Ground to Air Signals
Edit on GitHubThe standardized ground signals used to communicate with search aircraft, and how to make them readable from the air.
Ground to Air Signals
A helicopter or fixed-wing search aircraft can read messages written on the ground. The signals are standardized worldwide, which means the crew does not need to guess what your pattern means.
The standard symbols
| Symbol | Meaning |
|---|---|
| V | Need assistance |
| X | Need medical assistance |
| Arrow (pointing) | Proceeding in this direction |
| Y | Yes |
| N | No |
| Triangle | Here is the landing direction |
| F | Need food and water |
Build them large enough to be seen from the search altitude: at least 2 - 3 meters per element, with high contrast against the ground (snow, trampled grass, rocks, clothing, or signal panels).
Making them readable
- Flat, open ground: a signal in a hollow cannot be seen.
- Contrast beats size: dark material on snow, light material on soil.
- Weight the edges so the wind does not scatter them.
- Walk away from the signal; standing in it makes it unreadable.
In snow
Trampled letters in deep snow work, but fresh snowfall buries them. Re-check and re-trample after every snowfall. The beacon keeps transmitting while you maintain the signals; radio and visual layers together are strongest.
Helicopter arrival
When the helicopter is landing, the classic signals apply: arms up in a Y shape to signal “yes, land here”, one arm up one down for “no, do not land”, and stand with your back to the wind, arms spread like a cross, once it is on the ground (crew instructions).
Related pages
- Signaling Techniques for the toolbox
- Mirror Signaling for daytime flashing
- Avalanche Rescue Operation for the snow context