PSS - Passenger Service System

The core transactional systems that power airline reservations, ticketing, and departure operations. Built on an Order-Centric Architecture where the Order is the Single Source of Truth.

Components

Order Management - THE FOUNDATION

The central Order Management System (OMS):

  • Order-Centric Model (UUID replacing PNR as primary)
  • State Machine: OFFERED → PAID → FULFILLED
  • "Seat as SKU" philosophy - all products as line items
  • Critical Rule: Check-in prohibited unless State == PAID
  • Single Source of Truth for all downstream systems

Inventory

Flight inventory management including:

  • Availability and capacity control
  • Nested booking class structures
  • Overbooking management
  • Codeshare and interline inventory
  • Real-time inventory updates

Reservations

Booking engine and order management:

  • PNR creation and lifecycle
  • Booking flows and validation
  • Passenger data management
  • SSR (Special Service Requests)
  • Group bookings
  • ONE Order implementation

Ticketing

Document issuance and management:

  • E-ticket generation (13-digit format)
  • EMD-A and EMD-S issuance
  • Void, refund, and exchange processing
  • Coupon status management
  • Interline ticketing

Fares & Pricing

Pricing engine and fare management:

  • ATPCO fare filing
  • Continuous pricing (NDC)
  • Tax calculation
  • Ancillary pricing
  • Dynamic bundling
  • Promo codes and discounts

Departure Control

Airport operations systems:

  • Check-in processing
  • Boarding pass generation (BCBP)
  • Seat assignment
  • Weight and balance
  • Gate management
  • Boarding control

Architecture Principles

  1. Event-Driven: Use EventBridge for inventory changes, booking events
  2. Saga Pattern: Step Functions for multi-step booking transactions
  3. Idempotency: Lambda Powertools for payment-critical operations
  4. Optimistic Locking: Version fields for concurrent seat/inventory updates

Data Flow (Order-Centric)

                         ┌─────────────────────────────────────┐
                         │         ORDER (Single Source        │
                         │           of Truth)                 │
                         └──────────────┬──────────────────────┘
                                        │
     ┌──────────────────────────────────┼──────────────────────────────────┐
     │                                  │                                  │
     ▼                                  ▼                                  ▼
┌─────────┐                      ┌─────────────┐                    ┌───────────┐
│Inventory│                      │   Payment   │                    │    DCS    │
│ (P1-P5) │                      │    Vault    │                    │  (View)   │
└─────────┘                      └─────────────┘                    └───────────┘

Order State Flow:
─────────────────
Shopping Request → OFFERED (10 min hold)
                       ↓
                 Payment Token Received
                       ↓
                   PAID (confirmed)
                       ↓
                 Service Delivered
                       ↓
                  FULFILLED

Key Integrations

  • Distribution (NDC/GDS) ← Inventory, Fares
  • Settlement (BSP/ARC) ← Ticketing
  • Operations ← DCS, Flight Data
  • Analytics ← All transactional data