Imported from personamanagmentlayer/pcl (stdlib/domains/aerospace-expert/SKILL.md). Install upstream with npx skills add personamanagmentlayer/pcl --skill aerospace-expert. Copyright stays with the author.

Aerospace Expert

Expert guidance for aerospace systems, flight management, maintenance tracking, aviation safety, air traffic control systems, and aerospace software development.

Core Concepts

Aerospace Systems

• Flight Management Systems (FMS)
• Maintenance, Repair, and Overhaul (MRO)
• Air Traffic Control (ATC) systems
• Aircraft Health Monitoring
• Flight Operations Quality Assurance (FOQA)
• Crew resource management
• Ground handling systems

Aviation Technologies

• Avionics systems
• ACARS (Aircraft Communications Addressing and Reporting System)
• ADS-B (Automatic Dependent Surveillance-Broadcast)
• Flight data recorders (black boxes)
• Weather radar systems
• Autopilot and fly-by-wire
• Satellite communications

Standards and Regulations

• FAA regulations (Federal Aviation Administration)
• EASA standards (European Union Aviation Safety Agency)
• ICAO standards (International Civil Aviation Organization)
• DO-178C (software airworthiness)
• DO-254 (hardware airworthiness)
• SPEC-42 (maintenance tracking)
• ATA chapters (maintenance organization)

Aircraft Maintenance System

from enum import Enum

class MaintenanceType(Enum):
    A_CHECK = "a_check"  # Every 400-600 flight hours
    B_CHECK = "b_check"  # Every 6-8 months
    C_CHECK = "c_check"  # Every 18-24 months
    D_CHECK = "d_check"  # Every 6-10 years
    LINE_MAINTENANCE = "line_maintenance"
    UNSCHEDULED = "unscheduled"

@dataclass
class Aircraft:
    """Aircraft information"""
    aircraft_id: str
    registration: str
    aircraft_type: str
    manufacturer: str
    model: str
    serial_number: str
    manufacture_date: datetime
    total_flight_hours: float
    total_cycles: int  # Takeoff/landing cycles
    last_a_check: datetime
    last_c_check: datetime
    airworthiness_certificate: str
    next_major_inspection: datetime

@dataclass
class MaintenanceRecord:
    """Maintenance work record"""
    record_id: str
    aircraft_id: str
    maintenance_type: MaintenanceType
    work_performed: str
    components_replaced: List[str]
    performed_by: str
    performed_at: datetime
    flight_hours_at_maintenance: float
    cycles_at_maintenance: int
    next_due_hours: Optional[float]
    next_due_date: Optional[datetime]

class AircraftMaintenanceSystem:
    """MRO (Maintenance, Repair, Overhaul) system"""

    def __init__(self):
        self.aircraft = {}
        self.maintenance_records = []
        self.component_tracking = {}

    def check_maintenance_due(self, aircraft_id: str) -> dict:
        """Check if maintenance is due for aircraft"""
        aircraft = self.aircraft.get(aircraft_id)
        if not aircraft:
            return {'error': 'Aircraft not found'}

        due_items = []

        # Check A-check (every 500 hours)
        hours_since_a_check = aircraft.total_flight_hours - self._get_last_check_hours(
            aircraft_id, MaintenanceType.A_CHECK
        )

        if hours_since_a_check >= 500:
            due_items.append({
                'type': 'A-check',
                'urgency': 'high' if hours_since_a_check >= 550 else 'medium',
                'hours_overdue': max(0, hours_since_a_check - 500)
            })

        # Check calendar-based C-check
        days_since_c_check = (datetime.now() - aircraft.last_c_check).days

        if days_since_c_check >= 540:  # 18 months
            due_items.append({
                'type': 'C-check',
                'urgency': 'critical' if days_since_c_check >= 600 else 'high',
                'days_overdue': max(0, days_since_c_check - 540)
            })

