[Federal Register Volume 65, Number 94 (Monday, May 15, 2000)]
[Notices]
[Page 31051]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-12145]



[[Page 31051]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular; Continued Airworthiness Assessments 
of Powerplant and Auxiliary Power Unit Installations on Transport 
Category Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of availability of proposed advisory circular and 
request for comments.

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SUMMARY: This notice announces the availability of proposed Advisory 
Circular (AC) No. 39XX, Continued Airworthiness Assessments of 
Powerplant and Auxiliary Power Unit Installations on Transport Category 
Airplanes.

DATES: Comments must be received on or before July 14, 2000.

ADDRESSES: Send all comments on the proposed AC to the Federal Aviation 
Administration, Attn: Engine and Propeller Standards Staff, ANE-110, 
Engine and Propeller Directorate, Aircraft Certification Service, 12 
New England Executive Park, Burlington, MA, 01803-5299.

FOR FURTHER INFORMATION CONTACT: Ann Azevedo, Engine and Propeller 
Standards Staff, ANE-110, at the above address, telephone (781) 238-
7117, fax (781) 238-7199. A copy of the subject AC may also be obtained 
electronically by writing to the following Internet address: 
``[email protected]''. Additionally, you may obtain a copy of the AC 
directly from the internet at the following address: http://www.faa.gov/avr/air/acs/draftach.htm.

SUPPLEMENTARY INFORMATION:

Comments Invited

    A copy of the subject AC may be obtained by contacting the person 
named above under FOR FURTHER INFORMATION CONTACT. Interested persons 
are invited to comment on the proposed AC, and to submit such written 
data, views, or arguments as they desire. Commenters must identify the 
subject of the AC, and submit comments in duplicate to the address 
specified above. All communications received on or before the closing 
date for comments will be considered by the Engine and Propeller 
Directorate, Aircraft Certification Service, before issuance of the 
final AC.

Background

    This Advisory Circular (AC) describes the Continued Airworthiness 
Assessment Methodologies (CAAM). The Federal Aviation Administration 
(FAA) Engine & Propeller Directorate (E&PD) and the Transport Airplane 
Directorate (TAD) may use CAAM, supplemented to meet each Directorate's 
needs, to identify those unsafe conditions in products that deserve 
priority attention. The FAA may issue an Airworthiness Directive (AD) 
under Part 39 of Title 14 of the Code of Federal Regulations (14 CFR 
part 39) to prescribe corrective actions that must be taken to address 
an unsafe condition in a product when ``the unsafe condition is likely 
to exist or develop in other products of the same type design.'' CAAM, 
as described in this proposed AC, is intended to be used for products 
associated with the Powerplant or Auxiliary Power Unit (APU) 
Installations on Transport Category Airplanes.
    Continued airworthiness requires that safety concerns within the 
existing fleet be addressed, and the knowledge gained applied for the 
benefit of future fleets as well. This AC provides CAAM guidance for 
estimating the risks associated with identified unsafe conditions; 
defining, prioritizing, and selecting suitable corrective actions for 
all identified unsafe conditions; and verifying that the corrective 
actions were effective. This AC is intended to present a tangible means 
of logically assessing and responding to the safety risks posed by 
unsafe conditions.
    This AC does not establish any requirement that the FAA must 
perform a risk assessment before issuing an AD, or that the FAA must 
wait to issue an AD until the design approval holder performs a risk 
assessment, or that the FAA must accept the findings of a risk 
assessment performed by the design approval holder. CAAM, as described 
in this proposed AC, assists the FAA in making decisions concerning the 
priority in which unsafe conditions should be addressed. The FAA may 
issue an AD for a particular unsafe condition before a risk assessment 
is performed, or without having an assessment performed at all.
    In this regard, CAAM does not define ``unsafe condition'' in a 
powerplant or APU installation. Rather, CAAM is a tool that the FAA 
usually will use to make the kinds of decisions described above.
    It is recognized that the proposed AC represents a significant 
change from the specific CAAM process detailed in draft AC39.XX that 
was published for public comment several years ago. Therefore, it is 
anticipated that comments will be received on the newly-proposed AC. 
The FAA does not intend to issue a final document until those comments 
have been appropriately reviewed and resolved.
    The FAA recognizes that many manufacturers use risk assessment 
practices to evaluate continued airworthiness. The FAA considers these 
current practices to be acceptable, and no reassessment will take place 
until all comments with the proposed are properly dispositioned.
    This proposed advisory circular, published under the authority 
granted to the Administrator by 49 U.S.C. 106(g), 40113, 44701-44702, 
44704, provides guidance for the use of CAAM.

    Issued in Burlington, Massachusetts, on May 4, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-12145 Filed 5-12-00; 8:45 am]
BILLING CODE 4910-13-M