%-25% of total production at the beginning of the 10-year production cycle, increasing linearly to 50% at the end of the cycle. IV. Regulatory Notices and Analyses A. Regulatory Evaluation Changes to Federal regulations must undergo several economic analyses. First, Executive Order 12866 and Executive Order 13563 direct that each Federal agency shall propose or adopt a regulation only upon a reasoned determination that the benefits of the intended regulation justify its costs. Second, the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires agencies to analyze the economic impact of regulatory changes on small entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits agencies from setting standards that create unnecessary obstacles to the foreign commerce of the United States. In developing U.S. standards, this Trade Act requires agencies to consider international standards and, where appropriate, that they be the basis of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies to prepare a written assessment of the costs, benefits, and other effects of final rules that include a Federal mandate likely to result in the expenditure by State, local, or tribal governments, in the aggregate, or by the private sector, of $100 million or more annually (adjusted for inflation with base year of 1995). This portion of the preamble summarizes the FAA's analysis of the economic impacts of this final rule. We suggest readers seeking greater detail read the full regulatory evaluation, a copy of which we have placed in the docket for this rulemaking. In conducting these analyses, FAA has determined that this final rule: (1) Has benefits that justify its costs; (2) is not an economically ``significant regulatory action'' as defined in section 3(f) of Executive Order 12866; (3) is not ``significant'' as defined in DOT's Regulatory Policies and Procedures; (4) will not have a significant economic impact on a substantial number of small entities; (5) will not create unnecessary obstacles to the foreign commerce of the United States; and (6) will not impose an unfunded mandate on state, local, or tribal governments, or on the private sector by exceeding the threshold identified above. These analyses are summarized below. 1. Total Benefits and Costs of This Rule This final rule will be relieving for both government and industries with the estimated net benefits. The FAA assesses cost savings based on resources saved for reducing regulatory burden on both industry and the FAA. This rule results in cost savings by reducing the number of exemptions and special conditions. Over a 10-year period, the average total present value savings to manufacturers and the FAA are about $29.03 million at a 7% discount rate with annualized savings of about $4.13 million. The lower and the higher estimates of the total present value savings are $16.17 million and $41.93 million at a 7% discount rate, with annualized savings of $2.30 million and $5.97 million, respectively. The final rule will maintain achieved safety levels related to fuel tank structure and system lightning protection commensurate with the current requirements. Parties Potentially Affected by this Rulemaking will be: Part 25 airplane manufacturers. Operators of part 25 airplanes. The Federal Aviation Administration. Assumptions and Data Sources. Data related to industry savings mainly come from airplane manufacturers. Data related to requests for exemptions and special conditions come from FAA internal data sources and the judgments of agency subject matter experts. [[Page 47555]] The FAA would process 4 special conditions and 7 exemptions in the next 10 years in the absence of this rule.\14\ --------------------------------------------------------------------------- \14\ FAA internal data source and the judgment of agency subject matter experts. --------------------------------------------------------------------------- Domestic airplane manufacturers would petition for two special conditions and three exemptions before reaching their cost- benefit steady-state.\15\ --------------------------------------------------------------------------- \15\ See footnote 14. --------------------------------------------------------------------------- While foreign manufacturers may benefit also from this final rule, cost savings directly attributable to foreign entities are not included in this analysis. For the final rule, the FAA estimates cost savings from avoided petitions for exemption and special conditions occur at the beginning of a 10-year production cycle. Projected impacts on manufacturers and the government are for a 10-year period associated with one production cycle. All monetary values are expressed in 2016 dollars. B. Regulatory Flexibility Determination The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) establishes ``as a principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisdictions subject to regulation.'' To achieve this principle, agencies are required to solicit and consider flexible regulatory proposals and to explain the rationale for their actions to assure that such proposals are given serious consideration.'' The RFA covers a wide-range of small entities, including small businesses, not-for-profit organizations, and small governmental jurisdictions. Agencies must perform a review to determine whether a rule will have a significant economic impact on a substantial number of small entities. If the agency determines that it will, the agency must prepare a regulatory flexibility analysis as described in the RFA. However, if an agency determines that a rule is not expected to have a significant economic impact on a substantial number of small entities, section 605(b) of the RFA provides that the head of the agency may so certify and a regulatory flexibility analysis is not required. The certification must include a statement providing the factual basis for this determination, and the reasoning should be clear. This final rule amends certain airworthiness regulations that were not always practical for transport category airplanes regarding lightning protection of fuel tanks and systems. This final rule provides burden relief and savings to airplane manufacturers, who are large entities. Therefore, as provided in section 605(b), the head of the FAA certifies that this final rule will not have a significant economic impact on a substantial number of small entities and also certifies that a regulatory flexibility analysis is not required. The FAA solicited comments in the NPRM and did not receive comments with regard to this certification. Therefore, the FAA Administrator certifies that this rule does not have a significant economic impact on a substantial number of small entities. C. International Trade Impact Assessment The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal agencies from establishing standards or engaging in related activities that create unnecessary obstacles to the foreign commerce of the United States. Pursuant to these Acts, the establishment of standards is not considered an unnecessary obstacle to the foreign commerce of the United States, so long as the standard has a legitimate domestic objective, such as the protection of safety, and does not operate in a manner that excludes imports that meet this objective. