Search and rescue signals
Learning objectives
- State the manoeuvres an aircraft flies to tell a ship "follow me to a craft in distress" and "your help is no longer needed", and the replies a ship may give.
- Identify the meaning of each of the five survivors' ground symbols and each of the seven rescue units' ground symbols.
- State the minimum size of a ground symbol and how survivors can make it stand out.
- Explain how an aircraft shows, by day and by night, that it has understood a ground signal, and what it means when it shows nothing.
The idea
Imagine you are lost, with no radio, and an aircraft is circling far above you. You cannot shout, so you have to write on the ground. Everybody who flies over you has to read your message the same way, or the whole thing is pointless. That is why search and rescue (SAR) has a small, fixed vocabulary: a few shapes laid out on the ground, a few moves an aircraft makes over a ship, and one simple way to say "I got it". You do not need to be clever. You need to remember a short list and to never use those shapes for anything else.
Where these signals come from
For this page, ICAO Annex 12 is the rule in force. No EU act replaces it.
SERA, the EU rules of the air, covers distress and urgency signals, but it does not contain the surface-craft, ground-air or air-to-ground SAR codes. Those come straight from the ICAO appendix on search and rescue signals.
The appendix has three groups. The first is signals between an aircraft and a surface craft, meaning a ship or boat. The second is a code laid out on the ground, with one set for survivors and one for rescue units. The third is the aircraft's reply to a ground signal.
One general rule sits over all three, and another page teaches it in full: these signals keep exactly the meaning they are given, and nobody may use other signals that could be mistaken for them. An aircraft that sees one must act on what it means. See the page on SAR definitions and pilot procedures (010-10-01).
Where radio contact with a surface craft is possible, the aircraft directs it with precise radio instructions. The visual surface-craft signals are for when no radio communication can be established. Likewise, where practicable, a dropped message or dropped communication equipment is used rather than the visual "understood" signal. Those procedures belong to 010-10-01.
Signals with surface craft
Think of it from the ship's point of view. The crew sees an aircraft, but it has no idea why. The aircraft needs to say three things in order: "I am talking to you", "look at me", and "go this way". The signal is built exactly like that.
To direct a ship towards an aircraft or a craft in distress, you fly three manoeuvres in sequence.
- Circle the surface craft at least once.
- Cross the ship's projected course close ahead, at low altitude, while rocking the wings, or opening and closing the throttle, or changing propeller pitch.
- Fly off on the heading the ship is to follow.
The projected course is the track the ship will follow if it holds its present heading. Repeating the manoeuvres has the same meaning. It is not a different signal.
Of the three attention-getters in step two, rocking the wings is the visual one. Throttle and propeller-pitch changes are sound signals that may be lost in the noise aboard a ship, so they are treated as alternatives.
Describe this figure
A plan view shows a surface craft heading up the page with a dashed projected course ahead of it. In step 1 the aircraft circles the craft at least once. In step 2 it crosses the projected course close ahead at low altitude, rocking its wings, or opening and closing the throttle, or changing propeller pitch. In step 3 it flies off on the heading the craft is to follow, towards the craft in distress, and repeating the manoeuvres means the same. An inset shows the other signal: to say help is no longer required, the aircraft crosses the wake close astern, low, with the same wing, throttle or pitch movements, and does not circle or head off.
The figure is a plan view from above. A ship steams along a line that continues ahead of it as the projected course. The aircraft track loops once around the ship, then cuts across the course line just in front of the bow, with a wing-rock symbol marking that crossing, and then runs off in the direction the ship is to take. An inset in the corner shows the opposite signal, described next.
Telling the ship it is released
When the ship's help is no longer needed, you do something deliberately different. You cross the ship's wake close astern, at low altitude, while rocking the wings, or opening and closing the throttle, or changing propeller pitch. The wake is the disturbed water behind the vessel.
The contrast is the whole trick. "Follow me" is circle, cross close ahead, then head off on a heading. "No longer required" is cross close astern, with no circling and no heading-off. Ahead means "come along". Behind means "you can stop".
The "follow me" signal is three manoeuvres in sequence: circle at least once, cross the projected course close ahead at low altitude with a wing rock, throttle change or pitch change, then fly off on the heading to follow. The "no longer required" signal is a crossing of the wake close astern at low altitude with the same attention-getters.
How the ship may answer
A ship may reply, and these replies are written as "may", not "shall".
To say "understood", a ship may hoist the code pennant close up, which is a flag with vertical red and white stripes. It may flash a succession of the letter T in Morse code by signal lamp. Or it may simply change heading to follow the aircraft.
