Air carriers and other certificate holders have cited the ambiguity of existing policies and procedures for developing, substantiating, and documenting maintenance and/or alteration data for civil aviation products. Usually, this confusion arises when a certificate holder performs a maintenance or alteration task (or allows an existing condition to remain in service) that differs from that called out in a manufacturer’s service document, such as a Structural Repair Manual, service bulletin, or maintenance manual. In response, the Federal Aviation Administration (FAA) Aircraft Certification and Flight Standards Services have jointly developed this AC.

 
1. PURPOSE. This advisory circular (AC) provides one means, but not the only means, of
ensuring that the contemplated maintenance, alteration, or continue-in-service condition is in
compliance with applicable regulations and existing policy. This AC is not mandatory and is not
a regulation. This AC recommends acceptable methods by which:

a. Air carriers and commercial operators, operating under Title 14 of the Code of Federal
Regulations (14 CFR) Part 121, Part 129, section 129.14, and Part 135, section 135.411(a)(2),
may apply the special provisions of Part 43, section 43.13(c).

Download AC 120-77

b. Repair stations certificated under 14 CFR Part 145 may perform work for the operators
identified in paragraph a above in accordance with section 145.2 and the special provisions of
section 43.13(c).

c. These air carriers and commercial operators may continue articles in service or perform
maintenance and alterations in a different manner from the following:

Methods, techniques, and practices contained in manufacturer’s Instructions for
Continued Airworthiness (ICA),
Maintenance and restoration/overhaul manuals (such as a Structural Repair Manual
(SRM)), or Other methods, techniques, and practices acceptable to the Administrator.
NOTE: The special provisions of section 43.13(c) do not exempt these air
carriers and commercial operators from the “approved data” requirement of
sections 121.379(b) and 135.437(b), nor does it exempt a repair station from the
requirement of 145.51(d)(3).

2. SCOPE. This AC applies to 14 CFR Parts 121, 135, and section 129.14 operators that are
required to provide a continuous airworthiness maintenance and inspection program and to the
aircraft they operate. The aircraft include:
a. All that are type certificated in accordance with 14 CFR Part 25 and Civil Air Regulation
(CAR) 4b, and

b. Aircraft that have been type certificated in accordance with 14 CFR Parts 23, 27, 29, and
Special Federal Aviation Regulation (SFAR) 41.

3. REGULATIONS AND GUIDANCE MATERIAL.

a. Regulations. These acceptable means of compliance with operating regulations refer to
the applicable sections of 14 CFR Parts 91, 121, and 135.

Part 1, Definitions and abbreviations
Part 21, Certification procedures for products and parts
Part 23, Airworthiness standards: Normal, utility, acrobatic, and commuter category
airplanes
Part 25, Airworthiness standards: Transport category airplanes
Part 27, Airworthiness standards: Normal category rotorcraft
Part 29, Airworthiness standards: Transport category rotorcraft
Part 33, Airworthiness standards: Aircraft engines
Part 35, Airworthiness standards: Propellers
Part 39, Airworthiness directives
Part 43, Maintenance, preventive maintenance, rebuilding, and alteration
Part 65, Certification: Airmen other than flight crewmembers
Part 91, General operating and flight rules
Part 119, Certification: Air carriers and commercial operators
Part 121, Operating requirements: Domestic, flag, and supplemental operations
Part 129, Operations: Foreign air carriers and foreign operators of U.S.-registered
aircraft engaged in common carriage
Part 135, Operating requirements: Commuter and on demand operations and rules
governing persons onboard such aircraft
Part 145, Repair stations

Part 183, Representatives of the Administrator
SFAR 36
SFAR 41
b. Related Guidance Materials (Latest Revisions):

(1) FAA Orders. Copies of the following Orders may be purchased from the
Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA, 15250-7954. These Orders
may also be accessed online at http://www.faa.gov/RegulatoryAdvisory/index.htm.

Order 8100.9, DAS, DOA, and SFAR 36 Authorization Procedures
Order 8110.4, Type Certification Handbook
Order 8110.37, Designated Engineering Representative (DER) Guidance Handbook
Order 8130.2, Airworthiness Certification of Aircraft and Related Products
Order 8300.10, Airworthiness Inspector’s Handbook
Order 8310.6, Airworthiness Compliance Check Sheets Handbook
(2) Advisory Circulars. You may obtain copies of these documents from the U.S.
Department of Transportation, Subsequent Distribution Center, SVC-121.23, Ardmore East
Business Center, 3341 Q 75th Avenue, Landover, Maryland 20785.

AC 20-107 , Composite Aircraft Structure
AC 20-114 , Manufacturers’ Service Documents
AC 23.1309-1, Equipment, Systems, and Installations in Part 23 Airplanes
AC 25.571-1, Damage Tolerance and Fatigue Evaluation of Structure
AC 25.1309-1, System Design and Analysis
AC 25.1529-1, Instructions for Continued Airworthiness of Structural Repairs on
Transport Airplanes
AC 27-1, Certification of Normal Category Rotorcraft
AC 29-2, Certification of Transport Category Rotorcraft
AC 33-2, Aircraft Engine Type Certification Handbook
AC 33.4-1, Instructions for Continued Airworthiness

AC 43-9, Maintenance Records
AC 43.13-1, Acceptable Methods, Techniques and Practices—Aircraft Inspection and
Repair
AC 43.13-2, Acceptable Methods, Techniques and Practices—Aircraft Alterations
AC 91-56, Continuing Structural Integrity Program for Large Transport Category
Airplanes
AC 91-60, The Continued Airworthiness of Older Airplanes
AC 140-6, The Development and Use of Major Repair Data Under Provisions of
Special Federal Aviation Regulation No. 36
AC 145-3, Guide for Developing and Evaluating Repair Station Inspection
Procedures Manuals
(3) Other documents.

