Add on-condition (RCM) maintenance mode for TBO-tracked components

Operators following Reliability-Centered Maintenance can mark a component
as "Maintained On-Condition" when TBO tracking is enabled. This switches
the hours-remaining display from red/orange warning colors to a positive
blue→teal→green gradient (approaching/at/past TBO), and shows the status
badge as blue rather than red when over TBO. Calendar remaining uses a flat
informational blue when over TBO — no gradient, to avoid encouraging over-TBO
calendar operation the same way hours does. An "On-Condition" label appears
in the expanded component detail panel. Service-interval (replacement_critical)
warnings are unaffected.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: marbindrakon

core/export.py

@@ -116,6 +116,7 @@ def _component_dict(component):
         'replacement_hours': component.replacement_hours,
         'replacement_days': component.replacement_days,
         'tbo_critical': component.tbo_critical,
+        'on_condition': component.on_condition,
         'inspection_critical': component.inspection_critical,
         'replacement_critical': component.replacement_critical,
     }

core/import_export.py

@@ -670,6 +670,7 @@ def _check_fk(record_type, field, value, valid_set, nullable=True):
                         replacement_hours=c_data.get('replacement_hours'),
                         replacement_days=c_data.get('replacement_days'),
                         tbo_critical=c_data.get('tbo_critical', True),
+                        on_condition=c_data.get('on_condition', False),
                         inspection_critical=c_data.get('inspection_critical', True),
                         replacement_critical=c_data.get('replacement_critical', False),
                     )

core/static/css/app.css

@@ -653,6 +653,22 @@
     font-weight: 500;
 }
 
+/* On-condition TBO: inverted/positive coloring (blue approaching TBO, teal at TBO, green past 150%) */
+.hours-on-condition {
+    color: var(--pf-v5-global--info-color--100);
+    font-weight: 500;
+}
+
+.hours-on-condition-over {
+    color: #009596;
+    font-weight: 600;
+}
+
+.hours-on-condition-extended {
+    color: var(--pf-v5-global--success-color--100);
+    font-weight: 600;
+}
+
 /* ========================================
    Theme Toggle
    ======================================== */
@@ -1028,6 +1044,18 @@ html.pf-v5-theme-dark .pf-v5-c-label.pf-m-gold   { color: var(--pf-v5-global--pa
         background-color: var(--pf-v5-global--danger-color--100, #c9190b);
     }
 
+    .component-progress-fill.hours-on-condition {
+        background-color: var(--pf-v5-global--info-color--100, #06c);
+    }
+
+    .component-progress-fill.hours-on-condition-over {
+        background-color: #009596;
+    }
+
+    .component-progress-fill.hours-on-condition-extended {
+        background-color: var(--pf-v5-global--success-color--100, #3e8635);
+    }
+
     .component-fraction-sublabel {
         font-size: 0.78rem;
         opacity: 0.75;

core/static/js/aircraft-detail-components.js

@@ -41,6 +41,7 @@ function componentsMixin() {
             replacement_hours: '',
             replacement_days: '',
             tbo_critical: true,
+            on_condition: false,
             inspection_critical: true,
             replacement_critical: false,
         },
@@ -99,6 +100,31 @@ function componentsMixin() {
         },
 
