age or total flight hours or total flight cycles. In these situations, guidance for developing and implementing DT Data for existing and new repairs is provided in Appendix 7 of this AC.
222. FAA Oversight Office Approval. The FAA Oversight Office responsible for the affected airplane’s TC or STC will approve the TC or STC Holder submissions whether submitted as separate documents or consolidated in a Compliance Document. This approval process also includes any documents referenced from a Compliance Document. Any subsequent revisions to the submissions, either separate documents or a Compliance Document, or to DTIs for repairs must be submitted to the FAA Oversight Office for review and approval. The DT Data submitted by TC or STC Holders may be approved by a FAA Designee, as coordinated with and authorized by the FAA Oversight Office.
223. thru 299. [RESERVED].
CHAPTER 3. TC AND STC HOLDER TASKS FOR ALTERATIONS AND REPAIRS
TO ALTERATIONS
300. General Information About This Chapter. This chapter provides guidance to TC and STC Holders for developing a list of fatigue critical alteration structure (FCAS) and DT Data for alterations that affect fatigue critical baseline structure (FCBS). This information will enable operators to comply with §§ 121.1109(c)(2) and 129.109(b)(2) with respect to alterations and repairs to alterations. The final product of this guidance is a document containing the FCAS list and DTIs. This document is called the TC or STC Holder Compliance Document, and upon approval by the FAA Oversight Office, will constitute compliance with § 26.45 or § 26.47. The guidance in this chapter applies to new and existing alterations installed on the baseline structure of the airplane. TC and STC Holders must (per §§ 26.45 and 26.47) make available to operators DTIs for their alterations that affect FCBS and for repairs they developed that affect any FCAS.
a. There are three categories of alterations that may be installed on a transport category airplane, all three categories may require the development of DT Data:
(1) STC Holder alterations – normally developed by persons other than the TC Holder.
STCs are approved by the FAA Oversight Office under Subpart E of 14 CFR part 21.
(2) TC Holder alterations – are developed by the TC Holder, either through an amended type certificate approved by the FAA under Subpart I of 14 CFR part 21, or through FAA-approved service documents such as SBs.
(3) Individual alterations – alterations developed by and for an operator that are approved through an individual FAA Form 337, Major Repair and Alteration, or other means acceptable to the FAA Administrator.
b. The DT Data will be applicable to a specific alteration (see Appendix 9 of this AC) developed by the TC or STC Holder and should provide the data necessary for developing, in part, an operator’s implementation plan (OIP). In developing the DT Data, the TC and STC Holders should coordinate closely with the affected operators.
c. For alterations that are not developed by a TC or STC Holder, the operator is responsible for determining whether the alteration falls into any of the categories listed in Appendix 9 of this AC. These alterations would typically be identified during the operator records review or in the airplane repair survey (see paragraph 218 of this AC). The operator is responsible for developing or obtaining DTI for these alterations. Chapter 4 of this AC addresses the operator tasks for developing an OIP and developing or obtaining DTIs.
301. Contents of Compliance Document. The Compliance Document developed by the TC or STC Holder will be used by operators to develop their OIP. The TC and STC Holders should use the guidance in this paragraph for developing and making available compliance documentation. If the TC or STC Holder already has FAA-approved DT Data for the required § 25.571 amendment level, the TC or STC Holder should include in its Compliance Documents the status of the alteration with respect to damage tolerance. In order for the OIP to fulfill the requirement for a means to address adverse effects of alterations, and of repairs on FCAS, the following should be included in the Compliance Document for each alteration that affects FCBS.
a. “Airplane Applicability” that contains specific airplane model, series, airplane serial number, and the certification amendment level of the alteration.
b. “Affected Alterations” that contains the following:
(1) A list of alterations that affect FCBS, and
(2) A list of alterations that have FCAS.
c. DTIs for:
(1) Alterations developed by the TC or STC Holder that affect FCBS.
(2) Repairs developed by the TC or STC Holder that affect FCAS.
NOTE: If the results of the DTE determine that supplemental inspections are not required, the DTI documentation should contain a statement to that effect.
d. A description of the process used to document and make available to operators new DTIs required for existing and future alterations and repairs to alterations.
Figure 2, below, shows the process for producing a Compliance Document for repairs that affect FCBS.