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards. The FAA has assessed the potential effect of this final rule and determined that it could result in the same benefits to domestic and international entities in accord with the Trade Agreements Act. D. Unfunded Mandates Assessment Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104- 4) requires each Federal agency to prepare a written statement assessing the effects of any Federal mandate in a proposed or final agency rule that may result in an expenditure of $100 million or more (in 1995 dollars) in any one year by State, local, and tribal governments, in the aggregate, or by the private sector; such a mandate is deemed to be a ``significant regulatory action.'' The FAA currently uses an inflation-adjusted value of $155 million in lieu of $100 million. This final rule does not contain such a mandate; therefore, the requirements of Title II of the Act do not apply. E. Paperwork Reduction Act The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires that the FAA consider the impact of paperwork and other information collection burdens imposed on the public. The FAA has determined that there is no new requirement for information collection associated with this final rule. F. International Compatibility In keeping with U.S. obligations under the Convention on International Civil Aviation, it is FAA policy to conform to International Civil Aviation Organization (ICAO) Standards and Recommended Practices to the maximum extent practicable. The FAA has determined that there are no ICAO Standards and Recommended Practices that correspond to these regulations. G. Environmental Analysis FAA Order 1050.1F identifies FAA actions that are categorically excluded from preparation of an environmental assessment or environmental impact statement under the National Environmental Policy Act in the absence of extraordinary circumstances. The FAA has determined this rulemaking action qualifies for the categorical exclusion identified in paragraph 5-6.6 and involves no extraordinary circumstances. V. Executive Order Determinations A. Executive Order 13132, Federalism The FAA has analyzed this final rule under the principles and criteria of Executive Order 13132, Federalism. The agency determined that this action will not have a substantial direct effect on the States, or the relationship between the Federal Government and the States, or on the distribution of power and responsibilities among the various levels of government, and, therefore, does not have Federalism implications. B. Executive Order 13211, Regulations That Significantly Affect Energy Supply, Distribution, or Use The FAA analyzed this final rule under Executive Order 13211, Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use (May 18, 2001). The agency has determined that it is not a ``significant energy action'' under the executive order and it is not likely to have a significant adverse effect on the supply, distribution, or use of energy. [[Page 47556]] C. Executive Order 13609, International Cooperation Executive Order 13609, Promoting International Regulatory Cooperation, promotes international regulatory cooperation to meet shared challenges involving health, safety, labor, security, environmental, and other issues and to reduce, eliminate, or prevent unnecessary differences in regulatory requirements. The FAA has analyzed this action under the policies and agency responsibilities of Executive Order 13609, and has determined that this action would have no effect on international regulatory cooperation. D. Executive Order 13771, Reducing Regulation and Controlling Regulatory Costs This final rule is considered an E.O. 13771 deregulatory action. Details on the estimated cost savings of this rule can be found in the rule's economic analysis. VI. How To Obtain Additional Information A. Rulemaking Documents An electronic copy of a rulemaking document may be obtained from the internet by-- 1. Searching the Federal eRulemaking Portal (http://www.regulations.gov); 2. Visiting the FAA's Regulations and Policies web page at http://www.faa.gov/regulations_policies/; or 3. Accessing the Government Printing Office's web page at http://www.thefederalregister.org/fdsys/. Copies may also be obtained by sending a request (identified by notice, amendment, or docket number of this rulemaking) to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence Avenue SW, Washington, DC 20591, or by calling (202) 267-9680. B. Comments Submitted to the Docket Comments received may be viewed by going to http://www.regulations.gov and following the online instructions to search the docket number for this action. Anyone is able to search the electronic form of all comments received into any of the FAA's dockets by the name of the individual submitting the comment (or signing the comment, if submitted on behalf of an association, business, labor union, etc.). C. Small Business Regulatory Enforcement Fairness Act The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 1996 requires FAA to comply with small entity requests for information or advice about compliance with statutes and regulations within its jurisdiction. A small entity with questions regarding this document, may contact its local FAA official, or the person listed under the FOR FURTHER INFORMATION CONTACT heading at the beginning of the preamble. To find out more about SBREFA on the internet, visit http://www.faa.gov/regulations_policies/rulemaking/sbre_act/. List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. The Amendment In consideration of the foregoing, the Federal Aviation Administration amends chapter I of title 14, Code of Federal Regulations as follows: PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES 0 1. The authority citation for part 25 continues to read as follows: Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and 44704. 0 2. Revise Sec. 25.954 to read as follows: Sec. 25.954 Fuel system lightning protection. (a) For purposes of this section-- (1) A critical lightning strike is a lightning strike that attaches to the airplane in a location that, when combined with the failure of any design feature or structure, could create an ignition source. (2) A fuel system includes any component within either the fuel tank structure or the fuel tank systems, and any airplane structure or system components that penetrate, connect to, or are located within a fuel tank. (b) The design and installation of a fuel system must prevent catastrophic fuel vapor ignition due to lightning and its effects, including: (1) Direct lightning strikes to areas having a high probability of stroke attachment; (2) Swept lightning strokes to areas where swept strokes are highly probable; and (3) Lightning-induced or conducted electrical transients. (c) To comply with paragraph (b) of this section, catastrophic fuel vapor ignition must be extremely improbable, taking into account flammability, critical lightning strikes, and failures within the fuel system. (d) To protect design features that prevent catastrophic fuel vapor ignition caused by lightning, the type design must include critical design configuration control limitations (CDCCLs) identifying those features and providing information to protect them. To ensure the continued effectiveness of those design features, the type design must also include inspection and test procedures, intervals between repetitive inspections and tests, and mandatory replacement times for those design features used in demonstrating compliance to paragraph (b) of this section. The applicant must include the information required by this paragraph in the Airworthiness Limitations section of the Instructions for Continued Airworthiness required by Sec. 25.1529. 