In the case of the mountain, the avionics have a terrain database built in, so it can follow an LPV WAAS approach from a fix above the terrain. I don't know if

In the case of the mountain, the avionics have a terrain database built in, so it can follow an LPV WAAS approach from a fix above the terrain. I don't know if this can deal with the engine out, but in theory there isn't any reason it couldn't. There is an IPad app called "Xavion". With an engine out, Xavion will calculate an approach for you follow to a suitable airport, based on the aircraft's best glide speed + required runway length. Interestingly it doesn't use the published best glide speed and stopping distances, the app uses your flight history to figure out the aircraft's actual best glide and stopping distance.