TC/STC Holder Tasks for Alterations
ACO Operator TCH: 90 days from eff. date of rule STCH: 180 days June 30, 2009
26.45(c)
26.47(c)
26.45(d)
26.47(d) § 26.49
• Review repair data and identify repairs that affect FCAS
• Develop DT data for repairs to alterations Identify Airplane Info
26.45(b)
26.47(b)
26.45(b)
26.47(b)
• Identify alterations that affect FCBS
• Identify FCAS Compliance Plan
• Airplane info
• Milestones / means of compliance for o Identifying alterations that affect FCBS o Identifying FCAS o Developing DT data for alterations o Developing DT data for repairs to alterations FCAS list Develop DT data for alterations 360 days from effective date of rule
Compliance Doc
• Airplane info
• List of alterations that affect FCBS
• List of FCAS for each alteration
• DTIs developed for alterations
• DTIs developed for repairs to alterations TCH & STCH PMIApproval Compliance with AASR Means to address alterations that affect FCBS December 20, 2010 = Figure 2 - TC and STC Holder Tasks for Alterations and Repairs to Alterations
302. Applicability. For each alteration affecting FCBS, the TC or STC Holder will develop model-specific data detailing the airplane make, model, model variations or serial numbers on which the alteration may be installed, and the certification amendment level of the alteration.
These data will be presented to the FAA Oversight Office as required under §§ 26.45 and 26.47.
The certification amendment level used for determining DT Data for a specific existing alteration should be the same certification level established for assessing repairs (see Chapter 2 of this AC).
For certification of new alterations, the Changed Product Rule (§ 21.101) may require the current § 25.571 amendment level to be used.
303. Certification Amendment Level. In order to understand what data are required, the TC or STC Holder should identify the amendment level of the original certification relative to § 25.571. The amendment level is useful in identifying what DT Data may be available and what standard should be used for developing new DT Data. The two relevant airplane groups are:
a. Group A - Airplanes certified to CAR 4b or § 25.571, prior to Amendment 25-45.
These airplanes were not evaluated for damage tolerance as part of the original type certification. Therefore, the requirements of the AASFR are beyond the scope of the original certification amendment level. Unless previously accomplished, alterations to FCBS will need DT Data developed.
b. Group B - Airplanes certified to § 25.571, Amendment 25-45 or later. These airplanes were evaluated for damage tolerance as part of the original type certification. Alterations to these airplanes will need to meet their certification level. Because some of the alterations for certain of these airplanes may not have alteration data that includes DT Data, the TC or STC Holder and operators may need to identify and perform a DTE of these alterations and develop DTIs.
304. Obtaining the List of FCBS. The STC Holder should obtain the list of FCBS directly from the TC Holder. Section 26.43 requires the TC Holder to make the list of FCBS available to STC Holders that are required to comply with § 26.47 and to operators required to comply with §§ 121.1109 and 129.109.
305. Identifying Alterations That Affect FCBS.
a. Sections 26.45(b)(1) and 26.47(b)(1) require TC and STC Holders to review their existing alteration data and identify all alterations that affect FCBS. For each alteration that affects FCBS, the TC or STC Holder must perform a DTE and develop DTIs that address any adverse effects the alteration may have on FCBS. The TC or STC Holder should develop a list of FCBS that the alteration affects. An alteration that meets any of the following conditions is considered an alteration that affects FCBS:
(1) The alteration is installed on or interfaces with FCBS.
(2) The alteration changes the fatigue load environment of FCBS.
(3) The alteration degrades the inspectability of the FCBS for existing inspection methods developed for the FCBS.
b. The TC and STC Holder can limit their review of alteration data to those alterations that fall into any of the categories listed in Appendix 9 of this AC. For the TC Holder, this would include data for its FAA-approved alterations and STCs it owns for alterations. For STC Holders, the alteration data would be limited to its STC alterations. This data must be reviewed to determine if the defined alteration, when installed, would affect FCBS, regardless of the size or complexity of the alteration. The review must also determine if the alteration data complies with § 25.571 and contains associated DTIs, if applicable.
