Expedition & Adventure Directory |
Reflective Signalling SOS signalling Reflecting signalling (heliography) is an extremely effective method of gaining attention from great distances, especially when trying to attract the attention of aircraft. While a signal fire is great it's not so good after a rain storm and cannot be created quickly while on the move. In contrast a reflective surface is available instantly, easy to carry, may even improve when wet and unlike any old fire it is very obviously a signal when done correctly. Correct Technique The first thing to do is to ensure you are actually aiming the surface at the intended target. That may sound obvious but you'll find people shooting from the hip for the first time invariably aim too high and people pointing mirrors tend to aim too low. One technique is to hold the mirror or similar in the palm of your hand with 2 fingers pointing up as a 'V'. The idea is to aim by putting the plane or helicopter between the 2 fingers. There are other such techniques plus you can buy proper signalling mirrors complete with a little hole in the middle for aiming with but there's a much easier and more certain way. Hold your thumb out at arm's length and cover the target with your thumb. With your other hand move the mirror or similar until you see the sun's reflection on your thumb. Lower your thumb a little and viola, you're aiming the reflection at the target. Tempo It is best to not frantically flash the mirror from side to side or up and down, as short rapid flashes, to an aircraft, mean 'reflecting water'. Instead use slow deliberate flashes of around one full second, checking with your thumb every now and then to ensure you're still on aim. Any pilot or flight crew seeing repeated flash on, flash off, flash on, flash off style signalling will immediately realise they are being signalled to, even if they were not actively looking for anyone. Once you're certain you have been spotted, stop flashing, as no-one wants to be dazzled. Helicopters, low altitudes and dazzled pilots are not a good combination. Almost any reflective surface will do but in cloudy weather a true mirror finish is required. Either polish one side of your knife, choose a knife with a chromium-plated blade or ensure you have a small mirror handy. Alternatively any polished or shiny surface can be useful, even a credit card or compact disc. If you're with a broken down vehicle you'll often find the rear-view mirror is only held on by sticky glue. A good yank and you can usually remove it. Generally the less-polished the object the larger it needs to be, while an actual mirror can work even if it's only a single square inch of mirror. Don't underestime the power of a mirror signal. Signals have been spotted over 10 miles and under ideal conditions with a true mirror over 70 miles away! |