AC 25-27A

0 U.S. Department of Transportation Federal Aviation Administration Advisory Circular

Subject: Development of Transport Date: 05/04/10 AC No: 25-27A Category Airplane Electrical Wiring Initiated By: ANM-100 Interconnection Systems Instructions for Continued Airworthiness Using and Enhanced Zonal Analysis Procedure

1. Purpose.

a. This advisory circular (AC) describes parts of the compliance process for the “Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety (EAPAS/FTS)” rule. That rule requires design approval holders (DAHs) and applicants to develop instructions for continued airworthiness (ICA) consisting of maintenance and inspection tasks, intervals, and procedures for the representative airplane’s electrical wiring interconnection systems (EWIS) for each affected type design. The DAH must also review any fuel tank system ICA it has developed in compliance with Special Federal Aviation Regulation No. 88 (SFAR 88) in order to ensure compatibility with the EWIS ICA, including minimizing redundant requirements. The DAH must then submit the EWIS ICA to the Federal Aviation Administration (FAA) oversight office for review and approval.

b. This AC provides guidance for developing maintenance and inspection instructions for EWIS using an enhanced zonal analysis procedure (EZAP). For the purposes of this AC, the term “maintenance” encompasses both “maintenance” and “preventive maintenance,” as those terms are defined in Title 14, Code of Federal Regulations (14 CFR) 1.1. For airplane models whose maintenance programs already include a zonal inspection program, the logic described here provides guidance on improving those programs. For airplanes without a zonal inspection program, use of this logic will produce zonal inspections for wiring that can be added to the existing maintenance program. This AC contains information that can be used by operators to improve EWIS maintenance practices. It stresses the importance of inspecting EWIS and promotes a philosophy of “protect and clean as you go” when performing maintenance, repair, or alterations on an airplane.

2. Applicability and Explanation of Requirements.

a. Applicability.

(1) The guidance in this document is directed towards design approval holders (DAHs) (type certificate (TC) and supplemental type certificate (STC) holders) and applicants. This guidance can also be used by air carriers and air operators, maintenance providers, and repair stations.

(2) This AC provides the following information and guidance:

(a) Development of EWIS ICA in accordance with 14 CFR part 25, appendix H, paragraph H25.5(a)(1) as required by:

1 Section 25.1729 (paragraph H25.5(a)(1) fulfills part of the requirements of § 25.1729).

2 Section 26.11(b) and (c).

Note: This AC only contains guidance for the requirements of paragraphs H25.5(a)(1) and (b). AC 25.1701-1, Certification of Electrical Wiring Interconnection Systems on Transport Category Airplanes, contains guidance for paragraph H25.4(a)(3) (Airworthiness Limitations), and the remaining requirements of section H25.5:

• Paragraph H25.5(a)(2) (standard wiring practices manual),

• Paragraph H25.5(a)(3) (EWIS separation),

• Paragraph H25.5(a)(4) (EWIS identification), and

• Paragraph H25.5(a)(5) (electrical load analysis).

(b) Development of the EWIS ICA source document in accordance with part 25, appendix H, paragraph H25.5(b) as required by:

1 Section 25.1729.

2 Section 26.11(b) and (c).

(c) Explanation of who is required to comply with § 26.11.

(d) Explanation of the § 26.11(e)(4) requirement to make the design approval holder EWIS ICA available to affected persons.

(e) Information on when air carriers and air operators must obtain FAA oversight office approval for changes to EWIS ICA already incorporated into their maintenance program.

Note: Guidance for air carriers and air operators on how to make changes to the FAA-approved EWIS ICA will be contained in AC 120-99, Incorporation of Electrical Wiring Interconnection System (EWIS) Instructions for Continued Airworthiness into an Operator’s Maintenance Program.

(f) EWIS maintenance practices that can be helpful when identifying and developing EWIS maintenance tasks using an EZAP.

(3) The material in this AC is neither mandatory nor regulatory in nature and does not constitute a regulation. It describes acceptable means, but not the only means, for showing compliance with the applicable regulations. We will consider other methods of showing compliance that an applicant may elect to present. While these guidelines are not mandatory, they are derived from extensive FAA and industry experience in determining compliance with the relevant regulations. If, however, we become aware of circumstances that convince us that following this AC would not result in compliance with the applicable regulations, we will not be bound by the terms of this AC, and we may require additional substantiation or design changes as a basis for finding compliance.

