Intersection take-off sign

What an intersection take-off sign is

An intersection take-off sign tells a flight crew how much runway is available for take-off when they begin the roll from a taxiway/runway intersection rather than from the full length. It shows the take-off run available (TORA) from that intersection as a numeral, together with an arrow indicating the direction of the take-off, and it is one of the information signs, so it carries a black numeral and arrow on a yellow background. It gives the crew a direct, at-a-glance figure to weigh against their required take-off distance before they commit to an intersection departure.

The TORA it displays

The intersection take-off sign is defined in ICAO Annex 14 Volume I (listed in 5.4.3.2, detailed at 5.4.3.29), showing the take-off run available (TORA) in metres together with a directional arrow; EASA CS-ADR-DSN carries the same named sign. The value it carries is the take-off run available — the same TORA concept used in the declared distances for a runway — but measured from the intersection rather than from the runway threshold, because part of the runway lies behind the aircraft and cannot be used. The FAA has an equivalent intersection takeoff sign in its advisory circulars (AC 150/5340-18). The face keeps the yellow-and-black information scheme so it reads as guidance, not as an instruction.

How it reads: the numeral and arrow

The sign pairs a distance with an arrow: the numeral is the take-off run available from that intersection and the arrow shows the direction in which that distance runs. A crew lining up at an intersection reads the figure, compares it with the take-off distance their aircraft and conditions require, and decides whether the intersection departure is acceptable or whether a full-length take-off is needed.

Reading it against the runway distance signs

The intersection take-off sign answers "how much runway is available if I start here", which is a different question from the one answered by the runway distance signs that count down the length remaining during the roll. Both support the go/stop decision, but the intersection take-off sign is read before the roll begins, at the intersection, while distance-remaining information is read during the take-off or landing run. Keeping the two distinct — and holding the intersection sign to the ICAO, EASA and FAA information-sign scheme — avoids any confusion between "available from here" and "remaining ahead".

Further reading: two deep dives on TORA signs

We have written about this sign in more depth than any other, because it hides two surprisingly hard design problems:

• The width of lowercase m — the TORA value is posted in metres, and the lowercase "m" is the one glyph whose dimensions ICAO and EASA never define. The article works through typography principles and standard font comparisons to a qualified best guess — and explains why we ended up not using it.
• TORA Proposal — our analysis of the shortcomings of today's intersection take-off signage and a proposed redesign for more consistency and clarity.

Draw them in Wingframe

Wingframe draws intersection take-off signs to the ICAO, EASA and FAA information-sign scheme — black numeral and directional arrow on yellow — so the posted take-off run available reads cleanly at the intersection. See what Wingframe can do.