The Fuel Tank Safety/CDCCL Phase 1 & 2 Initial & Recurrent Training NOK AIR Pithan Bholnivas COURSE OBJECTIVES OVERVIEW COURSE DESCRIPTION COURSE DESCRIPTION TARGET GROUP AIRCRAFT LIFE CYCLE EASA Regulations Council Regulation (EU) No. 2018/1139 (Basic Regulation) Commission Regulation (EU) No. 748/2012 (Initial Airworthiness) Annex I Part-21 Commission Regulation Regulation (EU) No. 1321/2014 (Continuing Airworthiness) Annex I Part-M Annex Vb Part-ML AMC & GM AMC & GM AMC & GM Annex Va Part-T Annex III Part-145 Certification Specifications PART 21 Subpart J regulatory approval provides for the Design of Aircraft and Components Design Organization Approval (DOA) PART 21 Subpart G provides for a Production Organization approval (POA). Annex Vc Commission (EU) No. 965/2012 (Air Operations) Annex I DEF Annex II ARO Annex III ORO Part-CAMO Annex II Part-66 AMC & GM Annex Vd Part-CAO Annex IV Part-147 AMC & GM Basic Regulation, Initial Airworthiness, Continuing Airworthiness and Air Operations regulatory structure AMC & GM Annex IV CAT Annex V SPA Annex VI NCC Annex VII NCO Annex VIII SPO AMC & GM Other Regulations concerning flight crew licensing, air traffic control, aerodromes etc Annex I ACL Annex IV MED Annex V CC Annex VI ARA Annex V Annex Introduction – Regulatory Framework CS Certification Specifications ❖ ❖ Technical standards Building blocks AMC GM Acceptable Means of compliance Guidance Material ❖ ❖ Technical procedures material Presumption of compliance ❖ ❖ Interpretative or explanatory material Guidance Non-binding Non-binding Non-binding Adopted to meet the requirements of the essential requirements of the ANA and Cover regulation. CSs are used to establish the certification basis. Serves as a mean by which the requirements contained in the TCARs, can be met. These AMCs may be used to demonstrate compliance with the provisions of TCAR PEL Part 66 and Part 147. Explanatory and interpretation material on how to achieve the requirements contained, in the IRs, the AMCs and the CSs. It contains information, including examples, to assist the user in the interpretation and application of the IRs, AMCs and the CSs. (e.g. for FSTDs) 9 Certification Specifications (Airworthiness Codes/Requirements) AIRCRAFT LIFE CYCLE AIRCRAFT LIFE CYCLE AIRCRAFT LIFE CYCLE AIRCRAFT LIFE CYCLE AIRCRAFT LIFE CYCLE AIRCRAFT LIFE CYCLE PART M Requirements Continuing Airworthiness Pre-Flight Inspections Airworthiness Directives Defect Rectification Technical Records MEL / CDL Maintenance Programme Reliability Monitoring Maintenance Check Flights Modifications and Repairs Lifing Control Technical Log Parts control The objectives of Part-M – Continuing Airworthiness EASA Regulations Part-M Operator Flight Crew Licensing and Air Operations Part-145 Maintenance Organisation Approvals Part-21 Design, Manufacture and Certification of New Products Part-66 Certifying Staff Part-147 Training Organisation Requirements Certification Specifications (CS) EASA Regulation (EU) 1321/2014 relationships for large aircraft ABBREVIATION HISTORICAL BACKGROUND Historical Background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background Historical background REGULATORY BACKGROUND &OVERVIEW TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case TWA 800 Study-Case SFAR88 FAA 14 Code of Federal Regulation • Part 25: Rules governing airworthiness standards • Part 91: General operating and flight rules (general aviation) • Part 121: Rules for scheduled air carriers (ie. regional and major airlines) • PART 125:Rules for Aircraft having seating capacity of 20 or more or a maximum payload capacity of at least 6,000 pounds or more as set out by FAA regulation (Aircraft used for personnel use ) • Part 135: Rules for commuter and on-demand operations (ie corporate & government & all helicopter ops) AC 25.981-1C AC 25.981-2A JAA TGL 47 FTS / CDCCL Aircraft Life Cycle FTS/CDCCL and Aircraft Life Cycle PART 21 Subpart J regulatory approval provides for the Design of Aircraft and Components Design Organization Approval (DOA) PART 21 Subpart G provides for a Production Organization approval (POA). Different between FTS &CDCCL • The term CDCCL – Critical Design Configuration Control Limitations – actually refers to design characteristics that have to be retained during maintenance or modification. This means that