To say "I cannot comply", a ship may hoist the international flag N, a blue and white chequered square. It may also flash a succession of the letter N in Morse code.
A memory hook: the ship's "no" uses the letter N, the same letter that means "No or Negative" in the survivors' ground code. The letter T has no counterpart in the ground code.
The survivors' ground-air code
If you are the one on the ground, your message is one big symbol. The survivors' code has five of them, and each is a single shape, because a person with few resources can only build something simple.
Describe this figure
Five tiles show the survivors' ground-air code, drawn as thick strokes on a ground-coloured tile. V means require assistance; X means require medical assistance; N means no or negative; Y means yes or affirmative. A single arrow means proceeding in this direction, and its head points the way the survivors are going. Below, a separate dashed tile marked as a Portuguese national addition shows SOS and says: in doubt, use the international symbol. It is not part of the Annex 12 code of five. A note says survivors use single symbols and rescue units use doubled or tripled ones.
The figure shows five tiles, each with one thick-stroked symbol on a ground texture and its meaning underneath. A separate tile, labelled as Portuguese and kept apart from the five, shows SOS.
- V (two strokes meeting at a point at the bottom): require assistance.
- X (two crossing diagonal strokes): require medical assistance.
- N: no, or negative.
- Y: yes, or affirmative.
- A single arrow: proceeding in this direction, with the arrowhead pointing the way the survivors are going.
The sense of V is "something is wrong, I need help", and X is a more specific "someone is hurt". Keep the order in mind: V first, X is the medical one.
Portugal reproduces the survivors' table with one added row: "In doubt use the International symbol: SOS". The five Annex 12 symbols are unchanged. This is context only. The code to learn for the exam is the ICAO one.
The rescue units' ground-air code
Rescue units answer on the same ground, but they use a different set. There are seven symbols, and they are doubled or tripled forms, so that a rescue unit's message cannot be mistaken for a survivor's.
Describe this figure
Seven tiles show the rescue units' code. Three Ls side by side mean operation completed; two Ls with a straight line under both mean we have found all personnel; a line crossed by two short vertical strokes means we have found only some personnel. XX means we are not able to continue and are returning to base. A line crossed by two arrows in opposite directions means the team has divided into two groups, each proceeding in the direction indicated; two arrows in line, pointing the same way, mean information received that the aircraft is in this direction. NN means nothing found, will continue to search. A box warns that a single X is survivors needing medical help, while XX is the rescue team unable to continue and returning to base.
The figure shows seven tiles in the same style as the first card: each holds one symbol with its meaning. The drawings are described in the list below.
- LLL (three capital Ls side by side): operation completed.
- LL with a straight line under both Ls: we have found all personnel.
- A horizontal line crossed by two short vertical strokes (like two plus signs on one bar): we have found only some personnel.
- XX: we are not able to continue, returning to base.
- A horizontal line with two arrows crossing it diagonally in opposite directions: we have divided into two groups, each proceeding in the direction indicated.
- Two arrows one behind the other, pointing the same way: information received that the aircraft is in this direction.
- NN: nothing found, will continue to search.
The pattern is the best memory aid. Survivors use single symbols (V, X, N, Y, one arrow), and rescue units use doubles and triples (LLL, LL, the plus bar, XX, two-arrow forms, NN). So a single X asks for a doctor, while XX means the rescue team is not able to continue and is returning to base.
Describe this figure
Twelve tiles show the ground-air symbols of Annex 12: five single symbols for survivors (V, X, N, Y and a single arrow) and seven doubled or tripled symbols for rescue units (LLL, two Ls with a line, a bar with two strokes, XX, a bar with two opposite arrows, two arrows in line, and NN). With JavaScript the meanings are hidden until you choose a tile, by mouse, touch or keyboard (arrow keys move, Enter or Space chooses). A button shows or hides all meanings. The static version shows every symbol with its meaning and who uses it.
The interactive card lets you pick any of the twelve symbols and see its meaning and who uses it, survivors or rescue units. It works with the keyboard. A static version of the same twelve symbols and meanings is shown if the interactive version is not available.
Without looking, say what X, XX, N and NN each mean and who lays each one out. Then explain how the "single or double" pattern helps you.
Size, materials and getting noticed
Ground symbols must be at least 2.5 m (8 ft) long and made as conspicuous as possible. The reason is simple: an aircraft passing at speed and height has only seconds to see them.
