Boeing reportedly left out safeguards for 737 MAX that were present in an earlier version of flight control system

Engineers who worked on the Boeing 737 MAX's flight control system, MCAS, which accident investigators have implicated in two deadly crashes in Indonesia and Ethiopia that killed a combined 346 people, omitted key safeguards that had been included in an earlier version of the same system that was used on a military tanker jet, The Wall Street Journal reports.

The engineers who designed the system for the military plane over 10 years ago reportedly made sure it relied on input from multiple sensors and limited power to move the plane's nose. One person familiar with the design said those checks were deliberate to prevent the system from acting erroneously or causing the pilot to lose control. "You don't want the solution to be worse than the initial problem," the person said.

The MAX's version of MCAS, on the other hand, relied on input from one sensor and was reportedly more difficult to override, which ultimately led to the fatal crashes.

The 737 Max has been out of commission since the second crash in Ethiopia in March. Boeing has said that when the MAX returns to the skies with a revised version of MCAS that will reportedly mirror the earlier one used in the tanker jet, it will be among the safest planes ever to fly. Read more at The Wall Street Journal.