Exemption No. 10138

UNITED STATES OF AMERICA DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION RENTON, WASHINGTON 98057-3356

In the matter of the petition of

Embraer
for an exemption from § 25.981(a)(3) at Amendment 25-102 of Title 14, Code of Federal Regulations Regulatory Docket No. FAA-2009-1206

GRANT OF EXEMPTION

By letter dated November 17, 2009, Mr. Ricar do Lavell Hollerbach, Embraer, 12227-901, Sao Jose dos Campos, Brazil, petitioned for an exem ption from the fuel-ta nk safety provisions of Title 14, Code of Federal Regulations (14 CFR) 25.981(a)(3), as amended by Amendment 25-102, as it relates to the fuel tank structural lightning protection. If granted, the exemption would permit type certification of Embraer Model EMB-135BJ Enhanced airplanes. The petitioner requests relief from the following regulation: Section 25.981(a)(3) as ame nded by Amendment 25-102: (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 i gnition of fuel or vapors. This must be shown by: (3) 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. The effects of manufacturing va riability, aging, wear, corrosion, and likely damage must be considered. The petitioner supports its request with the following information: This section quotes the relevant information from the petitioner’s request with minor edits for clarification. The complete petition is availabl e at the Department of Transportation’s Federal Docket Management System, on the Internet, at http://www.regulations.gov, in docket No. FAA-2009-1206.For clarification purposes, th is petition is related to EMB-135BJ m odel with the modifications presented in the DC A 0145-000-00020-2008/FAA, herein called EMB-135BJ Enhanced. Embraer is petitioning for an exempti on from 14 CFR 25.981(a)(3) for the EMB-135BJ Enhanced model, which included Amendm ent 25-102 to its certification basis. Section 25.981(a)(3) text: (a) No ignition source may be present at each po int in the fuel tank or fuel tank system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by: (3) Demonstrating that an igni tion source could not result from each single failure, from each single failure in combination with ea ch latent failure cond ition not shown to be extremely remote, and from all combinations of failures not shown to be extremely improbable. The effects of manufacturing va riability, aging, wear, corrosion, and likely damage must be considered. The requirement applied to the structure uses triple redundancy with independent lightning-protective features in the fuel-t ank design. Embraer has “state-of-the-art” design solutions, implemented on the EMB- 135BJ model, which have successfully demonstrated compliance with previous tests/ requirements and further detailed design review concerning direct effects of lightni ng, providing an adequate level of safety. Description of the EMB-135BJ Enhanced desi gn is presented belo w, following Federal Aviation Administration (FAA) Policy Memo ANM-112-08-0 02 instructions. 1. Supportive Information
1.1 Introduction
EMB-135BJ has been certified consideri ng amendment 1 through amendment 84 and several other amendments up to amendmen t 98. On September 18, 2008, a design change was applied (EMB-135BJ Enhanced) and its certification basis was proposed to be updated, where Amendment 25-102 was included. EMB-135BJ had already performed a Design Review to verify the need for modifications to comply with SFAR 88 requirements and the applicability of respective modifications, as required. Consequently, EMB-135BJ Enhanced also considers the requirements above. EMB-135BJ Enhanced is eligible to submit a petition for exemption of §25.981(a)(3) for structural lightning protection ba sed on FAA Policy Memo ANM-112-08-002, considering flammability standards of 7% as per current regulation by the application time.
1.1.1 Overview
EMB-135BJ Enhanced has seven fuel ta nks installed as described below:

 External Wing Fuel Tanks - as part of the wing, there is a wing stub below the fuselage which is not exposed to lightning direct effects;

2 External Underbelly Fuel Tanks - below fuselage, forward of the wing;

 External Ventral Fuel tank - be low fuselage, aft of the wing;

 Internal Rear Fuselage F uel Tanks - inside rear-fuselage section.
The external fuel tanks follow common de sign solutions for structural lightning protection, where “spark-free” design was a dopted. Additionally, electrical bonding and sealing in lightning-imp act areas is employed. The internal rear-fuselage fuel tanks are not exposed to dire ct effects of lightning since they are installed inside the fuselage. There is no fuel tank exposed to lightning zone 1. The wing fuel tank ends before lightning zones 1 and 2 in the wing tip. The wi ng fuel tank is exposed to lightning-impact zone 2 only 0.5m near the region between fuselage and wing root. 1.2 Manufacturing Process, Quality Control and Training
Embraer is certificated to manufacture aircra ft, where manufacturing processes applied to the production of the tanks were established to provide a high level of conformity with the original design. Accuracy, repeatabi lity and traceability of the processes are controlled by a set of operations applied by qua lified personal, according to an internal quality system, which is period ically audited for compliance. For EMB-135BJ Enhanced, Statistical Process Control (SPC) for the drilling process is implemented in the production line. Data collec tion and immediate analysis of the data is performed by qualified production operators in SPC with applicable production activities, providing immediate feedback abou t the process and, if necessa ry, the application of the corrective actions. As with the drilling process, sealing is another important ope ration that is also performed by operators with specif ic qualifications, the process of wh ich meets all controls from the quality-system requirements such as controlled records of type of sealant, curing time, and the date of s ealant application. 1.3 Maintenance Program
1.3.1 Preventive Maintenance Tasks
The instructions for continued airworthine ss have been developed in accordance with AC 121-22 using Air Transport Association's Maintenance Program Development Document MSG-3 Rev. 2002.1. This process, approved by the FAA, ensures 100% accountability for all Maintena nce Significant Items (MSIs) and Structural Significant Items (SSIs). The inspection intervals listed in the Ma intenance Planning Guide (MPG) enable detecting and solving any latent defects. As required by AC 121-22, the second appe ndix of the MPG is the list of the airworthiness limitations. The appropriate insp ections to ensure the reliability of the lightning-protection features that are being developed, and will be included as Critical

