Boeing Redesigns MAX’s MCAS System Architecture

Boeing (BA) is redesigning the architecture of the 737 MAX aircraft’s MCAS (Maneuvering Characteristics Augmentation System). The company disclosed the information in a statement released after the final investigation report on the Lion Air crash.

Earlier today, Indonesia’s NTSA (National Transportation Safety Committee) released its final report on the Lion Air crash. The committee found that Boeing’s MCAS failure was the main reason behind the accident. The report also criticized Lion Air’s maintenance staff and pilots for their negligence, according to a CNBC report.

Lion Air investigators recommended that Boeing design its cockpit systems better. The NTSA also suggested that the FAA and other regulatory bodies check automated systems thoroughly.

In its released statement, Boeing conveyed “heartfelt condolences” to the Lion Air crash victims’ families. The company said it’s working with the FAA and global regulators to fix the problem. Boeing revealed it’s redesigning the problematic flight-control system so that the Lion Air crash situation never happens again.

The MCAS system prevents the airplane from entering into a stall. The system automatically guides the aircraft’s nose lower, which needs to be corrected manually by crew members, according to Boeing. However, the preliminary investigation report of the Lion Air accident pointed out software problems in the MCAS system. The system would have automatically taken control of the aircraft.

Boeing tried to fix the problem with a software update. However, the FAA’s pilots found a new issue with the MCAS during a simulator test in June. They discovered that the updated software was taking a long time to respond in a scenario where the aircraft’s nose is pitched down.

On August 5, The Seattle Times revealed that Boeing is redesigning the MAX MCAS system’s whole architecture. Today, Boeing confirmed the changes in its statement. The company said, “Boeing has redesigned the way Angle of Attack (AoA) sensors work with a feature of the flight control software.”

The redesign will allow MAX to take inputs from both of its MCAS computers instead of one. For decades, Boeing’s 737 series planes have only received data from one flight-control computer.

The input from both flight-control computers would minimize the risk of false alerts due to erroneous data. According to Boeing, the updated “MCAS will now only turn on if both AoA sensors agree” and “will activate once in response to erroneous AOA.”

In the statement, Boeing said that it’s working with the FAA and global regulators to fix the problem. During the third-quarter results on Wednesday, the company reaffirms its hope that the MAX will return to service in the fourth quarter. However, Boeing cautioned that the MAX might return in phases. Several countries plan to conduct independent reviews.

MAX’s quick return to service is important for Boeing’s growth prospects. The model accounts for 70% of Boeing’s overall aircraft shipment and contributes nearly 30% to its operating profit. However, the MAX deliveries have been since the global flying ban in mid-March.

Boeing’s overall commercial aircraft shipments fell 67% YoY to 62 units in the third quarter. As a result, the company’s third-quarter revenues and earnings fell 21% and 59%, respectively, year-over-year.

The delay in MAX’s return is also impacting airlines. Together, Southwest Airlines (LUV) and American Airlines (AAL) own 58 MAX aircraft. The two companies faced more than 25,000 flight cancelations in the third quarter. Southwest and American recorded a reduction of $210 million and $140 million in their respective third-quarter pre-tax income.