Imagine a pilot preparing to land at Austin-Bergstrom International Airport (AUS), carefully studying what appears to be a simple airport diagram. This document - designated as the "AL-556" chart - contains critical safety information that could mean the difference between a routine landing and a potential disaster.
Austin-Bergstrom International Airport Overview
Located in Austin, Texas, AUS serves as a major transportation hub for the region. The AL-556 chart provides pilots with essential geographical references to quickly orient themselves during approach procedures.
Runway Data: The Foundation of Safe Operations
The chart prominently displays two runways: 18R-36L and 18L-36R. These designations hold specific meanings:
- Numerical codes: Represent magnetic headings (180° and 360°) with "R" and "L" indicating right and left parallel runways
- Load ratings: 2D/2D2-1120 and 2D/2D2-1033 indicate maximum weight capacities (in thousands of pounds) for different aircraft configurations
- Lighting codes: R/B/W/T markings show runway light colors (Red/Blue/White/Threshold) for night operations
- Slope indicators: 0.3%UP and 0.6%DOWN specify critical elevation changes affecting aircraft performance
Communication Frequencies: The Lifeline of Aviation Safety
The chart details essential radio frequencies for pilot-controller communications:
- PDC/CPDLC: 125.5 MHz and 263.0 MHz for digital pre-departure clearances
- Clearance Delivery: 121.9 MHz and 348.6 MHz for flight plan approvals
- Ground Control: 121.0 MHz and 281.5 MHz for taxi instructions
- Tower Frequency: 124.4 MHz for active runway operations
- D-ATIS: Digital weather and airport condition broadcasts
Lighting Systems: Visual Guidance for Low Visibility
The chart specifies advanced lighting installations:
- RCLS: Runway Centerline Lighting System on 18L/36R
- TDZ/CL: Touchdown Zone and Centerline lights on 18L/36R
- HIRL: High Intensity Runway Lights on both runways
Additional Critical Information
The AL-556 chart includes numerous other safety details:
- Elevation data (474/492/487 feet) for precise altitude references
- Magnetic variation rates (0.1° West annually through January 2025)
- SAID (Situational Awareness and Identification Device) requirements
- Mandatory readback procedures for runway holding instructions
- Facility locations including terminals, hangars, and emergency services
Chart Legends and Validity
Understanding standardized symbols through the legend is essential for proper interpretation. Pilots must verify the chart's validity period (December 25, 2025 through January 22, 2026) before use, as outdated information compromises safety.
This comprehensive document exemplifies the meticulous planning behind every commercial flight. While passengers may never see these technical charts, they represent the invisible safety framework protecting millions of air travelers daily.