Chapter 5. Maintaining Compliance with AD-Mandated Design Changes
5-1. General. This chapter provides guidance to DAHs for helping owners and operators and maintenance providers avoid inadvertently undoing or modifying AD-mandated type designs through routine maintenance practices.
5-2. Maintenance of an AD-Mandated Design Change. Once a product’s approved design is changed by an AD, owners and operators may perform routine maintenance if that maintenance does not result in changing the AD-mandated configuration. The maintenance can be performed using a combination of the methods, techniques, and practices prescribed in the DAH maintenance manuals or ICA, or a person’s own maintenance practices developed under 14 CFR 43.13(c).
a. The potential for undoing an AD-mandated configuration should be evaluated during all stages of design and development of SBs, maintenance documents, or ICA (e.g., during the review/approval of the SB, maintenance, and ICA; SB prototyping/validation; and NPRM comment period).
b. To decrease the chances that maintenance will inadvertently undo or modify an AD-mandated type design, the following actions should be performed by DAHs:
(1) During the design change and SB development stages, evaluate the need for changes to maintenance manuals or ICA to eliminate the potential for undoing an AD-mandated condition or configuration. U pdate any maintenance manuals or ICA to support the AD-mandated type design changes.
(2) Provide awareness to owners and operators regarding availability of updated ICA documents.
(3) When drafting SBs, use notes for flexibility and refer to standard practices as much as possible.
(4) When drafting SBs, avoid duplicating entire procedures and instructions that reside in maintenance or other ICA documents. The SB should only list the specific requirement which must be met, not the entire procedure. Internal flags should then be placed in the associated maintenance document where the requirement is located to indicate that it addresses an AD compliance requirement (see paragraph 5-5).
(5) Create an SB-to-AD cross-reference listing upon release of the AD (see paragraph 5-6).
5-3. Availability of Maintenance Procedures or ICA. A DAH should make new maintenance procedures or ICA3 or changes to them available as early as possible to owners and operators when an AD-related SB is issued (e.g., prior to the effective date of the AD).
Doing so helps ensure that owners and operators have the appropriate maintenance procedures 3 Refer to 14 CFR 21.50 22
I I I I or ICA necessary to maintain the product upon accomplishing or complying with the AD.
5-4. Allowing Flexibility. Include notes and refer to standard practices in S Bs when possible.
This will help prevent conflicting requirements or configurations from being created, and thereby reduce the likelihood that subsequent maintenance would de-modify the type design mandated by an AD.
5-5. Flagging Procedures. When an SB specifies requirements that exist in a maintenance manual (e.g., an AMM), or when the SB instruction includes language to accomplish a procedure “in accordance with” a manual (see paragraph 2-9) that is approved by a regulatory authority (e.g., the SRM), the requirement or procedure in the manual from which the requirement was duplicated, or the referenced manual, should be flagged by the DAH. The procedure should be flagged in a manner that identifies the procedure or requirement in the manual held by the DAH is mandated by an AD. The flagged language should:
a. Be visible to the maintenance documentation authors for their use (i.e., not on the maintenance documents provided to the owners and operators).
b. Contain a note similar to the following or list the SB and AD number once it becomes available:
“Note: This procedure is used for maintaining compliance with SB XYZ, which is subject to or mandated by an AD. Do not alter this procedure without obtaining a global AMOC approval.”
5-6. SB-to-AD Cross Referencing. An SB -to-AD cross reference listing with SB revision levels should be included in the front of the DAH’s maintenance manual(s) to help owner and operators identify which SBs are related to ADs (see figure 3).
Figure 3: Example of Aircraft Maintenance Manual SB-to-AD Cross Reference Number Incorporated Started/ Completed ATA Subject MD80-28-222 A MD80-28-226 AD 2011-01-16 A MD80 -28-229 No Effect AUG 01/2009 No Effect - SECTION 28-20 - FUEL – Fuel Quantity Indicating – Install Line Replaceable Unit Jumper Wires FUEL – Switch Fuel Level Float – Fuel Level Float and Pressure Switch In-Line Fuse Installation FUEL – Fuel Quantity Indicating – Replacement of Metric Instruments and Dripless Dipsticks with English Units 23
Chapter 6. Indicating FAA Approval on Service Documents
6-1. General. This chapter provides guidance on when and how a service document may indicate FAA approval.
6-2. FAA Approval of a Service Document.
a. Within the context of this AC, a service document is defined as a publication that conveys useful information relative to safety, product improvement, and operational or maintenance practices. It does not include type design documents under 14 CFR 21.31, such as flight manuals and certain maintenance manuals.
b. Typically, a service document conveys recommended actions and information related to engineering data that is already FAA-approved. As such, do not mark or imply that an entire service document is approved in total by the FAA, unless total FAA approval is required by regulation and has been granted in accordance with prescribed procedures. In other words, there must be a regulatory basis for indicating FAA approval. F or example:
(1) An alteration, parts replacement, repair, etc. that is based upon a design approval (original or revised).
