Sandel ST3400 - Additional Required Sensors, Allowed Configurations (Class-B); Optional Capabilities for Class-B, Needed Sensors; Altitude Sources and Airdata

2.3.2 Additional Required Sensors, allowed configurations (Class-B)
Config
GPS Alt
Corr. Baro Alt
Baro Rate (VS)
OAT
1
x
2
x
x
x
(item shown blank not required)
Contact factory for configurations other than those listed.
2.3.3 Optional Capabilities for Class-B, needed Sensors
The following chart will assist in installation planning to add capabilities in
exceedence of Class-B requirements. Without these capabilities GPWS modes 2,
4 and 5 are inoperative. With all the capabilities enabled full Class-A
performance is provided, which provides autonomous GPWS protection if the
GPS/FMS should fail.
Capability Desired
Sensors Needed
GPWS Mode-2 ECRT
Radar Altitude; Baro Rate (VS); Flaps; Gear
2
Optional
GPWS Mode-4 FITNL
Radar Altitude, Baro Rate (VS); Flaps; Gear
2
GPWS Mode-5 Glideslope
1
Localizer; Glideslope; Gear
2
and/or Flaps
1
Sandel recommended.
2
Req’d only on retractable-gear aircraft
2.4 Altitude Sources and Airdata
Airdata hookup is one of the more complex installation planning issues since
there are many variations in types of airdata systems. This is particularly true of
aircraft upgraded for RVSM, where the altitude source may be a new digital
altimeter but the VS source may be the original airdata computer, which has been
left in the aircraft to interface with other existing systems. In order to make a
flexible system that requires as little additional equipment as possible, the ST3400
supports separate selection of sources for Altitude, Vertical Speed, and OAT.
Please pay careful attention this fact when planning installation. See section
2.4.1 Airdata System Block Diagram.
ST3400 software 1.05 and earlier requires Corrected Barometric Altitude for
either Class-A or Class-B installations. ST3400 software 2.00 and later supports
GPS altitude or Corrected Barometric Altitude, or both. If both are supplied CBA
is used as a backup to GPS altitude if available. See the installation diagrams for
a list of approved receivers which can supply GPS altitude to the ST3400
For Class-A, at a minimum Barometric Vertical Speed and Barometric Altitude
(either corrected or uncorrected) is required. This is used for the classic GPWS
portion of the alerting system, such as mode-1 “Excessive Descent Rate” etc.
For Class-B, if GPS altitude is used, no other source of altitude is required; i.e.
airdata is not required.
ST3400 INSTALLATION MANUAL 82002-IM-L
2-2