After some thoughts about the location of the GMU 11 magnetometer it was time to mount the bracket.
TAF has a new location for the GMU 11, which is behind rib 5. Reason is that if there is luggage containing metal pieces which are stored in the extended baggage compartment it could interfere the magnetometer’s signal. But i don’t like this location since it’s pretty close to the rudder cables and at that location the inspection panel is small.
Since I’m not installing the extended baggage compartment it fine to install it at the old location. This old location is behind rib 4 and is next to the larger inspection panel. These holes are not punched so I asked TAF for the correct location:
TAF provided small flange aluminum rivnuts. Other builders made a doubler because these rivnuts were not clamping sufficient. I used larger M4 aluminum rivnuts which hold perfectly in the thin bracket. With a magnet I verified the parts were non-magnetic:
According to the Garmin manual the magnetometer should be within 0.5 degrees of the longitudinal axis of the airplane. However on the VAF forum a Garmin employee explained this a bit more in detail: link