ADS-B Certified Heartburn

[gbigs]

The FAA mandate for ADS-B continues to give heartburn to those who object to the $3-5k price tag. 

 

None more so than the Experimental and SLSA crowd.  After all, experimentals and SLSA have no current requirement to have certified avionics on their panels.  So why should either experimentals or SLSA now be forced to install certified WAAS GPS?

 

http://www.flyingmag.com/news/homebuilders-want-answers-ads-b-questions?cmpid=enews122214&spPodID=030&spMailingID=21886187&spUserID=NDcyODMyMzM0MjUS1&spJobID=462417968&spReportId=NDYyNDE3OTY4S0

[Kennith]

One thing that came to my attention while reading the FAA article on how to install ADS-B, is the requirement to comply with 91.217 (:

 

( No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder or with ADS-B Out equipment unless the pressure altitude reported for ADS-B Out and Mode C/S is derived from the same source for aircraft equipped with both a transponder and ADS-B Out.

 

Since there are transponders that now use their own internal altitude encoder, and even some that dont allow an external encoder to be used (such as the Sandia STX-165) in place of the internal encoder, there will be some configurations where it would be possible for a UAT to have a different source for the altitude than the transponder, which is clearly disallowed by 91.217(.

 

For example, the NavWorkx ADS600-B requires that a DB-37 connection be made to the UAT from an altitude encoder source, and care must be taken to make certain that the transponder is getting its altitude information from the same source as the UAT.

 

This is an installation issue that makes the Dynon look a lot simpler, since there is no UAT that could potentially have a different alitude source than the transponder.