The upgrade includes a warning system that was previously just an optional feature that airlines had to pay extra for.
While investigations continue into the cause of two disasters involving its 737 MAX aircraft, Boeing says it has issued changes to controversial control systems linked to the crashes.
However, it is still not clear when the aircraft type, which has been grounded worldwide, will be allowed to take to the air again.
The upgrade includes a warning system for pilots, which was previously just an optional feature that airlines had to pay extra for.
The Lion Air and Ethiopian Airlines planes involved in the crashes both lacked this additional safety system.
The aircraft type’s Manoeuvring Characteristics Augmentation System, or MCAS, was designed to keep the 737 MAX from stalling. It reacts to sensors that feel whether the plane is climbing too steeply.
But an investigation into the Lion Air crash suggested that this system malfunctioned, repeatedly forcing the aircraft downward.
Another part of the new upgrade includes software that will disable the MCAS if the sensors show conflicting data.
While Boeing says the upgrades are not an admission that its own systems caused the crashes, a US Senate hearing yesterday quizzed the acting head of the regulator the FAA, Daniel Elwell, about whether the process of getting an aircraft manufacturer’s products inspected and certified is adequate.
One senator, Richard Blumenthal, described the practice of Boeing inspecting its own aircraft as like leaving “the fox guarding the henhouse”.
Elwell denied that it was essentially “self-certification”, stating that the FAA “retains strict oversight authority” over the process.