The actions the pilots undertook, after they had received a false smoke trigger the crash of EgyptAir plane, reports the Wall Street Journal. According to the source, the staff took risky and unnecessary measures due to the signal. 

The journal writes that in the aircrafts of the same model the functioning of smoke detectors can disconnect security systems, including protection of automatic flight control. The source said that the main cause of the crash at this moment is that the crew could accidentally disable important systems of the aircraft or undertake other dangerous activities.