disturbing systems related to, adjacent to or having a potential impact on fuel systems identified as being at risk (as identified during the accomplishment of the stipulations of SFAR 88 and related JAR or EASA documents) may be subject to special inspections identified as CDCCL tasks in ICA and in AMPs. • The term Fuel Tank Safety (FTS) is more accurate with regard to training considerations and comes in two phases. CDCCL Definition EASA Regulations EASA Regulations EASA Regulations EASA Regulations Annex 1 to Decision 2009/006/R EASA Regulations EASA Regulations Annex 1 to Decision 2009/007/R Annex 1 to Decision 2009/007/R EASA Regulations Annex 1 to Decision 2009/007/R EASA Regulations EASA Regulations EASA CS-25-1309 CHRONOLOGY Chronology TWA Full Episode Chronology Chronology Chronology Chronology Investigation-Cause Analysis Chronology Chronology Chronology Chronology Fuel and Fuel Analysis The Fire Triangle Kerosene Characteristics By volume of Kerosener vapor/Air mixture The different temperatures Flash Point :the lowest temperature at which the application of a flame to a heated sample causes the vapor to ignite momentarily, or “flash.” Flammability Envelope of Jet A Flammability Envelop JP-4 VS Jet A Flammability Sources Fuel Tank Ignition Source Consideration AC No. 25.981-1C Fuel Tank Ignition Source Prevention Guideline Electrical Sparks and Electrical Arcs Electrical Sparks and Electrical Arcs Electrical Sparks and Electrical Arcs Filament Heating Current Limits RMS Voltage What is RMS Voltage? The word RMS stands for Root Mean Square. An RMS voltage is defined as the square root of the mean square of instantaneous values of the voltage signal. The RMS voltage is also known as the equivalent DC voltage because the RMS value gives the amount of AC power drawn by a resistor similar to the power drawn by a DC source. The AC signal is a sinusoidal wave signal in most conditions, as shown in the above figure. Since in a sinusoidal wave signal the instantaneous value varies, we cannot use the instantaneous value to calculate the power. But if we find the RMS value of the above signal, we can use it to find the power.. The voltage we received at home is RMS voltage. Multimeters also give an RMS value for AC power. And in a power system, we use system voltage that is also an RMS value. Friction Spark AC No. 25.981-2A Fuel Tank Flammability Minimization Guideline Flammability Limits in the air Flammability Limits in the air Flammability Limits in the air Flammability Limits in the air Explosimeter INERTING vs VENTING Inerting :a process where a noncombustible gas is introduced into the ullage of a fuel tank so that the ullage becomes non-flammable Venting : Less or release noncombustible gas Fuel Tank Analysis – Flammability Exposure Purpose of CDCCL FUEL = Flammable Safety Approach for 5 Key Accidents Safety Approach for 5 Key Accidents Aircraft Fuel System Fuel System Tanks layout Venting Feature Fuel Capacity Auxiliary Central Tank (ACT) Auxiliary Central Tank (ACT) The different types of tanks Boeing 737Fuel System Boeing 737Fuel System Examples of fuel system equipment Examples of fuel system equipment Examples of fuel system equipment Examples of fuel system equipment Fuel transfers on the A380 Fuel Jettisoning Equipment of a Tank Action to limit risks Action to limit risks Action to limit risks Preventing energy sources 5 Sources of electric charges to be eliminated 5 Sources of electric charges to be eliminated 5 Sources of electric charges to be eliminated 5 Sources of electric charges to be eliminated 5 Sources of electric charges to be eliminated Bonding Lead Conditions Bonding Lead Conditions Example of modifications Example of modifications Experience Feedback FTS Maintenance Practices Fuel Tank Preparation Compliant Equipment Compliant Equipment Compliant Equipment Compliant Equipment Compliant Equipment Compliant Equipment Compliant Equipment Fuel Tank Safety Procedure 2/8/2024 186 Staff Protection Fuel Tank Safety Procedures Fuel Tank Safety Procedures Fuel Tank Safety Procedures Fuel Tank Safety Procedures Fuel Tank Safety Procedures Fuel Tank Safety Procedures NGS WARNING CAUTION PLACARD LOCATION ACCESS FOR FUEL TANK RH WHEEL WELL LH AIRCOND PACK BAY LH RAM AIR COMPT PLACARD Experience Feedback Work documents OEM Maintenance Planning Documents • A