0 3. Amend Sec. 25.981 by revising the section heading and paragraphs (a)(3) and (d) to read as follows: Sec. 25.981 Fuel tank explosion prevention. (a) * * * (3) Except for ignition sources due to lightning addressed by Sec. 25.954, demonstrating that an ignition source could not result from each single failure, from each single failure in combination with each latent failure condition not shown to be extremely remote, and from all combinations of failures not shown to be extremely improbable, taking into account the effects of manufacturing variability, aging, wear, corrosion, and likely damage. * * * * * (d) To protect design features that prevent catastrophic ignition sources within the fuel tank or fuel tank system according to paragraph (a) of this section, and to prevent increasing the flammability exposure of the tanks above that permitted in paragraph (b) of this section, the type design must include critical design configuration control limitations (CDCCLs) identifying those features and providing instructions on how to protect them. To ensure the continued effectiveness of those features, and prevent degradation of the performance and reliability of any means provided according to paragraphs (a), (b), or (c) of this section, the type design must also include necessary inspection and test procedures, intervals between repetitive inspections and tests, and mandatory replacement times for those features. The applicant must include information required by this paragraph in the Airworthiness Limitations section of the Instructions for Continued Airworthiness required by Sec. 25.1529. The type design must also include visible means of identifying critical features of the design in areas of the airplane where foreseeable maintenance actions, repairs, or alterations may compromise the CDCCLs. [[Page 47557]] 0 4. In appendix H to part 25, section H25.4, add new paragraph (a)(5) to read as follows: Appendix H to Part 25--Instructions for Continued Airworthiness * * * * * H25.4 Airworthiness Limitations section. (a) * * * (5) Each mandatory replacement time, inspection interval, and related inspection and test procedure, and each critical design configuration control limitation for each lightning protection feature approved under Sec. 25.954. * * * * * Issued under authority provided by 49 U.S.C. 106(f), 44701(a), and 44703 in Washington, DC, on September 6, 2018. Carl Burleson, Acting Deputy Administrator. [FR Doc. 2018-20174 Filed 9-19-18; 8:45 am] BILLING CODE 4910-13-P
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(e) Payment will be made only to the FOR FURTHER INFORMATION CONTACT: For effects to be extremely improbable; and
person or persons specified in the court questions concerning this action, requires applicants to add airworthiness
order. However, if the court order contact Stephen Slotte, Airplane and limitations to the airplane’s Instructions
specifies a third-party mailing address Flight Crew Interface Section, AIR–671, for Continued Airworthiness (ICA) to
for the payment, the TSP will mail to Transport Standards Branch, Policy and prevent catastrophic fuel vapor ignition
the address specified any portion of the Innovation Division, Aircraft caused by lightning. These changes
payment that is not transferred to a Certification Service, Federal Aviation align the rule with the current
traditional IRA, Roth IRA, or eligible Administration, 2200 South 216th understanding of lightning-related risk,
employer plan. Street, Des Moines, WA 98198; fuel tank flammability exposure, and
* * * * * telephone and fax (206) 231–3163; email current airplane design practices. It also
[FR Doc. 2018–20471 Filed 9–19–18; 8:45 am] steve.slotte@faa.gov. revises the title of § 25.981 to ‘‘Fuel tank
BILLING CODE 6760–01–P SUPPLEMENTARY INFORMATION: explosion prevention.’’
This amendment removes lightning
Authority for This Rulemaking from the ignition sources regulated by
The FAA’s authority to issue rules on § 25.981(a)(3). Inclusion of lightning in
DEPARTMENT OF TRANSPORTATION
aviation safety is found in Title 49 of the that section has resulted in applicants
Federal Aviation Administration United States Code. Subtitle I, Section showing that compliance was
106 describes the authority of the FAA impractical, leading them to seek
14 CFR Part 25 Administrator. Subtitle VII, Aviation exemptions to compliance with § 25.981
Programs, describes in more detail the for fuel tank structure and systems. The
[Docket No.: FAA–2014–1027; Amdt. No. scope of the agency’s authority. FAA has granted several exemptions for
25–146] fuel tank structure and systems. The
This rulemaking is promulgated
RIN 2120–AK24 under the authority described in FAA agrees, however, with the Large
Subtitle VII, Part A, Subpart III, Section Airplane Fuel System Lightning
Transport Airplane Fuel Tank and 44701, ‘‘General Requirements.’’ Under Protection Aviation Rulemaking
System Lightning Protection that section, the FAA is charged with Committee (Lightning ARC) 4 that
promoting safe flight of civil aircraft in common regulatory treatment of
AGENCY: Federal Aviation
air commerce by prescribing regulations structure- and systems-related lightning
Administration (FAA), DOT.
and minimum standards for the design protection in the fuel system is
ACTION: Final rule. appropriate. Applicants have also
and performance of aircraft that the
SUMMARY: The FAA is amending certain Administrator finds necessary for safety requested that the FAA develop special
airworthiness regulations for transport in air commerce. This regulation is conditions to allow the consideration of
category airplanes regarding lightning within the scope of that authority. It fuel tank flammability and the
protection of fuel systems. This action is prescribes revised safety standards for probability of lightning strikes when
relieving in several ways. It removes the the design and operation of transport meeting the requirement that a fuel tank
requirement for manufacturers to category airplanes. explosion caused by lightning be
provide triple-redundant fault tolerance extremely improbable. This amendment
I. Overview of Final Rule removes the necessity for such special
in lightning protection. It removes
regulatory inconsistency by establishing The FAA is amending the conditions by incorporating such
a single standard for lightning airworthiness regulations in title 14, considerations into the rule.
