S201 AFM
7 - AIRPLANE AND SYSTEMS
DESCRIPTION
7.7 - INSTRUMENTS AND
AVIONICS
27/06/2019
SONAIR-S2-D-MAN-006
Page : 7-30
Rev. : A
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Lateral Deviation Indicator (LDI)
A Lateral Deviation Indicator (LDI) is always displayed on the PFD above the
heading display. This LDI shows course deviation, navigation source, and VLOC
station identifier or GPS phase of flight. The LDI uses the same color convention
as the HIS.
The LDI incorporates automatic reverse sensing correction into the deviation
display. When the difference between the heading and the selected course is
greater than 107°, the LDI will enable reverse sensing correction. Reverse sensing
correction inverts the course deviation needle and to/from indicator so that they
correctly indicate the direction of the course and waypoint. The course deviation
needle will be deflected in the direction of the desired course, and the to/from
indicator will point in the direction of the waypoint (similar to how the HIS
depiction inverts with heading changes).
Message, waypoint, OBS, SUSP, phase of flight, LOI, and DR annunciations from
the GTN interfaced to the Txi are annunciated on the upper CDI.
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Vertical Deviation Indication (VDI)
Vertical guidance is shown by a vertical deviation indicator (VDI) inboard of the
barometric altitude tape. The VDI displays either glideslope (GS) information
from an ILS source or glidepath (GP) information from for a GPS approach.