majority of the tasks that come from the OEMs Maintenance Planning Document originate from the MRBR (Maintenance Review Board report) which uses an analytical philosophy called as MSG-3 (Maintenance Steering Group). This constitutes a baseline set of maintenance requirements for a given airplane type required to maintain the inherent levels of safety and reliability. • However the MSG-3 process only starts after design of aircraft. Furthermore MRBR tasks are not mandatory and the intervals and tasks themselves can be modified via a Reliability program. OEM Maintenance Planning Documents • On the other there is another set of Mandatory tasks that arise from initial design & certification requirements as a result of analysis and testing. They are CMRs (Certification Maintenance Requirements) and ALI or AWLs (Airworthiness Limitations). Both CMRs and AWLs are mandatory items. • Both CMRs and AWLs are derived from a fundamentally different analysis process than the maintenance tasks and intervals that result from the Maintenance Steering Group (MSG-3) Analysis associated with Maintenance Review Board (MRB) activities. CMRs and AWLs are approved by the Regulatory Authority Certification Maintenance Requirements (CMRs) Certification Maintenance Requirements (CMRs) • A CMR is a required periodic task, established during the design certification of the airplane as an operating limitation of the type certificate. • CMRs usually result from a formal, numerical analysis conducted to show compliance with catastrophic and hazardous failure conditions. As part of design a catastrophic failure should be extremely improbable i.e. (1X 10 to power of -9) and a hazardous failure should be extremely remote i.e (1X10 to power of -7). • The OEM as part of their Systems Safety Assessment (SSA) utilizes Failure mode and effect analysis and fault tree analysis at time of design to determine if system which have chances for catastrophic and hazardous failures meet the extremely improbable and extremely remote criteria respectively. • If the criteria is not met then creation of a CMR tasks is essential to demonstrate compliance with certification process. The CMRs form a mandatory limitation of the Type Certificate. Certification Maintenance Requirements (CMRs) • CMRs are purely failure finding tasks and are designed to detect hidden failures. CMRs limit the exposure time of a failure and reduce overall failure probability of the system. CMR scheduled maintenance tasks normally take the form of Operational or Functional checks. • The operator when including the CMRs in their maintenance progress need to ensure that they are clearly marked.CMRs are classified into types: CMR* , The tasks and intervals are mandatory and cannot be escalated or deleted with approval of certification authority. CMR** The tasks mandatory and cannot be deleted with approval of certification authority, however interval can be adjusted in accordance with a reliability program. BOEING Certification Maintenance Requirements (CMRs) FUEL SYSTEMS AIRWORTHINESS LIMITATIONS FUEL SYSTEMS AIRWORTHINESS LIMITATIONS • This section of the Airworthiness Limitations contains an FAA approved program of scheduled inspections and design limitations for operators to incorporate into their maintenance program for this type design to meet the new standards and assumptions introduced by § 25.981 and Special Federal Aviation Regulation (SFAR) No. 88. SFAR 88 - Fuel Tank System Fault Tolerance Evaluation Requirements and Title 14 Code of Federal Regulations § 25.981 - Fuel Tank Ignition Prevention require maintenance instructions, and control limitations for certain fuel tank critical design configurations. Paragraph 2(a) of SFAR 88 requires certain design approval holders of Type Certificates (TCs) and Supplemental Type Certificates (STCs) of large transport airplanes to conduct a safety review of the fuel tank systems. • The purpose of the safety review is to identify design features that may result in development of ignition sources in the fuel tank systems. Fuel System Airworthiness Limitation (AWL) items are mandatory maintenance actions required to ensure that unsafe conditions identified by the SFAR 88 safety review do not occur or are not introduced into the fuel tank system as a result of configuration changes, repairs, alterations, or