306. Identifying FCAS. For those alterations that affect FCBS, the TC or STC Holder of the alteration must determine if the alteration contains FCS. Guidance for identifying this structure can be found in AC 25.571, Damage Tolerance and Fatigue Evaluation of Structure, using the revision level of the AC that is consistent with the certification level of the airplane (initial issuance of the AC or later revisions may be used when the airplane certification level is prior to Amendment 25-45). This structure is referred to as “fatigue critical alteration structure.” The intent of the AASFR is to address the same structure that is required to have DT Data for compliance with § 25.571. Section 25.571(a) states “An evaluation of the strength, detail design, and fabrication must show that catastrophic failure due to fatigue…will be avoided throughout the operational life of the airplane. This evaluation must be conducted ….for each part of the structure which could contribute to a catastrophic failure (such as wing, empennage, control surfaces, fuselage, engine mounts, and their related primary attachments)….” The DTE performed to determine if an alteration has FCS would address the fatigue life and inspectability of any fatigue critical structure that may be added to an airplane by an alteration. For any alteration that affects FCBS, the TC or STC Holder is required to produce a list of any FCAS (§§ 26.45(b)(4) and 26.47(b)(4)).
307. List of Alterations. After identifying alterations that affect FCBS and identifying alterations that contain FCS, TC or STC Holders should produce a list of these alterations. The list of alterations affecting FCBS and list of alterations containing FCS should be submitted by the TC or STC Holder to the FAA Oversight Office for approval. This list must be made available to operators to support operators in determining if they have alterations installed on their airplanes that may adversely affect FCBS (§§ 26.45(b)(4) and 26.47(b)(4)). While the list will be submitted to the FAA before the Compliance Document submittal, the list, or a reference to the list, should also be included in the Compliance Document.
308. Description of Alteration. TC and STC Holders should describe in their Compliance Document each alteration that affects FCBS or contains FCS. The description should detail the location of the alteration on the airplane, major design aspects of the alteration, applicability, and certification level. Also, a reference to where DTIs are located if it is determined that DT Data exist for a particular alteration. This information may be incorporated by reference in the Compliance Document.
309. Certification Standard Applied in Performing a DTE. When developing DT Data, the certification level of the affected airplane determines the damage tolerance requirements. For Group A airplanes, as identified above, the TC or STC Holder should use the requirements of § 25.571, at Amendment 25-45, as a minimum standard. For Group B airplanes, the TC or STC
Holder should use the requirements that correspond to the original certification level as a minimum standard.
310. Performing a DTE on Alterations That Affect FCBS.
a. A DTE should be performed for each alteration that affects FCBS. The DTE would apply to the affected FCBS and alteration that may have FCS, and may consist of an individual analysis or the application of a DT-based process such as RAGs that would be used by an operator. The result of the DTE should lead to the development of DTIs that address any adverse effects the alteration may have on the FCBS. If the results of the DTE indicate that DTIs are not required to ensure the continued airworthiness of the affected FCBS, the TC or STC Holder should provide a means for documenting the results of the DTE. This will inform an operator that a DTE was performed for the affected FCBS. If it is found that an alteration does not affect FCBS, no further action is required.
b. The term ‘‘the adverse effects’’ refers to a degradation in the fatigue life or inspectability of FCS that may result from an alteration or repair to an alteration.
Degradation in fatigue life may result from an increase in loading, while degradation of inspectability may result from physical changes made to the structure. The evaluation would be performed within a time frame that ensures the continued airworthiness of affected or added FCS. In addition, any repairs to alterations that affect FCAS must also have a DTE performed. This would apply to those repairs developed by the TC or STC Holder for its alteration.
311. Reviewing Existing DT Data for Alterations That Affect FCBS. The review of alteration data to identify those alterations that may have an adverse effect on FCBS should include a determination if this data contains DT Data, such as DTIs for alterations and repairs to alterations. For each such alteration or repair to an alteration, unless previously accomplished, the TC or STC Holder must perform a DTE and develop any necessary DTIs for the affected FCBS and FCAS. This DT Data will provide operators a means for addressing these alterations for compliance with the AASFR. For some alterations, the DTE will conclude that no new DTIs will be required for the affected FCBS or any FCS of the alteration. In such a case, the TC or STC Holder should include a statement to that effect in the Compliance Document and the DT Data made available to the operator. Typical documents needing review would include, but are not limited to the following:
a. TC or STC Holder-developed SBs that provide:
(1) Instructions for alterations that may affect FCBS, or
(2) Inspections for repairs to alterations.
b. ADs that mandate:
(1) Alterations or repairs to alterations.
(2) Inspections of alterations.
c. RAG documents.
d. Individual alterations.
312. Developing DT Data for Alterations. The existing published alteration documentation may not provide the necessary DTIs. In this case, additional DT Data may need to be developed. This data may range from a DTE on a case-by-case basis to a revision of existing documents to incorporate the needed DTIs. The needed data may be published in various forms depending on the type of alteration. Based on the DTE performed for alterations that affect FCBS (see paragraph 310 of this AC) and on the review of existing DT Data (see paragraph 311 of this AC), a determination should be made as to any additional data required.
