X-Plane previous to version 12 treated all flying surfaces (wing, tail, horizontal and vertical stabilizer) as one when it came to ice accumulation and anti- or de-ice measures. Newer versions treat the tail surfaces different from the wing surfaces.
Tail surface ice datarefs
Now the wing surfaces are separate from the tail surfaces. Each tail and wing surface can accumulate ice separately. The new datarefs for ice on the tail are
sim/flightmodel/failures/tail_ice float y ratio Ratio of icing on tailplane (hstab and vstab) - left side
sim/flightmodel/failures/tail_ice2 float y ratio Ratio of icing on tailplane (hstab and vstab) - right side
The new dataref that decides what to do with the tail is:
sim/cockpit2/ice/ice_tailplane_man int y enum De-ice tailplane automatically with wing/airframe deice, or separately with new datarefs. 0 = Auto, Default: Tail is deiced with whatever acts on the wings. 1 = Man: Tailplane de-ice is no longer slaved and must be turned on with separate datarefs.
Legacy aircraft use the “0” default setting, so all surface de-ice will automatically de-ice the tail as well, to preserve behavior from previous versions that did not distinguish between wing and tail surfaces.
Tail anti- and de-ice
For the tail, you now have the set of datarefs for the same options as for the wings:
sim/cockpit2/ice/ice_tail_heat_left_on int y boolean De-ice switch, 0 or 1. Anto-ice – electric heat. This switch engages electrically heated leading edges. (Left tailplanes)
sim/cockpit2/ice/ice_tail_heat_right_on int y boolean De-ice switch, 0 or 1. Anti-ice – electric heat. This switch engages electrically heated leading edges. (Right tailplanes)
sim/cockpit2/ice/ice_tail_boot_on int y enum De-ice switch, 0, 1, 2, 3. De-ice – pneumatic. This switch inflates flexible bladders on the wing leading edges to pop off accumulated ice. 0 = Off, 1 = Continuous, 2 = Single/Auto (deflates automatically), 3 = Man (deflates when switch let go) (All tailplanes)
sim/cockpit2/ice/ice_tail_boot_left_on int y enum De-ice switch, 0, 1, 2, 3. De-ice – pneumatic. This switch inflates flexible bladders on the wing leading edges to pop off accumulated ice. 0 = Off, 1 = Continuous, 2 = Single/Auto (deflates automatically), 3 = Man (deflates when switch let go) (Left tailplanes)
sim/cockpit2/ice/ice_tail_boot_right_on int y enum De-ice switch, 0, 1, 2, 3. De-ice – pneumatic. This switch inflates flexible bladders on the wing leading edges to pop off accumulated ice. 0 = Off, 1 = Continuous, 2 = Single/Auto (deflates automatically), 3 = Man (deflates when switch let go) (Right tailplanes)
sim/cockpit2/ice/ice_tail_hot_bleed_air_on int y boolean De-ice switch, 0 or 1. Anti-ice – bleed air. This switch directs warm air from the engines into the tailplane leading edges to keep them free of ice. (All tailplanes)
sim/cockpit2/ice/ice_tail_hot_bleed_air_left_on int y boolean De-ice switch, 0 or 1. Anti-ice – bleed air. This switch directs warm air from the engines into the tailplane leading edges to keep them free of ice. (Left tailplanes)
sim/cockpit2/ice/ice_tail_hot_bleed_air_right_on int y boolean De-ice switch, 0 or 1. Anti-ice – bleed air. This switch directs warm air from the engines into the tailplane leading edges to keep them free of ice. (Right tailplanes)
sim/cockpit2/ice/ice_tail_tks_on int y enum De-ice switch, 0, 1, or 2. Anti-ice – TKS fluid. This switch activates the pump for the weeping wing, dissipating TKS fluid on the leading edges to keep them free of ice. 0 = Off, 1 = Norm, 2 = High. (All tailplanes)
sim/cockpit2/ice/ice_tail_tks_left_on int y enum De-ice switch, 0, 1, or 2. Anti-ice – TKS fluid. This switch activates the pump for the weeping wing, dissipating TKS fluid on the leading edges to keep them free of ice. 0 = Off, 1 = Norm, 2 = High. (Left tailplanes)
sim/cockpit2/ice/ice_tail_tks_right_on int y enum De-ice switch, 0, 1, or 2. Anti-ice – TKS fluid. This switch activates the pump for the weeping wing, dissipating TKS fluid on the leading edges to keep them free of ice. 0 = Off, 1 = Norm, 2 = High. (Right tailplanes)
By default ( ice_tailplane_man == 0) all these are slaved to the wing counterparts – so if you switch anything on the wing on, the tail counterpart will go on, to preserve the old behavior. Also, the bleed air, TKS fluid, etc usage is tweaked so that it stays unchanged if both tail and wing are switched on (i.e. with both tail and wing on resource use equals former use of wing only).
If you chose to set the tailplane to manual (1) you can use all the new datarefs independently.
Pneumatic De-icing boots operation and animation
For the boots themselves: Two new datarefs exist for the inflation – these could be used to animate actual boots:
sim/cockpit2/ice/ice_wing_boots_inflation float[2] y ratio De-icing boots inflation ratio, left and right wing
sim/cockpit2/ice/ice_tail_boots_inflation float[2] y ratio De-icing boots inflation ratio, left and right tailplane
The boots take 6 seconds to inflate fully, and about three to be sucked empty again by vacuum. Note that the de-ice failure affects inflation, while lack of vacuum effects deflation.
Each boot switch dataref now has four settings:
0 = Off
1 = Continuous – this is to provide compatibility with 11.30. The boots are repeatedly cycled in auto mode whenever ice up to 0.2 has accumulated.