(2) Procedures that will be mandated by an AD to resolve an unsafe condition or an associated AMOC to the AD.
6-3. I ndicating FAA Approval.
a. In the past, manufacturers have incorrectly marked entire service documents as “FAA Approved,” “FAA/DER Approved,” “DER Approved,” “DOA Approved,” or “ODA Approved.” Except for the type design data, there is no regulatory basis for FAA approval of other information in service documents. Therefore, only the appropriate page(s) of the document that contain engineering information supporting the original type design or a change to it should indicate FAA approval. The service document should be explicit as to what falls within the scope of FAA approval. For example:
(1) The resultant alteration (or repair) to the affected aircraft described by paragraph XX has been shown to comply with the applicable Federal Aviation Regulations and is FAA Approved.
(2) The retirement life limits of paragraph XX have been shown to comply with the applicable Federal Aviation Regulations and are FAA Approved.
b. Many parts of typical service documents do not require, and should not receive, FAA approval. These parts include, but are not limited to:
(1) Compliance times (except as referenced in an AD);
(2) Background information on the reasons supporting issuance of the document;
(3) Manpower estimates to complete an activity;
(4) Recommended maintenance actions, including inspections, that do not require FAA approval;
(5) Step-by-step routine alteration procedures;
(6) Cost of compliance estimates; and
(7) Tooling (not required by type design) and facility requirements.
c. Service document statements regarding approval status should read “FAA Approved” even though FAA designees may have been involved in determining compliance. Terms such as “DER (or UM) Approved,” “FAA/DER Approved,” “ODA Approved,” etc., should not be used in service documents.
6-4. Revisions to Service Documents. Changes to FAA-approved portions of service documents require FAA approval for the changes (or designee approval as appropriate).
Appendix A Appendix A. Examples of Notes in SBs The following are examples of general notes that can be used in an SB:
1. The instructions in Paragraph 3.B. l., Work Instructions and the figures can include operation of tools or test equipment. {Specify appropriate document} contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools.
2. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts.
Jacking and shoring limitations must be observed.
3. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51.
4. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part.
5. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems.
6. Some {Specify DAH name} parts are supplied in a temporary configuration. Those parts are identified with a “U”, “W”, or “Y” in place of the “-“ (dash) in the part number. It is permitted to install parts identified with a “U”, “W”, or “Y” as an alternative to the “-“ (dash) part number. {Specify document/drawing} contains more data.
A-1
Appendix B Appendix B. Examples of Notes that Provide Flexibility in SBs The following are examples of notes that can be used in an SB to allow flexibility:
1. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s) give the recommended sequence of steps. The sequence of steps may be completed first on either the right side or left side of the aircraft .
2. Equivalent parts are listed in drawing {drawing number}.
3. Refer to SRM Chapter 51 for approved fasteners and process material substitutions.
4. If the length of any fastener specified in this service bulletin does not meet the installation standards in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards in Chapter 51 may be used.
5. A 1/8-inch stack of the same type washers called for in this service bulletin is the maximum thickness which may be used under the fastener head or not to counteract accumulation of tolerances. EXCEPTION: When the available fastener length increments are greater than 1/16 inch, a 3/16-inch thick stack of the same type washers may be used.
6. Unless shown differently, these dimensions and tolerances are used:
a. Linear dimensions are in inches.
b. Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus
0.03 inch.
c. Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch.
d. Angular tolerance is plus or minus 2 degrees.
e. Hole dimensions for standard solid rivets are in {airplane model} SRM, Chapter 51.
f. Torque limits to tighten nuts and bolts are in {airplane model} SRM, Chapter 51.
7. The work instructions are divided into work packages. Task Hours and Elapsed Hours for each package are given in Paragraph 1.G., Manpower. You can do each work package independently.
8. Refer to the SWPM 20-10-01 as accepted wire installation procedures.
9. Refer to these SWPM chapters for applicable operations, as accepted procedures {list applicable SWPM chapters}.
10. Refer to {airplane model} AMM 20-15-11 for on-airplane software installation maintenance practices and data transfer times as accepted procedures.
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Appendix B
11.
Linear Tolerances Angular Tolerance X.XX in. (X.X mm) X.X in. (X mm) +/-0º30” +/-0.03 in. +/-0.1 in.
+/-0.8 mm +/-3 mm NOTE: The tolerances above apply to the dimensions given in this service bulletin except if specified differently.
12. This Service Bulletin Effectivity is divided into XX aircraft GROUPS according to the relevant configuration and the SB itself is divided into XX PARTS. The SB PARTS are featured to allow their independent accomplishment.
