(8) Paragraph A35.3(a)(9). The list of tools for maintenance should be adequate for completing the work. The list may include lists located in the sections of the ICA in which the work is described. However, the list of tools and equipment should be located in a manner that facilitates locating and ordering the tools and equipment. Also, the list should include a crossreference to the section in which the method of using each tool is described. Special tools should be noted, as there is a specific regulatory requirement for the use of a special tool when performing maintenance.
b. Guidance for A35.3(b), Propeller Overhaul Section. It is not necessary to define a single overhaul period for the entire propeller, modules, or assemblies. However, experience has shown that every part of the propeller is exposed for inspection at some point during the life of the propeller. The TC holder should clearly define what level or amount of inspection and repair or replacement of parts constitutes an overhaul. The modular maintenance concept is an efficient overhaul method, even though each part may effectively be overhauled at different times.
(1) Paragraph A33.3(b)(1). The propeller overhaul manual or section should contain enough details for the disassembly, overhaul, and re-assembly of the propeller. This manual or section should also include necessary warnings and guidance.
(2) Paragraph A35.3(b)(2).
(a) Adequate inspection criteria should enable the appropriate inspection of each part of the propeller, sub-assembly, assembly, and module, as well as systems and components.
Inspections should identify the required action at each level, such as part replacement, repair, or further detailed inspection.
(b) The accuracy and reliability of inspection techniques should be consistent with the criticality of the parts being inspected and the types of defects for which the part is being inspected. The ICA should identify parts and key features or areas for which special emphasis or a higher awareness is needed to assure continued airworthiness. Cleaning could have a significant effect on the inspection, as improper cleaning could result in missing potentially hazardous defects. Therefore, the ICA should emphasize the proper cleaning methods, with the appropriate cautions when improper cleaning could impede inspection.
(3) Paragraph A35.3(b)(3). The overhaul manual should contain details for all fits and clearances for the propeller and components, structural integrity, and functionality of new and worn parts. While these fits and clearances may be identified in the manual as limits, they are not considered airworthiness limitations. However, if these limits are exceeded, the component or part may not be airworthy.
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(4) Paragraph A35.3(b)(4).
(a) This requirement ensures that worn or substandard parts that do not meet the ICA inspection limits cannot be returned to service. To make the propeller airworthy, such parts should be either replaced or repaired. While the ICA does not have to include repairs for all propeller parts, it should identify when or under what conditions parts must be replaced or repaired. If a part or component fails to meet the inspection requirements of the ICA, replacement is an acceptable alternative to repair.
(b) Repairs specified in the ICA should be complete and may include personnel training requirements. When the repair is accomplished in accordance with the ICA, the part should conform to its approved type certificate and, if safe for operation, should constitute an airworthy part.
(c) The FAA may allow and approve other repair data that is not part of the TC and is not reflected in the ICA. However, when design change data for repair or alteration constitutes a major change to the type design, the need for such repair or alteration information in the ICA should be evaluated, because the repair or alteration could introduce a new feature that does not exist in the original type design. This is particularly true for an STC. Any major change in type design, whether in support of a repair or an alteration, that is substantive enough to require significant additions to the ICA should be approved as an STC or amended TC.
(5) Paragraph A35.3(b)(5). The ICA should also contain a means to ensure configuration control during overhaul such that the proper parts, components, and any combinations that comply with the type design are identified during assembly or replacement.
(6) Paragraph A35.3(b)(6).
(a) The ICA should provide test acceptance criteria identified as limits, although not identified as airworthiness limitations. Changes to such propeller test acceptance criteria that are safety related should be considered major design changes and may be changed with appropriate FAA-approved data to substantiate the change. The ICA should provide calibration requirements (frequency, accuracy, and protocol to be used) for all testing and measurement equipment used to return the propeller and its component parts to service.
(b) The manual or section should include instructions for testing a propeller after overhaul. When applicable, this should also include any minimum testing requirements for a single overhauled component or model.
(7) Paragraph A35.3(b)(7). The manual or section should identify special containers, equipment, and tools that may be necessary to comply with the instructions for storage. The storage limits should also include any environmental restrictions, such as limits for temperature or humidity.
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(8) Paragraph A35.3(b)(8). The list of tools for overhaul should be adequate for completing the work. The list may include lists located in the sections of the ICA in which the work is described. Also, the list should include a cross-reference to the section in which the method of using each tool is described or the tools are used. Any special tools should be highlighted, because §43.13 requires the use of special tools when performing maintenance.
10. GUIDANCE FOR APPENDIX A TO PART 35, A35.4 -- AIRWORTHINESS LIMITATIONS SECTION.
a. The ICA must include an Airworthiness Limitations section. The Airworthiness Limitations section may appear in both the maintenance and overhaul sections; this is acceptable as long as both sections remain identical. The Airworthiness Limitations section should be prominently located, entitled “Airworthiness Limitations,” and identified at the beginning of the section as having been approved by the FAA.
b. The CMACO approves the Airworthiness Limitations section. Changes to mandatory inspection intervals, as well as life limits and replacement times, require CMACO approval. The addition of restrictions to an existing Airworthiness Limitations section should be accompanied by an airworthiness directive (AD).
[Original signed 11/3/03 by P.A.W.]
Peter A. White Acting Manager, Engine and Propeller Directorate Aircraft Certification Service
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