diff --git a/engine/src/cmd/unit_generic.cpp b/engine/src/cmd/unit_generic.cpp
index 7d2687c3a..85e05dc80 100644
--- a/engine/src/cmd/unit_generic.cpp
+++ b/engine/src/cmd/unit_generic.cpp
@@ -3055,7 +3055,6 @@ bool Unit::UpAndDownGrade(const Unit *up,
         }
     }
 
-    bool upgradedshield = false;
 
     if (!csv_cell_null_check || force_change_on_nothing
             || cell_has_recursive_data(upgrade_name, up->faction, "Shield_Front_Top_Right")) {
@@ -3072,10 +3071,6 @@ bool Unit::UpAndDownGrade(const Unit *up,
                     shield->facets[i].health = shield->facets[i].max_health;
                 }
             }
-
-            if (touchme && retval == UPGRADEOK) {
-                upgradedshield = true;
-            }
         } else if (up->FShieldData() > 0 || up->RShieldData() > 0 || up->LShieldData() > 0 || up->BShieldData() > 0) {
             cancompletefully = false;
         }
@@ -3296,6 +3291,29 @@ int Unit::RepairCost() {
     if (LifeSupportFunctionalityMax < 1) {
         ++cost;
     }
+
+    // TODO: figure out better cost
+    if (afterburner.Damaged()) {
+        cost += 5;
+    }
+
+    if (afterburner_upgrade.Damaged()) {
+        cost += 3;
+    }
+
+    if (drive.Damaged()) {
+        cost += 7;
+    }
+
+    if (drive_upgrade.Damaged()) {
+        cost += 5;
+    }
+
+    if (ftl_drive.Damaged()) {
+        cost += 7;
+    }
+
+
     for (i = 0; i < numCargo(); ++i) {
         if (GetCargo(i).GetCategory().find(DamagedCategory) == 0) {
             ++cost;
@@ -3304,6 +3322,7 @@ int Unit::RepairCost() {
     return cost;
 }
 
+// This is called when performing a BASIC_REPAIR
 int Unit::RepairUpgrade() {
     vector<Cargo> savedCargo;
     savedCargo.swap(cargo);
@@ -3369,6 +3388,14 @@ int Unit::RepairUpgrade() {
         pct = 1;
         success += 1;
     }
+
+    // Repair components
+    afterburner.Repair();
+    afterburner_upgrade.Repair();
+    drive.Repair();
+    drive_upgrade.Repair();
+    ftl_drive.Repair();
+
     damages = Damages::NO_DAMAGE;
     bool ret = success && pct > 0;
     static bool ComponentBasedUpgrades =
@@ -3826,7 +3853,9 @@ bool isWeapon(std::string name) {
     }                                                        \
     while (0)
 
+// This is called every cycle - repair in flight by droids
 void Unit::Repair() {
+    // TODO: everything below here needs to go when we're done with lib_components
     static float repairtime = XMLSupport::parse_float(vs_config->getVariable("physics", "RepairDroidTime", "180"));
     static float checktime = XMLSupport::parse_float(vs_config->getVariable("physics", "RepairDroidCheckTime", "5"));
     if ((repairtime <= 0) || (checktime <= 0)) {
diff --git a/engine/src/components/afterburner.cpp b/engine/src/components/afterburner.cpp
index 8caaa9c8c..160afd4b7 100644
--- a/engine/src/components/afterburner.cpp
+++ b/engine/src/components/afterburner.cpp
@@ -47,6 +47,9 @@ void Afterburner::Load(std::string upgrade_key,
     speed = Resource<double>(UnitCSVFactory::GetVariable(unit_key, "Afterburner_Speed_Governor", std::string("0.0")), game_speed); 
     double consumption = UnitCSVFactory::GetVariable(unit_key, "Afterburner_Usage_Cost", 1.0);
     SetConsumption(consumption);
+
+    // We calculate percent operational as a simple average
+    operational = (thrust.Percent() + speed.Percent()) / 2 * 100;
 }      
 
 void Afterburner::SaveToCSV(std::map<std::string, std::string>& unit) const {
@@ -79,6 +82,7 @@ void Afterburner::Damage() {
     thrust.RandomDamage();
     speed.RandomDamage();
 
+    // We calculate percent operational as a simple average
     operational = (thrust.Percent() + speed.Percent()) / 2 * 100;
 }
 
diff --git a/engine/src/components/component.cpp b/engine/src/components/component.cpp
index 4ac7f8c33..84eefb8bd 100644
--- a/engine/src/components/component.cpp
+++ b/engine/src/components/component.cpp
@@ -123,7 +123,7 @@ void Component::Repair() {
 }
 
 bool Component::Damaged() const {
-    return operational.Damaged();
+    return operational.Value() < operational.MaxValue();
 }
 
 bool Component::Destroyed() const {
diff --git a/engine/src/components/drive.cpp b/engine/src/components/drive.cpp
index 57d838645..0c3a1aa20 100644
--- a/engine/src/components/drive.cpp
+++ b/engine/src/components/drive.cpp
@@ -96,6 +96,13 @@ void Drive::Load(std::string upgrade_key,
 
     speed = Resource<double>(UnitCSVFactory::GetVariable(unit_key, "Default_Speed_Governor", std::string("0.0")), 
                                                          game_speed, minimal_drive_functionality);
+
+    // We calculate percent operational as a simple average
+    operational = (yaw.Percent() + pitch.Percent() + roll.Percent() +
+                  lateral.Percent() + vertical.Percent() + forward.Percent() + 
+                  retro.Percent() + speed.Percent() +
+                  max_yaw_left.Percent() + max_yaw_right.Percent() + max_pitch_down.Percent() +
+                  max_pitch_up.Percent() + max_roll_left.Percent() + max_roll_right.Percent()) / 14 * 100;
 }      
 
 
@@ -164,6 +171,7 @@ void Drive::Damage() {
     max_roll_left.RandomDamage();
     max_roll_right.RandomDamage();
 
+    // We calculate percent operational as a simple average
     operational = (yaw.Percent() + pitch.Percent() + roll.Percent() +
                   lateral.Percent() + vertical.Percent() + forward.Percent() + 
                   retro.Percent() + speed.Percent() +