(4) The material in this AC does not change or create any additional regulatory requirements, nor does it authorize changes in, or permit deviations, from existing regulatory requirements.

(5) Except in the explanations of what the regulations require, terms such as “shall” or “must” are used in this AC only in the sense of ensuring applicability of this particular method of compliance when the acceptable method of compliance described here is used.

b. Differing Requirements of §§ 25.1729 and 26.11. The requirements to develop EWIS ICA vary depending on whether the applicant is complying with part 25, subpart H, § 25.1729, or with part 26, subpart B, § 26.11.

(1) Airplane models with § 25.1729 in their type certification basis.

(a) For TCs, amended TCs, and STCs with § 25.1729 in their certification basis, applicants must comply with the requirements of part 25, appendix H, paragraph H25.4(a)(3) and paragraphs H25.5(a) and (b). These rules mandate that the applicant provide, as part of the ICA:

1 Identification of any EWIS mandatory replacement times in the Airworthiness Limitations section of the ICA (paragraph H25.4(a)(3)).

2 EWIS maintenance and inspection requirements developed with an EZAP (paragraph H25.5(a)(1)).

3 EWIS maintenance practices in a standard format (paragraph H25.5(a)(2)).

4 EWIS separation requirements as determined under § 25.1707 (paragraph H25.5(a)(3)).

5 EWIS identification methods and requirements for identifying any changes to EWIS under § 25.1711 (paragraph H25.5(a)(4)).

6 Electrical load data and instructions for updating that data (paragraph H25.5(a)(5)).

7 A document that contains the EWIS maintenance inspection requirements or identifies their location in other ICA documents (paragraph H25.5(b)). This section also requires that the document be in a form appropriate for the information to be presented, and that the EWIS ICA be easily recognizable as such.

Note: The document required by paragraph H25.5(b) is commonly referred to as the source document. This document is considered to be part of the ICA required by section H25.5.

(b) Section 25.1729 applies to all transport category airplanes regardless of passenger- or cargo-carrying capacity.

(c) Guidance for § 25.1729 and, as noted earlier, appendix H, paragraph H25.4(a)(3) and paragraphs H25.5(a)(2) through (a)(5) is located in AC 25.1701-1, Certification of Electrical Wiring Interconnection Systems on Transport Category Airplanes.

(d) The EWIS ICA for airplane models with § 25.1729 in their type certification basis must be approved by the FAA aircraft certification office (ACO) or office of the Transport Airplane Directorate. Please note that this differs from the ICA requirements contained in § 25.1529, which requires that ICA be prepared that are acceptable to the Administrator.

(2) Airplane models required to comply with part 26, subpart B.

(a) For airplane models that must comply with part 26, the requirement for preparing EWIS ICA is § 26.11(b) or (c), depending on whether the DAH holds or is applying for a type certificate (§ 26.11(b)) or an amended or supplemental type certificate (§ 26.11(c)).

Section 26.11(b) and (c) states that EWIS ICA must be prepared in accordance with paragraphs H25.5(a)(1) and (b). Therefore, DAHs complying with § 26.11 must produce EWIS ICA developed with an EZAP (paragraph H25.5(a)(1)), and the ICA must be in an appropriate form and easily recognizable as EWIS ICA (paragraph H25.5(b)). The DAHs must make the ICA available to affected persons (operators and others required to comply with requirements of § 26.11, § 25.1729, § 121.1111, or § 129.111). The EWIS ICA for airplane models required to comply with part 26, subpart B, must be approved by the FAA oversight office. The FAA oversight office is defined in § 26.3 as “the aircraft certification office or office of the Transport Airplane Directorate with oversight responsibility for the relevant type certificate, supplemental type certificate, or manufacturer, as determined by the Administrator.”

(b) Section 26.11 applies to transport category, turbine-powered airplanes with a type certificate issued after January 1, 1958, that, as a result of the original certification or a later increase in capacity, have:

• A maximum type-certificated passenger capacity of 30 or more, or 4

• A maximum payload capacity of 7,500 pounds or more.

(3) Requirements for Applicants for STCs and amendments to TCs—§ 26.11(c).