Code of Federal Regulations (14 CFR) To maintain the integrity of lightning
protection of both fuel tank structure
part 25 related to the lightning protection features of airplanes, this
and fuel tank systems. It establishes a
protection of fuel systems 1 (including amendment adds a new paragraph (d) to
performance-based standard that the
fuel tank structure 2 and fuel tank § 25.954 and amends part 25, appendix
design and installation of fuel systems
systems 3). This amendment removes H, section H25.4(a) to require applicants
prevent catastrophic fuel vapor ignition
the requirement for prevention of to establish airworthiness limitations to
caused by lightning and its effects. This
lightning ignition sources from protect the continued function of the
performance-based standard allows
§ 25.981(a)(3), ‘‘Fuel tank ignition lightning protection features of fuel tank
applicants to choose how to provide the
prevention,’’ at amendment 25–102 and structure and fuel systems.
required level of safety. This action This rule applies to applications for
requires airworthiness limitations to modifies § 25.954, ‘‘Fuel system
lightning protection.’’ The modification new type certificates, and applications
preclude the degradation of design for amended or supplemental type
features that prevent catastrophic fuel to § 25.954 creates a performance-based
standard that provides definitions for certificates on significant product-level
vapor ignition caused by lightning. Its change projects in which § 25.954,
intended effects are to align ‘‘critical lightning strike’’ and ‘‘fuel
systems;’’ requires catastrophic fuel ‘‘Fuel system lightning protection,’’ is
airworthiness standards with industry’s applicable to the changed area.
and the FAA’s understanding of vapor ignition due to lightning and its
lightning, and to address issues of II. Background
1 Fuel system, in the context of this final rule,
inconsistency and impracticality that includes any component within either the fuel tank A. Statement of the Problem
applicants experienced with previous structure or the fuel tank systems and any airplane
lightning protection regulations. structure or system components that penetrate, Section 25.954, adopted in 1967,
DATES: Effective November 19, 2018. connect to, or are located within a fuel tank. required protection of the airplane from
2 Fuel tank structure, in the context of this final the effects of lightning, regardless of the
ADDRESSES: For information on where to
tkelley on DSKBCP9HB2PROD with RULES2
rule, includes structural members of the fuel tank likelihood that lightning would strike
obtain copies of rulemaking documents such as airplane skins, access panels, joints, ribs,
the airplane. The regulation did not
and other information related to this spars, stringers, and associated fasteners, brackets,
acknowledge that lightning protection
final rule, see ‘‘How To Obtain coatings, and sealant.
3 Fuel tank systems, or systems, in the context of
Additional Information’’ in the this final rule, include tubing, components, and 4 See the ‘‘Large Airplane Fuel System Lightning
SUPPLEMENTARY INFORMATION section of wiring that penetrate, connect to, or are located Protection Rulemaking Recommendations’’ report,
this document. within a fuel tank. May 2011, available in the docket.
VerDate Sep<11>2014 16:15 Sep 19, 2018 Jkt 244001 PO 00000 Frm 00002 Fmt 4700 Sfmt 4700 E:\FR\FM\20SER1.SGM 20SER1](https://thefederalregister.org/doc/83_FR_47731/page/1.svg)
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prevent catastrophic fuel vapor ignition The proposed definition of a ‘‘critical includes ‘‘any design feature or
due to lightning and its effects. This lightning strike’’ was ‘‘. . . a lightning structure.’’
final rule removes ‘‘corona and strike that attaches to the airplane in a Related to the definition of critical
streamering at fuel vent outlets’’ as a location that affects a failed feature or a lightning strike, the NPRM stated that a
lightning effect that applicants must structural failure, and the amplitude of critical lightning strike occurs ‘‘on the
consider, and adds ‘‘lightning-induced the strike is sufficient to create an order of once every 100,000 hours of
or conducted electrical transients’’ to ignition source when combined with airplane operation.’’ The SAE Lightning
the non-exclusive list of lightning that failure.’’ The SAE Lightning Group Group commented that the location of
effects against which the fuel system requested changes to this definition for the lightning’s attachment to the
must be protected. This amendment clarity. The commenter requested that airplane, whether the strike’s amplitude
adds definitions for ‘‘critical lightning the term ‘‘failed feature’’ be changed to is sufficient to create an ignition source,
strike’’ and ‘‘fuel system’’ to ensure ‘‘failed protection feature,’’ but did not and the effect of a failed feature or
common understanding and consistent provide a rationale. The commenter also structural failure are all design-
application of those terms. stated that it is unnecessary to list dependent. The SAE Lightning Group
To comply with the revised § 25.954, structural failures separately. The also commented that compliance with
this amendment requires applicants to commenter further stated that the § 25.954 would require use of a strike
show that catastrophic fuel vapor inclusion of ‘‘a failed [protection] rate of 1 in 100,000 hours. The
ignition is extremely improbable, taking feature’’ already includes structural commenter suggested that the FAA
into account flammability, critical failures, which otherwise could result in should allow applicants to identify how
lightning strikes, and failures within the an ignition source. The commenter also often a critical lightning strike might
fuel system. suggested revising the definition to, ‘‘A occur relative to their designs.
To protect those features of the critical lightning strike is a lightning The intent of the statement in the
airplane that prevent catastrophic fuel strike that attaches to the airplane in a NPRM that a critical lightning strike
vapor ignition due to lightning, this location that affects a failed protection occurs once per 100,000 hours was to
amendment adds a requirement that the feature with characteristics that could provide a general understanding of their
type design include CDCCLs identifying create an ignition source when average rate of occurrence. It was not
those features and providing combined with that failure.’’ intended as a rate to be used in
information to protect them. To ensure The FAA partially agrees with the demonstrating compliance. The FAA
the continued effectiveness of those SAE Lightning Group’s requests. The agrees with the SAE Lightning Group
features, the rule requires that the type FAA modified the definition of critical that the actual rate of a critical strike
design specify necessary inspections lightning strike by deleting ‘‘the would be based on an applicant’s
and test procedures, intervals between amplitude of the strike is sufficient,’’ analysis of the specific airplane design
repetitive inspections and tests, and but did not replace that text with features, which include additional
mandatory replacement times. The rule ‘‘characteristics that could,’’ as the factors such as location of the strike,
also requires the applicant to include commenter recommended. The characteristics of the lightning strike,
information regarding CDCCLs and definition is clear without either of failure of design features and structure,
methods for ensuring continued those phrases. The FAA also did not and specific ignition source thresholds
effectiveness of lightning protection replace ‘‘failed feature’’ with ‘‘failed for each feature failure and failure
features in the Airworthiness protection feature,’’ or delete the phrase mode.