         getHoursRemainingClass(component) {
+            // On-condition: positive color scheme (blue approaching TBO, green past TBO).
+            // Only applies when TBO is the primary tracked interval (not service replacement).
+            const useOnCondition = component.on_condition && component.tbo_critical &&
+                !(component.replacement_critical &&
+                    (component.replacement_hours || component.replacement_days));
+            if (useOnCondition) {
+                if (component.tbo_hours) {
+                    const ratio = (component.hours_since_overhaul || 0) / component.tbo_hours;
+                    if (ratio >= 1.5) return 'hours-on-condition-extended'; // > 150% TBO: green
+                    if (ratio >= 1.0) return 'hours-on-condition-over';     // 100–150% TBO: teal
+                    if (ratio >= 0.9) return 'hours-on-condition';          // 90–100% TBO: blue
+                    return '';
+                }
+                if (component.tbo_days) {
+                    const calDays = this.getCalendarDaysRemaining(component);
+                    if (calDays !== null) {
+                        const ratio = (component.tbo_days - calDays) / component.tbo_days;
+                        if (ratio >= 1.5) return 'hours-on-condition-extended';
+                        if (ratio >= 1.0) return 'hours-on-condition-over';
+                        if (ratio >= 0.9) return 'hours-on-condition';
+                    }
+                }
+                return '';
+            }
+            // Standard alert coloring
             const remaining = this.calculateHoursRemaining(component);
             if (remaining !== 'N/A') {
                 const hours = parseFloat(remaining);
@@ -173,6 +199,24 @@ function componentsMixin() {
             return Math.round((due - now) / (1000 * 60 * 60 * 24));
         },
 
+        // CSS class for the "Calendar Remaining" value in the expanded detail panel.
+        // On-condition mode uses a flat informational blue when past TBO (no gradient —
+        // calendar time is a secondary indicator and we don't want to reward over-TBO
+        // operation the way the hours gradient does).
+        getCalendarRemainingClass(component) {
+            const calDays = this.getCalendarDaysRemaining(component);
+            if (calDays === null) return '';
+            const useOnCondition = component.on_condition && component.tbo_critical &&
+                !(component.replacement_critical && component.replacement_days);
+            if (useOnCondition && component.tbo_days && calDays <= 0) {
+                return 'hours-on-condition';
+            }
+            if (calDays <= 0) return 'hours-overdue';
+            if (calDays < 30) return 'hours-critical';
+            if (calDays < 90) return 'hours-warning';
+            return '';
+        },
+
         // Formats a signed number of days as a human-readable duration string.
         // Negative values append " over".
         formatDuration(days) {
@@ -284,6 +328,7 @@ function componentsMixin() {
                 replacement_hours: '',
                 replacement_days: '',
                 tbo_critical: true,
+                on_condition: false,
                 inspection_critical: true,
                 replacement_critical: false,
             };
@@ -313,6 +358,7 @@ function componentsMixin() {
                 replacement_hours: component.replacement_hours || '',
                 replacement_days: component.replacement_days || '',
                 tbo_critical: component.tbo_critical ?? true,
+                on_condition: component.on_condition ?? false,
                 inspection_critical: component.inspection_critical ?? true,
                 replacement_critical: component.replacement_critical ?? false,
             };
@@ -342,6 +388,7 @@ function componentsMixin() {
                     hours_in_service: parseFloat(this.componentForm.hours_in_service) || 0,
                     hours_since_overhaul: parseFloat(this.componentForm.hours_since_overhaul) || 0,
                     tbo_critical: this.componentForm.tbo_critical,
+                    on_condition: this.componentForm.on_condition,
                     inspection_critical: this.componentForm.inspection_critical,
                     replacement_critical: this.componentForm.replacement_critical,
                 };
@@ -540,6 +587,11 @@ function componentsMixin() {
 
         getStatusClass(component) {
             if (component.status === 'IN-USE') {
+                // On-condition: suppress red/orange warnings; blue when at/past TBO
+                if (component.on_condition && component.tbo_critical && component.tbo_hours) {
+                    const ratio = (component.hours_since_overhaul || 0) / component.tbo_hours;
+                    return ratio >= 1.0 ? 'pf-m-blue' : 'pf-m-green';
+                }
                 const hoursToTBO = this.calculateHoursToTBO(component);
                 if (hoursToTBO !== 'N/A') {
                     const hours = parseFloat(hoursToTBO);

