FAA Approved Airplane Flight Manual Supplement

190-00716-02 Rev. 3 Hawker Beechcraft King Air 300/300LW
Page 165 of 167
Autopilot Interface
The GFC700 autopilot uses the GP mode via the APR button to follow approach baro-VNAV guidance as
opposed to the VNAV mode via the VNV button. When coupled in GP mode, the autopilot will not
capture a preselected altitude while tracking a baro-VNAV glidepath.
Approach Downgrades
For approaches with minimums that support both SBAS and baro altitude vertical guidance, downgrading
or reverting to barometric altitude guidance is allowed prior to one minute before the FAF. If SBAS
becomes unavailable after the approach is active but prior to 60 seconds before the FAF, an approach
downgrade may be performed (e.g. LPV to LNAV/VNAV) or a vertical source reversion to baro altitude
may be performed (e.g. SBAS LNAV/VNAV to baro LNAV/VNAV).
If a loss of SBAS occurs prior to 60 seconds before the FAF, the system will determine whether or not the
approach mode can be supported using baro VNAV. If baro VNAV can be supported, the “APR
ADVISORY - SBAS VNAV not available. Using Baro VNAV.” message will be displayed on the PFDs and
the VDI will be flagged. If SBAS is required for the approach, the approach mode (e.g. LPV) will be
shown in amber but the GPS/SBAS VDI will be displayed until one minute prior to the FAF. If the SBAS
integrity has not been restored at one minute prior to the FAF, the system will display the “APR
DWNGRADE - Apr downgraded. Baro VNAV.” message and flag the VDI.
Once the pilot acknowledges either message by viewing it on the PFD, the VDI will be restored using
baro altitude vertical guidance instead of SBAS. There is no downgrade from SBAS to barometric
altitude after the FAF or within one minute of the FAF; “LNAV” is the only downgrade option in those
cases. For approaches using barometric vertical guidance, downgrade is not allowed; if altitude or
temperature data becomes invalid, the vertical deviation will be flagged.
Sensor Failures
Outside Air Temperature (OAT) Probe
The OAT from the selected side Air Data Computer will be used. If the OAT becomes invalid the VDI on
that side will be flagged as invalid. The crew must select the off-side Air Data Computer sensor and VDI
will return regardless of if prior to or after the FAF.
Sensor Comparison Annunciation
The temperature compensated altitudes from the pilot and co-pilot side are continuously compared. If a
miscompare of > 50 feet is detected the text “VDI MISCOMP” is displayed in the sensor comparison
annunciation area on the PFD in black text with an amber background.
When a temperature compensated altitude is not available for comparison, a “VDI NO COMP”
annunciation is posted in comparison annunciation area on the PFD in black text with a white
background.
Refer to the VDI MISCOMPARE ON BARO VNAV APPROACHES (VDI MISCOMP on PFD) and the
LOSS OF TEMPERATURE INPUT ON BARO VNAV APPROACHES (VDI NO COMP on PFD)
procedures in the Abnormal Procedures Section for additional information.