3Design Configuration Control L imitations (C DCCLs) in these airworthiness limitations in accordance with § 25.981. 1.3.2 Repairs/Restoration Sealing defects are repaired in accordance with the approved Stru ctural Repair Manual (SRM) - ATA 51 Standard Practices (procedur e 51-20-01-PR). This procedure restores the protections to the same level and with the same products and techniques as the original design specifications. Structural defects are repaired in accordance with the approved SRM or must be reported to Embraer for disposition, as per the SRM Introduction. In addition to the CDCCL for the fuel system, a procedure for inspection of sealing and structural conditions (no corrosi on or spark mark, and integrit y of fasteners and sealing) of the integral tanks (wing and fuselage tanks) is being developed and will be included in the Aircraft Maintenance Manual (AMM) to be performed whenever maintenance in the area of the integral tanks is done. Also, apart from the maintenance tasks, the pi lot’s daily preflight check will contribute to detecting fuel leaks and a ssociated fastener damage. 1.4 Lightning Protection 1.4.1 Design Considerations EMB-135BJ was designed with a “spark-free” vapor-ignition philosophy. The design has demonstrated compliance to lightning prot ection by exhaustive la boratory tests. The adopted solutions have also shown to be appropriate by the field service data of the whole fleet, which accumulated more than 16 millions flight hours. The need for a third leg of protection, necessary to comply with § 25.981(a)(3), would require a great design change of the fuel ta nks and it would represen t a great impact to the EMB-135BJ Enhanced model. In other wo rds, the modification of the fuel tanks would require a design solution still not to tally known, different from those actually existent in the market. These modifications would considerably reduce the performance and efficiency of the aircraft , what would make the developm ent of this aircraft unviable, provided it would not be competitive when comp ared to the existent aircraft in the market. Therefore, complete compliance with § 25.981(a)(3) is impracti cal, considering the present aircraft-construction technology. Conse quently, an exemption is being petitioned based on the assessment in the next sections , through tests and failu re-mode identification in fuel-tank structure, following the recommendations from FAA policy memo ANM 112-08-002.

41.4.2 Potential Failure-Mode Identification An analysis was performed considering struct ural failure m odes that would occur while in production or during operation/maintenance of a fuel tank in the aircraft life cycle. These structural failures would prevent a fuel tank from being protected against lightning, being dependent on the lightning current leve l and the localization in the fuel tank. Identification of these failures is being pe rformed through a Design Review of the fuel tanks. Analysis was performed with the objectiv e to identify structural joints with the following conditions:

 Fault-Tolerant: design solutions that are able to provide 2 independent protective features for structural lightning protection;

 Non-Fault-Tolerant: design solutions that are able to provide a protective feature for structural lightning protection. In both cases, analyses were performed of the failures that would occur and these conditions will be tested or assessed as described in the next sections. 1.4.3 Fault-Tolerant Joint Types For all the joints analyzed, the worst cases shal l be tested for direct effects of lightning. Structural joints that have two lightning protective featur es are presently used in EMB-135BJ Enhanced fuel-tanks skins. 1.4.3.1 Direct Effects of Lightning (DEL)Test
In order to demonstrate that EMB-135BJ Enhanced has two independent protective features, a Direct Effects of Lightning Te st will be performed, where the following conditions will be verified:

 Testing first protective feat ure without sealant applied over fasteners collars and nearby structural joints;

 Testing second protective f eature (sealant) with failure added to the first protective feature.
First Protective Feature: Fast eners and structure skin
Fasteners used on fuel-tank skin have a countersunk head and conductive coating. Drilling of fuel-tank skin is done prior to inst allation of the fasteners. As a consequence, adequate electrical bonding between the fasten er and fuel-tank skin is provided, since no nonconductive coating nor painting is applied during the crimping of the fasteners over the fuel-tank skin.
Second Protective Feature: Sealant Sealants used in fuel tanks are implemented to retain eventual lightning spark inside fuel tank that would outreach the first protective feature. They are applied over fastener collars and around fuel-tank-skin structural joints.

