737 MAX Boeing Faults.jpg

MAX Fixes Will Take Until At Least September, Boeing Says

A new flight control computer issue was discovered during engineering simulator tests last week.

Boeing will need at least until September to address a new flight control computer (FCC) issue and wrap up changes needed to get the fleet flying again, Aviation Week has learned.

The issue came to light during engineering simulator tests with FAA test pilots during the week of June 17. During a runway horizontal stabilizer troubleshooting procedure, FAA determined that line pilots would need more time to correctly diagnose the failure and execute the appropriate checklist. The tests also showed that a computer chip malfunction could lead to uncommanded stabilizer movement during the emergency procedure. FAA told Boeing to address the issues, and the manufacturer is complying. 

"We are working through the software update and the potential implications for the timeline for the safe return to service of the 737 MAX fleet and resuming MAX deliveries,” a Boeing executive told Aviation Week. "Our current assessment is we will submit our final certification package to the FAA in the September timeframe.”

Boeing is confident that the latest issues can be addressed with software changes. The alternative—replacing computer chips on more than 500 MAXs—could prolong a worldwide grounding that started in mid-March.

Boeing is modifying specific FCC software linked to two 737 MAX accident sequences within five months. The second accident, the March 10 crash of Ethiopian Airlines Flight 302, triggered the global grounding. 

The software changes focus on the MAX’s maneuvering characteristics augmentation system (MCAS), which helps the MAX mimic the flight characteristic of its 737 Next Generation predecessor in certain scenarios. The latest FCC issue is not believed to be linked to the proposed MCAS changes.

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