Section 26.11(c) requires that applicants for STCs or amendments to type certificates evaluate whether the design change for which approval is sought necessitates a revision to the EWIS ICA that have been previously developed and approved in compliance with § 26.11(b). Guidance for how an applicant can make this evaluation is contained in appendix B of this AC.

c. Representative Airplane and SFAR 88 Compatibility Requirements of § 26.11(b).

(1) Representative airplane. Section 26.11(b) requires that EWIS ICA be developed for the “representative airplane.” The representative airplane is the configuration of each series airplane model that incorporates all variations of EWIS used in production on that series airplane, and all TC-holder-designed modifications mandated by airworthiness directives (ADs) as of the effective date of § 26.11(b). For example, a particular airplane model may be offered in both passenger and cargo versions. For that airplane model, the resultant EWIS ICA must account for any differences between the two versions. Another example would be the situation where the airplane manufacturer offered various interior configurations of a passenger model.

The placement of galleys, lavatories, seats, and other interior furnishings might impact the type and frequency of inspections identified by the EZAP analysis. So the resultant EWIS ICA must reflect any such differences. Also, if any changes mandated by ADs have been incorporated, and those changes impact the EWIS ICA, then the EWIS ICA produced to comply with § 26.11(b) must reflect those changes.

(2) EWIS ICA compatibility with fuel tank system ICA. Section 26.11 requires a review of any fuel tank system ICA developed to comply with SFAR 88. This is to ensure compatibility with the EZAP-generated EWIS ICA and to minimize duplication of requirements between them. It is likely that some of the EWIS on an airplane will be part of the airplane’s fuel tank system. In that case, the requirements for their maintenance and inspection might be more specific than those for EWIS in general and might contain additional requirements. For compatibility, it is important that the maintenance and inspections for these EWIS be carefully reviewed. If there are inspection or maintenance requirements for EWIS and for the fuel tank system within the same zone, there should be an effort to align the task interval. The two ICAs should be reviewed to ensure that any maintenance tasks for EWIS do not compromise fuel tank system EWIS requirements, such as separation or configuration specifications. In addition, design holders’ existing documents containing EWIS and fuel tank system ICA should be reviewed to either remove or cross-reference redundant information.

d. EWIS ICA Identification Requirements. Part 25, appendix H, paragraph H25.5(b) requires that EZAP-derived EWIS ICA be easily recognizable as such, so there is traceability during future changes to maintenance programs that contain these EWIS ICA. This is intended to prevent inadvertent deletion, changes to the type of task, or escalation of EZAP-derived EWIS ICA without proper consideration of the reason for the task and its interval. Following approval of the EWIS ICA by the FAA oversight office, ACO, or office of the Transport Airplane Directorate, an operator may propose changes to maintenance or inspection program tasks that were based on the approved EWIS and fuel tank ICA. AC 120-99, Incorporation of Electrical Wiring Interconnection System (EWIS) Instructions for Continued Airworthiness into an 5

Operator’s Maintenance Program, will contain guidance related to making changes to the approved-ICA-based maintenance and inspection program tasks.

e. Requirements of §§ 121.1111 and 129.111. The EAPAS/FTS rule also requires part 121 certificate holders and part 129 air carriers operating U.S.-registered airplanes to incorporate into their maintenance program tasks based on FAA-approved EWIS ICA.

AC 120-99, Incorporation of Electrical Wiring Interconnection System (EWIS) Instructions for Continued Airworthiness into an Operator’s Maintenance Program, will contain guidance for these regulations.

f. Explanation of Maximum Payload Capacity. For purposes of the requirements in § 26.11, payload capacity is defined by § 119.3. The current text of § 119.3 is found in appendix E of this AC.

3. How this Information was Derived. The guidance in this AC is based on recommendations given to us by the Aging Transport Systems Rulemaking Advisory Committee (ATSRAC). It is drawn from maintenance, inspection, and alteration best practices identified through extensive research by ATSRAC and Federal government working groups.

4. Objective.

a. The objective of this AC is to improve maintenance and inspection programs for all EWIS (as defined by § 25.1701) installed on transport category airplanes. Applying this information will improve the likelihood that EWIS degradation from many causes, including environmental, maintenance-related, and age-related problems, will be identified and corrected.

