fix(a380x/air cond): wasm crash during rapid decompression (flybywire…

…sim#9543) * fix: wasm crash during decompression * docs: changelog * fix: comments in update_ambient_conditions in cpiom_b
BlueberryKing · Nov 24, 2024 · ebb7cca · ebb7cca
1 parent a526ab6
commit ebb7cca
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Showing 6 changed files with 17 additions and 7 deletions.
diff --git a/.github/CHANGELOG.md b/.github/CHANGELOG.md
@@ -76,6 +76,7 @@
 1. [A32NX] Fixed appearance of FCU decals on MSFS2024 - @tracernz (Mike)
 1. [FMS] Fixed issue with airport loading timing out on MSFS2024 - @tracernz (Mike)
 1. [A32NX] Fixed APU fire detection - @tracernz (Mike)
+1. [A380X/COND] Fix wasm crash during rapid decompression - @mjuhe (Miquel Juhe)
 
 ## 0.12.0
 

diff --git a/fbw-a380x/src/wasm/systems/a380_systems/src/air_conditioning/cpiom_b.rs b/fbw-a380x/src/wasm/systems/a380_systems/src/air_conditioning/cpiom_b.rs
@@ -1287,7 +1287,11 @@ impl<C: PressurizationConstants> CabinPressureControlSystemApplication<C> {
                 && (altimeter_setting.unwrap_or_default().get::<hectopascal>() - Air::P_0).abs()
                     > f64::EPSILON)
         {
-            altimeter_setting.unwrap()
+            if altimeter_setting.unwrap() == Pressure::default() {
+                Pressure::new::<hectopascal>(Air::P_0)
+            } else {
+                altimeter_setting.unwrap()
+            }
         } else {
             Pressure::new::<hectopascal>(Air::P_0)
         }

diff --git a/...ystems/a380_systems/src/air_conditioning/local_controllers/full_digital_agu_controller.rs b/...ystems/a380_systems/src/air_conditioning/local_controllers/full_digital_agu_controller.rs
@@ -363,7 +363,7 @@ impl<const ENGINES: usize> PackFlowController<ENGINES> {
 
         if self.should_open_fcv {
             self.pid
-                .change_setpoint(pack_flow_demand.get::<kilogram_per_second>());
+                .change_setpoint(pack_flow_demand.get::<kilogram_per_second>().max(0.));
             self.pid.next_control_output(
                 self.pack_flow.get::<kilogram_per_second>(),
                 Some(context.delta()),

diff --git a/fbw-a380x/src/wasm/systems/a380_systems/src/air_conditioning/mod.rs b/fbw-a380x/src/wasm/systems/a380_systems/src/air_conditioning/mod.rs
@@ -385,7 +385,7 @@ pub(super) struct A380AirConditioningSystem {
 }
 
 impl A380AirConditioningSystem {
-    const CAB_FAN_DESIGN_FLOW_RATE_L_S: f64 = 550.; // litres/sec
+    const CAB_FAN_DESIGN_FLOW_RATE_L_S: f64 = 1250.; // litres/sec
 
     fn new(context: &mut InitContext, cabin_zones: &[ZoneType; 18]) -> Self {
         Self {

diff --git a/fbw-common/src/wasm/systems/systems/src/air_conditioning/acs_controller.rs b/fbw-common/src/wasm/systems/systems/src/air_conditioning/acs_controller.rs
@@ -693,8 +693,8 @@ impl ZoneController {
         pressurization: &impl CabinAltitude,
         zone_measured_temperature: ThermodynamicTemperature,
     ) -> ThermodynamicTemperature {
-        let altitude_correction: f64 =
-            pressurization.altitude().get::<foot>() * Self::K_ALTITUDE_CORRECTION_DEG_PER_FEET;
+        let altitude_correction: f64 = pressurization.altitude().get::<foot>().max(0.)
+            * Self::K_ALTITUDE_CORRECTION_DEG_PER_FEET;
         let corrected_selected_temp: f64 =
             self.zone_selected_temperature.get::<kelvin>() + altitude_correction;
 

diff --git a/fbw-common/src/wasm/systems/systems/src/air_conditioning/mod.rs b/fbw-common/src/wasm/systems/systems/src/air_conditioning/mod.rs
@@ -7,7 +7,7 @@ use crate::{
         ControllablePneumaticValve, PneumaticContainer, PneumaticPipe, PneumaticValveSignal,
     },
     shared::{
-        arinc429::Arinc429Word, low_pass_filter::LowPassFilter, AverageExt, CabinSimulation,
+        arinc429::Arinc429Word, low_pass_filter::LowPassFilter, AverageExt, CabinSimulation, Clamp,
         ConsumePower, ControllerSignal, ElectricalBusType, ElectricalBuses,
     },
     simulation::{
@@ -534,10 +534,15 @@ impl CabinFan {
         let mass_flow: f64 = (self.outlet_air.pressure().get::<pascal>()
             * self.design_flow_rate.get::<cubic_meter_per_second>())
             / (Air::R * self.outlet_air.temperature().get::<kelvin>());
+        let max_mass_flow = mass_flow * Self::FAN_EFFICIENCY;
         // If we have flow demand calculated, we assign this directly to the fan flow
         // This is a simplification, we could model the fans, send the signal and read the output
         recirculation_flow_demand
-            .unwrap_or(MassRate::new::<kilogram_per_second>(mass_flow) * Self::FAN_EFFICIENCY)
+            .unwrap_or(MassRate::new::<kilogram_per_second>(max_mass_flow))
+            .clamp(
+                MassRate::default(),
+                MassRate::new::<kilogram_per_second>(max_mass_flow),
+            )
     }
 
     pub fn has_fault(&self) -> bool {