Signal area (ICAO Annex 2 Appendix 1)

Not every aerodrome has a radio service — and even where one exists, your radio can fail. For exactly these situations, aerodromes use standardised ground signals displayed in a signal area, which every pilot must be able to read from overhead before joining the circuit. The signal definitions come from ICAO Annex 2, Appendix 1 and are binding EU-wide through SERA Appendix 1; they are a favourite topic in the Air Law exam.

What the signal area is

The signal area is a level square surface of at least 9 m × 9 m on the aerodrome, normally surrounded by a white border, on which ground signals are laid out. It must be visible from aircraft in flight at 300 m (1 000 ft) above the aerodrome. The intended procedure is simple: before joining the traffic circuit, overfly the aerodrome, look down at the signal area (and the runway thresholds, where some signals may also be displayed), and read the current operating instructions.

Prohibition and caution signals

Red square panel with two yellow diagonals = landing prohibited, and the prohibition is likely to be prolonged.
Red square panel with one yellow diagonal = special precautions required when approaching or landing, e.g. owing to the poor state of the manoeuvring area.
White or yellow crosses displayed horizontally on a runway, taxiway or part thereof = that surface is unfit for the movement of aircraft and must not be used.

Memory aid: two stripes — stay away entirely; one stripe — you may land, but take care.

Direction signals

Landing "T": a horizontal white or orange "T". Landings and take-offs are made parallel to the shaft of the T, towards the cross-arm.
Two-digit number in black on a yellow background, displayed vertically at or near the aerodrome control tower = the direction for take-off, rounded to the nearest 10° magnetic with the last digit omitted (e.g. "27" = approximately 270° magnetic).
Right-angled arrow pointing right, conspicuously coloured, in the signal area or displayed horizontally at the end of the runway in use = turns before landing and after take-off are to be made to the right (right-hand circuit).

Reporting and glider signals

Letter "C" in black on a yellow background, displayed vertically = indicates the location of the reporting office; visiting pilots must report there (think "C" for Communication).
White double cross, displayed horizontally in the signal area = glider flying is in progress; powered aircraft must expect glider traffic, winch cables or towing operations.

The dumbbell signals

The dumbbell tells you which surfaces you may use, and the distinction turns on black bars across the two circular ends:

Plain horizontal white dumbbell = aircraft must land, take off and taxi on runways and taxiways only.
White dumbbell with a black bar placed perpendicular to the shaft across each circular portion = aircraft must land and take off on runways only, but other manoeuvres (taxiing) need not be confined to runways and taxiways — typical of grass aerodromes where the runway is paved but taxiing on grass is permitted.

So: no bars — everything on paved surfaces; black bars — only take-off and landing are restricted to the runway.

Europe and Germany

The ground signals are binding throughout the EU via SERA Appendix 1 (annex to Regulation (EU) No 923/2012), which reproduces ICAO Annex 2, Appendix 1. The design requirements for the signal area itself follow ICAO Annex 14 Vol I and apply in the EU via Regulation (EU) No 139/2014 (Part-ADR). Many German VFR aerodromes maintain a signal area; the "C" signal and the double cross for glider operations are particularly common. The exact location and the signals in use are published for each aerodrome in the AIP VFR Germany.

Exam essentials

The signal area is a level square of at least 9 m × 9 m, visible from 300 m (1 000 ft) above the aerodrome.
Red square + two yellow diagonals = landing prohibited (prolonged); red square + one yellow diagonal = special precautions when approaching or landing.
White or yellow crosses on a runway or taxiway mark it as unfit for use.
The landing T indicates the landing/take-off direction along its shaft towards the cross-arm; a black two-digit number on yellow at the tower gives the take-off direction in tens of degrees magnetic.
A right-pointing right-angled arrow means all turns in the circuit are to be made to the right.
A vertical black "C" on yellow marks the reporting office; a white double cross means glider operations are in progress.
Plain white dumbbell = land, take off and taxi on runways and taxiways only; dumbbell with a black bar across each circular portion = land and take off on runways only, but taxiing is not confined to runways and taxiways.