Document ID: FAA-2011-1134-0001
Agency: faa
Document Type: Notice
Title: Technical Standard Orders: Airborne Supplemental Navigation Equipment Using Global Positioning System
Posted Date: 2011-10-13T04:00Z

[Federal Register Volume 76, Number 198 (Thursday, October 13, 2011)]
[Notices]
[Page 63714]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-26449]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

Technical Standard Order (TSO)-C129a, Airborne Supplemental 
Navigation Equipment Using the Global Positioning System (GPS)

AGENCY: Federal Aviation Administration (FAA), DOT

ACTION: Notice of cancellation of TSO-C129a, Airborne Supplemental 
Navigation Equipment Using the Global Positioning System (GPS).

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SUMMARY: This notice announces the FAA's cancellation of TSO-C129a, 
Airborne Supplemental Navigation Equipment Using the Global Positioning 
System (GPS) effective October 21, 2011. TSO cancellation will not 
affect production according to an existing TSO authorization (TSOA). 
Articles produced under an existing TSOA can still be installed 
according to existing airworthiness approvals and applications for new 
airworthiness approvals will still be processed.
    The effect of the cancelled TSO will result in no new TSO-C129a 
design or production approvals. However, we will accept applications 
for new TSO-C129a TSO Authorizations (TSOA) until October 21, 2012 if 
we know that you were working toward a TSO-C129a approval prior to 
October 21, 2011.

DATES: Comments must be received on or before October 20, 2011.

FOR FURTHER INFORMATION CONTACT: Mr. Kevin Bridges, AIR-130, Federal 
Aviation Administration, 470 L'Enfant Plaza, Suite 4102, Washington, DC 
20024. Telephone (202) 385-4627, fax (202) 385-4651, e-mail to: 
kevin.bridges@faa.gov.

SUPPLEMENTARY INFORMATION: The FAA published a Federal Register notice 
on August 16, 2011 (76 FR 50808) describing our intent to cancel TSO-
C129a to solicit feedback. We received a total of six comments from 
three parties with questions or concerns about the cancellation. For 
example, there was a comment to provide a transition period for 
applicants working toward a TSO-C129a approval prior to the 
cancellation date. The FAA agreed with this comment and has included a 
transition period in this notice. Another comment expressed concern 
regarding how an existing TSO-C129a technical standard order 
authorization (TSOA) would be addressed on an article with multiple 
TSOAs that has a change not affecting TSO-C129a. The FAA agrees to 
address this issue through a policy revision and/or policy memo. 
However, none of the parties providing comments expressed an objection 
to TSO-C129a being cancelled or provided reasons to not cancel the TSO.

Comments Invited

    You are invited to comment on the cancellation of the TSO by 
submitting written data, views, or arguments to the above address on or 
before October 14, 2011. The Director, Aircraft Certification Service, 
will consider all comments post-marked or received before the TSO 
cancellation date.

Background

    On September 21, 2009, the FAA published TSO-C196, Airborne 
Supplemental Navigation Sensors for Global Positioning System Equipment 
Using Aircraft-Based Augmentation; an updated minimum performance 
standard for GPS sensors not augmented by satellite-based or ground-
based systems (i.e., TSO-C129a Class B and Class C). The FAA has also 
published two TSOs for GPS augmented by the satellite-based 
augmentation system (TSO-C145c, Airborne Navigation Sensors Using the 
Global Positioning System Augmented by the Satellite-Based Augmentation 
System; and, TSO-C146c, Stand-Alone Navigation Equipment Using the 
Global Positioning System Augmented by the Satellite-Based Augmentation 
System).
    TSO-C145c, TSO-C146c, and TSO-C196 incorporate more stringent 
standards and testing requirements that make the GPS equipment more 
accurate and robust than sensors built to the minimum requirements in 
TSO-C129a. Two examples of these improvements are: (1) A requirement 
for the receiver to properly account for satellite range error if it is 
reflected in the User Range Accuracy index (commonly referred to as 
being ``Selective Availability aware''); and, (2) requirements to 
ensure performance is not degraded due to an increasing radio frequency 
noise environment as other satellite systems become available.
    Since 2005, there has only been one application for a TSO-C129a 
TSOA on a new article. Many manufacturers informally indicate they are 
transitioning, or planning to transition, their product lines to the 
new TSOs. Therefore, we believe cancelling TSO-C129a is an appropriate 
way to assist the natural phase-out/upgrade cycle given the eventual 
obsolescence of TSO-C129a equipment and industry's lack of interest in 
new TSO-C129a designs.

    Issued in Washington, DC, on October 7, 2011.
Susan J.M. Cabler,
Assistant Manager, Aircraft Engineering Division, Aircraft 
Certification Service.
[FR Doc. 2011-26449 Filed 10-12-11; 8:45 am]
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