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Aircraft Audio Systems and Equipment

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Information about this document as published in the Federal Register.

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Federal Aviation Administration (FAA), DOT.


Notice of availability and requests for public comment.


This notice announces the availability of, and requests comments on proposed Technical Standard Order (TSO)-C139, Aircraft Audio Systems and Equipment. The proposed TSO is for audio systems designers, manufacturers, and installers seeking a TSO authorization or letter of design approval. In it, we (the Federal Aviation Administration, or FAA) describe what minimum performance standards (MPS) their audio systems and equipment must meet for approval and identification with applicable TSO marking. We also combine and update the requirements of TSO-C50c, Audio Selector Panels and Amplifers; TSO-57a, Headsets and Speakers; and TSO-C58a, Aircraft Microphones (except carbon).


Comments must be received on or before March 28, 2005.


Send all comments on proposed TSO-C139 to: Federal Aviation Administration, Aircraft Certification Service, Aircraft Engineering Division, Avionic Systems Branch, Room 815, 800 Independence Avenue SW., Washington, DC 20591. ATTN: Mr. Gregory Frye, AIR-130.

You may also deliver comments to: Federal Aviation Administration, Room 815, 800 Independence Avenue SW., Washington, DC 20591.

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Mr. Gregory Frye, AIR-130, Federal Aviation Administration, Room 815, 800 Independence Avenue SW., Washington, DC 20591. Telephone (202) 385-4649, fax (202) 385-4554, or e-mail

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Comments Invited

You may comment on the proposed TSO by sending written data, views, or arguments to the address listed above. You can also examine comments received on the proposed TSO before and after the comment closing date. Examine comments in room 815, Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591, weekdays except Federal holidays, between 8:30 a.m. and 4:30 p.m. The Director, Aircraft Certification Service, will consider all comments received by the closing date before issuing the final TSO.


TSO-C139 contains audio systems characteristics and MPS for aircraft microphones (except carbon), headsets, handsets, speakers, audio selector panels, and amplifiers. These standards specify system characteristics that should be useful if you are a designer, manufacturer, installer, or user of the equipment. If you comply with these standards, the equipment will perform its intended functions satisfactorily under all conditions normally encountered in routine aeronautical operations.

How To Get Copies

You can get a copy of the proposed TSO on the Internet from the FAA's Regulatory and Guidance Library (RGL) at​rgl. On the RGL Web site, select “Technical Standard Orders (TSO) and Index.” Or, contact the person listed in the section titled FOR FURTHER INFORMATION CONTACT.

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Issued in Washington, DC, on February 17, 2005.

Susan J.M. Cabler,

Acting Manager, Aircraft Engineering Division, Aircraft Certification Service.

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[FR Doc. 05-3607 Filed 2-24-05; 8:45 am]