In addition, this information has been reviewed to ensure that maintenance actions, such as inspection, repair, overhaul, replacement of parts, and preservation, do not (1) cause a loss of EWIS function, (2) cause an increase in the potential for smoke and fire in the airplane, and

(3) inhibit the safe operation of the airplane. This objective is met through the adoption of the following:

(1) Enhanced zonal analysis procedure (EZAP). The EZAP will allow the user to determine the appropriate general or detailed inspections and any cleaning tasks (also referred to as restoration tasks by some manufacturers) needed to minimize the presence of combustible material. An EZAP can be used to develop new wiring cleaning and inspection tasks for both zonal and non-zonal inspection programs. Using this procedure to develop a maintenance program will help ensure that proper attention is given to wiring installations during maintenance. The EZAP provides a logical procedure for selecting inspections (either general or detailed) and other tasks to minimize combustibles. Examples could be cleaning (or restoration) procedures or the changing of an air filter. For an airplane without a zonal inspection program, an EZAP will identify new wiring inspection tasks. Appendix A of this AC provides step-by-step details of the EZAP process.

(2) Guidance for a general visual inspection (GVI). This AC clarifies the definition of a general visual inspection and provides guidance on what is expected from such an inspection, whether performed as a stand-alone GVI or as part of a zonal inspection.

(3) Protections and cautions. This AC provides guidance for developing actions and cautionary statements to be added to maintenance instructions for the protection of wire and other EWIS components. Maintenance personnel will use these enhanced procedures to minimize contamination and accidental damage to EWIS while working on an airplane.

(4) “Protect and clean as you go” philosophy. This philosophy is applied to airplane EWIS through inclusion in operators’ maintenance and training programs. This philosophy stresses the importance of protective measures when working on or around wire bundles, connectors, and other EWIS components. It stresses how important it is to protect EWIS during structural repairs, STC installations, or other alterations by making sure that metal shavings, debris, and contamination resulting from such work are removed. The “protect and clean as you go” philosophy is translated into specifics by the protection and caution recommendations described in section 15 of this AC. More information is contained in section 13 of this AC, Causes of Wire and Other EWIS Component Degradation.

(5) Consolidation with fuel tank requirements. The FAA has developed an extensive program to address safety problems associated with fuel tanks. Fuel tank systems contain EWIS that may be routed independently or may be integrated with other airplane systems’ EWIS. One part of the Fuel Tank Safety Rule, SFAR 88, requires development of maintenance and inspection instructions to ensure the safety of the fuel tank system. Other sections of the Fuel Tank Safety Rule require operators to include fuel tank safety maintenance and inspection instructions in their maintenance or inspection programs. An objective of this AC is to ensure that fuel tank system ICA developed to comply with SFAR 88 are compatible with the EWIS ICA, including minimizing redundant requirements. See section 2 of this AC for details.

b. To fully realize the objectives of this AC, type certificate holders, STC holders, air carriers, air operators, maintenance providers, and repair stations will need to redefine their current approach to maintaining and altering airplane wiring and systems. This redefinition must reach both overall philosophy and specific maintenance tasks. This may require more than simply updating maintenance manuals and work cards and improving training. Maintenance personnel need to be aware that airplane EWIS must be maintained in an airworthy condition.

They also need to recognize that a visual inspection of EWIS has inherent limitations. Small defects such as breached or cracked insulation, especially in small-gage wire, may not always be apparent. Therefore, effective EWIS maintenance combines good visual inspection techniques with improved wiring maintenance practices and training.

c. General Compliance Information. Sections 5 through 12 of this AC provide general information regarding the performance of the EZAP. The EZAP process is described in detail in appendix A and appendix B of this AC.

d. EWIS Degradation and Maintenance Information. Sections 13 through 15 of this AC contain general information on (1) causes of wire and other EWIS component degradation,

(2) EWIS maintenance guidance, including the levels of inspection applicable to EWIS maintenance, and (3) protection and caution recommendations. The information in these sections can be used by manufacturers in developing EWIS maintenance guidance and by operators to improve EWIS maintenance practices.