AN 8110.7, Approved Data
FAA-G-8082-11, Inspection Authorization Knowledge Test Guide
4. BACKGROUND. Air carriers and other certificate holders have cited the ambiguity of
existing policies and procedures for developing, substantiating, and documenting maintenance
and/or alteration data for civil aviation products. Usually, this confusion arises when a certificate
holder performs a maintenance or alteration task (or allows an existing condition to remain in
service) that differs from that called out in a manufacturer’s service document, such as a
Structural Repair Manual, service bulletin, or maintenance manual. In response, the Federal
Aviation Administration (FAA) Aircraft Certification and Flight Standards Services have jointly
developed this AC.

5. DEFINITIONS. For the purposes of this AC, the following definitions apply:

a. Airworthiness Limitations Section. The FAA-approved section of the ICA that sets
forth mandatory replacement times, structural inspection intervals, and related structural
inspection procedures, such as those established in accordance with section 23.573 and
section 25.571. Compliance with the Airworthiness Limitations section is required under
section 43.16 and Part 91, section 91.403 unless an alternative is approved by the Administrator.
(Reference sections 21.50(b), 43.16, and 91.403.)

b. Airworthy. To be airworthy:

(1) The aircraft must conform to its Type Certificate (TC). Conformity to type design is
considered attained when the aircraft configuration and the components installed are consistent
with the drawings, specifications, and other data that are part of the TC and would include any
Supplemental Type Certificate (STC) and field approved alterations incorporated into the
aircraft.

(2) The aircraft must be in a condition for safe operation. The condition of the aircraft
relative to wear and deterioration (e.g., skin corrosion, window delamination/crazing, fluid leaks,
tire wear, etc.) must be acceptable.

c. Approved Data. Technical and/or substantiating data that has been approved by the
FAA.

d. Article. An aircraft, airframe, aircraft engine, propeller, appliance, or component part.

e. Certificate Holder. Within the context of this AC, a person holding an Operating
Certificate (air carrier or commercial operator) issued under Part 119 and conducting operations
under Part 121 or section 135.411(a)(2), or a Part 145 repair station performing work under
section 145.2 (new rule cross-references section 145.205). This also includes section 129.14
operators.

f. Certification Maintenance Requirements (CMR). Required periodic tasks established
during the design certification of the airplane as an operating limitation of the TC.

g. Change. A variation from the method, technique, or practice specified in the
manufacturer’s service document for the article being maintained, altered, or otherwise
evaluated. Such changes include, but are not limited to, developing new repairs, revising
existing work instructions, using a substituted part other than the one “called out” in a
maintenance manual, or revising a damage limit or wear tolerance.

h. Continue-in-Service Condition. An article that is authorized to operate with wear or
damage outside a specified limit, tolerance, or other parameter specified in a manufacturer’s
service document.

i. FAA Designees. Designated Engineering Representatives (DER), Delegation Option
Authorization (DOA) holders, and Designated Alteration Stations (DAS).

j. Instructions for Continued Airworthiness (ICA). The methods, techniques, and
practices for performing maintenance, preventive maintenance, and alterations, which are
provided by the design approval holder or its component manufacturers, and are considered
acceptable to the Administrator under section 43.13(a). For example, under Part 25, appendix H,
the ICA includes an airplane maintenance manual or section, maintenance instructions, and an
Airworthiness Limitations section. (Reference sections 21.50(b), 25.1529, Part 25, appendix H,
and 43.13(a).)

k. Major Alteration. An alteration not listed in the aircraft, aircraft engine, or propeller
specifications.

(1) An alteration that might appreciably affect weight, balance, structural strength,
performance, powerplant operation, flight characteristics, or other qualities affecting
airworthiness, or
(2) An alteration that is not done according to accepted practices or cannot be done by
elementary operations. (Reference Part 1, section 1.1.)

l. Major Repair.

(1) A repair that, if improperly done, might appreciably affect weight, balance, structural
strength, performance, powerplant operation, flight characteristics, or other qualities affecting
airworthiness, or

(2) A repair that is not done according to accepted practices or cannot be done by
elementary operations. (Reference Part 1, section 1.1.)

m. Manufacturer’s Service Documents. Publications by a design approval holder that
provide acceptable methods, techniques, and practices for performing maintenance, preventive
maintenance, and alterations. They include, but are not limited to, maintenance manuals,
restoration/overhaul manuals, ICAs, Component Maintenance Manuals, Structural Repair
Manuals, service bulletins, letters, or other similar information.

n. Methods, Techniques, and Practices. The step-by-step, “how-to” instructions for
accomplishing maintenance, preventive maintenance, and alterations. These instructions are
considered “acceptable to the Administrator” if the certificate holder shows that the instructions
will return the aircraft, engine, or other article to its original or properly altered condition.
(Reference sections 21.50(b), and 43.13(a).)

o. Minor Alteration. An alteration other than a major alteration. (Reference section 1.1.)

p. Minor Repair. A repair other than a major repair. (Reference section 1.1.)

q. Structural Repair Manuals (SRM). These typically provide repair instructions,
material substitutions, and allowable damage limits for the aircraft’s structure.

r. Substantiating Data. Technical data used to show that an article complies with the
applicable airworthiness standards (e.g., Parts 25 or 33). Compliance may be shown by tests,
analysis, experience, and/or computations appropriate to the maintenance, alteration, or continue-
in-service condition of the article being evaluated. Substantiating data shown to comply with the
applicable airworthiness standards is acceptable to the Administrator. This is because it
establishes that the article meets the regulatory requirements and would be returned to its original
or properly altered condition by use of this data. (Reference sections 21.31, 25.603, and
43.13(b).)

s. Supplemental Type Certificate (STC). A certificate issued by the Administrator
approving a change in the type design of the product. (Reference section 21.117.)

t. Technical Data. Drawings and specifications, including a list of drawings and
specifications, needed to define the configuration and design features of a particular article,
repair, or alteration. Typically, this includes information on materials, dimensions, and
processes necessary to define structural strength, any required airworthiness limitations, and any
data necessary to determine the airworthiness, noise characteristics, fuel venting, and exhaust
emissions (as applicable) of the altered or repaired aircraft. Technical data also includes test data
and engineering analyses and other engineering information, such as engineering handbooks or
approved military or industry specifications. It may also include operational and service
experience, maintenance and alteration experience, reliability data, and other documented factual
information that can be shown to be directly applicable to the airworthiness of the article.
(Reference Part 21, section 21.31.)

u. Type Certificate. The type design, the operating limitations, the type certificate data
sheet (TCDS), the applicable regulations with which the Administrator records compliance, and
any other conditions or limitations prescribed for the product in the pertinent airworthiness
regulations. (Reference section 21.41.)

v. Type Design. In pertinent part, this includes:

(1) The drawings and specifications, and a listing of those drawings and specifications,
necessary to define the configuration and the design features of the product shown to comply
with the requirements applicable to the product;

(2) Information on dimensions, materials, and processes necessary to define the
structural strength of the product; and

(3) The Airworthiness Limitations section of the ICA as required by Parts 23, 25, 27, 29,
33, and 35, or as otherwise required by the Administrator.

