[Federal Register Volume 71, Number 98 (Monday, May 22, 2006)]
[Notices]
[Page 29377]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-7794]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular 120-YY, Widespread Fatigue Damage on 
Metallic Structure

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of Availability of Proposed Advisory Circular (AC) 120-
YY, and request for comments.

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SUMMARY: This notice announces the availability of and requests 
comments on a proposed advisory circular (AC) which provides guidance 
to design approval holders for certain transport category airplanes and 
on repairs and alterations to those airplanes for developing means to 
preclude widespread fatigue. This proposed AC complements revisions to 
the airworthiness standards that are being proposed by a separate 
notice. This notice is necessary to give all interested persons an 
opportunity to present their views on the proposed AC.

DATES: We must receive your comments by July 17, 2006.

ADDRESSES: You must mail two copies of your comments on the proposed AC 
to: Federal Aviation Administration, Attention: Walter Sippel, Airframe 
and Cabin Safety Branch, ANM-115, FAA, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, WA 98055-
4056. You can inspect comments at the above address between 7:30 a.m. 
and 4 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Jan Thor, Transport Standards Staff, 
at the address above, telephone (425) 227-2127.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite interested people to comment on the proposed AC by 
sending written data, views, or arguments. You should identify AC 120-
YY and send two copies of your comments to the address specified above. 
We will consider all communications received by the closing date for 
comments. We will consider comments received late if it is possible to 
do so without incurring expense or delay. The proposed AC can be found 
and downloaded from the Internet at http://www.faa.gov/aircraft/draft_docs. A paper copy of the proposed AC may be obtained by contacting the 
person named above under the caption FOR FURTHER INFORMATION CONTACT.

Discussion

    This proposed AC provides guidance to design approval holders on 
establishing operational limits (initial and extended) to preclude 
widespread fatigue damage for certain transport category airplanes. It 
also provides guidance for evaluating repairs and alterations to those 
airplanes for developing a means to preclude widespread fatigue damage. 
This AC also provides guidance to operators of those airplanes for use 
in incorporating Airworthiness Limitations sections with corresponding 
initial operational limits and airworthiness limitations items into 
their maintenance program. This guidance material applies to transport 
category airplanes operated under 14 CFR part 121 or part 129, that 
were certificated under the fail-safe and fatigue requirements of Civil 
Air Regulations (CAR) 4b or 14 Code of Federal Regulations (CFR) part 
25; and
    1. Have a maximum gross takeoff weight greater than 75,000 pounds, 
or
    2. Were certificated with maximum takeoff gross weight of 75,000 
pounds or less, and later increased to greater than 75,000 pounds by an 
amended type certificate or supplemental type certificate.
    It is one means, but not the only means, of complying with the part 
25 revisions proposed in Notice No. 06-04 entitled ``Widespread Fatigue 
Damage,'' which was published in the Federal Register on April 18, 2006 
(71 FR 19928). Issuance of AC 120-YY is contingent on final adoption of 
the proposed revisions to part 25.

    Issued in Washington, DC, on May 12, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
Ricardo Domingo,
Acting Manager, Aircraft Maintenance Division, Flight Standards 
Service.
 [FR Doc. E6-7794 Filed 5-19-06; 8:45 am]
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