The additional data would be developed in accordance with the revision level of AC 25.571 that corresponds to the certification level of the airplane to meet the requirements of §§ 26.45 and
26.47. Depending on the alteration, additional data may be published in various forms.
a. STC alterations – The additional DT Data for existing alterations may be published in the form of an amended STC, or an individual approval.
b. TC Holder alterations – The additional DT Data for existing alterations may be published in the form of an amended TC, TC Holder service information, etc.
c. Alterations not developed by a TC or STC Holder – For alterations identified in Appendix 9 of this AC that affect FCBS and were not developed by a TC or STC Holder, the operator is responsible for obtaining DT Data for those alterations. These types of alterations include, but are not limited to, alterations approved through FAA Form 337, Major Repair and Alteration (a field approval). See Chapter 4 of this AC for guidance operators can use to establish acceptable timelines for developing DT Data and for incorporating the DTI into their maintenance program.
313. Timelines for Developing DT Data for Alterations. This paragraph provides the required timelines for developing DT Data for both existing and new alterations that affect FCBS. These timelines reflect the compliance dates specified in §§ 26.45 and 26.47.
a. For existing alteration data developed and approved before the effective date of §§ 26.45 and 26.47, the TC or STC Holder must make available to the operator DTI for its alteration by December 18, 2009. Operators will have until December 20, 2010, to incorporate a means to address alterations into their maintenance programs for compliance with §§ 121.1109 and 129.109.
b. For alteration data developed after the effective date of the rule, the TC or STC Holder must perform a DTE and develop DTIs (if required) for the affected FCBS and any FCAS before the alteration is approved. The DT Data must be submitted to the FAA Oversight Office to support FAA approval of the alteration data.
314. Developing DT Data for Repairs Affecting FCAS. In determining what DT Data will need to be developed for repairs to alterations TC and STC Holders should review repair data developed by the TC or STC Holder and identify each repair that affects any FCAS. For each repair identified that affects FCS of an alteration, unless previously accomplished, perform
a DTE and develop DT Data according to the minimum standard determined in paragraph 205 of this AC. The DTE should address the effects that the repair may have on any FCBS that is affected by the alteration. Repair data may include, but is not limited to, the following:
a. SRM repairs.
b. SB repairs.
c. AD mandated repairs.
d. TC and STC Holder reviewed and approved repairs that have general interest (multiple airplane approvals).
315. Timelines for Developing DT Data for Repairs Affecting FCAS. The timelines in this paragraph provide the required timelines for developing DT Data for both existing and new repairs made to alterations that affect FCBS. These timelines reflect the compliance dates specified in §§ 26.45 and 26.47.
a. For repair data developed and approved before the effective date of §§ 26.45 and 26.47, the TC and STC Holder must submit required DT Data to the FAA Oversight Office by June 30, 2009.
b. For repair data developed and approved after the effective date of the §§ 26.45 and 26.47, the TC and STC Holder should submit required DT Data to the FAA Oversight Office within 12 months after initial approval of the repair data and before making the DTIs available to persons required to comply with §§ 121.1109 and 129.109.
c. For repairs not developed by the TC or STC Holder that affect FCAS of the TC or STC Holder’s alteration, the operator is responsible for obtaining the DTIs required for the repair and affected FCAS. The operator is encouraged to coordinate development of the necessary DT Data with the TC or STC Holder of the affected alteration.
316. FAA Oversight Office Approval.
a. If the FAA Oversight Office finds the required data submitted by the TC or STC Holder acceptable, it will approve the data. This data may be submitted as individual documents, in a Compliance Document, or both. The FAA Oversight Office will also approve any documents or data referenced in a Compliance Document. Any subsequent revisions to the data must be submitted to the FAA Oversight Office for review and approval. FAA approval is also required for revisions to documents or data referenced in the Compliance Document, or to DTIs for alterations or repairs to alterations.
b. If a TC or STC Holder responsible for developing an alteration that affects FCBS is no longer in business, or has surrendered its TC or STC, the operator is responsible for submitting DT Data to the FAA Oversight Office for approval. This includes timelines for when the operator will develop DT Data and incorporate it into the operator’s maintenance program.
317. thru 399. [RESERVED].