Make symbols from whatever is to hand, such as strips of fabric, parachute material, pieces of wood or stones. You can also tramp the surface (snow, sand or crops) or stain it with oil. Contrast with the background is what makes a symbol visible. You can draw attention to a symbol with radio, flares, smoke or reflected light such as a signal mirror.
Describe this figure
A ground panel shows a symbol made of stones with a person standing beside it for scale. A dimension line under the symbol marks the minimum length, 2.5 m (8 ft), labelled as a rule; the symbol must also be as conspicuous as possible. Text says that contrast with the background is what makes a symbol visible, which is practice. Below, one list gives ways to make a symbol: strips of fabric or parachute material, pieces of wood or stones, tramping snow, sand or crops, or oil staining. A second list gives ways to attract attention to it: radio, flares, smoke and reflected light such as a signal mirror. Both lists are marked as practice.
The figure shows a symbol made of stones beside a scale bar marked 2.5 m (8 ft) and a person standing next to it for scale, with small icons for a flare, smoke, a mirror and a radio.
The aircraft's reply from the air
Survivors want to know whether they have been understood. An aircraft that has understood a ground signal answers like this.
- By day: rock the wings.
- By night: flash the landing lights on and off twice. If the aircraft has no landing lights, switch the navigation lights on and off twice.
If the aircraft makes no such signal, the ground signal has not been understood. There is no separate "not understood" signal.
Describe this figure
Four rows show how an aircraft answers a ground signal. By day it rocks its wings, shown by two tilted aeroplanes. By night it flashes its landing lights on and off twice, shown as two pulses. If it has no landing lights, it switches its navigation lights on and off twice instead, shown as two dotted pulses. In the last row an aeroplane flies past with no wing rock and no lights. No such signal means the ground signal was not understood, and there is no separate signal for not understood.
The figure splits into a day half and a night half. By day, an aircraft rocks its wings over a group of survivors. At night, the same aircraft shows its landing lights flashing twice, or its navigation lights twice if it has none. A caption states that no signal means not understood.
These replies match an aircraft's acknowledgement of aerodrome light signals in flight, which helps memory. SERA adds an exception there for base and final legs that does not appear in the SAR rules. See the page on signals (010-05-04).
Light switching is done with your own aircraft's controls. Check your aircraft's POH/AFM for which lights it has and how they are switched. This lesson does not replace ATO instruction or the aircraft's POH/AFM.
Flashing the landing lights twice means "ground signal understood". Repeated switching of the landing lights on and off is a different signal, the urgency signal for an aircraft with difficulties that force it to land without needing immediate help. Count and context decide. The urgency signals are taught on 010-05-04.
In the real world
In early August 2020, three mariners in a small skiff went missing on a short trip between atolls in Chuuk, in the Federated States of Micronesia. A US Air Force KC-135 crew searching at about 1 500 ft saw a large "SOS" laid out on the beach of Pikelot Island, next to a boat. A Coast Guard HC-130 then airdropped a radio and a message block telling them a vessel was coming, and the three were later picked up.
Notice two lessons. The signal was big and sat next to something conspicuous, so it was found. And the aircraft answered with a dropped radio and a message, the preferred approach that 010-10-01 covers. SOS is not one of the five ICAO survivor symbols, where V means require assistance, but it was understood at once.
No investigation report exists, because this was a rescue and not an aircraft accident. The account is based on the official US Coast Guard release, "Coast Guard, partners rescue three stranded mariners from island in Federated States of Micronesia" (3 Aug 2020, DVIDS story 375188): https://www.dvidshub.net/news/printable/375188
Exam traps
- X is not "require assistance". V means require assistance and X means require medical assistance. Likewise Y is yes, not help.
- XX is not a stronger X. XX is a rescue-unit symbol meaning not able to continue, returning to base.
- N and NN are different. For survivors, N means no or negative. For rescue units, NN means nothing found, will continue to search.
- LLL and LL are different. LLL means operation completed, and LL with a line underneath means all personnel found.
- Rocking the wings has many meanings. It can be "ground signal understood", part of the surface-craft signals, an aerodrome-light acknowledgement, and part of interception. Context decides.
- Dated note. The Annex states that the visual signals are published in the IAMSAR manual until 25 November 2026 and from 26 November 2026 in the Annex appendix and the IAMSAR manual. The signals themselves are taught here as the rule.
Explain it back
Imagine a student pilot asks you how to tell a ship "come with me" and later "you can stop". Explain both manoeuvres, say how the ship may reply, and name the one detail that tells the two signals apart.