5. Enhanced Zonal Analysis Procedure (EZAP)—General Guidance.

a. The EZAP described in this AC was developed to identify tasks to (1) minimize accumulation of combustible materials, (2) detect EWIS component defects, and (3) detect EWIS installation discrepancies that may not be reliably detected by inspections contained in existing maintenance programs. An EZAP logic diagram and an accompanying step-by-step explanation are contained in appendix A of this AC. The EZAP process outlined in appendix A is to be used by type certificate holders. It is also to be used by modifiers such as STC holders/applicants to determine if the design change requires new EWIS ICA, or revisions to existing EWIS ICA. If the STC applicant/holder does not have access to the data required to perform the EZAP outlined in appendix A, then the process outlined in appendix B of this AC may be used.

b. An EZAP will result in safety improvements for airplanes operated with a maintenance or inspection program that includes a zonal inspection program (ZIP). It is unlikely that ZIPs developed in the past considered wire or other EWIS components, except for the most obvious damage that could be detected by a GVI.

c. For airplane models without a ZIP, the EZAP logic is likely to identify a large number of EWIS-related tasks that will need to be consolidated into the existing systems maintenance or inspection program. DAHs who have airplane models without a ZIP might find it worthwhile to develop a ZIP in accordance with an industry-accepted method, such as Maintenance Steering Group 3 (MSG-3), in conjunction with an EZAP.

d. When performing the EZAP, evaluate items such as plumbing, ducting, control cables, and other system installations located in the zone for possible contributions to wiring or other EWIS component degradation or failures. The results of the analysis will indicate whether a restoration task, a zonal GVI, a stand-alone GVI, or a detailed inspection (DET) is required to inspect the EWIS in the zone. The way to determine the best type of inspection is graphically represented in figure 2, step 8, of appendix A of this AC. The type of inspection is determined by completing EZAP Worksheet 3A or EZAP Worksheet 3B of appendix A of this AC. EZAP Worksheet 3A is used for airplanes with a ZIP. EZAP Worksheet 3B is used for airplanes without a ZIP.

e. New tasks identified by the EZAP logic should be compared against existing tasks in the maintenance program to ensure that they are compatible with each other. Also, existing maintenance task type and frequency should not affect the outcome of the EZAP analysis. The analysis for a particular zone should be completed to identify appropriate EWIS tasks and their frequency. After the analysis is complete, these new EWIS tasks should be compared to existing maintenance program tasks to assess where the new tasks and the existing maintenance program tasks can be logically combined. The EZAP analysis should not be adjusted in order to make the tasks and intervals fit the existing maintenance program just for the sake of aligning tasks. Refer to the description in figure 1, step 9, of appendix A of this AC for a detailed discussion on task consolidation and alignment.

f. Operators may want to use the EZAP logic to identify additional inspection and cleaning tasks for any design changes on their airplanes for which EZAP ICA are not available. EWIS ICA developed by a DAH might not have taken into account modifications made to the airplane 8

by someone other than the DAH who developed the EWIS ICA. Also, when an STC is no longer supported by the STC holder, operators may want to perform an EZAP on the zone(s) affected by the modification.

6. EWIS ICA Developed Using an EZAP.

a. An EWIS ICA task is either an inspection task or a restoration task. The inspection task can be a zonal general visual inspection (GVI), stand-alone GVI, detailed inspection (DET), or a combination of these. A restoration task is usually a cleaning task, but it can also be a task such as replacing an air filter in order to reduce the likelihood of contamination build-up within a zone. EWIS ICA are comprised of all the data required to perform these inspection or restoration tasks. The EWIS ICA can be, and almost always are, comprised of several different data components. It is all of these data components put together that define any particular EWIS ICA. The data components of EWIS ICA can be, and often are, located in multiple documents produced by the applicant or DAH.

b. As an example, EWIS ICA data components can be located in a Maintenance Review Board Report (MRBR), a maintenance planning document (MPD), a maintenance implementation document (MID), an airplane maintenance manual (AMM), a standard wiring practices manual/electrical standards practices manual (SWPM/ESPM), or a stand-alone ICA document produced by a DAH or STC applicant. These data components are items such as:

• Task reference number(s).

• Task type (for example, DET, stand-alone GVI).

• Task interval.

• Task description (for example, perform a DET inspection of the power feeders and connected EWIS components).

• Task procedure (in other words, instructions on how to perform the actual task(s)).