6. AIRWORTHINESS DIRECTIVES, THE AIRWORTHINESS LIMITATIONS
SECTION OF THE ICA, AND CERTIFICATION MAINTENANCE REQUIREMENTS.

a. In several situations, prior approval must be obtained from the Administrator before a
certificate holder or a repair station may implement changes to documents that are required by
the regulations. For example, changes to Airworthiness Directives (AD) may not be made
without the prior approval of the Administrator. Typically, this means that an alternative method
of compliance (AMOC) must be obtained from the Aircraft Certification Office (ACO) or other
designated FAA office. This is because Part 39, section 39.3 requires the operator of any
product to which an AD applies to comply with the provisions of an AD. The AMOC procedure
is incorporated into an AD; therefore, complying with an AMOC constitutes compliance with the
AD. The aircraft manufacturer may have made arrangements for some of its DERs to approve
repairs as an AMOC for an AD.

b. The Airworthiness Limitations section includes each mandatory replacement time,
structural inspection interval, and related structural inspection procedures approved under
sections 23.573, 25.571, etc. (damage tolerance and fatigue evaluation of structure). Changes to
the Airworthiness Limitations section of an ICA require the approval of the Administrator. (See
sections 43.16 and 91.403.)

c. CMRs incorporated by reference into the appropriate TCDS also require prior approval of
the Administrator. For example, the TCDS for the Boeing 777-200/300 series airplanes states
that the CMRs are listed in either the FAA-approved Section 9 of the Boeing Maintenance
Planning Document (Airworthiness Limitations and CMRs) or the applicable engine TCDS. The
TCDS for the aircraft specifically states that “the more restrictive requirement from these two
documents shall be in force.”

7. MANUFACTURERS’ SERVICE DOCUMENTS.

a. Manufacturers’ service documents contain methods, techniques, and practices acceptable
to the Administrator for performing maintenance, preventive maintenance, and alterations.
Manufacturers’ service documents include maintenance manuals, restoration/overhaul manuals,
ICA, component maintenance manuals, SRM, service bulletins, service letters, and other similar
information. Under section 21.50(b), design approval holders are required to prepare and make
ICA available to operators, repair stations, and others required to comply with ICA. While the
FAA does not approve all service documents, it approves the Airworthiness Limitations section
of the ICA. Typically, for Part 25 airplanes, both the SRM and service bulletins are approved by
the FAA.

b. Under 14 CFR Parts 65, 121, 135, and 145, maintenance providers are responsible for
obtaining FAA approval of technical data prior to approving a major repair or major alteration
for return to service. Sometimes, manufacturers elect to obtain the FAA’s approval of technical
data supporting a maintenance or alteration action before issuing a service document. This is
often the most efficient and cost-effective way to approve technical data because it eliminates the
need for affected operators and maintenance providers to secure independent approval before
doing the work. However, it remains the operator’s responsibility to ensure that the
Administrator’s approval of technical data is obtained, if required, before approving for return to
service a repair or alteration based on the advice or recommendation of a manufacturer. A No
Technical Objection (NTO) letter or a statement that a particular maintenance or alteration action
is “DER approvable” does not constitute FAA approval. However, such a statement may be
considered, when supported along with other technical information, when evaluating the
airworthiness of a particular maintenance or alteration action or continue-in-service condition.

c. When a manufacturer has obtained the FAA’s approval of technical data, a service
document is often marked “FAA-Approved,” “FAA/DER-Approved,” or “DER-Approved.”
Although the entire document is reviewed by the FAA, only the technical data (i.e., engineering
information) associated with it is approved. In many cases, the technical data is not included in
the body of the service document. This is because that document typically contains only the
instructions (methods, techniques, and practices) for performing a particular repair or alteration,
rather than the engineering information that established compliance with the applicable
airworthiness standards. Refer to AC 20-114, Manufacturers’ Service Documents, for methods a
manufacturer may use to indicate that the FAA has approved service information.

8. THE STRUCTURAL REPAIR MANUAL, MAINTENANCE AND
RESTORATION/OVERHAUL MANUALS, AND THE INSTRUCTIONS FOR
CONTINUED AIRWORTHINESS.

a. Under section 21.50(b), the holder of a design approval for which application was made
after January 28, 1981 must prepare and give the ICA to the owner of the aircraft. The holder of
the design approval must thereafter make it available to any other person (such as repair stations)
required to comply with the ICA’s instructions. For transport category aircraft certificated under
Part 25, the ICA requirements are in section 25.1529 and Part 25, appendix H. Similar ICA
requirements exist for small airplanes, rotorcraft, engines, and propellers. (Reference Parts 23,
27, 33, and 35.)

b. The SRM provides repair instructions, material substitutions, and allowable damage limits
data for continue-in-service condition of the aircraft’s structure. Thus, the SRM sets forth
acceptable methods, techniques, and practices for performing structural repairs in the same
manner as other service documents (e.g., maintenance, component, or restoration/overhaul
manual in compliance with 43.13(a)). Manufacturers typically request FAA approval of the
SRM so the operator or a repair station may have ready access to approved data to perform major
repairs and return aircraft to service in accordance with the airworthiness standards and
sections 121.379(b) and 145.201(c)(2) (formerly 145.51(d)).

