According to what I was told by those who are/were at Hendrick, expired/improper equipment along with the fact that the accident Captain routinely used it as his ONLY source of information in flight, without cross-checking other instruments, is why the crash occured. Complacency, bad decision-making, and generally poor airmanship. All respect to the deceased, but it is what it is. No other way to say it, unfortunately.Which is why they were flying with an expired GPS data base plugged inside a non-certified GPS receiver?