My choice: A Leatherman Flair. In a situation like this, you need an olive fork.
There once was a young Air Force pilot who finished his training and was assigned to fly cargo planes to the most remote radar installation in Alaska. These missions would involve long flights over thousands of square miles of frozen, deserted wilderness in foul weather. So, he was first sent to Air Force Arctic Survival School and then to his post.
Upon arrival, he was told that for the first few flights he'd fly as co-pilot with an older, more experienced pilot.
As they boarded the plane for the first time, the young fellow noticed the old man stash a black case behind the pilot's seat. He didn't recall from any of the briefings any mention of any such case. So, he asked, "Hey, what's in that case there?"
"Oh, that's my special emergency rescue it. It's got everything we need to guarantee that we're found instantly if we crash out there."
Well, the fellow had just come from Air Force Arctic Survival School and he didn't know of anything that could fit in such a case that would guarantee being rescued immediately. But, he had an idea. "Oh, a radio set. Right?"
"No, radios are to delicate to survive a crash landing."
"Well, I suppose that that's true.... A flare gun then. Yes?"
"Are you kidding!?! What if it went off in flight? The idea is to get us found IF we crash, not to get us crashed."
"Gee... I hadn't thought of that.... A signal light. It's a signal light!"
"Come on. We could crash a thousand miles from the nearest person. There's no signal light that'll carry that far."
"Well... what is it then? What could possibly fit in that little case that'll guarantee us of being found immediately if we crash anywhere in the Alaska wilderness?"
The old pro pulled the case out, opened it, and slowly unpacked... A bottle of gin, a bottle of vermouth, a jar of olives, a cocktail shaker, and two martini glasses.
"That's all very nice, I'm sure," the young fellow said, "but how's that gonna get us found?"
"Simple. If we go down, I'll just unpack and start mixing. Don't ask me how, but somehow, from somewhere, someone will appear and say 'Hey, that's not how you make a Martini. Let me show you how.' And, at that point, we're found."