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Integrated Modular Avionics (IMA) Hardware Elements.

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Federal Aviation Administration, DOT


Notice of availability for public comment.


This notice announces the availability of and requests comments on a proposed Technical Standard Order (TSO) pertaining to integrated modular avionics hardware elements (IMA). The proposed TSO prescribes the criteria for the minimum performance standard (MPS) that IMA hardware element equipment must meet to be identified with the appropriate TSO marking.


Comments must be received on or before January 16, 2002.


Send all comments on the proposed technical standard order to: Technical Programs & Continued Airworthiness Branch, AIR-120, Aircraft Engineering Division, Aircraft Certification Service, Federal Aviation Administration, 800 Independence Avenue, SW., Room 815, Washington, Start Printed Page 65024DC 20591. Or deliver comments to: Federal Aviation Administration (FAA), Room 815, 800 Independence Avenue, SW., Washington, DC 20591. Comments must identify the TSO file number.

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Mr. John Lewis, Technical Programs & Continued Airworthiness Branch, AIR-120, Aircraft Engineering Division, Aircraft Certification Service, Federal Aviation Administration, 800 Independence Avenue, SW., Room 815, Washington, DC 20591; Telephone No.—(202) 493-4841; FAX No.—(202) 267-5340; E-mail address—

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Comments Invited

Interested persons are invited to comment on the proposed TSO listed in this notice by submitting such written data, views, or arguments as they desire to the above specified address. Comments received on the proposed TSO may be examined, before and after the comment closing date, in Room 815, FAA Headquarters Building (FOB-10A), 800 Independence Avenue, SW., Washington, DC 20591, weekdays except Federal holidays, between 8:30 a.m. and 4:30 p.m. All communications received on or before the closing date for comments specified above will be considered by the Director, Aircraft Certification Service before issuing the final TSO.


Traditionally, avionics systems consisted of dedicated Line Replaceable Units (LRUs) which performed specific functions such as autoflight, flight management, and flight deck display. TSOs were written for these LRUs and their functions. Advancements in digital technology have created a trend toward higher levels of integration and modularity. In many modern integrated systems software determines functionality, while hardware serves as a platform for input, output, data storage, and software execution. Since these basic attributes tend to be similar for various applications, efficiencies can be gained by using various types of generic airborne hardware elements to execute these functions.

This TSO refers to these generic hardware elements as “IMA hardware elements”, which includes modules, cabinets, or racks. A module may contain software to enable electronic part marking and/or future loading of functional software. These modules will not function without being installed in specific cabinets or racks. Module types may include data processing modules, power supply modules, communication and data bus modules, or others. Cabinets or racks are use to host IMA modules. These cabinets or racks may be simple mechanical enclosures, or they may incorporate active cooling elements, power supplies, communication interfaces, backplanes for data and power, or any combination of these features.

How to Obtain Copies

You may obtain a copy of the proposed TSO via Internet (​software/​drafts.htm) or on request from the office listed under For Further Information Contact. Copies of Document Nos. RTCA/DO-160D (change 2), RTCA/DO-178B, and RTCA/DO-254 may be purchased from the RTCA Inc., 1828 L Street, NW., Suite 807, Washington, DC 20036 (website: Aviation Recommended Practice number ARP-4754 may be obtained from the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 15096-0001 (website:

You may inspect the RTCA documents at the FAA office location listed under ADDRESSES. However, RTCA documents are copyrighted and may not be reproduced without the written consent of RTCA, Inc.

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Issued in Washington, DC on December 11, 2001.

David W. Hempe,

Acting Manager, Aircraft Engineering Division, Aircraft Certification Service.

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[FR Doc. 01-31002 Filed 12-14-01; 8:45 am]