Latest Boeing 737 Max fault that alarmed test pilots rooted in software

The 737 Max family of aircraft has been grounded by the US since March 13 and has cost Boeing and airlines billions of dollars

As US government test pilots ran through dozens of flight scenarios on the Boeing Co 737 Max in recent weeks, a potential failure got their attention. 

The plane's flight computer tried to push the aircraft's nose down repeatedly during a simulator run, prompted by a stream of erroneous flight data. The Federal Aviation Administration pilot concluded commercial pilots might not have time to react and avoid a tragedy in a real plane.

That flaw -- the latest discovered on the family of jets involved in two fatal crashes since October triggered by a different failure that pushed their noses down