I was pleased to see X-bow step and confirm their commitment directly to the end customer.  This illustrated the benefits of having dealing with a company that has a presence in the certified aircraft market. I hope that X-bows treatment of one of its larger customers, D2, does not serve as a model.

It was interesting to note that while solid state rate sensors do not have twirling masses, the urge to spin appears irresistible. There were two comments in the X-bow response that do not represent the whole truth.

The statement "customers have experienced intermittent startup, GPS, and EMI problems when the Crossbow NAV425EX AHRS is used in conjunction with the Direct-To Avionics EFIS products" leaves the impression that only in combination do the problems manifest. D2 is a Chelton licensee and the Chelton EFIS products (both hardware and software)  have been flight tested with most of the commercially available AHRS systems (LITEF, Rockwell Collins,  X-bow 500, Omnipless, Watson, etc.) and none of these systems have demonstrated the 425's consistent predilection to go Tango Uniform.  (Watson was disqualified as a supplier for performance issues.)  D2's customers discovered the problem with the 425 and D2 brought it to X-bow's attention. Don't  blame the messenger.

"The NAV425EX is a modified low cost version of our standard NAV420 catalog product and is built to a Direct-To Avionics specification."  One of D2's "specifications" was that the 425 perform reliability. While the 425 may have been "built" to meet this requirement, its performance does not. Thus the problem.

Engineers fix problems. Lawyers fix blame.

Regards
Brent Regan