deficiencies in the maintenance program throughout the operational life of the airplane. An AWL may be: an Airworthiness Limitation Instruction (ALI) or a Critical Design Configuration Control Limitation (CDCCL) FUEL SYSTEMS AIRWORTHINESS LIMITATIONS • CDCCLs are a means of identifying certain design configuration features intended to preclude a fuel tank ignition source for the operational life of the airplane. CDCCLs are mandatory and cannot be changed or deleted without the approval of the Seattle FAA ACO that is responsible for the airplane model Type Certificate, or applicable regulatory agency. • A critical fuel tank ignition source prevention feature may exist in the fuel system and its related installation or in systems that, if a failure condition were to develop, could interact with the fuel system in such a way that an unsafe condition would develop without this limitation. Strict adherence to configuration, methods, techniques, and practices as prescribed is required to ensure compliance with the CDCCL. • Any use of parts, methods, techniques or practices not contained in the applicable CDCCL must be approved by the Seattle FAA ACO that is responsible for the airplane model Type Certificate, or applicable regulatory agency. ALIs identify inspection tasks related to fuel tank ignition source prevention which must be done to maintain the design level of safety for the operational life of the airplane. • These ALIs are mandatory and cannot be changed or deleted without the approval of the Seattle FAA ACO that is responsible for the airplane model Type Certificate, or applicable regulatory agency. Strict adherence to methods, techniques and practices as prescribed is required to ensure the ALI is complied with. Any use of methods, techniques or practices not contained in these ALIs must be approved by the Seattle FAA ACO that is responsible for the airplane model Type Certificate, or applicable regulatory agency BOEING FUEL SYSTEMS AIRWORTHINESS LIMITATIONS BOEING FUEL SYSTEMS AIRWORTHINESS LIMITATIONS BOEING FUEL SYSTEMS AIRWORTHINESS LIMITATIONS ALS Part 5 - Fuel Airworthiness Limitations Sample of AWL / FAL for A310 ALS Part 5 - Fuel Airworthiness Limitations 2/8/2024 CDCCL Requirement Reference Applicability 1 Air gap between a fuel quantity indicating probes and the airplane structure. Critical to prevent spark generation during lightning strike conditions and must not be compromised The gap stated in the relevant maintenance procedure in the AMM must be achieved during installation of a fuel quantity probe. AMM 28-42-31 pb 401 28-42-32 pb 401 28-42-33 pb 401 ALL ALL ALL 2 Separation of fuel quantity and level indicating system wiring from other wiring. To prevent cross coupling of high voltage transients and thereby keep unsafe ignition energies from inside the tank it is required that operators obey the wire routing and separation standards given in the Electrical Standard Practices Manual (ESPM). ESPM 20-10-00 20-33-20 20-33-21 20-33-22 ALL ALL ALL ALL 209 ALS Part 5 - Fuel Airworthiness Limitations 3 2/8/2024 CDCCL Requirement Reference Applicability Direct bonding on items of equipment inside a fuel tank. Direct bonding is critical to prevent spark generation during component failure and lightning strike conditions and must not be compromised Direct bonding in fuel tanks must be carried out during component installation to the appropriate bonding method and standard stated within the installation procedure in the AMM. AMM 28-00-00 pb 401 28-11-21 pb 401 28-11-22 pb 401 28-11-24 pb 401 28-11-32 pb 401 28-12-21 pb 401 28-12-33 pb 401 28-12-34 pb 401 28-21-13 pb 401 28-21-21 pb 401 28-24-31 pb 401 28-25-15 pb 401 28-27-12 pb 401 28-43-21 pb 401 28-46-21 pb 401 ALL ALL ALL ALL A310-300 ALL A310-300 A310-300 ALL ALL ALL ALL A310-300 ALL ALL 210 ALS Part 5 - Fuel Airworthiness Limitations Sample of AWL / FAL for A310 4 2/8/2024 CDCCL Requirement Reference Applicability Safety critical features of fuel pumps These features must be maintained throughout the full life of the fuel pump to avoid the possibility of generation of an ignition source by overheating or sparks caused by arcing, friction etc. Repair and overhaul of fuel pumps must be carried out in accordance with the equipment manufacturer’s maintenance instructions or other maintenance instructions acceptable to the certifying authority. CMM 28 09 01 28 24 11 ALL ALL 211 MANAGEMENT / CONTROL OF CDCCL 2/8/2024 212 MANAGEMENT / CONTROL OF CDCCL ➢It is the responsibility of certifying staff / maintenance personnel to ensure that the above stated CDCCL configurations are maintained to reduce the risk of any ignition source penetration into the fuel tank (s). ➢If any of these CDCCL is compromised, this may lead to wire chaffing, fault current (short circuit), or overheating of the CWT fuel pumps. ➢This in turn may result in fuel tank explosion. 