B-2
0 LEGEND
1. Inboard MLG door.
3. Fwd member.
-4. OVter skin ..
s. oos.s member.
7. An member.
9. OUterdoubler, NOTES 1 Shaded areas are · to be examined.
2. Oulboaril MLG door noc $hown tor e1anfy, 5 4 , © ®
LEFT SIDE SHOWN
RIGHT SIDE OPPOSITE 1
OUTSOARO
MLGDOOR (REF) 06/16/2014 AC 20-176A Appendix C Appendix C. Examples of Concepts to Clarify Illustrations
1. Shade or Cross Hatch Important Areas. Use this method to show important areas, such as those to be inspected. This method can also be used for other situations as long as the intent of the shading or cross-hatching is communicated clearly.
Figure C-1. Example of the Use of Shading Important Areas C-1
D 0
WASHER ----, PN NAS1149FNl32P (REMOVE AND DISCARD) DET. D (PRE-MOD) 0 BOLT (2 POSITIONS) PN NAS1091>-2•8 (REMOVE AND DISCARD) 0 ----- WASHER (2 POSITIONS) PN NAS1149FN832P (REMOVE AND DISCARD) 0 MICROSW!TCH SUPPORT ASSY PN 145-40193-401 (REMOVE AND DISCARD) 06/16/2014 AC 20-176A Appendix C
2. Phantom Lines. Use this method to show the location of a part, etc. for reference purposes.
This method can be used for other situations as long as the intent is communicated clearly.
Figure C-2. Example of the Use of Phantom Lines
3. Enlarged Views in Illustrations. Use this method to provide emphasis on a certain part of an illustration. This can also be used for other situations as long as the intent is communicated clearly.
C-2
FRAME
•• (JIEF)
1.FPER I llfT'ERCOSTAL n+n UPl'ER INfEACOSTAL (REF) (REF) l~ I ,- : ,; U :,;, STGR FRAME ..
(JIEF) ...... .;-·+ •t ~ - 6 I
OPTIONAL (REF) CUTUNE LOWER
INTERCOSTAL l"EF) STGR
• (JIEF) STOil 7 (JIEF) STGR 7 (REF) . . -· ....... 261240 1 L -1..,_ CLOSE:OUT (IS) STGR
- .
STOil t::::>- 11 (JIEF)
OPTIONAL Cl/TUN E LOWER INTEFIOOSTAl (REF) (REF) STGR 10 (REF) Detail B . FWD FRAME 24 (JIEF) ,,I i,-~. - :n -~ n: : : ; i l : :: : V 1,..: 1..;:
•-·-·+o-·-·-·4 . u~••••••••H••'••
FRAME CAP
CUT LINE (JIEF) I +----·: if"' n ni : , : . ~·-!i--1---- FRAME CAP ,_i_k,: •• ~·L;":.:i., 2612240p2 ,., _,,,, .. ,,,,, .. \SCRAP) . . -.
(VPPE.R FRAME CAP CUT UNE}
(l.H SHOWN) Detail C 06/16/2014 AC 20-176A Appendix C Figure C-3.Example of Enlarged Views in Figures C-3
D-D Appendix C
4. Dimensions and Tolerances. Use this method to show dimensions and tolerances for particular locations on parts.
Figure C-4. Example of Dimensions and Tolerances C-4
WITHIN &.lOO FLIGHT
CYCLES LNSPECT THE
YOKE A SSEMBLY AHO
THE PCU LUG FOR
DAMAG E l l
DAMAG E NODAIAAG E
FOUND FOUND I l l NO DAt..iAGE TO PCU
BUT YOKE ASS EMBLY NICKS AND'OR REP EAT THE
HAS VISUAL BEARING GAUGES F OUN D FRETTI NG REPLAC E INSPECTION ROTA.TtON OR ON P CU LU G B UT DAMAGETO YOKE WITI-IIN 500 ,_ MIGRATION, SIGNS OF t~O FRETTING PCU LUGS ASSEMBl. Y FLIGHT WEARTOA.NTI DAMAGE TO PCU CYCLES
ROTATION LUGS OR LUG FRi:ITU4G 1
REPLAC E REPLACE REMOVEPCU
YOKE YOKE ANO REPA IR OR
ASSEMBLY ASSEMBLY REPLAC E THE BEFORE WITHIN 3000 PCUBE FORE
FURTH ER F LIGHT FURTH ER
FLIGHT CYCLES FLIGHT I l
REPEAT TH E
INSPECTION WfTHIN 3000 FLIGHT
CYC LES 06/16/2014 AC 20-176A Appendix D Appendix D. Example of Logic-Based Diagrams The following is an example of a logic-based diagram.
Figure D-1. Example of Logic Based Diagram Note: The logic-based diagram only supplements the information in the accomplishment instructions and compliance paragraphs and is not intended to serve as the primary source for tasks or compliance times in this SB.
D-1