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

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Federal Aviation Administration (FAA), DOT


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


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.


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

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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:

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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.


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.

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Issued in Washington, DC, on October 7, 2011.

Susan J.M. Cabler,

Assistant Manager, Aircraft Engineering Division, Aircraft Certification Service.

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[FR Doc. 2011-26449 Filed 10-12-11; 8:45 am]