51.4.4 Non-Fault-Tolerant Joint Types Fatigue analysis is being perform ed to id entify the regions that may have fatigue cracking. There are 3 areas of possible fatigue cracking:

 Fuel-tank skin, on a region without fasteners;

 Joint between two fuel-tank skins, with fasteners;

 Ribs, spars, stringers, skin, a nd support joints, with fasteners. Structural design, analysis and fatigue testing have demonstrat ed that fastener failure due to high load tension is not expected du ring the aircraft's operational life cycle. 1.4.4.1 Numerical Probability Assessment Numerical Probability Assessment will be performed considering the failure modes above, concerning the following data:

 Probability of failure per flight hour;

 Determination of ignition thresholds through tests;

 Probability of current at joint exceeding threshold;

 Joint Spark Probability per flight hour;

 Probability of fuel-vapor ignition per flight hour, applying flammability data. All non-fault-tolerant joint types’ probability of occurrences will be ca lculated in order to demonstrate that fuel-vapor i gnition is extremely improbable. The Numerical Probability Assessment will be provided as soon as lightning tests and fatigue analysis are finalized, which is estimated to be the end of January 2010.
2. Issue of Public Interest Requirement § 25.981(a)(3) for structural light ning protection leads to the use of three highly reliable, independent, and redundant protective features to prevent ignition sources. For EMB-135BJ Enhanced, where Amendment 25-102 was included, the modifications proposed for the fuel tanks’ st ructure followed the same design criteria required prior to Amendment 25-102. However, they are not sufficient to comply with all scenarios of § 25.981(a)(3). Compliance demonstration of § 25.981(a)(3) for structural lightning protection would be impractical to be implemented provided it wi ll require considerable design modifications of the fuel tanks and not yet totally k nown, considerably reducing performance and efficiency of the aircraft, with consequent loss of competitiveness when compared to existing aircraft in the market.
EMB-135BJ Enhanced has state-of-the-art de sign solutions implemented on the fuel tanks which comply with § 25.954 and SFAR 88 requirements. Embraer considers that

6the solutions im plemented on EMB-135BJ Enhan ced have an adequate level of safety and considers a grant of exempti on applicable for this aircraft. 3. Effect of the Exemption on Safety EMB-135BJ Enhanced was designed consid ering the following mitigation means:

 Reduction of likelihood of flammable vapors;

 Prevention of ignition sources. Reduction of likelihood of flammable vapors wi ll be complied considering flammability standards of 7%, as per curre nt regulation by the applicati on time for all fuel tanks. Additionally, the fuel tanks were designed to have continuous vent ilation during flight and to be far from aircraft heat sources. Ignition prevention due to lig htning strikes is analyzed through FAA policy memo ANM 112-08-002 and the possible failure modes were defined as Fault-Tolerant and Non-Fault-Tolerant For Fault-Tolerant joint types, it will be demonstrated the independence of the two protective features already cons idered in the design of EMB-135BJ Enhanced fuel tanks. For Non-Fault-Tolerant joint types, numerical probability assessment is being performed to verify probability of fuel-vapor igniti on so that failure is extremely improbable. Embraer verified that manufacturing quality and control is adequately performed and maintenance procedures consider CDCCL fo r fuel-system and fuel-tank structure. Verification of the low level of flammability exposure, and the analysis and tests to be performed for the failure modes identified on fuel-tank structure, will show that EMB135BJ Enhanced has an adequate level of safet y, even with the absen ce of the third leg of protection against lightning. Th erefore, granting of exemp tion for EMB-135BJ Enhanced would be in the public interest. 4. Summary
EMB-135BJ Enhanced has included Amendm ent 25-102 due to a design change, and compliance with § 25.981(a)(3) is considered for the fuel system. However, for structural lightning protection, the compliance w ith § 25.981(a)(3) is not feasible. The following tasks are considered to substantiate the exemption:

 Design Review for the fuel tank structure;

 Identification of failures that co uld cause fuel-vapor ignition;

 Direct Effects of Lightning Tests for Fa ult-Tolerant and N on-Fault-Tolerant structural joint types;

 Numerical Probability Assessment for Non-Fa ult-Tolerant structural joint types;

 Manufacturing and Quality Control Process;

