Kerbal Space Program

Some missions on Kerbin at low tech tier stages may take like an hour to complete because the Physics warp is not always a good idea. Therefore I left the game playing on second plane while I do some work stuff, However, the pilot is unable to maintain the plane fixed to an altitude and sometimes the plane starts losing altitude and because I'm not looking at the screen but listening to it, I don't know when they are dangerously close to the ground and the next thing I hear is a big explosion and my tears falling because I just lost 40 minutes of my life.

There is a MOD that includes a terrain warning sound, however I'm a Vainilla guy and I DON'T want to use any mods. Could you please make that a stock feature, even add it as a part if neccesary.