737 Updates

MCAS, or Maneuvering Characteristics Augmentation System, is a flight control law implemented on the newer models of the 737 to provide consistent airplane handling characteristics at elevated Angles of Attack in certain unusual flight conditions only. MCAS is not expected to operate in regular commercial flight conditions. With the changes we have made to the airplane, most flight crews are likely never to experience a situation that would activate MCAS.

Angle of Attack is the angle between the direction that the nose of the airplane is pointing and the direction of the oncoming wind.

The Maneuvering Characteristics Augmentation System (MCAS) flight control law was designed and certified for newer models of the 737 to provide consistent handling qualities in unusual flight conditions.

The Maneuvering Characteristics Augmentation System (MCAS) only activates in the rare instance when all of these three conditions occur at the same time:

• • The airplane Angle of Attack approaches a value higher than normal due to very slow speeds or aggressive maneuvering.
  • The pilot is flying manually.
  • The airplane flaps are up.

We redesigned how the airplane’s flight control computers process the information provided by the Angle of Attack (AOA) sensors. They now compare information from both AOA sensors — instead of one — before activating, adding a new layer of protection. Also, the Maneuvering Characteristics Augmentation System (MCAS) will now only activate once and will never provide more input than the pilot can counteract using the control column alone. Pilots will continue to have the ability to override MCAS at any time.

We’ve redesigned how the airplane’s flight control computers process the information provided by the Angle of Attack (AOA) sensors. They now compare information from both AOA sensors — instead of one — before activating, adding a new layer of protection. Also, MCAS will now only activate once and will never provide more input than the pilot can counteract using the control column alone. Pilots will continue to have the ability to override MCAS at any time.

Yes. As a result of the work done to return the airplane to service, we made additional changes. These changes were described in detail in publications from the regulators and include, for example:

• Enhancing the flight control computer software to provide for more cross-checking between flight control computers.
• Providing for modification of and greater separation in some wiring to satisfy regulator requirements.

During training, pilots complete a suite of computer-based training modules that provide them with an enhanced understanding of the 737 flight control system, including MCAS, and related changes to airplane software. Pilots demonstrate their knowledge by completing scenarios in a full-motion flight simulator that reinforce key procedures.

We have taken a number of actions to further enhance the safety culture of our company. These actions include:

• Established a permanent aerospace safety committee of the company’s board of directors and reorganized the company’s engineering organization, with all engineers reporting up through Boeing’s chief engineer.
• Created a new Product & Services Safety organization, which will review all aspects of product safety and maintain oversight of our Accident Investigation team as well as our safety review boards.
• Established a formal Design Requirements Program and enhanced our Continued Operational Safety Program.
• Strengthened partnerships with airline customers and other industry stakeholders to ensure that flight deck designs and general training anticipate the needs of future pilot populations.

• Airlines received regulatory approval for their training programs.
• Pilots completed all required training.

• Delivered Airplanes: Airlines implemented all required changes specified by the regulator on airplanes in their fleets and completed all activation tasks.
• Undelivered Airplanes: The FAA performs in-person, individual reviews of each undelivered airplane prior to issuing an airworthiness certificate.

We engaged closely with international regulators around the world, providing them with the information they need to evaluate the updates to the airplane and training.

Boeing’s pilot training proposal is currently being reviewed by regulators and includes computer-based training, simulator training and additional documentation review that are designed to provide pilots with an improved understanding of flight control systems, reinforce their technical knowledge of associated flight deck effects and operational procedures, and help restore overall confidence in the airplane.