FAA sign standards

The United States standard

In the United States, airfield signs are regulated by the Federal Aviation Administration (FAA) through advisory circulars (ACs). Two work together:

• AC 150/5340-18, Standards for Airport Sign Systems — the design and siting standard: which signs are needed, where they go, and how a sign array reads. This page draws on the current edition, AC 150/5340-18H (2024).
• AC 150/5345-44, Specification for Runway and Taxiway Signs — the equipment specification: the physical sign, its sizes, colours and construction, published alongside FAA equipment specification L-858. Current edition AC 150/5345-44L (2024).

The FAA writes its standards independently of ICAO Annex 14 and EASA rather than transposing them, but it recognises the same two colour-coded families — red for instructions, yellow and black for information.

The same signs, named by equipment type

The FAA identifies signs by their L-858 equipment type rather than by family name:

• L-858R — the mandatory instruction / holding position sign: a white inscription on a red background with a black outline (a 3/4-inch, about 19 mm, outline around the legend). This is the FAA runway holding position and no-entry sign.
• L-858L — the taxiway location sign: a yellow inscription on a black background, the direct equivalent of the ICAO location sign.
• L-858Y — the direction, destination and runway-boundary sign: a black inscription on a yellow background, matching the ICAO direction and destination signs.

The FAA also standardises signs ICAO and EASA leave to guidance, such as the runway distance remaining boards (type L-858B) and the taxiway ending marker (type L-858C).

Sizing by discrete sign sizes

Where ICAO and EASA key their dimensions to the runway code number, the FAA defines five discrete sign sizes, numbered 1 to 5, each a fixed physical size in AC 150/5345-44's Table 3-1. Sizes 1, 2 and 3 — legend heights of 12, 15 and 18 inches — are the ordinary taxiway guidance signs. Sizes 4 and 5 are reserved for the runway distance remaining signs, with legend heights of 40 inches (Size 4) and 25 inches (Size 5). Choosing a fixed size rather than deriving a height from the runway code is the clearest structural difference from the ICAO/EASA approach.

Alongside the character standards, AC 150/5345-44 fixes the geometry of standalone symbols carried on some signs — the runway safety area / obstacle free zone boundary, the ILS critical area boundary, and the NO ENTRY roundel — each dimensioned per sign size.

Draw to the FAA standard in Wingframe

Wingframe draws airfield guidance signs to the FAA L-858 geometry — the equipment types, the discrete sign sizes and the family colours — so the sign you design matches the advisory circular it will be built and inspected against. See what Wingframe does.