(1) It is the operator’s responsibility to classify repairs as major or minor. An operator
may use an FAA-approved SRM to accomplish repairs it has classified as either major or minor.
An operator must support changes to repairs.

(2) The SRM also provides limits of damage that an operator may use to continue an
aircraft in service without repair. These damage limits are not necessarily the maximum limits
that the aircraft is capable of withstanding while still complying with the airworthiness standards.
An operator intending to operate an aircraft with damage beyond a manufacturer’s established
damage limit must support the position that the aircraft continues to meet the airworthiness
standards.

c. Performing maintenance in accordance with the SRM is one way to maintain certain areas
of an aircraft in an airworthy condition. Aircraft structural designs are certificated to meet the
applicable airworthiness standards that were in effect when the TC was issued. These rules form
the type certification basis for the aircraft. Any subsequent repairs must continue to comply with
applicable airworthiness standards and be accomplished in accordance with Part 43.

d. In addition to providing acceptable methods, techniques, and practices for performing
maintenance, the SRM may also be used, when supported by appropriate substantiating data, to
develop new or different repairs, or to authorize damage limits beyond those set forth in that
manual. The SRM may also contain specific procedures authorizing continued aircraft operation
for a period of time before a permanent repair is required to be completed.

e. The SRM is not considered part of the Airworthiness Limitations section of the ICA or the
CMR. Moreover, the SRM is not part of the type design, even though it is often referenced on
the TCDS under the heading of “Service Information,” as it is for the Boeing 777-200/300 series
airplanes.

9. MAINTENANCE PERFORMANCE RULES.

a. Section 43.13(a) states that maintenance, preventive maintenance, and alterations may be
performed in accordance with either of the following:

(1) Methods, techniques, and practices in the maintenance manual or the ICA prepared
by the manufacturer, or
(2) Other methods, techniques, and practices acceptable to the Administrator.

b. Under section 43.13(b), each person must perform work in such a manner and use
materials of such a quality that the article worked on will be returned to at least its original or
properly altered condition. This does not mean that an article must be maintained in factory-new
condition. Rather, it requires that the maintenance, preventive maintenance, and alterations
result in an airworthy product (i.e., one that complies with Part 25, any other applicable
airworthiness standards (such as Part 33), and the pertinent operating rules). Generally, that is
accomplished by following the maintenance manuals prepared by the manufacturers, or using
other information acceptable to the Administrator, such as ACs.

c. Section 43.13(c) states that (unless otherwise notified by the Administrator) the methods,
techniques, and practices in the air carrier’s maintenance manual constitute an acceptable means
of compliance with section 43.13. Therefore, an air carrier that follows its maintenance manual
procedures not only complies with sections 121.367 and 121.369 (see paragraph 11), but also
complies with section 43.13(a) and (b). The special conditions of section 43.13(c)
notwithstanding, each operator and repair station is responsible for determining that major
repairs and major alterations have been accomplished in accordance with technical data approved
by the Administrator. (Reference sections 121.379(b), 135.437(b), and 145.201(c)(2) (formerly
145.51(d)).

d. Pursuant to section 145.57 (new rule cross-references sections 145.109 and 145.201),
repair stations are also required to comply with section 43.13(a) and (b). In addition, when they
perform work for Part 121 air carriers, repair stations must do so in accordance with the carrier’s
maintenance manual, as required by section 145.2 (new rule cross-references section 145.205).
When a repair station follows an air carrier’s manual, it will also be in compliance with
section 43.13(a) and (b).

10. METHODS, TECHNIQUES, AND PRACTICES VERSUS TECHNICAL DATA.

a. The terms “methods, techniques, and practices” and “technical data” have often been
confused. While the concepts are related, each has a distinct meaning in 14 CFR.

(1) The methods, techniques, and practices referenced in section 43.13(a) are the step-
by-step instructions for performing maintenance (including inspections), preventive
maintenance, and alterations. These “how-to” instructions are normally contained in
manufacturers’ maintenance manuals and other service documents, and are usually based on
approved technical data developed by the approval holder.

(2) Technical data consists primarily of engineering information. It includes drawings
and specifications that define the configuration and design characteristics of an article, and
information on materials, dimensions, and processes necessary to define structural strength.
Substantiating data is technical data used to establish that the aircraft or other article, if repaired
or altered using the instructions that the substantiating data supports, would be returned to its
original or properly altered condition in accordance with section 43.13(b). The operator is
responsible for showing that any substantiating data is directly related to the change that is being
evaluated. This is especially important when it is necessary to substantiate a change using
service experience, maintenance and alteration experience, and reliability data. Accordingly, the
technical data, when substantiated, is considered acceptable to the Administrator even in cases
when it does not require the FAA’s explicit approval.

b. Maintenance manuals and/or restoration/overhaul manuals may contain technical data.
For example, if the manual specifies the required materials, dimensions, or other design
information, this represents technical data.

c. An allowable damage limit in an SRM represents an acceptable method for accomplishing
a repair or authorizing a continue-in-service condition. The TC holder’s damage “limit” is based
on approved substantiating data—i.e., an engineering analysis showing that even with such
damage, the airplane would then still meet the appropriate airworthiness standards. In many
cases a higher limit can also be shown to comply with those standards. (Refer to paragraph 12.)

11. MAINTENANCE AND RESTORATION/OVERHAUL MANUALS.

a. Parts 121, 135, and Section 129.14 Operators.

(1) Under sections 121.133 and 121.135, an air carrier must prepare and keep current a
manual containing these items, among others:

Instructions and procedures for performing maintenance, preventive maintenance,
and servicing
Time limitations, or standards for determining time limitations, for
restoration/overhaul, inspections, and checks of aircraft and related components
Airworthiness inspections, including instructions covering procedures, standards,
responsibilities, and authority of inspection personnel
(2) Additional maintenance manual requirements are in sections 121.367 and 121.369.
These rules also require the carrier to follow its manual when performing maintenance,
preventive maintenance, and alterations. Similar rules exist for Part 135 and section 129.14
operators.

