One of the things to consider when you look at your survival gear. You will most likely be injured. I went through a few survival courses with both the Navy and the Air Force. They told you to expect to be injured. Many here are obsessed with guns, well you may not be able to use them. They also taught us, tongue and cheek that we where more likely to hurt ourselves with it than do anything useful. They do come in handy as signaling devices (noise and .38 cal flares). When I was a NOAA pilot doing Arctic research, we where required to carry large caliber handguns, primarily to make noise and scare the bear off (we did actual darting and tagging of them). The common wisdom was to file the front sight off, so when the bear shoved it up your exhaust pipe, it didn't hurt so much.
Things you will most likely need are QuickClot, eye antibiotic, triangular bandage, burn treatments and irrigation fluids (your urine works well on YOUR wounds (it is sterile to you)). Why this stuff? Well lacerations are common, your windscreen shatters and you get plexi in your eyes , you sprain or break bones (typically your wrist and legs, as folks hold onto the controls through the crash and violent feedback of the controls breaks your wrists or thumbs and the rudder will break you leg or ankle). Then, planes burn, surprisingly well.
I have used this ex-Army vest for a long time. It is mesh, so it works in all climates. Has loads of pockets for various small survival items and a spot to put people's precious guns. Well, most of the world does not allow you to have a gun, and this was the case in S. America where I flew a lot and Africa, where I flew even more. Everybody else had guns, just not us (The little pin flares work just as well as a .38 up to 15'). However, when I do carry, I use my S&W Combat Magnum .357/.38. Good power, accurate, shoots flares, makes lots of noise, can kill a deer, or a squirrel with shot shells. You do not have to ever clean it, will always work and any moron can use it. I also carry the little survival gun shown. It is an Armalite .22 made specifically for the Israeli Air Force, to fit in an F4 seat pan. Good luck finding one, they only made a few hundred. It folds up small, holds three mags and is especially accurate and light.
Radios are really nice, but they won't work or the battery will be dead when you need it, or at least it always seems so for me. Spot is a nice touch, again hope it works. I have an old ACR Eprib that is SOLAS qualified and has a 20 year battery, still plugging along. Mirrors and smoke are the best signaling devices and I have a small ACR strobe. Flares seem like they should be good, but I have had friends actually hit the helicopter with them and they failed to notice. The best flares are the 25mm rocket parachute flare. They are big, heavy, expensive and are hard to find now. You can get self contained pop out SOLAS parachute flares that do work.
Lots of the items are climate specific. In Alaska, in the spring & summer you really, really, really want mosquito headnets. The rest of the world, repellent more or less works. In the tropics you want to carry Cipro, Flagyl or Septra DS. All these work on the infections you WILL get from the water. These infections WILL kill you from dehydration and electrolyte loss, not a joke, seen it. You need at least 6-8 oz of water immediately after the crash. You will need to take a pee almost immediately to flush out the stress toxins from the enormous dose of adrenaline you received from your adrenal glands in response to the accident. A small amount of food, like a power bar and some electrolyte powder. You need to concentrate on the 1st 48 hours, cause after that your gonna die (statistics).
I have had friends crash on the ice with a nice, well equipped NOAA helicopter. The pilot was more or less OK, the mechanic had a really healthy (or unhealthy, depends on your point of view) deep gash running the length of this thigh. The first thing that happened was the tail boom broke off and sank in the ice lead. Well that is where the ELT is. They had some old EBC-102's in their pocket. But the signal was bouncing off the hills near Nome and where actually stronger than the signal going straight up. So for days they looked in the hills, not the ice. Luckily WX came in on land and shielded that signal and they finally located the true position and found them. Took 3 days, one more and at least the mechanic would have died.