Emergency Signals & SOS Reference

The universal rule of distress signalling: three signals of any type = distress. Three whistle blasts, three fires, three flashes — any three of any consistent signal. Pause and repeat.

The Number Three — Universal Distress Pattern

Any pattern of three alerts rescuers to your presence and need for assistance. Three is unlikely to occur randomly in nature and is simple enough to produce under extreme stress.

Method	Distress Signal	Response Signal
Whistle	3 short blasts; pause 30s; repeat	1 blast (acknowledgement)
Gunshot	3 shots; pause 1 min; repeat	2 shots (acknowledged)
Fire	3 fires in triangle (25–30m apart)	—
Flashlight	3 flashes; pause; repeat	Continuous flash (acknowledged)
Mirror reflection	3 flashes toward target; pause; repeat	Signal back
Smoke puffs	3 puffs; pause; repeat	—

SOS in Morse Code

SOS is three dots, three dashes, three dots transmitted as a single continuous sequence.

Component	Morse	Transmission
S	...	3 short flashes/beeps/taps (1 second each)
O	---	3 long flashes/beeps/taps (3 seconds each)
S	...	3 short flashes/beeps/taps (1 second each)
Full SOS	...---...	No pause between letters; 7-second pause before repeating

Flashlight SOS timing: Short = 1s on; Long = 3s on; Pause between letters = 1s off; Pause before repeat = 7s off.

Signal Mirror

A signal mirror creates a pinpoint reflection visible up to 16 km in clear conditions.

Step	Action
1. Aim	Hold mirror reflecting sunlight; look through sighting hole at target
2. Align	Move mirror until bright reflection dot appears in sighting hole
3. Flash	Tilt mirror slightly to flash at target; repeat in SOS pattern
4. Improvised	Any shiny surface works: phone screen, foil, CD

⚠️ Even overcast days produce usable reflections from a signal mirror. Use it regardless of cloud cover.

Ground-to-Air Symbols

Lay symbols with rocks, logs, or trampled vegetation in the most open area available. Minimum size: 3 metres per element.

Symbol	Meaning
X (large X)	Need medical assistance
→ (large arrow)	Travelling in this direction
SOS	Require immediate assistance
▲ (triangle)	All is well / safe
F	Need food and water
LL (two vertical lines)	All is well
Y	Yes / affirmative
N	No / negative

Body Signals to Aircraft

Stand in the open when an aircraft passes. Use clear, exaggerated body positions.

Signal	Body Position
Need help	Both arms raised above head — Y shape
Do not need help	One arm raised, one arm down — diagonal
All well, can proceed	Both arms extended horizontal, palms down
Pick us up	Beckon with horizontal arm sweep
Land here	Kneel and point both arms at ground ahead
Do not land here	Cross forearms overhead repeatedly

Whistle Signals

Pattern	Meaning
3 short blasts	Distress — I need help
1 blast	Acknowledgement / I heard you
2 blasts	Come toward me
Continuous short blasts	Danger — stop / evacuate

Range: 1–3 km in quiet open terrain. Less in wind or forest.

Fire and Smoke

Condition	Best Signal	Fuel
Daytime, clear sky	Dark/black smoke	Rubber, oil, plastic, tyres
Daytime, overcast sky	White/light smoke	Green leaves, damp vegetation
Night-time	Bright flame	Dry wood; add fuel regularly
Any condition	Three-fire triangle	Spaced 25–30 m apart

Flares

Type	Effective Range	Best Use
Parachute rocket flare	20+ km at night	Maritime, open terrain, night
Hand-held red flare	5–10 km at night	Maritime distress; handheld
Orange smoke flare (hand-held)	20 km by day	Day use only; highly visible
Pen flare (aerial signal)	3–5 km at night	Wilderness carry; lightweight

Never point flares at aircraft. Indicate position, do not blind crew.

PLB and EPIRB Activation

Personal Locator Beacons (PLB) and Emergency Position-Indicating Radio Beacons (EPIRB) transmit on 406 MHz to the COSPAS-SARSAT satellite network, which relays position to search and rescue within minutes.

Step	Action
1. Activate	Lift cover and hold SOS/DISTRESS button 3–5 seconds
2. Position	Hold horizontally with antenna pointing skyward
3. Open sky	Move to clearest view of sky; do not enter buildings
4. Stay	Remain at activation site unless immediate danger requires movement
5. Wait	Keep beacon on; it continues transmitting your position

Registration is free at beaconregistration.noaa.gov (US). An unregistered beacon still triggers SAR but causes delays.

Night vs Day Signals

Method	Day Effectiveness	Night Effectiveness
Signal mirror	Excellent (up to 16 km)	None (no sunlight)
Orange smoke flare	Excellent	Poor
Fire (large bright flame)	Limited (look for smoke)	Excellent — visible for km
Flashlight / torch	Poor in daylight	Excellent
Parachute flare	Moderate	Excellent (20+ km)
Ground-to-air symbols	Excellent	None (not visible)
Dye marker (sea)	Excellent day visibility	None

Quick Reference

Situation	Action
Need to signal, have flashlight	Flash SOS: 3×1s, 3×3s, 3×1s; pause 7s; repeat
Have signal mirror and sun	Reflect toward aircraft/rescuer using sighting hole; flash SOS pattern
In wilderness — audible signal	3 whistle blasts every 30 seconds
Aircraft overhead	Y-body signal (both arms up) + SOS mirror flash
Maritime emergency	Red hand flare + orange smoke (day); EPIRB activation
Have PLB — life threatening	Activate outside with clear sky view; stay at location
Need ground marker	SOS or large X in open clearing (min 3m); use rocks, logs, trampled grass
Night — need to signal	Large bright fire; three fires in triangle; flashlight SOS