2/8/2024 213 MANAGEMENT / CONTROL OF CDCCL ➢Dry running of the fuel pumps should not be allowed as it has already resulted in catastrophic incidents. ➢This requirement has been addressed both by Airbus & Boeing by introduction of new logic circuitry to avoid dry running on CWT fuel pumps. ➢Introduction of Ground Fault Interrupter (GFI) relays also ensures NO overheating / fault current in the fuel pump circuitry. 2/8/2024 214 MANAGEMENT / CONTROL OF CDCCL 2/8/2024 215 OVERHAUL SHOP CONTROL FOR CDCCL ➢Fuel pumps CMM have also been revised in compliance of CDCCL requirements and provides specific instructions / procedures. ➢ Tools, kits, jigs, materials, test equipment required for servicing, repair or overhauling of a fuel system component should be used accordingly. 2/8/2024 216 2/8/2024 217 AD/ SB Control for CDCCL ➢AD/SB evaluation check list was updated to include a clause to check whether the literature under evaluation affects CDCCL or not. ➢Certifying staff / maintenance personnel should assess the affect of the current activity on any of the AWL/CDCCL, and if, it is confirmed that a CDCCL / AWL is directly or indirectly affected, work instructions provided by the AD / SB or task card should be revised / corrected in coordination with Airworthiness Management Division to preclude any chance of CDCCL violation. ➢A data base will be updated to have a record of all the ADs, SBs, and ECO which have an effect on any of the CDCCL requirements. 2/8/2024 218 Scheduled / unscheduled repair schemes control ➢Any scheduled /un-scheduled locally prepared repair scheme should be examined for effect on any of the CDCCL item(s). ➢Same level of understanding is required by shop personnel involved in the servicing / repair / overhaul of Fuel pumps, FQI Tank unit, Fuel Quantity Indicating Computer (FQIC), Fuel Quantity Processor Unit (FQPU), harnesses. 2/8/2024 219 Maintenance Program Control for CDCCL ➢Inspections/ tasks introduced through Locally generated task cards as per requirements of an AD, inspection SB, or any other local operational /maintenance requirement also requires assessment whether it affects the CDCCL or not. ➢Fleet Maintenance program should be scrutinized on a regular basis upon receipt of MPD revision, to sort out the newly introduced tasks for having an impact on the CDCCL. ➢This exercise should be continued in future as well. 2/8/2024 220 MAINTENANCE DATA - MANUAL CONSULTATION ➢Use of updated / latest maintenance data is of utmost importance for maintaining FTS design criteria / CDCCL. ➢Air Transport Association of America (ATA) Chapter 47 has been assigned for FRS / NGS in concerned airplanes Airplane Maintenance Manuals (AMM). ➢CDCCL warning notes have also been introduced in AMM and Components Maintenance Manuals (CMM). ➢All certifying staff / maintenance personnel are required to consult concerned AMM /CMM (as applicable). 2/8/2024 221 CDCCL Limitation AMM 2/8/2024 225 BOEING AMM 2/8/2024 226 Installation of the THS Front Spar Access Panels Electrical Standard Practice Manual Service Information Letter Service Bulletin SFAR 88 request the HYD comp is protected against fuel vapor ignition AD NOTE AD NOTE AD NOTE Work Card Example Consequences on design and maintenance Consequences on design Consequences on maintenance Consequences on maintenance Consequences on maintenance Consequences on maintenance What about the actual change in your professional activity? NGS SYSTEM ON BOARD Which elements to act upon? FTS/CDCCL Fuel replacement? → Improved Fuel Tank Ignition Source Consideration Flammability Reduction Mean (FRM) Flammability Reduction Means (FRM) Action upon oxidants? Inerting The inerting system Schematic diagram Principle OBIGGS OBIGGS NGS on BOEING NGS: Nitrogen Generator System WHY NITROGEN IS PUMPED