[Federal Register Volume 70, Number 37 (Friday, February 25, 2005)]
[Notices]
[Page 9438]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-3607]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Aircraft Audio Systems and Equipment

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of availability and requests for public comment.

-----------------------------------------------------------------------

SUMMARY: 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).

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

ADDRESSES: 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.

FOR FURTHER INFORMATION CONTACT: 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 [email protected].

SUPPLEMENTARY INFORMATION:

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.

Background

    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 http://www.airweb.faa.gov/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.

    Issued in Washington, DC, on February 17, 2005.
Susan J.M. Cabler,
Acting Manager, Aircraft Engineering Division, Aircraft Certification 
Service.
[FR Doc. 05-3607 Filed 2-24-05; 8:45 am]
BILLING CODE 4910-13-M