CHAPTER 4. OPERATOR TASKS FOR REPAIRS AND ALTERATIONS
400. General Information About This Chapter. This chapter provides guidance to operators for developing a means for addressing the adverse effects repairs and alterations may have on fatigue critical structure (FCS). The final product of this guidance is the development of an Operator Implementation Plan (OIP) which, upon approval by the operator’s Principal Maintenance Inspector (PMI) and incorporation into its maintenance program, constitutes compliance with §§ 121.1109(c)(2) and 129.109(b)(2). The OIP will contain the processes and timelines the operator will use for obtaining and incorporating into its continuous airworthiness maintenance program (CAMP) DTIs that address the adverse effects of repairs and alterations.
401. Developing an Operator Implementation Plan. Using the guidance in this chapter, operators can develop an OIP by incorporating processes, data, and schedules developed by TC and STC Holders, and by themselves. The OIP should contain information describing how the operator will identify repairs and alterations affecting FCS, how the operator will obtain and incorporate DTIs for those repairs and alterations, and the timelines of these actions. Operators will first need to determine how they will obtain the information necessary to develop the OIP by considering the following conditions:
a. The TC or STC Holder exists and will make the DTIs available to the operator;
b. The DTIs already exist and are available;
c. The DTIs are not available from TC or STC Holders;
d. DTIs are not available for alterations developed by persons other than TC or STC Holders.
NOTE: For paragraphs 401c and 401d, above, the operator is responsible for developing or obtaining the DT Data. If the operator is unable to obtain the data it will need to coordinate the development of necessary DT Data through a third party.
402. Contents of an OIP. The OIP should include processes and procedures to ensure that all new and existing repairs and alterations affecting FCBS are evaluated for damage tolerance and have implemented DTIs. Operators should use information contained in TC and STC Holder Compliance Documents (see Chapters 2 and 3 of this AC), which provide processes, timelines, lists of FCS, and airplane design service goals or other necessary data. For alterations developed by the operator or third parties, and those developed by TC or STC Holders that are no longer in business, the operator will need to use the guidance in this AC to develop the processes and timelines for obtaining and incorporating into its CAMP the DTIs for those alterations. The contents of the OIP should include:
a. A process that implements the elements of the Repair Evaluation Guidelines (REGs) obtained from the TC Holder’s Compliance Document that will assist the operator in obtaining, developing, and implementing DTIs on its airplanes. The REGs include:
(1) A process for conducting surveys to identify and determine if existing repairs and alterations affect FCBS,
(2) A process for obtaining DTIs, and
(3) An implementation schedule for repairs establishing timelines for accomplishing the survey and for incorporating DTIs into the CAMP.
b. A process to determine if DTIs exist for those repairs and alterations identified in the airplane survey.
NOTE: This includes alterations not developed by TC or STC Holders and those that have not been identified through operator records review.
c. A process to obtain DTIs for repairs. See Appendices 5 and 6 of this AC for an acceptable approach.
d. A process for producing a list of alterations that affect FCBS on an operator’s airplane(s).
e. A process to review documents (such as instructions for continued airworthiness) relating to alterations developed by persons other than a TC or STC Holder to ensure DTIs are provided or developed for those alterations.
f. A process for obtaining DTIs for new alterations.
g. A process for obtaining DTIs for alterations not supported by a TC or STC Holder.
h. A process describing how DTIs for repairs and alterations will be incorporated into the part 121 or part 129 operator’s maintenance program, and for showing where the DTIs exist within the operator’s maintenance program.
i. A means of ensuring that the airplane will not be operated past the time limit established for obtaining DTIs.
403. Repairs. Repairs affecting FCBS need to be evaluated to determine if DT-based inspections are needed to ensure continued airworthiness. If a repair survey is utilized, use the survey parameters from Chapter 2 of this AC to identify repairs that may need DT Data developed. The survey plan may be divided into three groups of airplanes, as described in paragraph 404 of this AC. The DTIs will be implemented in accordance with paragraph 406 of this AC. Unless already required by the airplane certification level or other FAA-approved program, beginning December 21, 2010, and thereafter, all new repairs affecting FCBS must have a DTE performed. Implement any DTIs established from the DTE according to the process described in Appendix 5 of this AC. This includes blendouts, trim-outs, etc. that are beyond published TC Holder limits. For repairs installed on structure that has been altered, the operator is responsible for coordinating development of the required DT Data with the party responsible for the design of the alteration.