Almost every crash is a confluence of errors. The GPS issues should not have been a surprise to the pilots, a NOTAM warned of military jamming at the time of the flight was active and should have been taken into account as they planned the flight. www.aopa.org/news-and-med...

GPS jamming active when King Air struck mountainA preliminary NTSB report on the May 14 accident in which a Beechcraft King Air on an ambulance mission collided with terrain notes that military GPS jamming was active during the short, fatal flight.www.aopa.org