(3) An operator’s maintenance manual generally includes two basic kinds of
information. The first is product-specific and consists of the methods, techniques, and practices
for performing maintenance and alterations on specific aircraft, engines, and related components.
The second includes the carrier’s maintenance practices, policies, and procedures, usually found
in a General Maintenance Manual, Maintenance Policies and Procedures Manual, or similar
document. Both kinds of information—the product-specific and the operator’s general and
policies and procedures manuals—are part of the operator’s manual system required by Parts 121
and 135. When preparing its maintenance manual, the operator may designate the
manufacturer’s manuals as its own, develop its own maintenance information, or use some
combination of the two. However, once its manual is established, the operator is required to
comply with its terms.
(4) Operators may generally change their maintenance manuals without obtaining prior
FAA acceptance. These changes, however, must be acceptable to the FAA. If an operator is
following its maintenance manual, including its procedures for processing proposed changes to
service documents, section 43.13(c) states that the operator will be in compliance with
section 43.13(a) and (b). However, if the Administrator notifies an operator that a procedure in
its manual is unacceptable, the carrier would no longer be authorized to use that procedure until
the issue is resolved. Many operators have adopted procedures in their maintenance manuals to
evaluate proposed changes to existing manufacturers’ service documents. An operator’s
procedures must ensure that changes (and continue-in-service conditions) result in an aircraft
configuration that meets the airworthiness standards. The procedures must also ensure that when
interim changes are made, an appropriate maintenance action is accomplished at the appropriate
time, as determined during the analysis phase of the operator’s procedures. These changes (or
variations) may involve the use of a different maintenance procedure, such as an interim repair,
an equivalent part substitution, inspection technique, or revising repair or damage “limits,”
including those in an SRM. In some cases, revising a limit results in an article being approved
for return to service without a repair having been performed.

(5) Operators typically process proposed changes through their engineering
organizations. The engineers document the damage, condition, or contemplated action; conduct
a technical analysis to determine whether the change would comply with the pertinent
airworthiness standards (i.e., Parts 25, 33, etc.); and classify the maintenance action, alteration
action, or continue-in-service condition as major or minor. If major, the technical and
substantiating data supporting the change must be approved by the Administrator. If minor, an
engineering analysis should be performed and documented in accordance with the procedures in
the operator’s maintenance manual, appropriate to the complexity of the situation. The change
may be implemented if the analysis reveals that the proposed change would comply with the
applicable airworthiness standards.

(6) Some operators may desire repair stations to develop technical and substantiating
data on their behalf. These operators should have procedures in their maintenance manuals
governing the manner in which this data may be evaluated under their procedures, including
appropriate documentation and approval.

b. Repair Stations.

(1) Pursuant to section 145.2 (new rule cross-references section 145.205), repair stations
performing work for air carriers must follow the procedures in the air carrier’s manual for
developing, documenting, and using technical data. An air carrier may use the technical data,
substantiating data, or approved data developed by the repair station under this AC in accordance
with the air carrier’s procedures.

(2) A repair station manual submitted in accordance with section 145.45 (new rule cross-
references section 145.207) governs the operations of certificated repair stations. Like the air
carrier maintenance manual, the repair station manual is an accepted manual. This manual must
be followed by the repair station when it performs maintenance, preventive maintenance, and
alterations under Part 145. Unless otherwise prohibited by the repair station manual, repair
stations may also implement changes to their manuals without obtaining prior FAA acceptance.
If the FAA notifies a repair station that a particular change to its manual would not comply with
14 CFR, the repair station would be required to rescind the change.

(3) Like air carriers, repair stations are governed by section 43.13 when they perform
work. They must use methods, techniques, and practices acceptable to the Administrator, which
are normally those in the manufacturer’s or air carrier’s service documents. However, when they
are working on behalf of non-air carrier customers, the regulations allow repair stations to use
other methods, techniques, and practices that are acceptable to the Administrator for performing
the work. Paragraph 12(a) describes the general requirements for demonstrating that a particular
variation from an existing service document would be acceptable to the Administrator.

(4) Like air carriers, a repair station must also obtain FAA approval of the technical data
supporting a major repair or major alteration.

12. EVALUATING PROPOSED CHANGES TO DATA IN SERVICE DOCUMENTS.

a. General. Before an air carrier or repair station may change a repair, limit, or other
procedure in an SRM or other service document, the following three requirements must be met.
First, the change must be processed in accordance with procedures in the air carrier’s
maintenance manual. Second, the change must be shown to comply with the relevant
airworthiness standards. Compliance with these standards will establish that the article will be
returned to its original or properly altered condition in accordance with section 43.13(b). Third,
if the change is classified as “major” in accordance with the operator’s procedures, the technical
data supporting the change must be approved before the article may be approved for return to
service.

b. Manual Procedures. The certificate holder’s manual procedures should be sufficiently
detailed, but flexible enough to allow it to classify a change. If required, it should be able to
obtain FAA-approved data, apply the approved data to the aircraft, and approve the aircraft for
return to service. To help accomplish this, the certificate holder may take advantage of the latest
communication media (fax, electronic mail, video, telex, etc.). These media can also be used to
collect and transmit substantiating data in support of a proposed change. A certificate holder
should not rely only on verbal communications. This could interfere with the proper
classification of the data required to determine airworthiness. If a certificate holder intends to
use these media, it should have procedures in its manual that explain how the media will be used.
Procedures should also provide for a continuous loop of timely information and communications
among the certificate holder, FAA principal inspector, ACO, designees, and the manufacturer, as
appropriate. The procedures to evaluate proposed changes to service documents should be
included in the air carrier manual. The procedures should contain the following elements:

(1) A method of ensuring only appropriately qualified and experienced personnel will
make the engineering determinations required.

(2) A method of determining whether the proposed change requires FAA approval
because it affects an AD, CMR, Airworthiness Limitation, Minimum Equipment List (MEL),
maintenance program tasks, intervals, etc., and if the change requires FAA approval, procedures
for obtaining that approval.
(3) A method of determining whether the proposed change is major or minor (see
Appendix 1) and, if major, procedures to obtain FAA approval (or its equivalent, such as SFAR
36 in the case of repair data) of the technical data supporting the change.

