A directive issued after the Indonesian crash instructed pilots to use cut-out switches to disengage the system in the event of problems and leave it switched off. Doing so does not shut down the MCAS system completely but severs an electrical link between the software and aircraft systems, a person familiar with the technology said. Investigators are studying whether there are any conditions under which MCAS could re-activate itself automatically, without the pilots reversing the cut-out maneuver. Boeing is in the midst of upgrading the software while adding extra training. After the pilots turned off MCAS, the airplane over the next few minutes gained roughly 2,000 feet, but dived into the ground after the renewed succession of nose-down inputs from MCAS.

Source: Ethiopian News April 03, 2019 09:26 UTC