INTO THE CWT BOEING 737 NGS STORY NITROGEN GENERATION SYSTEM IN B737-800 NGS on BOEING NGS: Nitrogen Generator System BOEING NGS: LEFT AIRCOND PACK BAY BOEING NGS: LEFT AIRCOND PACK BAY INSIDE AIR COND MIX BAY AIR COND MIX BAY RH PACK BAY ACCESS DOOR FWD RH PACK BAY RH WHEEL WELL AFT SIDE RH WHEEL WELL AFT SIDE RH WHEEL WELL AFT SIDE Inerting system AIRBUS A320 Inerting system AIRBUS A320 Inerting system AIRBUS A320 Inerting system AIRBUS A320 Inerting system AIRBUS A320 NEW RISKS Innovations on new aircraft A350 A350 Inerting system on AIRBUS A350 Dual-bonding leads on Carbon Fuel pipes on Airbus A350 Flammability Reduction System Review & Conclusion REGULATORY ACTION/ REQUIREMENTS ➢Special Federal Aviation Regulation 88 (SFAR 88), advising airplane manufacturers to carry out a design review of fuel tank system to avoid entry of any ignition source into the fuel tanks in compliance of FAR 25-901 & 25.981 (a) and (b). ➢Joint Aviation Authorities (JAA) using NT/POL/25/12, JAR 25.901 / 25.1309 & Technical Guidance Leaflet (TGL) 47. 2/8/2024 298 SFAR No. 88--Fuel Tank System Fault Tolerance Evaluation Requirements Applicability ➢ the holders of type certificates, and supplemental type certificates that may affect the airplane fuel tank system, for turbine-powered transport category airplanes, provided the type certificate was issued after January 1, 1958, and the airplane has either a maximum type certificated passenger capacity of 30 or more, or a maximum type certificated payload capacity of 7,500 pounds or more. ➢ This SFAR also applies to applicants for type certificates, amendments to a type certificate, and supplemental type certificates affecting the fuel tank systems for those airplanes identified above, if the application was filed before June 6, 2001, the effective date of this SFAR, and the certificate was not issued before June 6, 2001. 2/8/2024 299 SFAR No. 88--Fuel Tank System Fault Tolerance Evaluation Requirements Compliance (a) Conduct a safety review of the airplane fuel tank system to determine that the design meets the requirements of §§ 25.901 and 25.981(a) and (b). (b) Develop all maintenance and inspection instructions (c) Submit a report for approval to the FAA Airplane Certification Office (ACO) 2/8/2024 300 FAR §25.981 Fuel tank ignition prevention 2/8/2024 a. “No ignition source may be present at each point in the fuel tank or fuel tank system where catastrophic failure could occur due to ignition of fuel or vapors.” b. Critical Design Configuration Control Limitations (CDCCL), inspections, or other procedures must be established, as necessary, to prevent development of ignition sources within the fuel tank system and must be included in the Airworthiness Limitations section of the Instructions for Continued Airworthiness. c. The fuel tank installation must include either: (1) Means to minimize the development of flammable vapors in the fuel tanks (in the context of this rule, “minimize'' means to incorporate practicable design methods to reduce the likelihood of flammable vapors); or (2) Means to mitigate the effects of an ignition of fuel vapors within fuel tanks such that no damage caused by an ignition will prevent continued safe flight and landing.” 301 THE CONCEPT OF IGNITION SOURCE PREVENTION ➢Fuel tank explosions can only occur when an ignition source is in contact with flammable fuel vapor. ➢Fuel vapors become flammable when they are mixed in certain proportions with oxygen, and are under specific temperature and pressure conditions. ➢some fuel tanks have a significantly higher exposure to flammable vapors than other tanks. 2/8/2024 302 THE CONCEPT OF IGNITION SOURCE PREVENTION ➢First Line of Defense to prevent recurrence of such events, Airplane manufacturer’s reviewed the airplane fuel system designs to meet the above requirements. ➢a number of service Bulletins (SBs) /Production Modifications (Production Revision Record: PRR) have been introduced for incorporation on Production and In-Service airplanes, trying to build the airplane fuel system design immune to such occurrences. ➢FAA legislation requires that airplane types that have fuel tanks, which exceed the average flammability exposure level (> 7%), specified in the rule shall be fitted with either a Flammability Reduction System (FRS), or an Ignition Mitigation Means (IMM). 