(4) A method of developing technical/engineering justification, which includes the
following: (Also see paragraphs 12d through f, below.)

A review to determine if the existing technical data is sufficient to proceed with
the proposed change.
A method of consulting with the manufacturer, as appropriate. Such consultation
brings together the best available knowledge and experience in the areas of
design, production changes, and operations to ensure a well-designed repair.
A procedure for obtaining additional technical data, as necessary.
A procedure for substantiating compliance with pertinent airworthiness
regulations, including citing the specific 14 CFR Part(s) for which compliance has
been determined. This should be accomplished through tests, analyses, and/or
computations appropriate to the complexity of the change being proposed.
NOTE: In each case, the procedures must establish the airworthiness
standards that are applicable to the change and provide for documenting
that the aircraft configuration after the change meets those standards.

Document the substantiation process.
(5) The method of notification/reporting to principal inspector(s) of changes
accomplished, as appropriate.

(6) For repair stations, a method of coordinating with the air carrier as required by
section 145.2 (new rule cross-references section 145.205).

(7) A method of retaining the records of each action consistent with the recordkeeping
requirements of 14 CFR.
c. Evaluating the Proposed Change. When determining whether a contemplated
change from an existing service document is major or minor, the focus should be the change’s
effect on the capability of the aircraft configuration after the change to meet the applicable
airworthiness standards. For example, a structural repair performed in accordance with an SRM
may call for a specific size fastener, fastener edge margin, finish, corrosion treatment, or similar
method, technique, or practice. In evaluating whether a proposed change (such as using an
oversized fastener or a different finish than specified in the SRM) is major or minor, the analysis
should address whether the change (including its effect on the repair and the aircraft
configuration) will meet the definition of a major repair in Part 1. This is because the FAA only
considered the configuration of the aircraft with the repair described in the repair instructions
when it previously approved the technical data supporting that repair in the SRM. This
evaluation should be made within the meaning of Part 1.
NOTE: Only major changes to FAA-approved technical data require
FAA approval.

d. Showing Compliance with the Relevant Airworthiness Standards. Regardless of
whether a proposed change is classified as major or minor, the certificate holder must establish
that after the change the aircraft configuration complies with the pertinent airworthiness
standards in Parts 23, 25, 27, 29, 33, 35, etc. This would therefore return the article to its
original or properly altered condition in accordance with section 43.13(b). The certificate holder
must document its determination so that the FAA can evaluate whether it is following its manual
procedures. The certificate holder’s procedures must ensure that the evaluation considers the
effect of the change on the entire aircraft or article. This includes any other changes (approved
or acceptable) that are affected by the change under consideration. The following procedure
(paragraph 12f) will help certificate holders evaluate whether appropriate technical and
substantiating data exists to accomplish the proposed change. The nature and extent of the data
required will vary according to the complexity of the change and the other factors described
below.

e. Initial Assessment.

(1) Description of the Affected Article. This description should include, but is not
limited to:

Nomenclature
Part number
Assembly number
Serial number(s), if applicable
Make and model of the article
If known or as appropriate: hours or cycles, time-in-service, time since new, time
since last maintenance action
(2) Description of the Discrepancy or Contemplated Change. A complete description
of the damage, discrepancy, or change should include, but is not limited to:

Specific location on the article
Type (i.e., corrosion, limit exceeded, cracks, dents)
Extent and/or dimensions
Remaining dimensions of the affected area(s) or part(s)
Associated, hidden and/or adjacent discrepancies, damage, or alteration(s)

 Previous maintenance action(s)or disposition(s) thereof, or alteration(s) at or
adjacent to the affected area(s) or part(s)
Cause, if known (i.e., environmental, accidental, design)
(3) Review Existing Data. As appropriate, review and document existing information
(e.g., applicable maintenance documents, procedures, or process specifications) to determine
whether it applies to the proposed change.

(4) Circumstances in Which Additional Data May Be Required. Situations in which
further data collection and analysis may be required include, but are not limited to:

Noticing that no methods, techniques, and practices are specified in the applicable
service document, or the existing condition is beyond allowable limits or repair
tolerances
Performing an action in a different manner than prescribed by manufacturers’
service documents
Using maintenance or alteration data intended for a specific product on a like
product
Observing a substitution of materials or processes
Noticing that an AD applies to the product in the area of the damage, discrepancy,
or contemplated change
Discovering that the area of the damage, discrepancy, or contemplated change has
been defined as a primary structure or will create a Principle Structural Element
(PSE) (see section 25.571)
Noticing that CMRs apply in the area of the damage, discrepancy, or
contemplated change
Discovering that the article has an Airworthiness Limitation
f. Data Development.

(1) Technical Qualifications. The operator’s procedures should prescribe the steps for
reviewing, approving, and overseeing engineering authorizations, and specifying the minimum
qualifications (particularly knowledge of applicable airworthiness standards) for the individuals
engaged in these activities. These procedures should identify an individual who is responsible
for the process, can delegate final engineering approval authority, and has the following
qualifications:

A thorough working knowledge of the applicable airworthiness standards of
14 CFR

 At least 1 year of satisfactory experience in processing engineering work, in direct
contact with the FAA for type certification or major repair/alteration approval
At least 8 years of aeronautical experience, which may include the 1 year of
processing engineering work described above
(2) Technical Data. The data needed to substantiate changes may range from
maintenance information referencing existing technical data to (in the case of critical systems)
critical engine parts and primary structure, fully documented engineering analyses, and/or test(s).
Additional data (such as endurance runs or destructive testing) should be collected if both of the
following conditions apply:

The proposed change uses processes that affect the part’s performance
characteristics, structural strength, or material properties
Available data, analysis, or computation cannot satisfactorily establish
compliance with the applicable airworthiness standards
(a) Assessment. As appropriate to the action being considered, the functions,
interactions, environment, and consequence of the article’s failure, as applicable, must be
assessed. The assessment must determine the extent of analysis and the expertise needed to
develop technical and substantiating data to comply with the airworthiness regulations. This
assessment may include, but is not limited to:

Functional information describing how the article functions within the
assembly, how the assembly functions within the system, and/or how the
system functions within the product
Operating environment of the product
Interaction with other systems and consequences of failure that could be most
influenced by the maintenance, disposition, or alteration. Consider the most
probable effect on its ability to perform its intended function
Effect of the maintenance, alteration, or continued in service condition on the
article’s ability to meet the airworthiness standards specified in its type
certification basis, including its operational characteristics or performance
(b) Substantiating Data. The technical data should be evaluated against each
applicable regulatory section. The evaluation should be documented with sufficient detail to
determine whether the technical data meets the applicable airworthiness standards.