7 Maintenanc e tasks including CDCC L for fuel-tank structure; and

 Embraer participation in th e Society of Automotive Engi neers (SAE) international committee meetings regarding petitions for exemption from § 25.981(a)(3) related to fuel-tank structure.
These tasks will demonstrate that EMB-135BJ Enhanced fuel tanks are assembled with strict control of the production process, wh ich guarantees the co rrect installation of fasteners and application of sealant on the fuel tanks. Additionally, maintenance procedures adequately verify fastener inst allation and sealant app lication over aircraft operational life cycle. Fatigue cracking and fastener fa ilures have periodic interval times to verify any sign of damage during aircraft op erational life cycle. Therefore, Embraer considers EMB-135BJ Enha nced has an adequate level of safety considering the protections of the structure against direct effects of lightning and the benefits of flammability characteristics of the fuel tanks, and an exemption to § 25.981(a)(3) is being petitioned. The following quotes the relevant information fr om the petitioner’s reply by letter, dated May 31, 2010, to the FAA’s request for more informa tion with minor edits for clarification. The petitioner’s complete response is available at the Department of Transportation’s Federal Docket Management System, on the Internet, at ht tp://www.regulations.gov, in docket No. FAA-2009- 1206. FAA Statement/Inquiry 1 The petitioner should show that all practica l measures have been taken to meet the requirements of § 25.981(a)(3) for the fuel-tank structure. For the design features for which an exemption is sought, the petitioner should show what potentially compliant design changes were examined, and what design changes were ruled out based on impracticality. IMPRACTICALITY OF 25.981(A)(3) STRUCTUR AL THIRD PROTECTIVE FEATURE
EMB-135BJ Enhanced model has included F AA Amendment 25-102 to its certification basis as a result of a major change, where an external ventral fuel tank was added to the aircraft. Requirement §25.981(a)(3) for structural lightni ng protection leads to the use of three highly reliable, independent a nd redundant protective features to prevent ignition sources. For EMB-135BJ Enhanced, modifications propose d for the fuel tanks structure followed the same design criteria required prior to Amendment 25-102. However, they are not sufficient to comply with all scenarios of §25.981(a)(3). During design review process, fuel tank structur e has been analyzed in order to determine if it would be possible to incl ude one more protective feature, besides the other existent ones. Below is the list of alternatives s earched for the third protective feature:

 Anti static fuel bladder;

8 Machined s tructural element with insert;

 Protective cover for the structural joint (besides sealant);

 One more skin layer (metal or composites);

 Sealant application over the skin surface; and

 Adhesive bonded structural elements. Incorporation of alternatives above would involve considerable design changes on the whole structure of the fuel tanks. This would affect considerably:

 Fuel volume: lower capacity due to accommodation of the third protective feature;

 Maintenance: increased workload due to more parts (bladder, bonded parts, another skin layer) added inside fuel tanks;

 Repair: in the case of fuel bladder, re moval and installation of a new bladder would be required prior to di spatch of the aircraft; and

 Structural Analysis: novel design. Therefore, addition of a third protective feature to comply with §25.981(a)(3) is impractical since it would demand a new design of the fuel tanks with aircraft lower flight performance and greater maintenan ce and repair workload from the design envisioned for EMB-135BJ Enhanced model, wh at would make the development of this aircraft unviable, provided it would not be competitive when compared to the existent aircraft in the market. For EMB-135BJ Enhanced, compliance demonstration will be based on the following conditions:

 FAA/ANAC/EASA §25.581, §25.899, and §25.954 are already complied through EMB-135BJ certification basis.

 FAA/ANAC §25.981(a)(3) for structural lightning protection: petition for exemption with execution of DEL tests and analysis according to ANM-112-08- 002. Policy Guidance developed by SAE AE-2 and EUROCAE WG -31 lightning committees regarding FAA Policy Memo ANM 112-08-002 wa s used as reference for definition of DEL tests and fault tolerance analysis for compliance of structural lightning protection according to §25.981(a)(3). In the next section, it will be described the process for determ ination of structural joints to be tested and analyzed for fault toleran ce. Lightning tests and analysis results are presented subsequently.
FAILURE CONDITIONS ASSESSMENT For clarification purposes, all external fuel tanks are made of aluminum.

9A list of all structural joints in fuel tanks was generated after design review analysis, covering any type of structural present in the fuel tanks. All parts existent in each structural join t were analyzed and they were reviewed according to their lightning zone (2A or 3). Sealing was analyzed in the structural joints , especially on the fasteners heads, in each fuel tank. Based on the assumptions above, structural jo ints were represented in specimens for lightning tests. Typical failure modes were adde d to the specimens. In order to check if the lightning protective features are indepe ndent, reliable and effective, they were adequately disabled in the specimens and tested for lightning.
TEST RESULTS
Fault Tolerant Features Lightning tests were performed and it was ve rified that access door required to be modified in order to have two lightning fau lt tolerant features. Additional tests were performed and the access door passed with modification to a bonded dome nut. There were two configurations of bonded dome nut that passed the test. The new dome nuts will be incorporated to the production line of EMB-135BJ Enhanced for compliance of this exemption which requires two fault tolerant features.
Non-fault-tolerant Features In this case, analysis was performe d, as described in the next question. FAA Statement/Inquiry 2 Instead of compliance with the requirement s of § 25.981(a)(3), the applicant must show that the design includes at least two independent, effect ive, and reliable lightningprotection features (or sets of features) such that fault tolerance to prevent lightningrelated ignition sources is provided for each area of the structural design proposed to be exempt from the requirements of that regulation. Fault tolerance is not required for any specific design feature if: a. providing fault tolerance is shown to be impractical for that feature, and b. fuel-tank vapor ignition because of t hat feature and all other nonfault tolerant features, when their fuel-tank vapor igniti on event probabilities are summed, is shown to be extremely improbable.
NUMERICAL PROBABILITY ASSESSMENT It was verified, through lightning tests and analysis presente d above that there are two non-fault-tolerant features, as described below:
1. Structural element fatigue cracking
2. Fastener fatigue cracking

10In this case, it is im practical to provide fau lt tolerance of the structural element itself, since fatigue cracking will disable any type of additional protection feature implemented for the structural element. Following Policy Memo ANM 112-08-002 recomme ndations, a probability analysis was performed, as illustrated by the flow chart in figure 1, which is in accordance to Policy Guidance developed by the lightning comm ittees SAE AE-2 and EUROCAE WG-31. The calculation method is based on three main probability parameters, as described below:
1. R L-CRITICAL : Rate of critical lightning attachment. This probability is related to the following parameters:
a. R LIGHTNING : Lightning strike rate
b. F ATTACH : General attachment area factor
c. F SPARK : Spark threshold factor
2. P STRUCT-n : Probability of structural failure
3. P FLAM : Fleet flammability exposure By multiplying the main three parameters, the ignition rate for one failure is obtained. Total Fuel tank ignition rate is the sum of all single failures.

