NORTHROP GRUMMAN NAVITWIN IV, Руководство по эксплуатации, установке и обслуживанию

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NAVITWIN IV 056360/E
Sequence of Events and Actions 3-3
Note
The compass status of the new heading source changes also immedi-
ately within the PPLAN message from „1“ to „2“.
The track controller/INS and other devices connected to the GAS
serial data output are transmitted the GAS substitute heading under
alignment conditions.
These devices will continue to operate without disruption.
– The substitute heading value is indicated
as the active heading in the heading dis-
play.
– A „GAS Changeover Gyro 2“
(CHANGEOVER GYRO) warning mes-
sage appears in the alarm window.
The second line of the message indicates
the secondary source which will now
become the internal heading reference.
While, initially, the substitute heading equals the last known heading
from the active source, dynamic changes of the secondary heading
(vessel turning) are applied to the substitute heading immediately.
3.
Event:
GAS substitute heading is aligned with secondary source.
– The substitute heading value gradually
approaches the secondary source’s
heading.
– Once both headings are equal, the sub-
stitute heading value disappears from
the display.
– The GAS mode is automatically termi-
nated after the GAS heading substitution
is completed.
To prevent sudden rudder actions, the NAVITWIN IV performs a soft
transition at the GAS serial data output from the last known heading
of the failed source to the actual heading from the secondary source:
The difference (if any) between the two headings at the time of fail-
ure of the active source is gradually reduced. The rate at which this
approach takes place is determined by the “GAS time constant” as
set in the Service Setup.
Change over to manual steering.
As a recommendation, the operator may change to the manual
steering mode and steer the vessel by hand to gain an overview of
the navigational situation.
Changing over to the manual steering mode is not necessarily
required and does not terminate the GAS heading substitution.
The track controller/INS will continue to receive valid heading data
by the second source and no alarm will be raised.
DISPLAY DATA
MONITOR
ALARM (2/2)
CHANGEOVER
GYRO
Hdg. Diff
10°
Gyro 1
Gyro 2
GYRO
1
GYRO
2
MAGN
COMP
247.7
247.0
12.8 kn
AUTO
SPEED
- - - . -
DISPLAY DATA
MONITOR
ALARM (2/2)
CHANGEOVER
GYRO
Hdg. Diff
10°
Gyro 1
Gyro 2
GYRO
1
GYRO
2
MAGN
COMP
247.7
247.0
12.8 kn
AUTO
SPEED
- - - . -