(c) Methods, Techniques, and Practices. The methods, techniques, and practices
should establish, as applicable, detailed work instructions, inspection criteria (incoming (initial),
in-process, and/or final inspection), and description of or reference to processes and the
instructions. For example, processes and instructions could include:

i. Heat-treating, surface treatment, blending, and welding;
ii. Consideration of specialized processes on engine hardware, such as, but not
limited to:

HPT turbine blade repair (especially single crystal alloys)
LPT turbine blade repair
Subjecting engines and parts thereof to specialized processes (acid
stripping, ultrasonic cleaning, etc.) outside of the manufacturer’s ICA
iii. Continuous inspection requirements and/or future maintenance action
requirements; and

iv. Acceptance of condition without further specific maintenance action.

13. RETENTION OF RECORDS. The above documentation must be retained for the period
specified in sections 91.417(b), 121.380(c), 135.439(b), 145.61 (new rule cross-references
section 145.219), and/or SFAR 36, as appropriate. Because the operator is responsible for the
continuing airworthiness of these changes, it should retain these records for a sufficient period.
These records may need to be used as reference material in addressing possible airworthiness
concerns related to a repair or alteration.

/s/

James J. Ballough

Director, Flight Standards Service

 
APPENDIX 1. MAJOR AND MINOR DETERMINATIONS—REPAIRS,
ALTERATIONS, AND CONTINUE-IN-SERVICE CONDITIONS

 
DOES CHANGEAFFECT WEIGHT?
ALTERATIONLISTED IN MFR’SSPECS?
STARTNoNoNoNoNoNoNoNoNoYesNoYesNoYesYesYesYesYesYesYesYesBALANCE?
STRUCTURALSTRENGTH?
PERFORMANCEPOWER PLANTOPERATION?
FLIGHTCHARACTERISTICS?
OTHERAIRWORTHINESSQUALITIES?
PRINCIPALSTRUCTURALELEMENT?
CONTINUE IN SERVICECONDITION?
YesYesYesMAJORIF IMPROPERLY DONE,
WOULD APPRECIABLYAFFECT AIRWORTHINESS?
MINORNoMAJOR AND MINOR DETERMINATIONS –
REPAIRS, ALTERATIONS,
AND CONTINUE IN SERVICE CONDITIONSNoACCEPTED PRACTICES ORELEMENTARY OPERATIONS?
REPAIR?
ALTERATION

AAC Information Bulletin No 6 CASA Guidance Material for Engine Ground Run Training

This guidance information supports the CASA CAO 100.66 Paragraph 10. Privileges of holder of an Authority

26 September 2007

Engine Ground Run Training

PURPOSE

The purpose of this document is to provide guidance to persons preparing and conducting engine ground run training and assessment of the competence of trainees.

OBJECTIVE

The objective of this document is to:

1. assist trainers to achieve a consistent standard of engine ground run training
2. assist trainers to achieve a consistent standard of assessment; and
3. assist trainers to ensure persons trained and assessed are competent to perform engine ground running.

TERMS USED

The terms used in this document are not all inclusive and should be used as a guide. Where the engine or aircraft includes similar systems and functions not included in this document, or included under other terms, these should be included in the training as though this document included those systems and functions.

REGULATORY BACKGROUND

CAR 230(3)(a) authorises an appropriately rated Licensed Aircraft Maintenance Engineer to ground run the engine(s), of an aeroplane that is having maintenance carried out on it or is being used for the provision of maintenance training provided s/he has “sufficient knowledge of the aircraft’s controls and systems to ensure the starting or running does not endanger any person or damage the aircraft.”

CAR 30(2C)(d) includes a condition that the holder of a Certificate of Approval must ensure that each person employed by or working under an arrangement with the holder receives adequate training in the work performed by that person and any equipment used in connection with the work.

CAR 214 place responsibility on the holder of a Certificate of Registration of an aircraft used in commercial operations (Registered Operator) to ensure persons performing maintenance are adequately trained.

CAO 100.66 paragraphs 10.6 and 10.7 permits an Authority holder to start and run an engine (on fixed and rotary wing aircraft) only if he/she has completed a course of training or experience and that the CAR 30 organisation is satisfied that the holder has the requisite qualifications and experience.

GRANT OF AME LICENCES

AME Licences and Licence Ratings are granted by CASA on the understanding that CAR 30, CAR 214 and CAR 230 will be complied with. Therefore, it cannot be assumed that the holder of an appropriate AME Licence rating (CAR31 licence or CAO 100.66 MA) is adequately trained and qualified to ground run the engines of a particular aircraft, aircraft type or model. The CAO 100.66 Appendix 7 Type Training requirements do not include training for engine running.