core/templates/aircraft_detail.html

@@ -596,7 +596,7 @@ <h2>Components</h2>
                                         <template x-if="getCalendarDaysRemaining(component) !== null">
                                             <div>
                                                 <div style="font-size: 1.1em; font-weight: 600;"
-                                                     :class="getCalendarDaysRemaining(component) <= 0 ? 'hours-overdue' : ''"
+                                                     :class="getCalendarRemainingClass(component)"
                                                      x-text="formatDuration(getCalendarDaysRemaining(component))"></div>
                                                 <div x-show="getDueDate(component)"
                                                      x-text="'Due ' + formatDate(getDueDate(component))"
@@ -615,10 +615,17 @@ <h2>Components</h2>
                                     <div class="component-detail-grid" style="display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem;">
                                         <!-- TBO -->
                                         <div>
-                                            <span class="pf-v5-c-label pf-m-compact"
-                                                  :class="component.tbo_critical ? 'pf-m-blue' : 'pf-m-grey'">
-                                                TBO
-                                            </span>
+                                            <div style="display: flex; align-items: center; gap: 0.35rem; flex-wrap: wrap;">
+                                                <span class="pf-v5-c-label pf-m-compact"
+                                                      :class="component.tbo_critical ? 'pf-m-blue' : 'pf-m-grey'">
+                                                    TBO
+                                                </span>
+                                                <template x-if="component.tbo_critical && component.on_condition">
+                                                    <span class="pf-v5-c-label pf-m-compact pf-m-cyan" title="Reliability-Centered / On-Condition maintenance — over-TBO operation is intentional">
+                                                        On-Condition
+                                                    </span>
+                                                </template>
+                                            </div>
                                             <template x-if="component.tbo_critical">
                                                 <div style="margin-top: 0.3rem; font-size: 0.9em;">
                                                     <div x-show="component.tbo_hours" x-text="component.tbo_hours + ' hr'"></div>
@@ -3535,24 +3542,37 @@ <h1 class="pf-v5-c-modal-box__title" x-text="editingComponent ? 'Edit Component'
                             </div>
                         </div>
 
-                        <!-- TBO Intervals (shown when tbo_critical) -->
+                        <!-- TBO Intervals + On-Condition (shown when tbo_critical) -->
                         <template x-if="componentForm.tbo_critical">
-                            <div style="display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;">
-                                <div class="pf-v5-c-form__group">
-                                    <label class="pf-v5-c-form__label" for="comp-tbo-hours">
-                                        <span class="pf-v5-c-form__label-text">TBO Hours</span>
-                                    </label>
-                                    <div class="pf-v5-c-form__group-control">
-                                        <input id="comp-tbo-hours" class="pf-v5-c-form-control" type="number" min="0" x-model="componentForm.tbo_hours">
+                            <div>
+                                <div style="display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;">
+                                    <div class="pf-v5-c-form__group">
+                                        <label class="pf-v5-c-form__label" for="comp-tbo-hours">
+                                            <span class="pf-v5-c-form__label-text">TBO Hours</span>
+                                        </label>
+                                        <div class="pf-v5-c-form__group-control">
+                                            <input id="comp-tbo-hours" class="pf-v5-c-form-control" type="number" min="0" x-model="componentForm.tbo_hours">
+                                        </div>
+                                    </div>
+                                    <div class="pf-v5-c-form__group">
+                                        <label class="pf-v5-c-form__label" for="comp-tbo-days">
+                                            <span class="pf-v5-c-form__label-text">TBO Days</span>
+                                        </label>
+                                        <div class="pf-v5-c-form__group-control">
+                                            <input id="comp-tbo-days" class="pf-v5-c-form-control" type="number" min="0" x-model="componentForm.tbo_days">
+                                        </div>
                                     </div>
                                 </div>
-                                <div class="pf-v5-c-form__group">
-                                    <label class="pf-v5-c-form__label" for="comp-tbo-days">
-                                        <span class="pf-v5-c-form__label-text">TBO Days</span>
+                                <div style="margin-top: 0.75rem;">
+                                    <label style="display: flex; align-items: flex-start; gap: 0.5rem; cursor: pointer;">
+                                        <input type="checkbox" x-model="componentForm.on_condition" style="margin-top: 0.2rem; flex-shrink: 0;">
+                                        <span>
+                                            <span style="font-weight: 500;">Maintained On-Condition</span>
+                                            <span style="display: block; font-size: 0.85em; color: var(--pf-v5-global--Color--200);">
+                                                Enables RCM/on-condition maintenance mode. Over-TBO hours are shown in blue/green rather than red/orange.
+                                            </span>
+                                        </span>
                                     </label>
-                                    <div class="pf-v5-c-form__group-control">
-                                        <input id="comp-tbo-days" class="pf-v5-c-form-control" type="number" min="0" x-model="componentForm.tbo_days">
-                                    </div>
                                 </div>
                             </div>
                         </template>

