Boeing has finished the software update to fix the grounded 737 Max that was involved in two fatal crashes

AP Photo/Ted S. Warren

A Boeing 737 Max.

• Boeing announced on Thursday that it has finished development work on the software fix for the grounded 737 Max airliner.
• The company is now working with the FAA to schedule certification test flights and to submit its final certification documents.
• All 371 Boeing 737 Max airliners in service have been grounded since March 13 following the deadly crashes of Lion Air Flight JT610 and Ethiopian Airlines Flight ET302.
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Boeing announced on Thursday that it finished development work on the software fix for the grounded 737 Max airliner.

The Chicago-based aviation giant also said it has completed the simulator testing and engineering test flights associated with the software fix for the plane's Maneuvering Characteristics Augmentation System (MCAS).

"With safety as our clear priority, we have completed all of the engineering test flights for the software update and are preparing for the final certification flight," Dennis Muilenburg, Boeing's chairman and CEO, said in a statement. "We're committed to providing the FAA and global regulators all the information they need, and to getting it right."

Muilenburg added, "We're making clear and steady progress and are confident that the 737 MAX with updated MCAS software will be one of the safest airplanes ever to fly."

Read more: American Airlines CEO reveals when he would feel safe flying on the Boeing 737 Max again.

According to Boeing, it's currently providing the Federal Aviation Administration with details on "how pilots interact with the airplane controls and displays in different flight scenarios." The company is also working with federal regulators to schedule certification test flights and to submit final certification documents.

Boeing also announced that is has developed "enhanced" training materials that are under review by the FAA, international regulators, and airlines.

All 371 Boeing 737 Max airliners in operation have been grounded around the world since March 13 following the crashes of Lion Air Flight JT610 and Ethiopian Airlines Flight ET302, both of which occurred less than five months apart. A total of 342 passengers and crew died in the two crashes.

At the heart of the controversy is MCAS. It's a control system found on board the 737 Max that was not disclosed to airlines and pilots until the Lion Air crash in late October. Boeing confirmed in April that faulty readings from malfunctioning angle-of-attack sensors triggered MCAS ahead of both crashes.

In late March, Boeing rolled out a series of proposed software updates designed to roll back the intrusiveness of MCAS along with additional pilot training on the differences between the previous generation 737NG and the 737 Max.

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