GRT Avionics, Inc.
May 2019
Sport SX Install. Manual
16
Rev. A
The PFD display unit also contains the Air Data Computer. The ADC requires connection
to the aircraft
’s pitot-static system. Connections on the display unit take a 1/8 – 27 NPT
male fitting. To facilitate installation and removal of the display unit, quick disconnect
fittings may be helpful. Connections and the entire pitot-static system must be leak tight.
Refer to AC 43.13-2B for approved methods to achieve this.
Consider placing a water trap or drain in the lowest part of the pitot-static system to
prevent water from getting into the electronics. Make sure the drain is of a high enough
quality that it seals completely airtight when closed.
3-6: Angle-of-Attack Pressure Port Connection
When equipped with the sensed angle-of-attack (AOA) option, the pitot-static block will
also include a port for sensing the AOA using a dual port pitot tube. This type of pitot tube
provides the pitot pressure for sensing indicated airspeed and a second pitot pressure for
sensing AOA. Typically, this AOA pitot is positioned about 60° down from the pitot used
to sense indicated airspeed. This probe is available from several third-party sources, or
may be fabricated by the builder by adding a second pitot tube, bent to point 60° below
the pitot used for airspeed. When constructing your own AOA pitot, it should be mounted
as close as practical to the airspeed pitot.
Use the appropriate tubing to make an air-tight connection between the AOA pitot and
t
he AOA port on the EFIS. The AOA port is located between the pitot (marked “P”) and
the static (marked “S”) ports.