Limitations section (ALS) of the ICA. ‘‘structural failure.’’ To address the Related to this same discussion in the
The following is a discussion of comments, we have revised the NPRM, Parker Aerospace (‘‘Parker’’)
comments the FAA received on the definition by removing the phrase requested that the FAA add a paragraph
changes to § 25.954 as they were ‘‘failed feature’’ and stating instead that, to § 25.954 that describes all of the
proposed in the NPRM. ‘‘A critical lightning strike is a lightning conditions and guidance regarding
strike that attaches to the airplane in a probabilities that the applicant must
1. Definitions
location that, when combined with the consider, such as flammability exposure
The NPRM proposed adding failure of any design feature or and failure latency of inerting systems.
definitions of ‘‘critical lightning strike’’ structure, could create an ignition The FAA disagrees with Parker’s
and ‘‘fuel system’’ to § 25.954(d). This source.’’ request. Rather than make such
final rule revises these definitions and In this revised definition, a ‘‘design conditions and guidance on
moves them to paragraph (a) of the feature’’ means any feature specifically probabilities mandatory via a new
section. designed for lightning protection or any
The AE–2 and WG–31 Lightning paragraph in § 25.954, such guidance is
other design feature whose failure,
Committees (SAE Lightning Group) included in AC 25.954–1, ‘‘Transport
when combined with a lightning strike,
supported the proposed definition of Airplane Fuel System Lightning
could cause ignition. An example of a
‘‘fuel system.’’ However, the FAA Protection.’’ 9 The AC discusses the
design feature that is specifically
determined that the inclusion of the probability for different airplane
designed for lightning protection is a
word ‘‘other’’ in the definition, ‘‘A fuel composite tank structures and threat
metal foil layer installed between the
system includes any component within levels.
laminate layers of a composite wing. An
either the fuel tank structure or the fuel example of a design feature that is not 2. Relationship of § 25.954 to §§ 25.901
tank systems, and any other airplane specifically designed for lightning and 25.1309
structure or system components that protection but whose failure, when The SAE Lightning Group suggested
penetrate, connect to, or are located combined with a lightning strike, could
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that the FAA clearly state that the
within a fuel tank,’’ could be cause ignition is a swaged fitting on a revised § 25.954 takes precedence over
misinterpreted to exclude basic hydraulic tube located within the fuel the general requirements of §§ 25.901,
structure, such as wings, in the context tank. Structural failures that could
of the definition. Therefore, the create an ignition source in the event of 9 AC 25.954–1 is available in the docket and on
definition of fuel system in the final rule a lightning strike must also be addressed the internet at http://www.faa.gov/regulations_
does not include ‘‘other.’’ and, therefore, the final definition policies/advisory_circulars/.
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![Federal Register / Vol. 83, No. 183 / Thursday, September 20, 2018 / Rules and Regulations 47551
‘‘Installation’’ (‘‘Subpart E— fuel vapor ignition due to lightning and limited the requirement to fault
Powerplant’’), and 25.1309, its effects, including . . . .’’ tolerance as requested by the SAE
‘‘Equipment, systems, and The SAE Lightning Group Lightning Group, such a design
installations.’’ The FAA disagrees. recommended the removal of ‘‘corona approach, or others as technology
Section 25.954 does not supersede the and streamering at fuel vent outlets’’ progresses, would not be allowed.
requirements of § 25.901 or § 25.1309. from the list of lightning effects because Regardless of the design approach
However, compliance with § 25.954 may that term is inconsistent with the chosen by the applicant to prevent
assist applicants in showing compliance terminology in the industry guidance lightning-induced catastrophic fuel
with other regulations. material recommended by AC 20–155A. vapor ignition, a safety analysis will be
The FAA agrees and has removed this necessary to demonstrate extreme
3. Lightning Effects term from the final rule. improbability. The complexity of the
The NPRM proposed adding analysis can range from a relatively
4. Fault-Tolerant Design
‘‘lightning-induced or conducted simple assessment to establish any
electrical transients’’ to the lightning Regarding § 25.954(c) [paragraph (b) maintenance requirements for reliable
effects in § 25.954(b) [paragraph (a) in in the NPRM], the SAE Lightning Group fault-tolerant ignition protection
the NPRM] that applicants must ensure requested that the FAA require that features, to a more in-depth analysis if
catastrophic fuel vapor ignition due to non-fault-tolerant design features are
will not cause ignition of fuel vapor
lightning be prevented by demonstrating used. For reliable fault-tolerant features,
within the fuel system. The SAE
that the fuel system ignition source this analysis would be substantially less
Lightning Group recommended that,
protection design is fault tolerant, or for costly than traditional methods for
rather than adding to the existing list of
designs that are not fault tolerant, by showing that catastrophic failures are
lightning threats in the rule, the FAA
showing catastrophic fuel vapor ignition extremely improbable. The supporting
delete the list of lightning effects.
to be extremely improbable, taking into AC 25.954–1 provides guidance on
Instead, the SAE Lightning Group
account flammability, critical lightning methods for both fault-tolerant and FRM
recommended that the rule include a
strikes, and failures in the fuel system. compliance approaches, including the
more general and inclusive reference to
The SAE Lightning Group argued that necessary safety assessment, which
lightning that requires that the airplane the proposed broader requirement to
be protected against catastrophic effects could be numerical, qualitative, or a
show that catastrophic ignition is combination of the two.