Analysis was performed and below are the results found for each fuel tank:

 Wing Tank Ignition Rate: 8,54 x 10 -11

11 Underbelly Tank Ignition Rate: 9,79 x 10 -10

 Ventral Tank Ignition Rate: 1,55 x 10 -10 The Wing and Ventral fuel tanks provide d probability failures lower than 1x10 -9 , which indicates that fuel vapor ignition would be extrem ely improbable to occur. In the case of Underbelly fuel tank, it was provided a probability failure of 0,98 x 10 -09

, being a marginal value ne xt to the scale of 1x10 -09

. This value is linked to the low quantity of FH accumulated for this fuel tank compared to the other ones. On the other hand, it shall be not ed that all external fuel tanks have adopted the same structural design philosophies. Similarly, lightning protection of the fuel tanks have the same approach, by providing the same type of fault tolerant protect ion features on them. Therefore, the probability failure obtained for the underbelly fuel tank is acceptable, based on the analysis detailed above, and can be considered as extremely improbable, too. FAA Statement/Inquiry 3 The applicant must perform an analysis to show that the design, manufacturing processes, and airworthiness limitations s ection of the instruc tions for continued airworthiness include all practical measures to prevent, and detect and correct, failures of structural lightning protect ion features because of m anufacturing variability, aging, wear, corrosion, and likely damage.” With regard to item 3, above, your petition di scusses manufacturing controls but it does not specifically address inspect ion of non-fault-tolerant de sign features. We request confirmation that any non-fault-toler ant design features will receive 100 percent inspection to validate that the features are present at the time of manufacture. We also request confirmation that the Critical Design Configuration Control Limitations (CDCCLs) discussed in your petition will incl ude periodic, in-service inspection of all ignition-prevention features, as well as non-fault-tolerant features.
MANUFACTURING PROCESS Fuel tank structure assembly is manufact ured based on the following SAE standards:
1. AS9100C “Quality Management Systems – Requirements for Aviation, Space and Defense Organizations”
2. AS9003 “Inspection and Test Quality System”
3. AS9102A “Aerospace First Article Inspection” It will be presented the whole production process of the fuel tanks, in order to comprehend the existent control for mitigation of typical failures modes which would produce quality escapes. Every Fault-Tolerant and Non-fault-tolerant Feature drilling, assembly and sealing is inspected as will be described below.

12Quality Management S ystem Quality Management System covers all stages of development and production, to achieve quality specifications and pr oduct safety, as illustrated in figure 2. The needs and opportunities for improvement and correc tion are flagged by the feedback and independent assessment of compliance with th e procedures and results are verified and guaranteed by the Quality Audit.
All actions occur in an envi ronment created by the quality system and processes related to this system.

Management qualification system keeps the records in the system of the company following process steps, as: es tablish processes, define th e requirements, train those involved. Requirements for Qualification: To be qualified in a given process, employee must meet the requirements for OJT (On the job training) and theoretical requirements. Requirements of Theoretical Knowledge: Carry theoretical training defined for a process. Requirements for Practical Knowledge (OJT):
The coach must record the at tendance requirements for OJT for the operators under their responsibility. The supervisor must verify and record the attendance requirements for qualification of personnel under their responsibility

13In the case of special procedures, the pers onnel m ust be checked and certified by Quality Leadership in the area. At their discretion, the Quality Leadership can apply theoretical examinations, practical examinations or othe r form of verification before certifying an employee. Employees certified in special processes, or critical processes will receive individualized stamps from quality department. Human resources training can be divided in part s as illustrated in figure 3. Each part is associated to a specific type of work and a set of training courses which will guarantee adequate assembly of the fuel tanks.

Control of Records The following records and evidence of qualif ication shall be kept for each qualified employee:

 Name plate and the employee;

 Identification of the process in which the employee is qualified;

 Identification of the specific procedure;

 Number stamp, if applicable;

 Date of qualification and validity;

 Date of commencement and completion of OJT;

 Employee experience in the process on the date of qua lification, including the period of OJT (years and months);

 Identification of the coach responsible for OJT;

14 Identification of the imm ediate superior;

 Identification of quality leadership in the area (only for special cases);

 Records and other evidence requir ed by the special procedure.

