A software update will be rolled out to Boeing’s now grounded aircraft, while all new 737 MAXs will get a previously optional onboard warning system as standard.

The changes, though, are still subject to approval by aviation regulators.

It comes after Lion Air flight 610 came down in the Java Sea shortly after taking off from Jakarta last October killing all 189 people on board.

Another 157 lives were lost when Ethiopian Airlines flight 302 crashed en route from from Addis Ababa to Nairobi earlier this month. Both flights were operated by Boeing 737 MAX 8 aircraft.

Ethiopian transport minister Dagmawit Moges said black box data from flight 302 showed “clear similarities” with the Lion Air crash.

Mike Sinnett, Boeing vice-president product strategy, said on Wednesday (March 27): “We are going to do everything we can to make sure that accidents like this never happen again.”

Boeing grounded all 737 MAX aircraft worldwide in the days following the Ethiopian Airlines crash.

Crash investigators have been focusing their attentions on the 737 MAX’s manoeuvring characteristics augmentation system (MCAS) designed to automatically correct the angle at which the aircraft is flying if it becomes too steep.

This system, Ethiopian Airlines chief executive Tewolde GebreMariam told the Wall Street Journal this week, was “to the best of our [Ethiopian’s] knowledge” active when flight 302 crashed.

Preliminary investigations into the fate of the Lion Air flight also suggest MCAS was a factor, with a combination of an “erroneous” sensor input and the MCAS causing the plane to nose-dive.

The BBC reports Boeing will install as standard a previously optional warning system on all 737 MAX aircraft, adding airlines will no longer be charged for the upgrade.

Neither of the aircraft operated by Lion Air and Ethiopian Airlines had the system installed, which warns the pilots when sensors relating to the MCAS produce conflicting readings.

The MCAS was designed as an under-the-hood, automated system that pilots theoretically would never have to concern themselves with.

However, after transcripts of the cockpit voice recorder from the Lion Air crash last week revealed the pilots searched through the aircraft’s manual to find a solution, it is understood the software update will enable pilots to manually override the MCAS.

According to Boeing, the MCAS “was designed and certified for the 737 MAX to enhance the pitch stability of the airplane so it feels and flies like other 737s”.

It says the MCAS update would provide “additional layers of protection if the AOA [angle of attack] sensors provide erroneous data”, believed to be part of the cause of the Lion Air crash.

“The software was put through hundreds of hours of analysis, laboratory testing, verification in a simulator and two test flights, including an in-flight certification test with Federal Aviation Administration (FAA) representatives on board as observers,” said Boeing.

Boeing has updated its training to cover the software update, and pilots must complete 21 or more days instructor-led and simulator training.

Pilots will also review the aircraft’s flight crew operations manual bulletin, an updated trim fail non-normal checklist, and revised quick reference handbook.