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CONTENT OF TRAINING

The following subjects, as applicable to the engine/aircraft combination, should be included:

a) Aircraft system operation as required for engine operation and/or aircraft and personnel safety;

b) Aircraft preparation for engine running;

c) Emergency procedures;

d) APU operation;

e) Engine ground safety precautions, including;

i. prop/jet/rotor blast area;

ii. inlet suction area; ,

iii. reverse blast area;

iv. fire protection/access;

v. securing aircraft, chocks and other restraint;

vi. safe areas and safety precautions for maintenance personnel during engine

operation;

f) Engine operational limits;

g) Engine performance parameters and corrections for ambient conditions;

h) Pre-start briefing of persons on the aircraft, including operating crew;

i) Preparation for engine start, internal and external pre-start checks;

j) Wet and dry motoring procedures;

k) Preparing aircraft and engine for test as required;

l) Normal and abnormal start procedures, including monitoring operation;

m) Post start checks;

n) Engine tests, including use of reference tables and record sheets

o) Normal shutdown procedures;

p) Emergency shutdown procedures;

q) Post engine run checks;

r) Use of built in test and monitoring equipment before, during and after engine

running; s) Restoring aircraft to normal shut down configuration, including recording and resetting of exceedance (s); and t) Completion of engine run and aircraft records.

Pre-start briefing should include functions of each crew member in normal operations and emergencies, including evacuation procedures and assembly point. Procedures should include any of the following which are applicable to the engine/airframe combination:

a) Start with external power/air; b) Start with APU; c) Cross bleed start; d) Battery power start; e) Start without N1, N2, Ng, Np, Fuel Flow or EGT indication; f) Start without automatic control and monitoring; g) Start without oil pressure; h) Start with tailpipe fire; i) Hung start; j) Surge/stall; k) Auto thrust recovery; l) Thrust reverser tests;

m) Propeller tests, including beta operation, governing operation, auto feather, manual

feather, NTS, pitch lock, reverse operation, auto power recovery; and n) Emergency shut down procedure, including extended motoring, if applicable.

Where a simulator is used all normal pre-start, start, shutdown post run and emergency procedures which are simulated should be performed under the control of each student. Functional checks may be performed in teams of two (or three if flight engineer station is fitted) provided each student is a participant.

Where an aircraft is used all normal pre-start, start, shutdown and post run procedures should be performed under the control of each student. Functional checks may be performed in teams of two (or three if flight engineer station is fitted) provided each student is a participant. Emergency procedures should be covered by a thorough briefing in the aircraft cockpit, with questions to confirm each student understands of the procedures.

Post run debrief should include completion of all records related to the operation of the simulator/aircraft and completion of all documentation related to each task performed during the training session. E.g. If a vibration analysis was conducted during the training session all documentation related to a vibration analysis should be completed as though they were to be incorporated into the actual aircraft records. Where appropriate, the trainees should complete and sign duplicate documentation as a demonstration of competence in satisfactorily completing the documentation and making the certifications related to the tasks undertaken during the training/assessment session.

CONDUCT OF ENGINE GROUND RUN TRAINING

Engine ground run training is intended to meet these requirements in relation to engine ground running. Engine ground run training may be conducted in an aircraft, in an aircraft simulator or a combination of both. Engine ground run training will usually involve a period of classroom training, briefing and debriefing.

Training should be conducted by a person with instructional and assessment training, such as Certificate IV in Workplace Training and Assessment, who is competent and authorised to carry out engine ground running for the engine/airframe combination. This authorisation may be limited to simulator training in which case the trainer need not hold an AME Licence rating for the engine. If the training is conducted in an aircraft the trainer will need to hold an appropriately rated AME Licence or other authorisation (eg pilot endorsed on aircraft) to run the engines.

All engine ground run training should be conducted using the appropriate procedures used in the course of normal maintenance. Additional documents may be used to assist student learning and to provide consistency of training and assessment.

Since this training usually involves both training and assessment, it is important that the trainer clearly differentiate between training and assessment. It would be unreasonable to subject a student to assessment of his/her handling of an emergency procedure without first being trained in the procedure.

ASSESSMENT

Satisfactory completion of engine ground run training would be demonstrated by each student satisfactorily completing each procedure assigned to him/her and satisfactorily answering questions related to the procedures and operation of the engine in the particular airframe.

The questions may be asked at any appropriate times during the pre-run briefing, the run session or the post run debriefing. Questions asked during the engine run session should be in context with the current operations to avoid distraction and confusion of the student(s) operating the aircraft/simulator.

RECORDING

An acceptable means of recording satisfactory completion of engine ground run training and assessment is via the use of a permanent recorded within the training records or personal file of the student. This entry must be verified by the Trainer/Assessor and show the date(s) the training/assessment was conducted.

Download AAC Information Bulletin No 6 – CASA Guidance Material for Engine Ground Run Training

This advisory circular is an update to AC 43.13-2A, Acceptable Methods, Techniques, and Practices  [ad]
Aircraft Alterations, dated January 1, 1977 and contains methods, techniques, and practices acceptable to the (FAA) Administrator for the inspection and alteration on non-pressurized areas of civil aircraft of 12,500 lbs gross weight or less. This Advisory Circular is for use by mechanics, repair stations, and other certificated entities. This data generally pertains to minor alterations; however, the alteration data herein may be used as approved data for major alterations when the AC chapter, page, and paragraph are listed in block 8 of FAA Form 337 when the user has determined that it is:

Download FAA ADVISORY CIRCULAR AC 43.132b

• Appropriate to the product being altered
• Directly applicable to the alteration being made
• Not contrary to manufacturer’s data This Advisory Circular contains the following chapters with information on:

1. STRUCTURAL DATA
2. COMMUNICATION, NAVIGATION, AND EMERGENCY LOCATOR TRANSMITTER SYSTEM INSTALLATIONS
3. ANTENNA INSTALLATION
4. ANTICOLLISION AND SUPPLEMENTARY LIGHT INSTALLATION
5. SKI INSTALLATIONS
6. OXYGEN SYSTEM INSTALLATIONS IN NONPRESSURIZED AIRCRAFT
7. ROTORCRAFT EXTERNAL-LOAD-DEVICE INSTALLATIONS CARGO SLINGS AND EXTERNAL RACKS
8. GLIDER AND BANNER TOW-HITCH INSTALLATIONS
9. SHOULDER HARNESS INSTALLATIONS
10. AIRCRAFT BATTERY INSTALLATIONS
11. ADDING OR RELOCATING INSTRUMENTS
12. CARGO TIEDOWN DEVICE INSTALLATIONS