Being found from the air: helicopters, aircraft, drones

Anyone searching from the air scans a huge area, often from great height and at high speed. The eye looks for things that do not fit into nature: strong colour contrasts, straight lines, geometric shapes and above all movement. A large X or triangle on a meadow stands out because nature rarely forms such shapes.

Under a dense canopy of leaves you are almost invisible from above. That is why an open area matters so much: a clearing, a meadow, a ridge, a snowfield or a beach. There you can be seen and have room to lay out signs.

At night, lights are visible from the air over long distances, especially in areas without other lighting. Some rescue services also use thermal cameras on helicopters or drones that can detect a person's body heat. But do not rely on that – light and movement always help.

Find an open spot nearby, but only if you can reach it safely. Avalanche slopes, rockfall zones and riverbanks are not good ‘open spots’, even if they are clear. Rather stay at the edge of a safe area, where you can shelter under trees if needed.

Spread out bright or fluorescent clothing, your pack or a cloth flat. If possible, lay out a large ground sign of branches, stones or clothing that stands out from the ground. The shiny side of a rescue blanket or a signal mirror can reflect sunlight and create a flash visible from far away.

Overflights often last only seconds. So keep your signals ready so that you can react at once when you hear an engine: swing a cloth, wave with both arms, use the mirror, flash a light at night. Do not wave with just one hand; that looks like a friendly greeting.

There are simple body signals that rescue crews in aircraft understand. Both arms stretched diagonally upwards, so that your body looks like a big Y, means: ‘Yes, I need help.’ One arm diagonally up and one diagonally down means: ‘No, I do not need help.’

These signals matter so that the crew decides correctly. A friendly wave may be read as ‘all OK’ and lead the helicopter to fly on. So show the Y clearly if you need help.

A simple memory aid: Y for ‘yes’ – both arms up. Practise the sign once so that it comes naturally in an emergency.

A helicopter that is hovering or landing creates a very strong downwash. It whips up sand, snow, branches and anything loose lying around. So secure tarps, cloths, rescue blankets and clothing as soon as you have been spotted, so that nothing gets into the rotors. Protect your eyes.

Never run towards a landing or hovering helicopter. Stay where you are and wait until the crew gives you a signal. Then approach only from the front, within the pilot's view, and follow the crew's instructions exactly.

Drones are increasingly used by rescue organisations. Do not touch, grab or throw things at them – the propellers can cause serious cuts. Waving is enough. Some drones have loudspeakers through which rescuers give you instructions. And if you have signal, call the local emergency number (112 in the EU) first.

Lost in the forest: you hear a helicopter, but you are sitting under dense trees. If it is safe, go to the nearest clearing or path and lay out your signals there. When the helicopter comes back, you are ready.

Injured and unable to walk: then make the best of where you are. Spread everything bright you have around you, keep a mirror or lamp within reach and move as well as you can as soon as you hear an aircraft.

At night: keep the lamp ready, but only switch it on or flash it when you hear an engine. That way you save battery for the moment when it really matters. Weather and darkness can also prevent flights altogether – then warmth, patience and the other signals count.