2/8/2024 303 THE CONCEPT OF IGNITION SOURCE PREVENTION ➢EASA has issued a Safety Information Bulletin (SIB 2010-10) which mandates the installation of a FRS on production airplane subject to high flammability exposure and manufactured after 31st December 2011. ➢EASA will publish a Notice of Proposed Amendment (NPA) by mid 2011 to address the in- service airplane retrofit. 2/8/2024 304 A Flammability Reduction System (FRS) ➢FRS is a system that is designed to prevent fuel vapors from being in a flammable condition ➢A practical Flammability Reduction System (FRS) will reduce fuel tank oxygen content to below the level that will support combustion (approach being adopted by Airbus). ➢Boeing has developed Nitrogen Generation System (NGS) to satisfy FRS requirement. 2/8/2024 305 An Ignition Mitigation Means (IMM) Example of Ignition Mitigation Means (IMM) ➢IMM is a system that detects an ignition source and releases a fire suppressant to prevent the development of a fire. ➢Such a technology is used on small military airplane but is not considered sufficiently robust for use in large commercial airplane and as such is not being pursued by Airbus or Boeing. 2/8/2024 306 CHANGES TO “INSTRUCTIONS FOR CONTINUING AIRWORTHINESS” (ICA) ➢Second Line of Defense of the FTS regulations account for this situation and requires updating of Instructions for Continued Airworthiness (ICA) / Airplane Maintenance Program for all the type certificated airplane to avoid any likelihood of compromise / violation of the fuel system design criteria during any scheduled and / or unscheduled maintenance. ➢This requirement ensures proper documentation of any maintenance action performed on the airplane and / or its components for safety, reliability and maintainability. ➢AWL / CDCCL tasks were introduced by airplane manufacturers in Maintenance Planning Documents and incorporate into operator maintenance program. 2/8/2024 307 CHANGES TO “INSTRUCTIONS FOR CONTINUING AIRWORTHINESS” (ICA) ➢Boeing MPD section-9 is related to Airworthiness Limitations (AWL) which describes the Fuel Airworthiness Limitation Items (ALIs) and the associated CDCCL tasks. ➢Airbus / ATR publishes “Airworthiness Limitations” (ALS) section -5 which is related to Fuel Airworthiness Limitations (FAL). These requirements, together with the Life Limits / Monitored Parts, structural Airworthiness Limitation Items (ALI) and systems Certification Maintenance Requirements (CMR) comprise the Airworthiness Limitation Section which satisfies the regulatory requirements. 2/8/2024 308 Airworthiness Limitation Items (ALIs) ➢ALIs identify inspection tasks related to fuel tank ignition source prevention which must be done to maintain the design level of safety for the operational life of the airplane. ➢These ALIs are mandatory and cannot be changed or deleted without the approval of applicable regulatory agency. ➢Strict adherence to methods, techniques and practices as prescribed is required to ensure the ALI is complied with. ➢Any use of methods, techniques or practices not contained in these ALIs must be approved by the applicable regulatory agency. 2/8/2024 309 Critical Design Configuration Control Limitations (CDCCLs) ➢CDCCLs are a means of identifying certain design configuration features intended to preclude a fuel tank ignition source for the operational life of the airplane. ➢CDCCLs are mandatory and cannot be changed or deleted without the approval of the applicable regulatory agency. ➢“A critical fuel tank ignition source prevention feature may exist in the fuel system and its related installation or in systems that, if a failure condition were to develop, could interact with the fuel system in such a way that an unsafe condition would develop without this limitation.” 2/8/2024 310 Critical Design Configuration Control Limitations (CDCCLs) ➢Strict adherence to configuration, methods, techniques, and practices as prescribed is required to ensure compliance with the CDCCL. ➢Any use of parts, ,methods, techniques or practices not contained in the applicable CDCCL must be approved by the FAA office that is responsible for the airplane model Type Certificate, or applicable regulatory agency. 2/8/2024 311 SUMMARY Flammability Reduction System SUMMARY SUMMARY CDCCL ACTIONS SUMMARY CDCCL ACTIONS SUMMARY CDCCL ACTIONS THANK YOU! Any question?
