File Structure

PFPX navdata files follow a well-defined structure with distinct sections for different types of navigation data.

Overall Organization

A typical navdata file is organized as follows:

┌─────────────────┐
│   File Header   │ ← Plaintext metadata
│   (Plaintext)   │
├─────────────────┤
│                 │
│   Runway Data   │ ← Encoded content begins
│     (RWY)       │
│                 │
├─────────────────┤
│                 │
│  Waypoint Data  │ ← Airports, VOR, NDB, etc.
│     (WPT)       │
│                 │
├─────────────────┤
│                 │
│  Airway Data    │ ← Route information
│     (AWY)       │
│                 │
├─────────────────┤
│                 │
│   SID Data      │ ← Departure procedures
│     (SID)       │
│                 │
├─────────────────┤
│                 │
│   STAR Data     │ ← Arrival procedures
│     (STR)       │
│                 │
└─────────────────┘

Section Details

File Header (Plaintext)

The header contains metadata about the navigation database:

• Database name and version
• Effective dates (AIRAC cycle)
• Data provider information

Runway Section (RWY)

Contains runway information for airports worldwide:

• Runway dimensions and orientation
• Surface type and condition
• Geographic coordinates

Waypoint Section (WPT)

Includes all types of navigation points:

• Airports (Type 0)
• VFR Waypoints (Type 1)
• VOR/TACAN (Type 2)
• TACAN (Type 3)
• VOR/DME (Type 4)
• NDB (Type 5)
• Route Waypoints (Type 6)
• DME (Type 9)

Airway Section (AWY)

Defines airways:

• High altitude airways
• Low altitude airways
• RNAV airways

SID Section (SID)

Standard Instrument Departure procedures:

• Departure procedures
• Runway transition procedures

STAR Section (STR)

Standard Terminal Arrival Route procedures:

• Arrival routes to airports
• Approach transitions
• Runway-specific arrivals

Data Encoding

Header vs Content

• Header: Stored in plaintext ASCII
• Content: Encoded using XOR encryption with key 0x85

Line-by-Line Format

Each encoded section follows a line-by-line format where:

• Each line represents one data record
• Lines are separated by standard newline characters
• Record format varies by section type

Record Identification

Each record type can be identified by its prefix:

Prefix	Section	Description
RWY	Runway	Runway information
WPT	Waypoint	Waypoints (including airports and navigation facilities)
AWY	Airway	Route segments
SID	Departure	Standard departures
STR	Arrival	Standard arrivals

File Size Considerations

Navdata files can be quite large:

• Typical size: 50-200 MB
• Record count: Hundreds of thousands of records
• Global coverage: Worldwide navigation data

Processing Notes

Batch Processing

Due to file size, consider processing in chunks:

• Process 3,000-4,000 lines at a time when using manual tools
• Use streaming for automated processing
• Implement progress tracking for large operations

Next Steps

• Learn about decoding - Convert encoded data to readable format
• Explore specific sections - Detailed format for each data type
• Use automation tools - Handle large files efficiently