 The records and evidence should be kept in the company system. Records are kept to demonstrate compliance with specific requirements and effective operation of the management system applied in the operational units of the manufacturer. Sheet Compliance – FIC It is a printed document, which allows recording of values, signatures and seal impressions, for evidence of production process operations. When all related documentation is closed, it is filed to preserve data traceability.
Rework Order Conformity end of the document is ex ecuted by members of the Product Quality.
Production Process Verification SAE AS9102A is the reference document for initial production of any new product or modification proposed for EMB-135BJ Enhanced. FAI - First Article Inspection Inspection process complete physical and f unctional, independent and documented to verify that prescribed production methods pr oduce an acceptable item, as specified by engineering drawings, planning, purchase order, engineering specifications and/or other relevant documents. FAI is a process that composes actions regarding “Approval of Initial Production Process,” in order to confirm the adequacy of the process to produce conforming items or detect deficiencies to be remedied before the start of serial production. Application to items manufactured at EMBRAER FAI should be applied in 100% of standard it ems manufactured and assembled internally. Reapplication of the FAI for validation of design, pr ocess and tooling changes Reapplication of the FAI should be an alyzed under the following conditions:
1. Modification of the sources of manufacturing processes, inspection methods, location of manufacturing, tooling or ma terial with the po tential to affect assembly, form, function and producibility.
2. Changes in the numerical control program or transition to other media with the potential to affect asse mbly, form or function.
3. Natural occurrence or event caused by hu man interference that may adversely affect the manufacturing process.
4. Stop production for two years or as specified by the customer.

15Control of Production Preparation for drilling (SETUP)
Measurement values of the holes are recorded in a specimen, before the start of drilling, for verification and va lidation of the tool. Items to check in the production instructions
1. Deburr holes after final drilling.
2. Holes for pins, as specific diameter (c hecked at determined intervals during drilling execution), r oughness, and step away from the edge.
3. Installation of the pins, as: correct grasp, settling of the head (head, collar, washer and nut) and protection of the collar.
4. Verify countersink for conventional rivets and pins, as the diameter of the countersunk, depth, radius of agreement (settlement) and finishing.
5. Holes for rivets as to: specific diameter , edge distance, distance between holes and finishing.
6. Rivets, as to: snap rivet head, conforma tion of the head (height x diameter), cracks and marks To avoid misalignment of the holes, during dril ling process a device is used to keep the tool at 90 degrees. Sealing Before sealing, employee makes a visual inspec tion so that installati on is clean and there are no foreign objects in the region. Then, seal ing process is initiated and performed by another employee (sealant specialist). This specialist will perform another visual inspection to ensure that no particle or foreign object remained in the area. Sealant application is verified for:

 Uniformity of the layer (interface)

 Heals

 Bubbles

 Retraction Special qualification is required for sealing. As detailed above in this section, typical modes of failures that could become quality escapes are adequately mitigated. When this type of non conformity is found, corrective actions are generated, as detailed in the next section, which eliminat es the possibility to have latent failures in the fuel tank.

16Correctiv e and Preventive Actions There is a system which implements correc tive and preventive actions, with emphasis on the production process, including at the stage of development in order to eliminate the root causes of nonconformities identified on the product or process, and preventing its recurrence (or occurrence). CAT (Corrective Action Team) Team of corrective and preventive action, unde r the coordination of quality, composed of representatives of different ar eas of the company, responsible for root cause analysis and definition of plans for corrective and prev entive actions relating to the production process. Stages of Process of Preven tive and Corrective Actions Definition Describe the nonconformance, providing in detail the necessary information for the characterization of the problem. Analysis Record and analysis of the data for identif ying the root cause of the problem (Ishikawa, correlation analysis, hypothesis testing, Kepner Tregoe, etc). Highlight the root cause.
Containment and Action Plan
Containment Blocking action of non-compliance to avoid or minimize the impact of a new occurrence and facilitate the co ntinuity of the production process until the completion of corrective action.
Research
Actions that will assist in the identification or confirmation of the root cause of the problem. Plan of Action Actions set for elimination of the root cause of the problem. Similarity Analysis To verify if non-conformity aff ects pieces or similar processes. Verification of effectiveness
Actions of verification of eff ectiveness of problem elimination, or improve of process; with their evidences. In order to guarantee that correction was performed, representative information can be used as evidence, for example: aircraft or sequence of operations observed during a representative period of time.

