Boeing is promising 3 fixes to the faulty system behind the 737 Max crashes to let pilots stop it from forcing the plane into an unstoppable nosedive

ama@businessinsider.com (Alexandra Ma)
Boeing 737 Max cockpit
  • Boeing is promising three key fixes to a system blamed for the fatal crashes of its 737 Max jet, according to a leaked presentation made public by CBS News.
  • The presentation deals with changes to the Maneuvering Characteristics Augmentation System, which was identified as a factor in the two crashes that led to the jet's worldwide ban from service.
  • MCAS was designed to automatically push the plane's nose down to keep it stable if it detects a stall. But investigators found that it could misfire because of faulty data from a sensor, forcing the plane into an unstoppable dive.
  • In the first of the two crashes, MCAS forced the plane's nose down more than 20 times, bringing about a fatal dive that the pilots tried — but failed — to override, investigators said.
  • Boeing will now require an agreement from two sensors in order to activate MCAS, as well as include a manual override and a mechanism to prevent it from reactivating repeatedly, the presentation said.
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Boeing is promising three fixes for the faulty system widely blamed for the two deadly 737 Max crashes, CBS News reported on Sunday.

The manufacturer told stakeholders in Seattle last week that it would introduce changes to the jets' Maneuvering Characteristics Augmentation System, CBS News reported, citing documents from a presentation by the company.

Investigators found that the pilots in both crashes struggled with MCAS, which was designed to automatically push the plane's nose down to stabilize it if it detects a stall.

Before a jet from Indonesia's Lion Air crashed last year, MCAS had activated at least 20 times, investigators said.

The software had relied on data from one of the plane's two "angle-of-attack" sensors, which monitored the plane's position in the sky. Both pilots tried to push back against the system by angling the plane back up dozens of times, but MCAS kept reactivating.

The two crashes killed a total of 346 people.

ethiopian airlines boeing 737 max plane crash

CBS News reported that Boeing said it had addressed these problems with updated software and would make these changes:

  1. MCAS will now rely on readings from two sensors as opposed to just one in the original system. The new software will activate only if both sensors agree that the plane's nose is too high. Boeing had announced this update earlier this year.
  2. Pilots will be able to override the system.
  3. When they do so, MCAS will not automatically reactivate, which the original system would do multiple times.

Boeing also told stakeholders that it had flown 1,850 hours with the software updates and spent more than 100,000 hours engineering and test-developing them, CBS News reported.

Multiple Boeing employees have spoken about internal pressures to develop planes quickly and keep manufacturing costs down.

Boeing did not immediately respond to Business Insider's request for comment on the reported changes.

Boeing 737 Max

The company's presentation last week was meant to reassure analysts, airlines, pilots, and flight attendants about the 737 Max, CBS News reported. Regulators around the world have grounded those jets, and pilots and flight staff members have publicly expressed fears about flying them again.

The US Federal Aviation Administration has also come under pressure for vouching for the 737 Max's safety before the two crashes. The agency now wants to dramatically change its certification process.

Internal messages exchanged by Boeing employees in 2016 and released in October also suggested they had known about the MCAS's problems but misled the FAA about its dangers.

The 737 Max is expected to return to service in March, though Boeing is trying to get it back in the air sooner.

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