RE: Is there any locating devises for when our planes go down in the bush ??
This is what I use in several of my planes, they work very well:
http://www.c-tronicsinc.com/Product-FlightAlarmDR.htm
If you are an electronic kind of person, here you have a circuit that works with an independent 9 v battery:
http://www.sentex.ca/~mec1995/gadgets/locator.htm