from lightning. The SAE Lightning extremely improbable, without The FAA disagrees with Bombardier’s
Group suggested that the list may not be requiring a fault tolerant design, would request to define fault-tolerant in
complete and may be inconsistent with be costly and would negate the savings § 25.954. Since a fault-tolerant design is
lightning environments defined in the to industry stated in the regulatory not a requirement for compliance with
industry documents accepted by the evaluation. In a related comment, this rule, there is no need to provide a
FAA in AC 20–155A, ‘‘Industry Bombardier S.A. (Bombardier) requested regulatory definition. However, the
Documents to Support Aircraft that ‘‘fault tolerant’’ be defined to clarify supporting AC 25.954–1 includes the
Lightning Protection Certification.’’ In if it is equivalent to single fault definition for fault-tolerant design noted
contrast, Parker supported keeping the tolerance and the type of compliance earlier in this section (4. Fault-Tolerant
text as proposed, including ‘‘lightning- that the FAA would expect, numerical Design), ‘‘A fault-tolerant fuel system
induced or conducted electrical analysis or qualitative. Although the design is a design that precludes
transients.’’ term was not used in the proposed rule ignition sources in the fuel system even
The FAA disagrees with the SAE (and is not in the final rule), Bombardier when a fault is present.’’
Lightning Group’s suggestion to include suggested more clarity was needed in Therefore, this amendment retains the
only a general lightning requirement. the rule and supporting guidance. requirement in § 25.954(c) that
Relying on guidance material to detail The FAA agrees that fuel systems catastrophic fuel vapor ignition be
the lightning effects that applicants designed with reliable fault-tolerant extremely improbable, and clarifies its
must consider could result in some ignition source protection features relationship with paragraph (b). The
applicants not addressing all effects. should comply with the requirement revised § 25.954(c) states, ‘‘To comply
However, the FAA recognizes that the that catastrophic fuel vapor ignition be with paragraph (b) of this section,
list of effects, as proposed, could be extremely improbable. As used in this catastrophic fuel vapor ignition must be
misinterpreted as an exhaustive list. context, a fault-tolerant fuel system extremely improbable, taking into
Therefore, the FAA added ‘‘including’’ design is a design that precludes account flammability, critical lightning
to the text that introduces the list to ignition sources in the fuel system even strikes, and failures within the fuel
clarify that the list is not exhaustive. when a fault is present; ‘‘reliable’’ system.’’
The FAA agrees to limit, in § 25.954(b), means the ability to maintain the The SAE Lightning Group also
the type of fuel vapor ignition that must effectiveness of the protection features commented that the FAA should revise
be prevented to ‘‘catastrophic’’ events. over the service life of the individual the regulatory evaluation if the FAA
This change will make the requirement airplane. does not adopt the SAE Lightning
consistent with Policy Statement PS– However, the FAA disagrees that fault Group’s recommendation to replace the
ANM–25.981–02, which states that ‘‘the tolerance should be required because requirement of extreme improbability
fuel tank structure and systems must be fault tolerance is only one possible with fault tolerance. The commenter
designed and installed to prevent means of compliance with the argued that the requirement to show
catastrophic fuel vapor ignition due to requirement that catastrophic fuel vapor that fuel tank ignition is extremely
lightning.’’ This change also makes ignition be extremely improbable. The
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improbable would be costly and negate
§ 25.954(b) consistent with § 25.581, use of a full-time flammability control the savings to industry shown in the
which requires that the airplane be system (e.g., fuel system inerting) regulatory evaluation. The SAE
protected against ‘‘catastrophic’’ effects exceeding the current part 25 Lightning Group did not submit any
from lightning. Thus, § 25.954(b) now flammability reduction means (FRM) supporting financial data.
states, ‘‘The design and installation of a performance standard could be another The FAA does not agree that the
fuel system must prevent catastrophic means of compliance. If the FAA requirement to show that fuel tank
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![47552 Federal Register / Vol. 83, No. 183 / Thursday, September 20, 2018 / Rules and Regulations
ignition is extremely improbable would the fuel tank being flammable, and the commenter stated that if the FAA does
be costly and negate the savings to creation of an ignition source due to the not agree with this approach, then only
industry. In general, an applicant that failure of fuel system or structural critical information necessary to
can show its design is reliably fault- lightning protection features. If demonstrate compliance, along with
tolerant will not need to conduct an designers develop a full-time fuel tank CDCCLs, should be included as
extensive safety analysis. The flammability control system that airworthiness limitations, and proposed
requirement to develop airworthiness prevents the fuel tanks from being that the regulatory text be amended to
limitations for critical lightning flammable during all foreseeable reflect this request. The SAE Lightning
protection features will result in the operating conditions and all phases of Group did not define what it considered
need for the applicant to assess the airplane operation (including descent), critical information.
reliability of the features and provide resulting in the probability of a fuel tank The FAA disagrees with the SAE
appropriate maintenance tasks to explosion being extremely improbable, Lightning Group’s request to move the
achieve an acceptable level of this could achieve the level of safety CDCCLs from the ALS of the ICA to the
reliability. that § 25.954 requires, and could be Cautions section of the maintenance
In addition, this rule allows both used as a means of compliance without manual. CDCCLs provide information
fault-tolerant and non-fault-tolerant the need for fault-tolerant lightning that is essential for protecting the design
design approaches. Under the rule, the protection features. While fuel tank features that are critical for preventing
fuel system must prevent catastrophic flammability control system technology fuel tank explosions. The Caution
fuel vapor ignition due to lightning. To has not evolved to a state where section of the maintenance manual is
comply with this requirement, flammability control can replace the not mandatory for U.S. operators, and
catastrophic fuel vapor ignition must be need for fault-tolerant ignition therefore CDCCLs need to be included
extremely improbable. If an applicant’s prevention, the FAA’s goal is to develop in the ALS of the ICA, which is
design achieves this requirement rules that are performance-based, and in mandatory.
