Why don't pilots parachute from small planes that are in distress? There was another question that asked why commercial flights don't have parachutes.  The almost ubiquitous response was that the parachutes would be useless because:


Most accidents with commercial airliners happen on take off and landing, and there is no time to parachute.
In order to get to a position where 100+ people can successfully jump out, you'd most likely need to descend some 20,000 ft and then maintain straight and level for a good 3 to 5 minutes once you got past 12,000 (so people have oxygen to breathe when they jump).  And if you can descend and maintain level flight, you might as well land.


But what about in a light, single engine plane (think Cessna 172 or Piper Cherokee)?  Engine failures in small aircraft, for example, seem to be more common, so you have more accidents that start high above the ground.  Thus, you usually have a few minutes before you're going to hit the ground and there's often only 1 or 2 passengers (rather than 100). Plus, you're usually already at an altitude where you don't need oxygen to bail out.

With that in mind, couldn't you put the plane into a shallow dive to keep it from stalling, trim it to keep it going straight and then bail out?  It seems like a somewhat practical solution, yet I have never heard of anyone doing it. 

Why do pilots often try to find a road to land on or a lake to ditch in when trouble strikes instead of just bringing a parachute and bailing out?
Mainly because in the situation that you describe, the airplane is perfectly capable of flying.  You don't need an engine to fly as airplanes are designed to glide without it. Part of every pilots training is how to land the airplane when this happens. 

Many of the same issues also apply in the smaller airplanes.  Unless the pilot and the passengers fly around with their parachutes on, it would be quite difficult to put them on in the confined space, in a high stress situation, and with the very limited time available.  Even if they did, untrained people are going to be hurt (probably quite badly) during the landing even if everything else with the jump goes well. (See my answer on your linked question for some of the things that can go wrong during the jump.)

You are also creating a hazard with the aircraft not being piloted and crashing into a random place on the ground.  All of this when the airplane could have just glided in for a landing in a field or on a road.  Most of these types of emergencies end quite well, and even a lot of the accidents will have fewer injuries and deaths than if people were jumping out all of the time. As an added bonus, the airplane can even be used again! 

On the other hand, a major structural failure that makes the aircraft incapable of flight could be a reason to jump.  This is extremely rare however, and even if one has a parachute in this situation it may be impossible to exit the airplane safely because of high G forces and the possibility of hitting the airplane as you are both tumbling through the sky.  

Some manufacturers are now building ballistic parachutes into the airplane which can bring the entire airplane down safely in these situations.  This is much more safer, reliable, and does  have a positive impact on safety in these extremely bad situations.  For just an engine failure though, I doubt that most pilots would even fire the ballistic parachute if there were suitable landing spots within gliding distance. 

My view is that you would have a far greater safety impact by requiring everybody in a moving car to wear a helmet.  Would it improve safety?  Absolutely.  Would people want to do it?  A few would (and perhaps a few do), but the general population doesn't want to be inconvenienced by something that is only a remote possibility.  The odds of a parachute helping you in a typical GA airplane is far more remote than the odds of the helmet helping you in a car.