17Supplier Supplier Development
The m anagement strategy for the developm ent of material and supplier based on the application of different management actions , in type, intensity and frequency, depending on the classification of material and supplier that is established from the criticality of the product versus risk of the supplier. Performance Management and Corrective Action/Preventive of Suppliers
There is a documentation which formalizes and sends corrective or preventive action to non-conformities detected in all phases of the product manufacturing.
Corrective Action: Action to eliminate the cause of non-co mpliance identified. Preventive action: Action to eliminate the cause of a poten tial non-conformity.
Audit
Internal Audit Audit quality is carried out by the Corporat e Quality (Auditing of Quality Management System) and the Product Quality Audit (Quality Auditing Product) as applicable to each Operating Unit and strategically defined by EMBRAER.
The audits of the various methods are conduc ted as appropriate, depending on definitions of strategic implementation of manage ment systems in Operational Units. The audits may be planned and implemented in an integrated ma nner, considering all Management Systems applicable to Operational Units. Audit of Quality System in Supplier There is a systematic, independent and doc umented audit process to obtain objective evaluation of the evidence of the Quality Syst em implemented by the suppliers in relation to the requirements specified in the procedures.
MAINTENANCE Embraer ensures that all practical measures to prevent, detect a nd correct failures of structural lightning protecti on features due to manufactur ing variability, aging, wear, corrosion and possible damage are adopted based on the Structural Inspection Requirements (Section 4) , Corrosion and Pr evention Control Program – CPCP (Section 5) and Zonal Inspection Requirements (Section 6) of the MPG-1483/SMRD-1533, developed under Air Transportation Associ ation’s Maintenance Program Development Document MSG-3 Rev. 2002.1. This process assures 100% accountability for all Structural Significant Items (SSIs). The airc raft maintenance manual presents internal general visual inspections fo r wing tanks, forward tanks, and ventral tank to comply with the aforementioned MPG-1483/SMRD-1533 requirements. Embraer also ensures that all the CDCCLs gene rated during this analysis will be included in the second Appendix of MPG-1483/SMRD- 1533 as an airworthiness limitation as well as in all the procedures related to any appropr iate inspection to assure the reliability of

18the applicable lightning prot ection features, checking any fault-tolerant and non-faulttolerant features. Additionally, a new procedure in the AMM (AMM 51-12-00/601) requiring the inspection of stru ctural elem ents (for loose or missing structural items, nicks, cracks, dents, erosion, corrosion, defo rmation, deteriorated protective treatment, foreign object, and integrity of the sealant) has been developed and will be referred to in the procedures for integral fuel tank access panel removal/installation to be carried out whenever an integral fuel tank access panel is open. This Structur al Lightning Protection inspection must be done in the associated integral fuel tank access panel removed from the internal area. FAA Statement/Inquiry 3 Submit flammability-compliance data showing the flammability to be equivalent to an unheated aluminum wing tank. Flammability exposure values obtained from Monte Carlo’s method for each fuel tank are shown below (based on unheated metallic wing fuel tank):

 Main Fuel Tank 1 = 2.63%

 Main Fuel Tank 2 = 2.62%

 Underbelly Fuel Tank 1 = 1.69%

 Underbelly Fuel Tank 2 = 1.69%

 Ventral Fuel Tank 1 = 1.78%

 Rear Fuselage Fuel Tank 1 = 1.34%

 Rear Fuselage Fuel Tank 2 = 1.34%
These are the values considered for the Nu merical Probability Analysis for non-faulttolerant values. Federal Register publication A summary of this petition was published in the Federal Register on January 20, 2010. The FAA received no comments. The FAA’s analysis In May 2001, the FAA issued the “Transport Airplane Fuel Tank System Design Review, Flammability Reduction, and Maintenance & In spection Requirements” final rule (Docket FAA-1999-6411, effective June 6, 2001) that was adopted as Amendment 25-102. This amendment added specific ignition-prevention requirements and a new flammability-minimization requirement to § 25.981. The amended ignition-prevention requirements in § 25.981(a)(3) require cons ideration of factors such as aging, wear, and maintenance errors as well as the existence of single failures, combinations of failures, and la tent failures that may be the cau se of ignition sources in fuel tanks.

19Section 25.981, as am ended by Amendment 25-102, re quires that airplane designs be protected from the effects of structural li ghtning with features that are failure tolerant. Prior to this amendment, only § 25.954 had been applied to light ning protection of fuel tanks. That provision requires only that the airplane design preven ts ignition of vapors in the tank with no consideration for anticipated design failures, aging, and wear, or maintenance errors. Systems with potentially catastrophic failure m odes would typically meet the requirements of § 25.981(a)(3) by providing at least tr iple redundancy in their protec tive features with periodic inspections, or dual-redundant feat ures with continuous system m onitoring to reduce the latency period. Dual-redundant design schemes could only comply with § 25.981(a)(3) when combined with either regular inspections at very short intervals or a m onitoring device to verify the functionality of the protective fe atures. Inspection of the various design features may be difficult or impossible if the feature is internal to th e fuel tank and part of the wing structure. When § 25.981 was applied to the st ructural lightning aspects of new airplane designs, applicants found it was impractical to meet the standard and incorporate additional pr otective features. We issued two exemptions and developed new polic y. The two exemptions were for the Dassault Falcon 7X, signed on April 20, 2007, and the other was for the Hawker 4000, signed on August 28, 2008. On May 26, 2009, following a public-comment period, we adopted new policy that defined criteria that we would consider regarding granting of exemptions and issuance of special conditions for structural lightning protection. Embr aer provided substantiati on in their exemption request that meets the crit eria of this policy. As it applies to fuel-tank lightni ng protection for basic airframe st ructure (airplane skins, joints, ribs, spars, stringers, and associated fasteners, brackets, and coatings), the petitioner argues that both the addition of a third, independent, ignition-source protective feature, and providing sufficient monitoring to detect latent failures in a dual-protective featur e, are impractical for certain areas of metallic airplane-wing structure. As discussed in the policy memo, the petitioner evaluated possible means of providing additiona l protective features as a condition of this exemption and found it was impractical to inco rporate those features into the EMB-135BJ enhanced. Embraer also identified two features through lightning tests and analysis that are not fault tolerant: structural-element fatigue crackin g and fastener fatigue cracking. Embraer showed the probability of fuel-vapor ignition, due to these non-fault-tolerant features, was extremely improbable, which satisfies the criteria in the policy memo. We agree with the petitioner that compliance w ith subsection (a)(3) woul d require a combination of redundant protective features and a high level of reliabili ty of those features that is excessively expensive to produce and maintain using ava ilable technology. Light ning energy can be transferred to fuel tanks insta lled in wings through the many fasteners and other structural elements. It is impractical to provide either continuous monitoring of the “health” of the protective features for these structures, or to in spect them frequently enough to detect latent failures. These features are typically integral to the fuel-tank structure, or internal to the fuel tanks, requiring access into the tank to verify the in tegrity of the feature. Inspections of airplane structure requiring fuel-tank entry may be sche duled only once or twice during the life of the airplane. As discussed in the preamble to Amendmen t 25-102, conventional, unheated, aluminum wing tanks minimize fuel-tank flammability exposure, as required by § 25.981(c). Even if a laten t failure of a protective feature occurred for such a tank, the risk of lightning-induced fuel-tank

