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below 950’ radar altitude. In a Class B installation without radar
altitude, the calculated height above terrain from the terrain
database is substituted. Note: In your installations, Mode 5 may
automatically inhibited when flying a back course approach
through interconnection to the HSI or Flight Control System.
VC
Mode 6 (Altitude Callout). Provides a voice callout “Five
Hundred” when the aircraft descends through 500 feet radar
altitude with the gear down. In a Class B installation without
radar altimeter, this callout will occur 500 feet above the runway
elevation using aircraft altitude compared to the nearest runway
touchdown zone elevation.
Mode 6 Enhanced:
On Radar Altitude equipped aircraft,
additional voice callouts at 400, 300, 200, 100, 50, 40, 30, 20,
and 10 feet of radar altitude may be enabled during installation.
Please refer to the AFMS for details on the specific installation
in your aircraft. (Radar Altitude equipped aircraft only)
On equipped aircraft, a voice callout of “Minimums, Minimums’
can be provided triggered by an external decision-height setter.
Please refer to the AFMS for details on the specific installation
in your aircraft.
Note: The “Minimums” callout is inhibited for 40 seconds after
power-up, and will only occur when the aircraft is airborne.
TAWS ALERTS
FLTA
(Forward Looking Terrain Avoidance)
Looks ahead of the aircraft along the lateral and vertical flight
path against the terrain database to provide an alert if a potential
terrain threat exists.
PDA (Premature
Decent
Alert)
Uses the vertical and lateral position of the aircraft compared to
the proximity of the nearest airport to determine if the aircraft is
abnormally below a reasonable altitude.
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CHAPTER 2. ST3400 SMART FEATURES
One characteristic of terrain displays is that they become more cluttered as
the aircraft approaches the ground, even during a normal approach. This
characteristic – more and more detail with more and more colors – may
have the unwanted effect of producing less and less information.
The concept of the ST3400 is “don’t show everything all the time”.
Instead, during normal conditions, the ST3400 allows the pilot to select
different views of the same terrain information specifically tailored to the
pilot’s needs and appropriate to emergency conditions. This concept is a
very direct way to reduce information overload during normal flight or
emergencies and assist the pilot in making the right choices.
Runway Awareness
¥
The conventional way to implement Terrain Warning is to use ever rising
concentric circles around the ARP (Airport Reference Point) and use these
to inhibit terrain alerts. The goal is to reduce nuisance alerts when
maneuvering or landing at airports.
Instead, the ST3400 recognizes each and every runway and tracks the
aircraft’s approach and landing to the touchdown zone. The ST3400
internal database contains the safe approach path – based on TERPS terrain
clearances – to every charted runway, whether it has an instrument
approach or not.