Andrew’s Note: Today we present another lesson from our Military Pedagogy series. This discussion, from FM 21-76, the U.S. Army Survival Manual [Approved For Public Release; Distribution is Unlimited] is on using a Signal Mirror and was inspired by my brother-in-law.
On a sunny day, a mirror is your best signaling device. If you don’t have a mirror, polish your canteen cup, your belt buckle, or a similar object that will reflect the sun’s rays. Direct the flashes in one area so that they are secure from enemy observation. Practice using a mirror or shiny object for signaling now; do not wait until you need it. If you have an MK-3 signal mirror[Andrew's Note: similar to many of the camping and survival mirrors sold in the civilian marketplace], follow the instructions on its back (Figure 19-3).
Wear the signal mirror on a cord or chain around your neck so that it is ready for immediate use. However, be sure the glass side is against your body so that it will not flash; the enemy can see the flash.
Haze, ground fog, and mirages may make it hard for a pilot to spot signals from a flashing object. So, if possible, get to the highest point in your area when signaling. If you can’t determine the aircraft’s location, flash your signal in the direction of the aircraft noise.
Note: Pilots have reported seeing mirror flashes up to 160 kilometers [99 miles] away under ideal conditions.
Figures 19-4 and 19-5 show methods of aiming a signal mirror for signaling.
Andrew’s Note: If you’re using a field expedient (makeshift) reflector you can aim it more easily by shining the reflection first on your hand (or between two fingers like in Figure 19-4) held out in front of you and move it towards the aircraft until you transfer the reflection to the aircraft.