        # Check component life limits
        component_items = self._check_component_life_limits(aircraft_id)
        due_items.extend(component_items)

        return {
            'aircraft_id': aircraft_id,
            'registration': aircraft.registration,
            'maintenance_required': len(due_items) > 0,
            'due_items': due_items,
            'airworthy': len([item for item in due_items if item['urgency'] == 'critical']) == 0
        }

    def _get_last_check_hours(self, aircraft_id: str, check_type: MaintenanceType) -> float:
        """Get flight hours at last check"""
        records = [
            r for r in self.maintenance_records
            if r.aircraft_id == aircraft_id and r.maintenance_type == check_type
        ]

        if records:
            latest = max(records, key=lambda r: r.performed_at)
            return latest.flight_hours_at_maintenance

        return 0.0

    def _check_component_life_limits(self, aircraft_id: str) -> List[dict]:
        """Check component life limits"""
        due_items = []

        components = self.component_tracking.get(aircraft_id, {})

        for component_name, component_data in components.items():
            if component_data['life_limit_hours']:
                hours_used = component_data['hours_since_new']
                life_limit = component_data['life_limit_hours']

                if hours_used >= life_limit * 0.9:  # Within 90% of life limit
                    due_items.append({
                        'type': 'component_replacement',
                        'component': component_name,
                        'urgency': 'critical' if hours_used >= life_limit else 'high',
                        'hours_remaining': max(0, life_limit - hours_used)
                    })

        return due_items

    def record_maintenance(self,
                          aircraft_id: str,
                          maintenance_data: dict) -> MaintenanceRecord:
        """Record completed maintenance"""
        aircraft = self.aircraft.get(aircraft_id)
        if not aircraft:
            raise ValueError("Aircraft not found")

        record = MaintenanceRecord(
            record_id=self._generate_record_id(),
            aircraft_id=aircraft_id,
            maintenance_type=MaintenanceType(maintenance_data['type']),
            work_performed=maintenance_data['work_performed'],
            components_replaced=maintenance_data.get('components_replaced', []),
            performed_by=maintenance_data['technician_id'],
            performed_at=datetime.now(),
            flight_hours_at_maintenance=aircraft.total_flight_hours,
            cycles_at_maintenance=aircraft.total_cycles,
            next_due_hours=maintenance_data.get('next_due_hours'),
            next_due_date=maintenance_data.get('next_due_date')
        )

        self.maintenance_records.append(record)

        # Update aircraft maintenance dates
        if record.maintenance_type == MaintenanceType.A_CHECK:
            aircraft.last_a_check = datetime.now()
        elif record.maintenance_type == MaintenanceType.C_CHECK:
            aircraft.last_c_check = datetime.now()

        return record

    def predict_maintenance_cost(self,
                                aircraft_type: str,
                                flight_hours_per_year: float) -> dict:
        """Predict annual maintenance costs"""
        # Base maintenance costs per aircraft type
        base_costs = {
            'B737': {
                'hourly_rate': 800,  # $ per flight hour
                'a_check': 25000,
                'c_check': 500000,
                'd_check': 5000000
            },
            'B777': {
                'hourly_rate': 1500,
                'a_check': 50000,
                'c_check': 1000000,
                'd_check': 10000000
            }
        }

        costs = base_costs.get(aircraft_type, base_costs['B737'])

        # Calculate annual costs
        hourly_maintenance = flight_hours_per_year * costs['hourly_rate']

        # A-checks (assume 2 per year for 1000 hours/year)
        a_checks_per_year = flight_hours_per_year / 500
        a_check_costs = a_checks_per_year * costs['a_check']

        # C-check (amortized over 18 months)
        c_check_annual = costs['c_check'] / 1.5

        # D-check (amortized over 8 years)
        d_check_annual = costs['d_check'] / 8

        total_annual = hourly_maintenance + a_check_costs + c_check_annual + d_check_annual

        return {
            'aircraft_type': aircraft_type,
            'flight_hours_per_year': flight_hours_per_year,
            'maintenance_costs': {
                'hourly_maintenance': hourly_maintenance,
                'a_checks': a_check_costs,
                'c_check_amortized': c_check_annual,
                'd_check_amortized': d_check_annual,
                'total_annual': total_annual
            },
            'cost_per_flight_hour': total_annual / flight_hours_per_year
        }

    def _generate_record_id(self) -> str:
        import uuid
        return f"MX-{uuid.uuid4().hex[:10].upper()}"

