Dynon Avionics SkyView System Installation Guide - Manual (Page 105)

SV-ADAHRS-200/201 Installation and Configuration
SkyView System Installation Guide – Revision S 5-13
adjustment affects both the displayed altitude and the encoded altitude that is sent to other
devices. It should only be adjusted if altitude is found to be incorrect (by comparing it against a
known source or field elevation, AFTER the BARO setting has been set to correctly to known
atmospheric conditions) after SkyView has fully warmed up.
Zero Pressure Airspeed Calibration
This calibration routine samples pitot and static pressures in a windless environment to allow
SkyView to provide the best indicated airspeed readings that are possible at very low airspeeds.
It is not a required calibration step, but performing this calibration may improve airspeed
accuracy at very low indicated airspeeds. It is important that this calibration is done in an
absolutely windless environment, such as a closed hangar. Additionally, before performing this
calibration, cover both the pitot and static ports with a sock or cloth to minimize airflow
WITHOUT putting any air pressure on the pitot or static ports.
Performing Pitot-Static Checks
Background
Dynon ADAHRS units use airspeed in the calculation of attitude (or GPS ground speed when
airspeed is unavailable). The internal rate sensors are monitored and calibrated in flight using
feedback from the accelerometers and from airspeed to achieve a highly accurate attitude
solution.
When a pitot or static test is performed the ADAHRS is being exposed to dynamics that are
impossible to achieve in a real aircraft flight environment, namely, large airspeed changes
without the accompanying accelerations and rotations. This false condition will cause a well-
calibrated unit to incorrectly adjust its calibration. Furthermore, when a unit is in a test
situation a change in applied pitot or static pressure will cause the attitude to pitch up or down.
This is expected.
Performing the following Dynon-prescribed pitot and static test procedure to a Dynon ADAHRS
will prevent problems with the unit’s performance in flight.
Pitot/Static Test Instructions
Basic Principles

Ensure SkyView is warmed up during each test reading.

SkyView should be powered off when changing pressures.

Keep aircraft still (do not move) when pressure is applied.
Steps
1. The aircraft itself should be temperature stable. For example, if the aircraft is moved
from outside in the sun to a hangar for testing, tests should not be started until the
airplane has stabilized at the hangar temperature.