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Underwater Locating Devices (Acoustic) (Self-Powered)

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Federal Aviation Administration (FAA), DOT.


Notice of the planned revocation of the Technical Standard Order (TSO) authorizations (TSOA) for TSO-C121 and C121a, Underwater Locating Devices (ULD), and request for public comment.


This notice announces the planned revocation of all Technical Standard Order authorizations (TSOA) issued for the production of Underwater Locating Devices (Acoustic) (Self-Powered) manufactured to the TSO-C121 and TSO-C121a specifications. These actions are necessary because the planned issuance of TSO-C121b, Underwater Locating Devices (Acoustic) (Self-Powered), with a minimum performance standard (MPS) that will increase the minimum operating life of Underwater Locating Devices from 30 days to 90 days.


Comments must be received on or before November 21, 2011.

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Mr. Gregory Borsari, AIR-130, Federal Aviation Administration, 470 L'Enfant Plaza, Suite 4102, Washington, DC 20024. Telephone (202) 385-4578, fax (202) 385-4651, e-mail to:

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Comments Invited

You are invited to comment on the revocation of the TSOAs granted for TSO-C121 and C121a, by submitting written data, views, or arguments to the above address. Comments received may be examined, both before and after the closing date, at the above address, weekdays except federal holidays, between 8:30 a.m. and 4:30 p.m. The Director, Aircraft Certification Service, will consider all comments received on or before the closing date.


On May 31, 2009, an Airbus A330-203 operated by Air France as flight number 447 (AF 447), bound for the Charles de Gaulle Airport, Paris, France, crashed into the Atlantic Ocean 2 hours and 10 minutes after taking off from Rio de Janeiro's, Galeão Airport. Search and rescue operations were conducted by the French and Brazilian authorities but the flight data recorder and cockpit voice recorder were not recovered until April 2011 during a fourth search and recovery effort.

The Bureau d'Enquêtes et d'Analyses pour la Sécurité de L'aviation Civile (BEA), which is the authority responsible for the investigation of the AF 447 accident, released a second interim report, dated December 17, 2009. The report includes safety recommendations to the European Aviation Safety Agency (EASA) and the International Civil Aviation Organization (ICAO), one of which is to “extend as rapidly as possible to 90 days the regulatory transmission time for underwater locator beacons installed on flight recorders on airplanes performing public transport flights over maritime areas.” The FAA agrees with the BEA's recommendation, and via a letter dated January 28, 2010, requested that SAE International form an industry working group to revise the minimum performance standard (MPS), AS8045, Underwater Locating Devices (Acoustic) (Self-Powered), to increase the minimum operating life of Underwater Locating Devices (Acoustic) (Self-Powered), from 30 days to 90 days. SAE International published AS8045A, dated August 3, 2011. The FAA will revise TSO-C121a to invoke the new SAE standard. When TSO-C121b is published the FAA will withdraw TSO-C121 and TSO-C121a authorizations no later than March 1, 2014. All Underwater Locating Devices (Acoustic) (Self-Powered) equipment manufacturers seeking TSO authorization will need to obtain authorization to manufacture in accordance with TSO-C121b.

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Issued in Washington, DC, on August 18, 2011.

Susan J.M. Cabler,

Assistant Manager, Aircraft Engineering Division, Aircraft Certification Service.

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[FR Doc. 2011-21536 Filed 8-22-11; 8:45 am]