Robert writes:
<< But the problem brought up a limitation to my panel - lack of ADHRS redundancy. I started shopping and found that a second Pinpoint might cost $17k whilst a new-and-improved Crossbow 425 is about $3k. >>

That is not how the system was designed to be configured. You can have two ADAHRS connected to the system, provided they are the same type. A menu page allows you to select which sensors (AHRS, ADC, GPS) are being displayed. All displays share the selected sensor. There is a monitor that flags when two sensors are reporting different values. This "Mis-compare" triggers a warning flag and tone. If the limits for the comparison were set so loose as to allow different sensors to be "compared" then the utility of the comparator would be very low.  Also, different ADAHRS speak in slightly different dialects. The CFS IDUs are multilingual but can only listen in one language at a time.

Since the 42x does not have an integral Air Data Computer, it must rely on GPS or air data from another sensor for part of its algorithm. This poses a significant limitation on response time. Even if it were possible, if a 42x (or most other ADAHRS) and a CFS ADAHRS were connected to the same system, the 42x would constantly be playing "catch up" and the mis-compare flags would be annoyingly chronic. To can play golf with Tiger Woods but  you shouldn't expect your scores to be the same.

The other problem is, as Micah and Bruce understand,  that if there is a failure, who do you believe? You need a mechanical gyro as a reference. Your standby gauges should not only be independent but they should also be based on different physics.  I cringe every time I see glass (such as a Dynon) as a standby in a glass panel. Whatever breaks your big glass will likely break your little glass too. A spinning mass gyro is a pretty good, basic "Gold Standard" that is familiar to most pilots. If the gyro says you are in a bank then you are probably in a bank or, as a diving buddy once said; "If you are at 160 feet, feeling the N2, and you bubbles are going "down".... Follow Them!"

As for price comparison,  you need to compare a TSO'ed AHRS with remote magnetometer and a TSO'ed Air Data Computer.  Even at $17 K the CFS ADAHRS is a bargain.  You would need to spend twice that for a Rockwell Collins or Litef AHRS to achieve the same level of performance.

Finally, I am pleased (especially given the demand for the ADAHRS) that CFS is giving you quality service and sending a replacement GADAHRS. I am aware of two other cases where they did this and neither time did it fix the root problem. Also be aware that if the dropout you experienced was due to a deficiency in the wiring at the connector, simply unplugging and reseating the connectors may "fix" the problem.  I will have CFS forward the returned unit for investigation. Once you are flying, be sure to allow sufficient testing time to qualify the system AND THE INSTALLATION before using it in a mission critical capacity.

Regards
Brent Regan