well that's cool....unitl I drop and loose my phone in the snow or the battery goes dead
or put your iphone back into your pocket on, near enough to your beacon to cause interference, get buried and have your buddy not find you and you die, or have your buddy get buried and you dig up a phantom signal from your iphone and he dies because you were playing angry birds in the skin track.
apps have no place in the bc. turn the iphone off and save the battery for a real emergency and use proper equipment for everything else.
you can get a little card from life-link with an inclinometer on it, K2 backside poles have one built in, you can also use any compass.