Re: Service Bulletins for Part 25 Aircraft

From: (Brian A. Reynolds)
Organization: Rockwell Avionics - Collins
Date:         21 Oct 96 02:29:19 
References:   1 2
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Brian A. Reynolds <> wrote in article
> What <FAR, AC, Order, et. al> regulates the issuance and control
> of Service Bulletins for Part 25 aircraft in Part 121 service?
"Stuart Law" <> replied:
This may be hard to believe, but maintenance manuals and
especially underlying service bulletins are generally not
regulated by the FAA.


Not sure that our brethern at the FAA flight Standards Office would
agree with this position :)

Part 25 (Airworthiness Standards, Transport Category Airplanes) Subpart
G, Operating Limitations and Information, subparagraph 25.1359,
instructions for Continued Airworthiness: The applicant must prepare
Instructions for Continued Airworthiness in accordance with Appendx H to
this part that are acceptable to the Administrator (generally accepted to
mean - approved by the FAA)

Part 25 Appendix H, Instructions for Continued Airworthiness subparagraph
H25.1(c): The applicant must submit to the FAA aprogram to show how changes
to the Instructions for Continued Airworthiness made by the applicant or
by the manufactures of products and appliances installed in the airplane
will be distribued.

Appendix H of Part 25 goes on to describe the required contencts of these

|side bar - In FAA parlance, the applicant is the entity which is asking
for an FAA finding of compliance with applicable regulations.  A product
is an airplane, engine or propeller (note that APUs are being added in
the next revision of FAR Part 21).  So in general, we think of the
applicant aa being an airframe manufacture (Boeing, Douglas, Airbus,
Ilyushin, et. al.) although it can also be an engine manufactuer (Pratt,
GE, Snecma, Rolls etc.)  So the entity which creates the product is
required, as a condition of a Finding of Compliance (i.e.  Type Design
Approval/Type Certificate) to have prepared and received approval of,
maintenance procedures.|

Part 121 (Certification and Opertions: ... Commercial Operators of Large
Aircraft) Subpart L (Maintenance, Preventatove Maintenance, and
Alterations), subparagraph 121.363 Responsibility for airworthiness(a)(2)
Each certificae holder is primarily responsible for the performance of
the maintenafne, preentive maintenance, and alteration of its aircraft...
in accordance with ITS manual and the regulations of this chapter.
Followed by 121.367(a) (Each certifiaqte holder shall have ... a program
that ensures that) "maintenance, preventive maintenance, and alterations
performed by it or by other persons, are performed in accordance with the
certificate holder's manual;"

But perhaps one of the most important (to this discussion anyway :) is
121.379(a) A certificate holder may perform ... maintenane, preventive
maintenace, and alterations as provided in its continuous airworthiness
maintenance program and its maintenance manual.  (and (b) However, in the
case of a major repair or major alteration, the work must have been done
in accordance with technical data approved by the Administrator.

Sooo.... unless the certificate holder separates the minor work from major
work, the technical data (i.e maintenance manuals) must be approved by
the Administrator.  (Geez that was tortuous! :)

The 'normal' way for a large carrier to do this is to show equivalancy
with the manufactures manuals - a process that is normally done during
the introduction to service of a new aircraft.  So there is NO rquirement
that a carriers maintance manuals be identical with the manufactues (the
maintenance procedrue used by AA for onwing engine replacement was per
their approved processes but were not in accordance with the Douglas

Chater carriers and those without a large in-house publications department
to support may chose to use the manufactures maintenance manual without
further approval.

So thanks to Stuart (for pointing me in the right direction) I've answered
my own question.  Maintenance manuals are changed in a manner acceptable
to the Administrator so in a deswcription of how MM are changed I need to
use the phrase 'it is common practice...' rather then 'As defined in'

Thanks Stuart!

(As another side remark, AC 121.22A defines the Maintenance Steering Group
which defines the initial maintenance requirements and intervalts.  There
is a dreft AC floating about which deals with Certification  Maintenance
Requirements which deals with the need to address safety issues identified
during the design and certification process.)