User's Manual Part 2

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
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4--79
FMC system supported: ARINC 702 Flight Management System and other
non-- ARINC standard interface.
The minimum External Sensor input accuracies accepted for Aircraft Position are:
• Phase I (Take Off) 1 nmi
• Phase II (Outside Terminal or final area) 2 nmi
• Phase III (Terminal area) 1 nmi
• Phase IV (Final area) 0.5 nmi
(8) Aircraft Altitude
The T
2
CAS Aircraft Altitude input parameter is updated from an ADC or GPS source.
The T
2
CAS uses (but is not limited to) the following altitude types: Corrected
Barometric Altitude, GPS Altitude -- MSL and Uncorrected Barometric Altitude.
The minimum External Sensor input accuracy accepted for Aircraft Altitude is 95 feet
with 95% confidence.
(9) Navigation Accuracy
When using GPS or FMS data for aircraft position determination, the T
2
CAS uses
the available GPS or FMS signals to determine accuracy of the Position information..
(a) GPS
For a GPS source, the minimum External Sensor input accuracy accepted is
100m (333 feet) for an HDOP (Horizontal Dilution of Position) of 1.5 with S/A on.
(b) FMS
The T
2
CAS determines the Navigation Accuracy parameter by using the RNP
data value if a valid RNP data is received AND a valid FMS Discrete Word is
received with the Nav Mode set to ”High Accuracy”.
For FMS Discrete Word -- Type 2, bit 15 indicates high or low navigation
accuracy and is set independently of the navigation mode, bits 16 -- 18. The
FMS sets bit 15 (high accuracy) if the estimated error of the FMS position is less
than the phase of flight position accuracy tolerance listed in Table 4-- 20.
Otherwise the FMS resets bit 15 (low accuracy).
Table 4--20. Navigation Accuracy
Phase of Flight
Accuracy Tolerance
Approach 0.5 nm
Terminal 0.5 nm
Enroute FMS not in Degrade
Oceanic FMS not in Degrade