Rescue

So... life could possibly be better. You are in a survival situation. You are just only managing to hang on, maybe someone in your team is injured or otherwise flagging. You're running out of beer, and the Stanley Cup playoffs are on. And you have no communications such as phone or radio. Things are serious! You have two key choices to make - Stay or Go. Which gives you the best odds?ResQLink+ GPS Locator beaconIf you can't move - you have seriously injured members or can't physically go on, then you have little choice. Shore up your shelter/water/food situation and think about signalling (below). I will deal with the injured member issue elsewhere. If you have submitted a hiking plan to some responsible persons - preferably someone who actually cares about you, and maybe a backup - then it is preferable to STAY. Someone will come looking. As an aside - don't rely on telling a group of your people where you are and when you will be back. For once, the shotgun approach won't work. Everyone will assume someone else will check up on you. If you have applications such as Alpify on your phone, now is a good time to use them. If you have an emergency beacon - well, if it is really serious use it. Just be aware that if the authorities decide that you getting disoriented 50m away from the carpark, while fretting about the last episode of Greys Anatomy doesn't really warrant a full satellite and aircraft search, you might get hit with a not-inconsiderable bill. I don't carry an emergency beacon.

Communication

If you are going to stay, you need to let folks know where you are in some way. For once we break the leave no sign philosophy. Go loud and visible.

Whistle signals

Whistles can be heard at great distances, and having a whistle conveniently stored with your survival stuff is a good idea. The ones without the little pea in them are preferable. If you just happen to have a firearm with you - gunshots are even better. Point at a safe place, people! We're not celebrating a wedding or the imminent overthrow of the Free World! What goes up, tends to come down. Note there are two versions of the 'recognised' distress signal - 3 vs 6 blows/shots. Regardless, the searching party will get the picture.

Communication Whistle/Gun shot signal
Distress signal by lost party 3 (three) blasts together, regularly spaced
Distress signal by lost party (International Mountain Distress signal) 6 (six) blasts together, separated by 1 minute
Searchers looking for lost party 1 (one) blast at regular intervals
Acknowledgement of distress signal 2 (two) blasts repeated regularly
Recall signal for search parties 4 (four) blasts

Signal mirrors

Signalling mirrors are surprisingly good at attracting attention from the air - even if the weather is kind of hazy. They can be improvised with any sort of mirror (mirror compasses, shaving kit, camouflage cream kit for all you survivalists out there, make-up kit for all the selfie-takers). Any reflective metal surface such as knife handles, old foil from cans or foil food packs. In short, there are plenty of reflective surfaces kicking around. Commercial survival signalling mirrors are available. I've played with them, and they have a cool little sighting hole for aiming the reflection at any aircraft. I admit however I've never carried one. If you are trying to signal an aircraft, use a bit of a shotgun approach and sweep around a bit trying to get its attention. The pilot or observer may not always be looking in your direction - they could be updating their Facebook page No sign yet. But here's a cool video of a kitten dancing on an aquarium lid. LIKE this if you like kittens... or more typically your aim could be off.

Signal fires

Smoke from a fire is a useful signal if you are well and truly lost. It will aid searchers, and in general anyone passing in an aircraft will check out smoke. Additionally, many national parks in various countries have forest fire observation towers.
Of course you will need to have a fire going, and some green vegetation to give a darker smoke at daytime and some readily flammable light material to make a bigger blaze at night. Don't go too overboard! Signal fires in dry areas have been known to get out of hand. You could end up having to run for your life.

Signals for aircraft

There are a range of pretty much universal codes used to signal to aircraft. If you have, for example, a signal fire then it pays to have a signal on the ground to communicate the nature of your problem. Figures should be approximately eight to nine metres in (24-27 feet to you barbarians from Imperial-land out there) using any contrasting materials such as rocks, logs bushes, trenches in sand, trampled snow. Be creative.

Require assistance
Require assistance signal
Serious injury
Serious injury signal
All is well
All is well signal
Am moving this way
Am moving this way signal
Affirmative/Yes
Affirmative/Yes signal
Affirmative/Yes
Affirmative/Yes signal
Negative/No
Negative/No signal
Do not understand
Do not understand signal
Indicate direction to proceed
Indicate direction to proceed signal
Unable to move on
Unable to move on signal
Need food and water
Need food and water signal
Need medical supplies
Need medical supplies signal
Need compass and map
Need compass and map signal
Need radio/lamp/batteries
Need radio/lamp/batteries signal
Safe to land here
Safe to land here signal
Aircraft badly damaged
Aircraft badly damaged signal

If your signals have been seen and understood by the aircraft, it will rock its wings from side to side at day or flash its navigation lights twice at night. If you don't get any response, don't totally despair. Yes, the message may have not been seen or understood, but it's also possible the pilot is a greenhorn at search and rescue and didn't think to signal back. Keep signalling until you get a response. Oh, and to all you Hollywood movie buffs - the pilot can't hear you if you yell at the aircraft. Sorry to burst the bubble.

Many survival books give detailed instructions on how to prepare for helicopter rescue. Short of trying to get to a place where a helicopter can land - and generally the pilot will show you where he/she wants you to go - removing any big items that can be picked up, making sure your own gear isn't going to fly around is the most you can do. It's best just to stay out of the way, downslope, and always stay where the pilot can see you. Yes, you can learn all the directing signals but from experience with civilian and military pilots - they are in all probability going to ignore you. Look at it from their point of view. They don't know you, your training, whether you can even play Flight Simulator let alone fly a rotary wing aircraft. Your opinion means very little to them and their $400,000 helicopter. They really just want you to stay out of the way. Follow their instructions.

Move...

Once you've made the decision to move its pretty much the same as organizing any other trip or patrol - with some disadvantages. First, you MUST have a plan. This will depend to a degree on the nature of your survival situation. This is almost invariably because you are lost. What route will you take? Even if you are geographically challenged there are some general geographic and physical features that hold. Going downhill takes you to areas where people live. Water travels downhill to larger watercourses. People, trade, transport, and habitation all occur along watercourses. If you are in a dry area, people still always travel on the low ground, through passes, valleys - nobody takes the hard route by choice. Powerlines cross ridgelines, and powerlines lead to people.
Leave sign when you move. A great big Am moving this way sign at your departure point will help, as will the same sign at each of your night locations. These are very visible to aircraft. Keep a fire at night as a signal.
Keep a log of your movements. Even if lost, use and record dead reckoning navigation legs. Think back to dead reckoning. Just as dead reckoning can be used to plan a route, so it can be used to reconstruct a route. It may be that your route along ridgelines and spurs, heading downhill, suddenly begins to look like the outline of a hill range on your map. You may have just relocated yourself. Associated with this retrospective dead reckoning, draw a map. This will help you with your possibility of working out where you are. And, unfortunately, you may have to backtrack and take a different route if you hit some impassable obstacle. Having your own mud-map will help.
At all times keep your head, and tend to your physical and mental welfare. Talk to yourself (if alone) and others in the group. It will maintain morale, you can keep track of the group members well-being, and as I mentioned in Route planning maintaining a narrative in your head helps keep you mentally grounded in where you are. Well at least relative to your last known point even if its just the signal arrow you left behind. Never give up. An old cave diving truism is As long as you can breathe, you're OK. There's always something you can do. As long as you're alive, you can always do something. If you're not, well it doesn't really matter then, does it? Be a leader. This doesn't imply mouthing off in a bossy way (I hate that type of people! Officer schools are full of them!) It implies taking responsibility in your situation, taking control of the situation, and working with the team to ensure that you all collectively are going to win. Nature is just another thing to deal with.