20explosions is relatively low when the tank is fuel ed with low- volatility fuels such as Jet A, as demonstrated by the service experience of thes e tanks. Because of the impracticality of full compliance with § 25.981(a)(3) for lightning prot ection and the reduced flammability exposure of these tanks, we believe granting an exemption is in the public interest if applicants can show that their design provides practic al dual-protective features fo r fuel-tank structural lightning protection that are both independent and robust, and show the probabi lity of fuel-tank ignition to be extremely remote for any non-fault-tolerant features. The FAA considers the petitioner’s request to be in the public interest because the EMB-135BJ Enhanced airplane design provides an acceptable level of safety, and full compliance to § 25.981(a)(3) would require signi ficant modifications to th e fuel-tank design, introduce additional complexity in the manufacturing a nd quality process as well as maintenance procedures, and add significant cost and schedule impact to th e EMB-135BJ Enhanced airplane program. The EMB-135BJ Enhanced airplane type-certification program is near completion. Without this exemption, Embraer would not receive design approval for the aircraft in a timely manner, putting it at an unfair disadvantage with its competitors. This would cause disruption to several major corporations in the US and the worl d that are anticipating the imminent delivery of the EMB-135BJ Enhanced airplane to meet their business needs. These Embraer customers may need to find alternatives fo r their aviation needs if this exemption is not granted. Embraer states in their petition that the results of their flammability analyses show that the fleet average flammability exposure of the fuel tanks is low and complies with § 25.981(c), adding that Embraer’s “‘state-of-the-art’ design so lutions implemented on EMB-135BJ model ... have successfully demonstrated compliance with prev ious tests/requirements and further detailed design review concerning direct effects of lightning, providing an adequate level of safety” per FAA Policy Memo ANM-112-08-002 in structions. Embraer has also conducted risk assessments and has shown the probability of fuel-tank igniti on to be extremely remote for the two non-faulttolerant features of th eir design. The FAA has verified these analyses and agrees with Embraer’s conclusion. In addition to validating independent and eff ective design means of lightning protection for certification on new production airp lanes, § 25.981(b) requires establishing critical designconfiguration-control limitations (CDCCLs), inspections, and othe r procedures to prevent the development of ignition sources within the fuel -tank system as the ai rplanes progress through their service life. These limitations, inspecti ons, and procedures must be included in the Airworthiness Limitations Section of the Instruct ions for Continued Airworthiness as required by § 25.1529. Embraer has identified maintenance-inspection ta sks with appropriate inspection intervals to ensure the needed reliability of structural lightning-protec tion features. These actions should maintain the lightning-protection characteristi cs of the protective features. The timely identification of fuel leaks, indicating a sealing de fect(s), and subsequent timely repair to restore the integrity of the lightning-pr otection feature, are also impo rtant. Embraer has identified maintenance-manual procedures that restore the pr otective features to the same level and with the same products and techniques as the original design specifications. The FAA has considered the information the petitioner provided and has determined that there is sufficient merit to warrant a grant of exemption.

2122 The FAA’s decision In consideration of the foregoing, I find that a grant of exemption is in the public interest. Therefore, pursuant to the au thority contained in 49 U.S.C. §§ 40113 and 44701, delegated to me by the Administrator, Embraer is hereby grante d an exemption from the requirements of 14 CFR 25.981(a)(3) as it relates to fuel-tank st ructural lightning prot ection to the extent necessary to permit type certification of the EMB-135BJ Enhanced airplane.

Issued in Renton, Washington, on September 21, 2010.

/s/
Ali Bahrami Manager, Transport Airplane Directorate Aircraft Certification Service