737 Updates

The U.S. Federal Aviation Administration (FAA) has lifted the order that suspended 737 operations for airlines under its jurisdiction, including those in the U.S. We continue to work with other global regulators and airlines as they take action to return the airplane to service in their jurisdictions.

View Frequently Asked Questions

Changes to the 737 MAX

Global regulators and aviation organizations from around the world collaborated to allow the airplane to safely return to service.

  • MCAS

    This required software function operates in unusual flight conditions only and now relies on two sensors, activates only once and never overrides pilots’ ability to control the airplane.

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  • Additional Updates

    A few items unrelated to the accidents are also being addressed. These include modifying some wiring to meet FAA requirements and installing two additional software updates.

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  • Validation

    Regulators determined the process, schedule and requirements for an effort that spanned hundreds of thousands of hours and more than a thousand test and check flights.

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Pilot Training

After evaluating feedback from the global aviation community, the FAA validated our proposal for pilot training.

  • Boeing Proposal

    We collaborated with pilots, engineers and safety experts to create a comprehensive proposal calling for current 737-8 and 737-9 pilots to complete additional training, thoroughly review technical documentation and demonstrate their knowledge in a regulator-qualified, full-motion flight simulator.

  • Airline Input

    Pilots from more than 80 of the world’s airlines tested the enhancements firsthand in a full-motion flight simulator. They also reviewed the course material and technical documentation. Each airline will work directly with its regulator to determine their training approach and receive approval for their training course.

  • Regulatory Review

    Following FAA approval, other global regulators are thoroughly reviewing the proposed training. Regulators will set the final training requirements.

Return to Service

Whether a plane was manufactured after the order was issued or is already in a customer’s fleet, it has to go through a rigorous FAA-defined process before returning to service.

  • Preparing Airplanes

    Airplanes that have been in storage must undergo a comprehensive activation process before they can be considered ready for return to service.

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    Inspecting Airplanes

    After each airplane is prepared, it will be thoroughly inspected against a robust set of criteria defined by the FAA.

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  • Supporting Airlines

    We have been working side-by-side with our customers to ensure safe storage and now we’re ready to support them as they safely return their airplanes to commercial service.

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Frequently Asked Questions

Here are answers to common questions about safely returning the 737-8 and 737-9 to service.

What is MCAS?

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.

What is the Angle Of Attack?

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

Why did Boeing install MCAS on newer models of the 737?

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.

When is MCAS activated?

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.

How did you enhance the flight control system on the newer models of the 737 to address the findings in the two accidents?

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.

Have you made other changes to the 737 MAX?

Yes. As a result of the work done to return the airplane to service, we have made additional changes. These changes were described in detail in recent publications from the U.S. Federal Aviation Administration (FAA) 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 FAA requirements.

What information will pilots receive about enhancements during their training?

During training, pilots will 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 will demonstrate their knowledge by completing scenarios in a full-motion flight simulator that reinforce key procedures. Note that final training requirements for each country will be determined by its regulator.

How have you responded to internal and external reviews and audits following the two accidents?

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.

How many newer 737 airplanes were built?

There are more than 800 737-8 and 737-9 airplanes. Just over half of them have not yet been delivered and are still at Boeing. The others were delivered and are in airline fleets around the world.

What has to happen for the airplane to return to commercial service?

The U.S. Federal Aviation Administration (FAA) has lifted the order that suspended 737 operations for airlines under its jurisdiction, including those in the U.S. Lifting the order allowed these airlines and Boeing to begin working with the FAA to complete the steps below. Regulators in other jurisdictions will make their own determinations. Training
  • Airlines must receive regulatory approval for their training programs.
  • Pilots must complete all required training.
Airplanes
  • Delivered Airplanes: Airlines must implement all required changes specified by the FAA on airplanes in their fleets and complete all activation tasks.
  • Undelivered Airplanes: The FAA will perform in-person, individual reviews of each undelivered airplane prior to issuing an airworthiness certificate.

Why is it taking more time to unground airplanes that are outside of the jurisdiction of the U.S. Federal Aviation Administration (FAA)?

The FAA has lifted the order that suspended operations for airlines under its jurisdiction, including those in the U.S. We continue to work closely with regulators around the world to meet their expectations. Safety is always our priority, and each country’s regulators will determine their own schedule for return to service.

How are you working with regulators around the world?

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

What is MCAS?

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.

What is the Angle Of Attack?

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

Why did Boeing install MCAS on newer models of the 737?

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.

When is MCAS activated?

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.

How did you enhance the flight control system on the newer models of the 737 to address the findings in the two accidents?

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.

How are you enhancing the flight control system on newer models of the 737?

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.

Have you made other changes to the 737 MAX?

Yes. As a result of the work done to return the airplane to service, we have made additional changes. These changes were described in detail in recent publications from the U.S. Federal Aviation Administration (FAA) 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 FAA requirements.

What information will pilots receive about enhancements during their training?

During training, pilots will 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 will demonstrate their knowledge by completing scenarios in a full-motion flight simulator that reinforce key procedures. Note that final training requirements for each country will be determined by its regulator.

How have you responded to internal and external reviews and audits following the two accidents?

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.

How many newer 737 airplanes were built?

There are more than 800 737-8 and 737-9 airplanes. Just over half of them have not yet been delivered and are still at Boeing. The others were delivered and are in airline fleets around the world.

What has to happen for the airplane to return to commercial service?

The U.S. Federal Aviation Administration (FAA) has lifted the order that suspended 737 operations for airlines under its jurisdiction, including those in the U.S. Lifting the order allowed these airlines and Boeing to begin working with the FAA to complete the steps below. Regulators in other jurisdictions will make their own determinations. Training
  • Airlines must receive regulatory approval for their training programs.
  • Pilots must complete all required training.
Airplanes
  • Delivered Airplanes: Airlines must implement all required changes specified by the FAA on airplanes in their fleets and complete all activation tasks.
  • Undelivered Airplanes: The FAA will perform in-person, individual reviews of each undelivered airplane prior to issuing an airworthiness certificate.

Why is it taking more time to unground airplanes that are outside of the jurisdiction of the U.S. Federal Aviation Administration (FAA)?

The FAA has lifted the order that suspended operations for airlines under its jurisdiction, including those in the U.S. We continue to work closely with regulators around the world to meet their expectations. Safety is always our priority, and each country’s regulators will determine their own schedule for return to service.

How are you working with regulators around the world?

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

What information will pilots receive about enhancements during their 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.