docs/user-guide/components.rst

@@ -66,13 +66,55 @@ Adding a Component
      this counter reaches the interval.
    - **TBO Critical** -- For parts with a Time Between Overhaul limit (engines,
      propellers). Set the **TBO Hours** and current **Hours Since Overhaul**.
+     When TBO Tracking is enabled, an optional **Maintained On-Condition**
+     checkbox appears (see below).
    - **Inspection Critical** -- For parts requiring periodic inspections. Tracked
      via the :doc:`inspections` system.
 
 5. Click **Save**.
 
 .. TODO: Screenshot of the Add Component modal with tracking options visible
 
+On-Condition (RCM) Maintenance
+-------------------------------
+
+For complex components such as engines and propellers, many operators follow
+**Reliability-Centered Maintenance (RCM)** or **on-condition** philosophy:
+the risk of a maintenance-induced failure around an overhaul event can exceed
+the risk of simply continuing the component in service past its nominal TBO,
+provided the component is monitored and shows no signs of deterioration.
+
+When **TBO Tracking** is enabled on a component, you can check
+**Maintained On-Condition** to reflect this operating decision.
+
+**Effect on the UI:**
+
+.. list-table::
+   :header-rows: 1
+   :widths: 30 70
+
+   * - Condition
+     - Color shown
+   * - Under 90 % of TBO
+     - Normal (no highlight)
+   * - 90–100 % of TBO
+     - Blue — approaching TBO reference point
+   * - 100–150 % of TBO
+     - Teal — operating past TBO on condition
+   * - Over 150 % of TBO
+     - Green — running well past TBO on condition
+
+The component badge (IN-USE) changes from the normal red/orange warning to
+**blue** once the component passes TBO, and the **On-Condition** label appears
+in the component detail panel.
+
+.. note::
+
+   On-Condition mode only suppresses TBO-based color warnings. If the
+   component also has a **Service Interval** (Replacement Critical) configured,
+   those service-interval warnings continue to use the standard red/orange
+   alert colors regardless of this setting.
+
 Resetting Service
 -----------------
 

health/migrations/0025_component_on_condition.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.11 on 2026-02-25 06:21
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('health', '0024_ad_document'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='component',
+            name='on_condition',
+            field=models.BooleanField(default=False),
+        ),
+    ]

health/models.py

@@ -80,6 +80,7 @@ class Component(models.Model):
     replacement_hours = models.IntegerField(blank=True, null=True)
     replacement_days = models.IntegerField(blank=True, null=True)
     tbo_critical = models.BooleanField(default=True)
+    on_condition = models.BooleanField(default=False)
     inspection_critical = models.BooleanField(default=True)
     replacement_critical = models.BooleanField(default=False)
 

health/serializers.py

@@ -65,6 +65,7 @@ class Meta:
                 'replacement_hours',
                 'replacement_days',
                 'tbo_critical',
+                'on_condition',
                 'inspection_critical',
                 'replacement_critical',
                 'components',
@@ -431,6 +432,7 @@ class Meta:
             'replacement_hours',
             'replacement_days',
             'tbo_critical',
+            'on_condition',
             'inspection_critical',
             'replacement_critical',
         ]