It would cost more than the FAA has deemed the passengers lives are worth. The last figure I saw was $2m per passenger.
According to Plane Crash Info, roughly 59% of all crashes in the 1990s and 2000s had a degree of pilot error involved. Only between 18-24% were due to mechanical error. A big chute would help some, but not much. I imagine the number of scenarios where it would help would be limited.
It could be incorporated into the onboard computer. If airspeed, pitch and altitude indicate an irreversible crash, chute automatically deploys.
It would be a nice invention, but the size of the chute would have to be MASSIVE to support the weight of 3/4 of a million pounds (747), coming out of the sky. In addition, a plane that's stalled, for example, is coming down, and even with a chute to slow it down, it's still going to impact hard; hard enough to break up, and that's where jp5 is more than likely to ignite. Moreover, since most crashes seem to occur on take off and landing, a chute wouldn't be any good at all. I'd love to see it be feasible, but don't think there's enough $ in it to make it work, and work well. Just my guess.
Maybe I'm wrong on this one. Gotta love the Internet: http://www.smithsonianmag.com/innov...-airplanes-have-parachutes-someday-180949373/
In addition to the initial expense you also have the ongoing expense of the weight of the chute. Weight that means a reduced payload, more fuel burn, reduced climb rate... It should also be pointed out that even planes with recovery chutes, still crash. Again it's the cost vs the benefit. Also, you guys are (naturally) assuming that there should be no expense spared by the airlines to save your bacon in an in flight emergency. You have to remember though they're in the business of making a profit not providing public safety. It's the FAA's job to ensure public safety. Unfortunately for airline passengers it's been stated that the FAA is probably the most poorly managed incompetent agency in the entire federal bureaucracy. And worse, they've been in bed with the airlines for many decades. That $2m per passenger figure I mentioned earlier. (which is somewhat dated now) Is part of a formula the FAA uses to means test known safety issues. They'll estimate the potential number of deaths x $2m and compare that to the cost of correcting the issue. If only a few deaths are anticipated and or the fix is particularly expensive. The FAA won't make the airlines/OEM fix it. Unless it becomes public of course. Then naturally they're all about maintaining the perception that they actually give a shit about doing their job. IOW like pretty much all government agencies. A landing drag chute on commercial aircraft is completely unnecessary. Just about all if not all have reverse thrust. As well as braking systems large enough for many many landings a day. The space shuttle and mostly older jet fighters the OP was using as an example. Have, relatively speaking, much smaller brake systems.
Lucrum is the expert on this stuff, but my guess is a parachute wouldn't offer you much protection at 30-40 thousand feet. You'd asphyxiate and freeze way before you got to the ground.