through the use of fault-tolerant design, this case, to allow designers to comply The SAE Lightning Group commented
the safety analysis (§ 25.1309) to support via the use of flammability control when that, since the Lightning ARC study and
the design will not have to be as the technology is adequately developed. report in 2011, the use of Air Transport
extensive as one that would be Allowing the use of fuel tank FRM for Association (ATA) Maintenance
necessary to support a non-fault-tolerant demonstrating compliance with the rule Steering Group (MSG)–3 11 processes
design. As a result, the rule allows could offer designers the opportunity to has not been effective in establishing
industry the flexibility to select the reduce the number of fault-tolerant maintenance requirements for lightning
means of compliance based on design features and mandatory maintenance protection features and does not take
approach, safety analysis, and costs. actions. into consideration the many factors that
Therefore, the FAA determined that the are critical for certification. This can
regulatory evaluation did not need to be 6. CDCCLs create conflicting or duplicate fuel tank
revised as a result of this comment. Section 25.954(d) [paragraph (c) in the entry requirements. To eliminate this
NPRM] requires that the type design potential duplication, the SAE
5. Flammability Reduction Means include CDCCLs identifying those Lightning Group stated that industry
(FRM) as a Means of Compliance design features that prevent catastrophic now recommends that maintenance
The SAE Lightning Group, fuel vapor ignition caused by lightning practices for both fault-tolerant and non-
Bombardier, and Parker all commented and providing information to protect fault-tolerant protection features be
on the discussion of fuel tank them. To ensure the continued established via the type certification
flammability reduction in the NPRM effectiveness of those features, process only, and that the ATA MSG–
and asked for clarification of how paragraph (d) also requires that the type 3 process should not be used for this
flammability reduction could be used as design include inspections and test purpose.
a means of compliance with § 25.954. procedures, intervals between repetitive Airbus and Airlines for America
Boeing stated that the majority of the inspections and tests, and mandatory disagreed with the request to establish
NPRM discussion of fuel tank FRM was replacement times. This paragraph also maintenance practices for both fault-
unnecessary because applicants could requires applicants to place all this tolerant and non-fault-tolerant
infer that the FAA would relax the information in the ALS of the ICA. protection features via the type
requirement for providing fault The SAE Lightning Group proposed certification process. Both commenters
tolerance if the FAA allowed FRM as a that CDCCLs be included as cautions 10 proposed that the FAA require
sole means of compliance. Boeing did in the airplane maintenance manual, not airworthiness limitations and CDCCLs
not agree that the FAA should accept as airworthiness limitations in the ALS for only non-fault-tolerant design
controlling fuel tank flammability as the of the ICA. The SAE Lightning Group features. Both commenters stated that an
primary means for preventing a fuel suggested that, as proposed, the airworthiness limitation requirement for
tank explosion without providing fault- requirement would create a burden on fault-tolerant design features could be a
tolerant lightning protection features. the airlines because the ALS documents disincentive to develop fault-tolerant
As discussed in the previous section are not used by the airline mechanics, designs and may increase the burden on
(4. Fault-Tolerant Design), the FAA does and therefore the CDCCL information operators unnecessarily. As an
not agree that the lightning protection must be duplicated and links created for alternative, they proposed reliance on
requirement in § 25.954 should dictate the information in both the ALS the current ATA MSG–3 process for
the use of fault-tolerant ignition documents and the maintenance establishing maintenance programs for
protection features in the design documents used by the mechanics. The
tkelley on DSKBCP9HB2PROD with RULES2
without allowing the use of 11 ATA MSG–3 is a maintenance steering group
flammability control means. As 10 Cautions in an airplane maintenance manual composed of regulatory authorities, operators, and
explained in the NPRM, the intent of the call attention to methods and procedures that must manufacturers that, through a process, develop
be followed to avoid damage to equipment (ATA documents that present a methodology for
amendment to § 25.954 is to require the iSpec 2200, Information Standards for Aviation developing scheduled maintenance tasks and
design to take into account the Maintenance, published by Airlines for America, intervals for aircraft structure, systems, and
likelihood of a critical lightning strike, 2014). components.
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![Federal Register / Vol. 83, No. 183 / Thursday, September 20, 2018 / Rules and Regulations 47557
■ 4. In appendix H to part 25, section objections will not be considered. and, except for those submitted as
H25.4, add new paragraph (a)(5) to read Electronic objections must be submitted ‘‘Confidential Submissions,’’ publicly
as follows: on or before October 22, 2018. The viewable at https://www.regulations.gov
https://www.regulations.gov electronic or at the Dockets Management Staff
Appendix H to Part 25—Instructions for
filing system will accept objections until between 9 a.m. and 4 p.m., Monday
Continued Airworthiness
midnight Eastern Time at the end of through Friday.
