Aerodrome General Concepts: Reference Code and Runway Surface Conditions

010-09-01Pablo Asensio Martínez2026-03-271 min

Aerodrome Reference Code

The Aerodrome Reference Code is used for planning purposes and determines whether the aerodrome dimensions are adequate for a specific type of aircraft. It consists of two elements:

  1. Element 1 (Number): Based on the Aeroplane Reference Field Length.
    • Example: 4 indicates a field length of 1800 m or more.
  2. Element 2 (Letter): Based on the Wingspan or the Outer Main Gear Wheel Span, whichever is more demanding.
    • Example: E indicates a wingspan between 52 m and 64.9 m.

Important: The number (Element 1) refers to the field length, and the letter (Element 2) refers primarily to the wingspan.

  • Note: The determination of the reference field length is solely for selecting the code and does not influence the actual runway length provided.

Runway Surface Condition

Specific terms are used to describe the state of the runway surface:

  • Dry: Free of visible contaminants.
  • Wet: The surface is soaked but there is no standing water.
  • Standing Water: Depth exceeding 3 mm.
  • Slush: Water-saturated snow which with a heel-and-toe slap-down motion will be displaced with a splatter; specific gravity 0.5 to 0.8.
  • Compacted Snow: Solid mass which resists further compression.
  • Wet Ice: Ice with water on top of it or ice that is melting (very poor braking).