Note: The task procedure should describe how to accomplish the maintenance task. For example, if the task description states to perform a stand-alone GVI of the EWIS in the zone, then the procedure should instruct the maintenance technician to inspect the EWIS within the zone. In the past, some task procedures have instructed the technician to merely inspect the “wires” or “wiring” in the zone.

Such a procedure would not be acceptable since wire is only one component of an EWIS. An EWIS includes many components such as clamps, connectors, bundle ties, and stand-offs as defined by § 25.1701. However, in certain cases it may be acceptable for the inspection task to specify a particular EWIS component, such as a wire bundle or high current carrying cable, as being the focus of a specific inspection. For example, service history may show that on a particular airplane model, the power feeders in a specific zone should be the focus of an inspection.

Therefore, specifying to perform a DET or stand-alone GVI of the power feeders 9

and their connected EWIS, instead of a DET or stand-alone GVI of the EWIS in the zone, would be more effective in aiding the maintenance technician to detect possible defects in the power feeder rather than instructing them to inspect all the EWIS within the zone. Such an approach should be considered on a case-by-case basis.

• Task applicability (in other words, model, engine type).

• Airplane zone identification.

Note: According to Air Transport Association (ATA) iSpec 2200, Information Standards for Aviation Maintenance, zones are identified by the airplane manufacturer “to facilitate maintenance, planning, preparation of job instructions, location of work areas and components, and a common basis for various maintenance tasks.” ATA iSpec 2200 contains guidelines for determining airplane zones and their numbering. The EZAP process uses these manufacturer-identified zones. The zones are not created uniquely for EZAP.

• Access instructions.

• Supporting procedures as necessary.

c. Both airplane manufacturers and STC holders/applicants produce EWIS ICA but the process they use is different, and each of these DAHs produce the EWIS ICA in different forms.

It is not possible to provide a one-size-fits-all answer for what comprises EWIS ICA. The DAH must identify all of the components comprising the EWIS ICA and identify all of these components in a single document. This single document has become known as the source document. The regulatory requirement for the source document is contained in part 25, appendix H, paragraph H25.5(b) and is discussed in section 7 of this AC.

7. EWIS ICA Source Document as Required Part 25, Appendix H, Paragraph H25.5(b).

a. Paragraph H25.5(b) imposes some specific requirements for documentation and identification of EWIS ICA. It requires that the EWIS ICA developed in accordance with paragraph H25.5(a)(1) must be in the form of a document appropriate for the information to be provided, and that they must be easily recognizable as EWIS ICA. This document must either contain the required EWIS ICA, or specifically reference other documents that contain this information. The document required by paragraph H25.5(b) is referred to as the source document (SD). The entire EWIS ICA must be contained or referenced in the SD. However, paragraph H25.5(b) does not prescribe a specific data form for either the EWIS ICA or the SD (if they are not one and the same). The form the EWIS ICA data takes, and the form of the SD, is at the discretion of the DAH or applicant, as long as it meets the requirements of paragraph H25.5(b) and the data it contains (or references) meets the requirements of paragraph H25.5(a)(1). Some airplane manufacturers plan to use existing documents as their SD.

This could be an MRBR, MPD, MID, or some other document. Others are planning to develop new forms of documentation to specifically address the new EWIS ICA SD requirement.

Whatever form the DAH uses to document the EWIS ICA, the SD must clearly identify the data that comprise the EWIS ICA or contain the actual data in order to be in compliance with paragraph H25.5(b).

(1) As described above, paragraph H25.5(b) requires that each EWIS ICA be easily recognizable as EWIS ICA. This means that the EWIS ICA will need to be uniquely identified as such. As an example, some DAHs place “(EZAP)” or “(EWIS)” after each task description to signify that the task is a part of the EWIS ICA. Keep in mind that the purpose of this requirement is to enable easy identification of ICA tasks after they have been incorporated into an operator’s maintenance program. The requirement is meant to ensure traceability. The identification requirement is not for the benefit of the technician who performs the actual maintenance task, but rather for the people who must keep track of the EWIS ICA, such as personnel at an operator or maintenance facility who track maintenance tasks, or an FAA principal inspector.

