Installing Dynon Skyview system. Reading install manual last night and I think it said to install at less than one degree from level of three axis. Of course it was getting late, and the letters were fuzzy, it was past 7:30 pm!
No, you didn't imagine it. The Dynon installation requirement seems to be far more stringent than Garmin's:
Mounting requirements for the SV-ADAHRS-200:• Must be mounted within one (1) degree of parallel to all three (3) aircraft axes,• The pneumatic fittings must face toward the front of the aircraft,• The mounting tabs must be towards the bottom of the aircraft, with the label towards the top of the aircraft.
Garmin GSU 25 allows several different orientations and precise alignment is only required in one axis:
19.4.1 Mounting/Calibration Overview
It is critical that the GSU 25 is mounted in alignment with the centerline of the aircraft. The GSU 25 must
be mounted with the connectors aligned within 1.0 degree of either the longitudinal or lateral axis of the
aircraft. (see Section 19.4.1 for complete requirements)
The specification for mounting the GSU 25 such that it is level with respect to pitch/roll of the aircraft is
not nearly as restrictive, and must only be within 30.0 degrees in each axis. In most installations, the
GSU 25 is mounted relatively level with respect to the zero waterlines of the aircraft (e.g. longerons), even
though it is not required (again, must only be within 30.0 degrees). (see Section 19.4.2 for complete
requirements
Calibrating the pitch/roll offsets is also a crucial part of the installation (see Section 35.4.7). During
calibration, while on the ground, the aircraft must be level in both pitch/roll such that it accurately
represents the in-cruise attitude of the aircraft. This part of the calibration determines that the displayed
measured attitude of the GSU 25 is zero degrees in pitch/roll when the aircraft is in level, coordinated
cruise flight. (Note that the PFD allows +/- 5 degrees of pitch offset adjustment in flight. This allows the
pilot to adjust the pitch offset while in flight to show a correct attitude indication on the PFD, even if the
pitch attitude was slightly off when the on the ground pitch/roll offset calibration was performed.)
I find it interesting that Garmin is able to calibrate for misalignment but Dynon is not. I have no experience with Dynon systems.