Section 3 In-Flight Procedures
2nd Ed Aug 2019
S-TEC 3100 Digital and Analog
3-4
3.6.1.
Envelope Speeds for FIKI Aircraft
FIKI aircraft may have two different underspeed protection limits if the prop
de-ice system power has been tied to the 3100. With the de-icing system
activated the underspeed limit increases to match the increase in stall
speed value for flying in icing conditions.
A remotely mounted LED in the aircraft panel labeled “AP ICE SPEED”
illuminates when the higher underspeed limit is in effect.
3.6.2. Passive Envelope Protection
Passive envelope protection is operating anytime FD mode is engaged,
indicated by the FD LED being illuminated.
1)
Underspeed
alert activates if the aircraft speed reaches the low speed
limit, which triggers an audible alarm followed by an “Airspeed, Airspeed”
voice alert. Alerts continue until the aircraft speed is increased beyond
the underspeed recovery limit as stated in the AFMS
2)
Overspeed
alert activates if the aircraft speed reaches the high speed
limit, which triggers an audible alarm followed by an “Overspeed,
Overspeed” voice alert. Alerts continue until the aircraft speed is
reduced below the overspeed recovery limit as stated in the AFMS.
3)
Excessive Bank
alert activates if the aircrafts roll attitude exceeds
60 degrees, which triggers an audible alarm followed by an “Attitude,
Attitude” voice alert. Alerts continue until the aircraft roll attitude is
reduced below 60 degrees.
3.6.2.1. Passive Envelope Protection on Approach
The overspeed and underspeed audible alarms and visual alerts are
disabled when the 3100 is in any of the approach modes (APR
LOC
, APR
GPSS
,
or APR
GPSV
) and the 3100 is in FD only (AP not engaged). This allows
pilots to hand fly slower approaches but retain flight director
command bar
guidance and to avoid nuisance speed callouts if AP is disconnected at
minimums but the FD remains engaged.
3.6.3. Active Envelope Protection
Active envelope protection is operating anytime AP mode is engaged,
indicated by the illuminated AP LED. Although excessive bank is still active,
it is not relevant while AP is engaged as the 3100 is already under control
of bank commands.