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Technical Standard Order (TSO)-C151b, Terrain Awareness and Warning System

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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Federal Aviation Administration (DOT).


Availability of final TSO document.


This notice announces the availability of TSO-C151b. The final TSO tells persons seeking a TSO authorization or letter of design approval what minimum performance standard (MPS) their Terrain Awareness and Warning System must meet to obtain and be identified with TSO-C151b Class A, B, or C markings.


This TSO is effective on December 17, 2002.

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Ms. Bobbie J. Smith, Program Support Specialist, Federal Aviation Administration, Aircraft Certification Service, Aircraft Engineering Division, Technical Programs & Continued Airworthiness Branch, AIR-120, Room 815, 800 Independence Avenue, SW., Washington, DC 20591, Telephone (202) 267-9546.

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This TSO is effective for new applications submitted after the effective date of this TSO. All prior revisions to this TSO are no longer effective and, in general, applications will not be accepted after the effective date of this TSO. However, applications submitted against the previous versions of this TSO may be accepted up to six months after the effective date of this TSO, in cases where we know the applicant was working against the earlier MPS before the new change became effective. Terrain Awareness and Warning Systems approved under a previous TSO authorization may continue to be manufactured under the provisions of their original approval, as specified in title 14 of the Code of Federal Regulations (14 CFR) 21.603(b). However, major design changes to TAWS equipment approved under previous versions of this TSO requires a new authorization under this TSO, per 14 CFR 21.611(b).

This is a revised TSO that sets forth minimum operational performance standards that a Terrain Awareness and Warning System (TAWS) equipment must meet to be identified with the TSO-C151b Class A, B, or C marking. This revision adds the requirements for a Class C designation.Start Printed Page 78563

The standards of this TSO apply to equipment intended to provide pilots and flight crews with both aural and visual alerts to aid in preventing an inadvertent controlled flight into terrain (CFIT) accident. Class A and B TAWS equipment are required by 14 CFR parts 91, 135, and 121. Class C equipment is intended for voluntary installations on aircraft not covered by the TAWS requirements in 14 CFR parts 91, 135, and 121.

How To Obtain Copies

A copy of the final TSO may be obtained via the internet at,​certification/​aircraft/​TSOA.htm, or by contacting the person listed in the section titled FOR FURTHER INFORMATION CONTACT.

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Issued in Washington, DC, on December 19, 2002.

David W. Hempe,

Manager, Aircraft Engineering Division, Aircraft Certification Service.

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[FR Doc. 02-32417 Filed 12-23-02; 8:45 am]