* * * * * October 22, 2018. Objections received • Confidential Submissions—To
H25.4 Airworthiness Limitations section. by mail/hand delivery/courier (for submit an objection with confidential
(a) * * * written/paper submissions) will be information that you do not wish to be
(5) Each mandatory replacement time, considered timely if they are made publicly available, submit your
inspection interval, and related inspection postmarked or the delivery service objections only as a written/paper
and test procedure, and each critical design acceptance receipt is on or before that submission. You should submit two
configuration control limitation for each date. copies total. One copy will include the
lightning protection feature approved under information you claim to be confidential
§ 25.954. Electronic Submissions
with a heading or cover note that states
* * * * * Submit electronic objections in the ‘‘THIS DOCUMENT CONTAINS
Issued under authority provided by 49
following way: CONFIDENTIAL INFORMATION.’’ We
U.S.C. 106(f), 44701(a), and 44703 in • Federal eRulemaking Portal: will review this copy, including the
Washington, DC, on September 6, 2018. https://www.regulations.gov. Follow the claimed confidential information, in our
Carl Burleson, instructions for submitting comments. consideration of comments. The second
Objections submitted electronically, copy, which will have the claimed
Acting Deputy Administrator.
including attachments, to https:// confidential information redacted/
[FR Doc. 2018–20174 Filed 9–19–18; 8:45 am]
www.regulations.gov will be posted to blacked out, will be available for public
BILLING CODE 4910–13–P
the docket unchanged. Because your viewing and posted on https://
objection will be made public, you are www.regulations.gov. Submit both
solely responsible for ensuring that your copies to the Dockets Management Staff.
DEPARTMENT OF HEALTH AND objection does not include any If you do not wish your name and
HUMAN SERVICES confidential information that you or a contact information to be made publicly
third party may not wish to be posted, available, you can provide this
Food and Drug Administration such as medical information, your or information on the cover sheet and not
anyone else’s Social Security number, or in the body of your comments and you
21 CFR Part 172 confidential business information, such must identify this information as
[Docket No. FDA–2017–F–3717] as a manufacturing process. Please note ‘‘confidential.’’ Any information marked
that if you include your name, contact as ‘‘confidential’’ will not be disclosed
Food Additives Permitted for Direct information, or other information that except in accordance with 21 CFR 10.20
Addition to Food for Human identifies you in the body of your and other applicable disclosure law. For
Consumption; Vitamin D3 objection, that information will be more information about FDA’s posting
AGENCY: Food and Drug Administration, posted on https://www.regulations.gov. of comments to public dockets, see 80
HHS. • If you want to submit an objection FR 56469, September 18, 2015, or access
with confidential information that you the information at: https://www.gpo.gov/
ACTION: Final rule. do not wish to be made available to the fdsys/pkg/FR-2015-09-18/pdf/2015-
SUMMARY: The Food and Drug public, submit the objection as a 23389.pdf.
Administration (FDA or we) is written/paper submission and in the Docket: For access to the docket to
amending the food additive regulation manner detailed (see ‘‘Written/Paper read background documents or the
for vitamin D3 to replace the current Submissions’’ and ‘‘Instructions’’). electronic and written/paper comments
Reference Daily Intake (RDI) percentage Written/Paper Submissions received, go to https://
values of calcium in 100 percent fruit www.regulations.gov and insert the
Submit written/paper submissions as
juices and fruit juice drinks with docket number, found in brackets in the
follows:
absolute values and to update the heading of this document, into the
• Mail/Hand Delivery/Courier (for
reference for vitamin D3 specifications. ‘‘Search’’ box and follow the prompts
written/paper submissions): Dockets
We are taking this action in response to and/or go to the Dockets Management
Management Staff (HFA–305), Food and
a food additive petition filed by the Staff, 5630 Fishers Lane, Rm. 1061,
Drug Administration, 5630 Fishers
Juice Products Association. Rockville, MD 20852.
Lane, Rm. 1061, Rockville, MD 20852.
DATES: This rule is effective September • For written/paper objections FOR FURTHER INFORMATION CONTACT:
20, 2018. Submit either electronic or submitted to the Dockets Management Judith Kidwell, Center for Food Safety
written objections and requests for a Staff, FDA will post your objection, as and Applied Nutrition (HFS–265), Food
hearing on the final rule by October 22, well as any attachments, except for and Drug Administration, 5001 Campus
2018. The Director of the Federal information submitted, marked and Dr., College Park, MD 20740–3835, 240–
Register approves the incorporation by identified, as confidential, if submitted 402–1071.
reference of certain publications listed as detailed in ‘‘Instructions.’’ SUPPLEMENTARY INFORMATION:
in the rule as of September 20, 2018. See Instructions: All submissions received
the ADDRESSES section and the must include the Docket No. FDA– I. Background
tkelley on DSKBCP9HB2PROD with RULES2
OBJECTIONS section IX of this 2017–F–3717 for ‘‘Food Additives In the Federal Register of July 26,
document for further information on Permitted for Direct Addition to Food 2017 (82 FR 34615), amended August
filing objections. for Human Consumption; Vitamin D3 22, 2017 (82 FR 39711), we announced
ADDRESSES: You may submit objections Final Rule.’’ Received objections, those that we filed a food additive petition
and requests for a hearing as follows. filed in a timely manner (see (FAP 7A4818) submitted on behalf of
Please note that late, untimely filed ADDRESSES), will be placed in the docket the Juice Products Association by Hogan
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Document Created: 2018-09-20 02:08:16
Document Modified: 2018-09-20 02:08:16
| Category | Regulatory Information | |
| Collection | Federal Register | |
| sudoc Class | AE 2.7: GS 4.107: AE 2.106: | |
| Publisher | Office of the Federal Register, National Archives and Records Administration | |
| Section | Rules and Regulations | |
| Action | Final rule. | |
| Dates | Effective November 19, 2018. | |
| Contact | For questions concerning this action, contact Stephen Slotte, Airplane and Flight Crew Interface Section, AIR-671, Transport Standards Branch, Policy and Innovation Division, Aircraft Certification Service, Federal Aviation Administration, 2200 South 216th Street, Des Moines, WA 98198; telephone and fax (206) 231- 3163; email [email protected] | |
| FR Citation | 83 FR 47548 | |
| RIN Number | 2120-AK24 | |
| CFR Associated | Aircraft; Aviation Safety and Reporting and Recordkeeping Requirements |
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