Self-check
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You are flying CS-ABC over open sea and see a ship you have been guiding towards a casualty. Radio contact is impossible. The ship is no longer needed. Which manoeuvre tells it so?mcq · medium
Show answer
Crossing the wake close astern at low altitude, with a wing rock, throttle change or pitch change, means help is no longer needed. The first option is the 'follow me' sequence. The third is the crossing used inside 'follow me' (ahead, not astern). The fourth is the night signal for 'ground signal understood' and is not a ship signal.
Reference: Annex 12, Appendix 1.1; Annex 12, Appendix 1.2
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A search aircraft sees XX laid out on the ground beside a team of people. What does it mean?mcq · easy
Show answer
XX is a rescue-unit symbol meaning not able to continue, returning to base. A single X (survivors) is the medical-assistance request, which is why the first option is wrong. Require assistance is V. Nothing found is NN.
Reference: Annex 12, Appendix 2.1; Annex 12, Appendix 2.2
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Survivors of a forced landing want to say that one of them is injured and needs a doctor. Which symbol do they lay out?mcq · easy
Show answer
X means require medical assistance. V means require assistance in general. Y means yes or affirmative. N means no or negative.
Reference: Annex 12, Appendix 2.1
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At night you are flying CS-ABC, which has no landing lights, and you see a ground signal that you understand. How do you show it?mcq · hard
Show answer
At night the aircraft flashes its landing lights twice, or, with no landing lights, switches its navigation lights on and off twice. Rocking the wings is the day signal. Repeated switching is the wrong count and resembles an urgency signal. Making no signal means the ground signal has not been understood.
Reference: Annex 12, Appendix 3.1; Annex 12, Appendix 3.2
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What is the minimum length of a ground-air visual symbol, in metres and feet?short · easy
Show answer
Symbols must be at least 2.5 m (8 ft) long and as conspicuous as possible. Shorter symbols are hard to see from an aircraft passing at speed.
Reference: Annex 12, Appendix 2.3
Key concepts
Written with ASD-STE100 writing principles: short sentences, one topic per sentence, active voice, one word for one meaning.
Survivors' ground-air code
The survivors' code has five single symbols. Each symbol passes one short message to an aircraft.
Rule: Annex 12, Appendix 2.1
Do: Learn V first, because it means require assistance. Learn X second, because it means require medical assistance.
Single and doubled symbols
Survivors use single symbols, and rescue units use doubled or tripled symbols. This pattern keeps the two codes apart.
Symbol size
A ground-air symbol must be at least 2.5 m (8 ft) long. Make the symbol as conspicuous as possible, because an aircraft has only seconds to see it.
Rule: Annex 12, Appendix 2.3
Rescue units' ground-air code
The rescue units' code has seven symbols. Each symbol passes one result from the rescue unit to the aircraft.
Do: Read LLL as operation completed, and NN as nothing found, will continue to search.
Follow me signal
To direct a surface craft towards a craft in distress, an aircraft flies three manoeuvres in sequence. The aircraft circles the surface craft at least once. It crosses the projected course close ahead at low altitude, then flies off on the heading to follow.
Rule: Annex 12, Appendix 1.1
The no longer required signal is the opposite pattern. The aircraft crosses the wake close astern. It does not circle the surface craft or head off.
Surface craft replies
A surface craft can say it understood the follow me signal. It can hoist the code pennant close up, flash a succession of the letter T in Morse code, or change heading to follow the aircraft.
A surface craft can say it cannot comply. It can hoist the international flag N, or flash a succession of the letter N in Morse code.
Rule: Annex 12, Appendix 1.2, Note
Understood signal
An aircraft shows that it understood a ground signal by wing rock by day. By night, it flashes its landing lights on and off twice. If it has no landing lights, it switches its navigation lights on and off twice.
Rule: Annex 12, Appendix 3.1
No such signal means the ground signal was not understood. No separate not understood signal exists.
Rule: Annex 12, Appendix 3.2
Context decides the meaning
Some light and wing signals look like other signals. Two flashes of the landing lights mean ground signal understood. A repeated on and off landing light pattern is the urgency signal. A wing rock has several meanings, so the context decides.
Do: Check the situation before you read a light or wing signal.
Flashcards
Print them: A6 landscape cards (PDF, front and back) · 4 cards per A4 landscape sheet (PDF, cut lines) · Key figures deck (PDF, 8 figures)
Print double-sided, flip on the short edge.
010-10-02-01How many symbols does the survivors' ground-air code have?
Five single symbols: V, X, N, Y and one arrow.
010-10-02-02Which survivors' symbol means require assistance?
