And ... not exactly a piece of survival equipment as such, but don't forget to tell the passengers how to turn on the ELT. Ever since that story about a plane crash in the Alps (IIRC): the pilot was killed in the crash, the passengers survived, but the ELT didn't go off by itself and when the wreck was found four days later the passengers had all died of exposure. If they'd been told to press the red button the chopper would have been with them in an hour - that little bit of knowledge would have been worth any amount of survival gear.