are routine. the memo follows some close calls. scary stuff here. abc's david kerley with more. >> reporter: a united airlines crew got so close to the ground unintentionally they heard something like this. >> terrain, terrain, pull up. >> reporter: and made an emergency pull up avoiding disaster. that as well as a crew landing with fuel below critical reserves. two of four major safety events. near misses recently that prompted an unusually blunt, brutally honest safety alert to all united airlines pilots last month. >> there should be no pussy footing around. it should go to the source of the worry, which is guys, pay attention to the basics. >> reporter: this crash in alabama is highlighted. noting that crew thought everything was normal until just before impact. it was a lack of crew communication. >> no one should be god and everybody follows. you have to have communication in the cockpit and no one should be ever worried to speak up to a