V: two strokes meeting at a point at the bottom.
010-10-02-03Which survivors' symbol means require medical assistance?
X: two crossing diagonal strokes.
010-10-02-04What does the survivors' symbol N mean?
No, or negative.
010-10-02-05What does the survivors' symbol Y mean?
Yes, or affirmative.
010-10-02-06What does a single arrow on the ground mean for survivors?
Proceeding in this direction. The arrowhead points the way the survivors are going.
010-10-02-07What does the rescue units' symbol LLL mean?
Operation completed. It is three capital Ls side by side.
010-10-02-08What does LL with a straight line under both Ls mean?
We have found all personnel.
010-10-02-09What does a horizontal line crossed by two short vertical strokes mean?
We have found only some personnel.
010-10-02-10What does the rescue units' symbol XX mean?
We are not able to continue. Returning to base.
010-10-02-11What does a horizontal line with two diagonal arrows mean?
Divided into two groups. Each group proceeds in the direction indicated.
010-10-02-12What do two arrows, one behind the other and pointing the same way, mean?
Information received that the aircraft is in this direction.
010-10-02-13What does the rescue units' symbol NN mean?
Nothing found. Will continue to search.
010-10-02-14Do survivors use single or doubled symbols?
Survivors use single symbols. Rescue units use doubled or tripled symbols.
010-10-02-15Is XX a stronger form of X?
No. XX is a rescue-unit symbol meaning not able to continue, returning to base. A single X asks for medical help.
010-10-02-16Do LLL and LL mean the same thing?
No. LLL means operation completed. LL with a line under both Ls means all personnel found.
010-10-02-17What is the minimum length of a ground-air symbol?
2.5 m (8 ft), and made as conspicuous as possible.
010-10-02-18Which three manoeuvres make up the follow me signal to a surface craft?
First, circle the surface craft at least once. Then cross its projected course close ahead at low altitude. Finally, fly off on the heading to follow.
010-10-02-19How often does the aircraft circle a surface craft in the follow me signal?
At least once.
010-10-02-20How can a surface craft say it understood a follow me signal?
It can hoist the code pennant close up, flash a succession of the letter T in Morse code, or change heading to follow the aircraft.
010-10-02-21How can a surface craft say it cannot comply?
It can hoist the international flag N, or flash a succession of the letter N in Morse code.
010-10-02-22Which signal tells a surface craft that its help is no longer required?
Cross its wake close astern at low altitude. Do not circle or head off.
010-10-02-23Where does the aircraft cross a surface craft for follow me, and where for no longer required?
Follow me: close ahead of the projected course. No longer required: close astern, across the wake.
010-10-02-24What is a projected course?
The track a surface craft follows if it holds its present heading.
010-10-02-25How does an aircraft show by day that it understood a ground signal?
It rocks its wings.
010-10-02-26How does an aircraft show by night that it understood a ground signal?
It flashes its landing lights on and off twice. With no landing lights, it switches its navigation lights on and off twice.
010-10-02-27What does it mean when an aircraft makes no such signal?
The ground signal has not been understood. No separate not-understood signal exists.
010-10-02-28Does repeated switching of the landing lights answer a ground signal?
No. Two flashes answer a ground signal. Repeated switching is the urgency signal for an aircraft with difficulties.
010-10-02-29Does rocking the wings always mean ground signal understood?
No. Context decides. It can also be a surface-craft signal, an aerodrome-light acknowledgement or part of interception.
010-10-02-30Portugal national addition: which survivors' symbol is added?
SOS. AIP Portugal says: in doubt, use the International symbol SOS. The Annex 12 code is the code to learn for the exam.
010-10-02-31From which date does the Annex 12 appendix publish the visual signals?
From 26 November 2026. Until 25 November 2026, the IAMSAR Manual publishes them in Volume III only.
010-10-02-32How many symbols does the rescue units' code have?
Seven, all doubled or tripled forms.
Sources
- ICAO Annex 12, Search and Rescue, 9th edition (2024), Chapters 1 and 5 and the Appendix (provisions applicable from 26 November 2026 taught, earlier wording noted).
- AIP Portugal GEN 3.6 (AIRAC 001-26), section 6.3: national addition to the survivors' code (Portugal note only).
- US Coast Guard District 14 / Oceania, release of 3 August 2020 on the Pikelot Island rescue (DVIDS 375188), cross-checked with the US Air Force 36th Wing release of the same date.
This page is educational. It does not replace instruction at your ATO or your aircraft's POH/AFM. Rules change: check the regulation in force.