Aviation Safety Analysis

class AviationSafetySystem:
    """Flight safety and FOQA analysis"""

    def __init__(self):
        self.safety_reports = []
        self.foqa_events = []

    def analyze_flight_data(self, flight_data: dict) -> dict:
        """Analyze flight data for safety events (FOQA)"""
        events_detected = []

        # Check for hard landings
        if flight_data.get('landing_vertical_speed_fpm', 0) < -600:
            events_detected.append({
                'event_type': 'hard_landing',
                'severity': 'medium',
                'value': flight_data['landing_vertical_speed_fpm'],
                'threshold': -600
            })

        # Check for unstabilized approaches
        if flight_data.get('approach_speed_deviation_kts', 0) > 10:
            events_detected.append({
                'event_type': 'unstabilized_approach',
                'severity': 'high',
                'value': flight_data['approach_speed_deviation_kts'],
                'threshold': 10
            })

        # Check for altitude deviations
        if flight_data.get('altitude_deviation_ft', 0) > 300:
            events_detected.append({
                'event_type': 'altitude_deviation',
                'severity': 'high',
                'value': flight_data['altitude_deviation_ft'],
                'threshold': 300
            })

        # Check for excessive bank angles
        if flight_data.get('max_bank_angle_deg', 0) > 30:
            events_detected.append({
                'event_type': 'excessive_bank',
                'severity': 'medium',
                'value': flight_data['max_bank_angle_deg'],
                'threshold': 30
            })

        # Calculate overall safety score
        safety_score = 100.0 - (len(events_detected) * 10)

        return {
            'flight_number': flight_data['flight_number'],
            'events_detected': events_detected,
            'safety_score': max(0.0, safety_score),
            'requires_review': len(events_detected) > 0
        }

    def calculate_safety_metrics(self, flights_data: List[dict]) -> dict:
        """Calculate safety KPIs"""
        total_flights = len(flights_data)
        total_hours = sum(f.get('flight_hours', 0) for f in flights_data)

        # Count safety events
        safety_events = sum(
            len(self.analyze_flight_data(f)['events_detected'])
            for f in flights_data
        )

        # Event rate per 1000 flights
        event_rate = (safety_events / total_flights * 1000) if total_flights > 0 else 0

        return {
            'total_flights': total_flights,
            'total_flight_hours': total_hours,
            'safety_events': safety_events,
            'event_rate_per_1000_flights': event_rate,
            'safety_rating': 'Excellent' if event_rate < 5 else
                           'Good' if event_rate < 10 else
                           'Needs Improvement'
        }

Best Practices

Flight Operations

• File complete and accurate flight plans
• Conduct thorough pre-flight checks
• Monitor fuel continuously
• Maintain communication with ATC
• Follow standard operating procedures (SOPs)
• Implement crew resource management
• Use automation appropriately

Maintenance Management

• Follow manufacturer maintenance schedules
• Track all component life limits
• Maintain detailed maintenance logs
• Use certified parts and technicians
• Implement predictive maintenance
• Conduct regular inspections
• Ensure airworthiness compliance

Safety Management

• Implement Safety Management System (SMS)
• Encourage safety reporting culture
• Analyze FOQA data regularly
• Conduct regular safety audits
• Maintain emergency procedures
• Train crew on CRM principles
• Track safety KPIs

Regulatory Compliance

• Maintain current certifications
• Follow DO-178C for software
• Implement quality management systems
• Conduct regular audits
• Maintain proper documentation
• Follow ATA chapter organization
• Ensure ETOPS compliance (if applicable)

Anti-Patterns

❌ Delaying required maintenance ❌ Poor flight planning ❌ Inadequate fuel reserves ❌ Ignoring weather conditions ❌ Poor crew communication ❌ No safety management system ❌ Inadequate record keeping ❌ Using uncertified parts ❌ Skipping pre-flight checks

Reference Documentation

Detailed material lives alongside this skill and is read on demand:

• Flight Management System

Resources

• FAA: https://www.faa.gov/
• ICAO: https://www.icao.int/
• EASA: https://www.easa.europa.eu/
• IATA: https://www.iata.org/
• Flight Safety Foundation: https://flightsafety.org/
• FAA Airworthiness Directives: https://www.faa.gov/regulations_policies/airworthiness_directives/
• DO-178C Standard: https://www.rtca.org/