2 = Auto/Single – this initiates a six second inflation followed by a 3 second deflation regardless whether switch is sprung back or held in position.
3 = Man – this initiates an inflation and keeps the boots inflated for as long as the switch is held. Upon switching back to 0, deflation happens with vacuum.
The following commands are new to satisfy the new switch positions and act as if the switch is spring-loaded (the existing commands work for 0/Off and 1/Continuous for compatibility):
"sim/ice/wing_boot_single" ,"Anti-ice: all wing, de-icing boots single auto."
"sim/ice/wing_boot0_single" ,"Anti-ice: left wing, de-icing boots single auto."
"sim/ice/wing_boot1_single" ,"Anti-ice: right wing, de-icing boots single auto."
"sim/ice/wing_boot_man" ,"Anti-ice: all wing, de-icing boots manual."
"sim/ice/wing_boot0_man" ,"Anti-ice: left wing, de-icing boots manual."
"sim/ice/wing_boot1_man" ,"Anti-ice: right wing, de-icing boots manual."
All commands now have counterparts for tail:
"sim/ice/tail_heat_on" ,"Anti-ice: all tail, anti-ice heat on."
"sim/ice/tail_heat0_on" ,"Anti-ice: left tail, anti-ice heat on."
"sim/ice/tail_heat1_on" ,"Anti-ice: right tail, anti-ice heat on."
"sim/ice/tail_heat_off" ,"Anti-ice: all tail, anti-ice heat off."
"sim/ice/tail_heat0_off" ,"Anti-ice: left tail, anti-ice heat off."
"sim/ice/tail_heat1_off" ,"Anti-ice: right tail, anti-ice heat off."
"sim/ice/tail_heat_tog" ,"Anti-ice: all tail, anti-ice heat toggle."
"sim/ice/tail_heat0_tog" ,"Anti-ice: left tail, anti-ice heat toggle."
"sim/ice/tail_heat1_tog" ,"Anti-ice: right tail, anti-ice heat toggle."
"sim/ice/tail_boot_on" ,"Anti-ice: all tail, de-icing boots on schedule."
"sim/ice/tail_boot0_on" ,"Anti-ice: left tail, de-icing boots on schedule."
"sim/ice/tail_boot1_on" ,"Anti-ice: right tail, de-icing boots on schedule."
"sim/ice/tail_boot_off" ,"Anti-ice: all tail, de-icing boots off."
"sim/ice/tail_boot0_off" ,"Anti-ice: left tail, de-icing boots off."
"sim/ice/tail_boot1_off" ,"Anti-ice: right tail, de-icing boots off."
"sim/ice/tail_boot_tog" ,"Anti-ice: all tail, de-icing boots toggle."
"sim/ice/tail_boot0_tog" ,"Anti-ice: left tail, de-icing boots toggle."
"sim/ice/tail_boot1_tog" ,"Anti-ice: right tail, de-icing boots toggle."
"sim/ice/tail_boot_single" ,"Anti-ice: all tail, de-icing boots single auto.",
"sim/ice/tail_boot0_single" ,"Anti-ice: left tail, de-icing boots single auto."
"sim/ice/tail_boot1_single" ,"Anti-ice: right tail, de-icing boots single auto."
"sim/ice/tail_boot_man" ,"Anti-ice: all tail, de-icing boots manual.",
"sim/ice/tail_boot0_man" ,"Anti-ice: left tail, de-icing boots manual."
"sim/ice/tail_boot1_man" ,"Anti-ice: right tail, de-icing boots manual."
"sim/ice/tail_tai_on" ,"Anti-ice: all tail, bleed anti-ice on."
"sim/ice/tail_tai0_on" ,"Anti-ice: left tail, bleed anti-ice on."
"sim/ice/tail_tai1_on" ,"Anti-ice: right tail, bleed anti-ice on."
"sim/ice/tail_tai_off" ,"Anti-ice: all tail, bleed anti-ice off."
"sim/ice/tail_tai0_off" ,"Anti-ice: left tail, bleed anti-ice off."
"sim/ice/tail_tai1_off" ,"Anti-ice: right tail, bleed anti-ice off."
"sim/ice/tail_tai_tog" ,"Anti-ice: all tail, bleed anti-ice toggle."
"sim/ice/tail_tai0_tog" ,"Anti-ice: left tail, bleed anti-ice toggle."
"sim/ice/tail_tai1_tog" ,"Anti-ice: right tail, bleed anti-ice toggle."
"sim/ice/tail_tks_on" ,"Anti-ice: all tail, TKS de-ice normal."
"sim/ice/tail_tks0_on" ,"Anti-ice: left tail, TKS de-ice normal."
"sim/ice/tail_tks1_on" ,"Anti-ice: right tail, TKS de-ice normal."
"sim/ice/tail_tks_high" ,"Anti-ice: all tail, TKS de-ice high."
"sim/ice/tail_tks0_high" ,"Anti-ice: left tail, TKS de-ice high."
"sim/ice/tail_tks1_high" ,"Anti-ice: right tail, TKS de-ice high."
"sim/ice/tail_tks_off" ,"Anti-ice: all tail, TKS de-ice off."
"sim/ice/tail_tks0_off" ,"Anti-ice: left tail, TKS de-ice off."
"sim/ice/tail_tks1_off" ,"Anti-ice: right tail, TKS de-ice off."
"sim/ice/tail_tks_tog" ,"Anti-ice: all tail, TKS de-ice toggle."
"sim/ice/tail_tks0_tog" ,"Anti-ice: left tail, TKS de-ice toggle."
"sim/ice/tail_tks1_tog" ,"Anti-ice: right tail, TKS de-ice toggle."