# Proposed Advisory Circular 120-YY, Widespread Fatigue Damage on Metallic Structure
**AGENCY:**
Federal Aviation Administration (FAA), DOT.
**ACTION:**
Notice of availability of proposed Advisory Circular (AC) 120-YY; extension of comment period.
**SUMMARY:**
This action extends the comment period stated in the Notice of Availability of proposed Advisory Circular (AC) 120-YY, “Widespread Fatigue Damage on Metallic Structure,” that was published on May 22, 2006. In that document, the FAA announced the availability of and request for comments on proposed revisions to an AC which provides guidance to design approval holders for certain transport category airplanes related to repairs and alterations to preclude widespread fatigue damage.
**DATES:**
Comments must be received by September 18, 2006.
**ADDRESSES:**
Send all comments on this proposed AC to: Walter Sippel, Airframe/Cabin Safety Branch, ANM-115, FAA, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, WA 98055-4056. Comments may be inspected at the above address between 7:30 a.m. and 4 p.m. weekdays, except Federal holidays.
**FOR FURTHER INFORMATION CONTACT:**
Madeleine Kolb, Standardization Branch, ANM-113, at the address above, telephone (425) 227-1134.
**SUPPLEMENTARY INFORMATION:**
**Comments Invited**
Interested persons are invited to comment on the proposed AC by sending such written data, views, or arguments, as they may desire. Commenters should identify AC 120-YY and send comments in duplicate to the address specified above. All communications received on or before the closing date for comments will be considered before the final AC is issued. The proposed AC can be found and downloaded from the Internet at the AIR Web site, *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* .
**Background**
On May 12, 2006, the Federal Aviation Administration (FAA) posted proposed AC 120-YY on the AIR Web site and requested comments. On May 22, 2006, we published a “Notice of Availability of Proposed Advisory Circular (AC) 120-YY, and request for comments,” in the *Federal Register* (71 FR 29377). This AC provides guidance on compliance with the proposed rule entitled “Widespread Fatigue Damage,” which was published on April 18, 2006, (71 FR 19928). Comments on proposed AC 120-YY were to be received by July 17, 2006.
Five petitioners, the Air Transport Association of America, Inc. (ATA), Airbus, the Cargo Airline Association (CAA), Boeing Commercial Airplanes, and National Air Carrier Association, Inc. (NACA), have asked the FAA to extend the comment period for the proposed AC. Each petitioner requested a 90-day extension to provide enough time to evaluate the proposed AC and related rulemaking and prepare comments to send to the FAA.
The FAA concurs with the petitioners' requests for an extension of the comment period on proposed AC 120-YY, but we believe that an extension of 90 days would be excessive. The FAA concludes that an additional 60 days would be adequate for the petitioners to review and comment on proposed AC 120-YY and, accordingly, extends the comment period to September 18, 2006. That date corresponds to the comment period extension date, announced in a separate *Federal Register* notice to be published today for the associated proposed rule, “Widespread Fatigue Damage.”
**Extension of Comment Period**
For the reasons provided in this notice, the FAA believes that good cause exists for extending the comment period for proposed AC 120-YY to September 18, 2006. Absent unusual circumstances, the FAA does not anticipate any further extension of the comment period for this proposed AC.
Issued in Washington, DC, June 29, 2006.
John M. Allen,
Acting Director, Flight Standards Service, Aviation Safety.
Dorenda D. Baker,
Acting Director, Aircraft Certification Service, Aviation Safety.