(2) There are some unique requirements regarding operator-requested revisions to approved EWIS ICA that necessitate they be easily identifiable. Refer to section 12 of this AC for information regarding operator-requested revisions to EWIS ICA.

b. Future Revisions to the FAA-Approved Source Document (SD). After initial approval of the source document, a DAH will likely need to revise the document at some point in order to account for any new or revised EWIS inspection or restoration procedures developed due to production changes or design changes mandated by ADs. Revisions to EWIS ICA such as task deletion, addition, or interval escalation could also occur due to a request by the Industry Steering Committee (ISC) and can be addressed by a specific airplane model’s Zonal Working Group. Any agreed to revisions would be reflected in an update to the MRBR. Proposed revisions to the SD should be submitted to the FAA oversight office, ACO, or office of the Transport Airplane Directorate, as applicable, for review and approval. Upon approval, the FAA oversight office will issue a formal FAA-letter approving the new SD revision. A DAH can then use that approval letter as proof that the EWIS ICA contained in, or referenced by, the SD has been FAA approved. The SD should be revised and submitted for FAA approval when an existing EWIS inspection or restoration task type or task interval is proposed, as well as any proposed task deletions. The revised SD should also be submitted for review and approval if any of the referenced procedures, such as an AMM procedure or procedures referenced within the AMM procedure, is revised such that that any references to that procedure by the SD would no longer be valid. An example of this would be a change to the AMM procedure number or title of the procedure.

8. EWIS ICA Developed by Type Certificate Holders or Applicants. For EWIS ICA data1 identified in the MRBR, MPD, MID, or other type of SD, the items listed below are considered to constitute EWIS ICA. The FAA oversight office must review this material for its 1 The MRBR, MPD, or other document used as the SD may reference the information comprising the actual EWIS ICA. The airplane manufacturer or operators would use this referenced information to develop the task cards (sometimes referred to as job cards) or other documents that are used by maintenance technicians.

acceptability before issuing an approval. The items listed below are also the data that airplane manufacturers and/or operators (or other FAA-approved maintenance providers) will use to develop the task, or job, cards used by the maintenance technician to perform the EWIS inspection or restoration tasks.

a. Controlling reference numbers for the individual EWIS ICA tasks as listed in the MRBR, MPD, MID, or other SD. These reference numbers can be referred to as MRBR reference number, Maintenance Manual (MM)/MPD reference number, Maintenance Significant Items (MSI) reference number, task number, and so forth. The nomenclature and the documents called out by the reference numbers can vary among DAHs. Also, tasks may have been given more than one number by the manufacturer to identify them as parts of different documents. So one task, for example, may have an MPD reference number as well as an MRBR reference number.

If more than one number identifies any single EWIS task, then each of those numbers must be considered part of the EWIS ICA. All numbers considered necessary to fully identify and track the EWIS ICA should be considered part of the ICA.

b. Type of task (for example, restoration/cleaning, stand-alone GVI, zonal GVI, and DET as identified in the SD).

c. Task interval (in other words, how often the maintenance task must be accomplished— for example, every 16,000 flight cycles or 3,000 days).

d. Applicability (for example, 767-200, A340, EMB-145) as identified in the SD. Some models within the same family of airplanes may have differing maintenance requirements based on available options (for example, freighter versus passenger version, engine types).

e. Airplane zone identification for airplanes with a zonal program (for example, Zone 201).

f. Task description as given in the SD (for example, Inspect (General Visual) all exposed EWIS in the wheel well. NOTE: Gear extended, doors in open position.)

g. Task procedure(s). These are the actual instruction(s) on how to perform the zonal GVI, stand-alone GVI, DET, and restoration/cleaning tasks that support the task description listed in the SD.

h. Supporting task procedure(s), if any, necessary to perform the task procedure in any other document referenced by the task procedure.

i. Instructions for protections and caution information that will minimize contamination and accidental damage to EWIS. (This can appear in different places, such as in the AMM or in the SWPM/ESPM.) If contained in the SWPM or ESPM (or other similar document), this information will be contained in chapter 20. Sometimes this information is repeated in the standard practices chapter (chapter 20) of the AMM. In any case, it is general caution and protection information, and we do not expect that unique procedures will be developed for individual EWIS ICA for a particular airplane model or even models produced by the same manufacturer. Any protection and caution information specific to EWIS ICA must be referenced in the SD.