Your 737 MAX Questions. Answered.

Get answers to questions on the 737 MAX, and how we're making the 737 MAX among the safest planes in the sky.

1. What has to happen for the 737 MAX to fly again?

We are working closely with the U.S. Federal Aviation Administration (FAA) and other regulatory authorities as we work toward certification and safe return to commercial service, and we are taking the time to answer all of their questions. There are five key milestones Boeing must complete with the FAA before return to service:
  1. Simulator Certification Session: A multi-day simulator evaluation with the FAA to ensure that the overall software system performs its intended function. COMPLETED
  2. Line Pilots Crew Workload Evaluation: A separate, multi-day simulator session with airline pilots to assess human factors and crew workload under various test conditions.
  3. Certification Flight Test: FAA pilots will conduct a certification flight(s) of the final updated software.
  4. Final Submittal to the FAA: After completion of the FAA certification flight, Boeing will submit the final certification deliverables and artifacts to support software certification.
  5. Joint Operational Evaluation Board (JOEB) Training Evaluation: The JOEB, a multi-regulatory body, conducts a multi-day session with global regulatory and airline pilots to validate training requirements. Following this session, the Flight Standardization Board will release a report for a public comment period, followed by final approval of the training.

2. How and why did Boeing decide to develop the 737 MAX?

Our development efforts always start with listening to our customers to understand their needs and requirements. Based on customer feedback and market data, the 737 MAX was the clear choice to succeed the Next-Generation 737. Over a six-year period, our team worked through a disciplined methodical development process that culminated with a robust test program that validated the airplane’s safety and performance.

3. How many 737 MAX airplanes have been delivered to customers?

Boeing has delivered more than 370 MAXs to 47 customers (through February 2019).

4. How many additional 737 MAX airplanes have been ordered?

About 5,000 737 MAX airplanes have been ordered by 107 customers.

5. What is MCAS?

MCAS, or Maneuvering Characteristics Augmentation System, is a flight control law implemented on the 737 MAX to provide consistent aircraft handling characteristics at elevated angles of attack in certain unusual flight conditions only. MCAS does not operate in regular commercial flight conditions – in fact, most flight crews are never likely to experience a situation that would activate MCAS.

6. Why did Boeing install MCAS on the 737 MAX?

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

7. When is MCAS activated?

MCAS only activates in the rare instance when all of these three conditions occur:
  • The airplane nose approaches a higher-than-usual angle.
  • The pilot is flying manually.
  • The airplane flaps are up.

8. 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.

9. How are you improving the flight control system on the 737 MAX?

We’ve redesigned how the airplane’s Angle of Attack (AoA) sensors work with a feature of the flight control software known as the Maneuvering Characteristics Augmentation System (MCAS). Now, MCAS compares 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.

10. Have you made other safety improvements to the aircraft?

Yes. Working under the guidance of the U.S. Federal Aviation Administration, we’ve also addressed certain highly improbable scenarios involving the flight control computers on the 737 MAX. We’ve modified the software for those computers so they now monitor one another continuously, “cross-checking” to prevent the delivery of inaccurate information. This resolves the already unlikely possibility of pilots having to react to a false command in these situations.

11. Since the updates, how many test flights and test miles has the 737 MAX flown?

As of June 29, we have conducted 1,248 737 MAX flights, totaling 2,398 hours with the updated software.

12. Are pilots being fully informed about all of these improvements to the 737 MAX?

We’ve been holding training and simulator sessions all over the world to engage pilots and regulators. We’ve updated pilot training and other educational materials for the 737 MAX and its systems. Every 737 MAX pilot will receive additional training before they’re permitted to fly the plane again. We’ve also put top engineering talent to work improving the 737 MAX, adding important safeguards and protections while incorporating feedback and input from regulators around the world, pilots, airlines and other experts.

13. How are you working with regulators around the world?

To ensure that our improvements address all safety and regulatory concerns, we’re holding daily reviews with the FAA and continue to cooperate closely with all regulatory authorities. We have provided tens of thousands of pages of technical documentation to regulators around the world. We also have submitted detailed responses to more than 1,000 questions.  The 737 MAX and its software are undergoing an unprecedented level of global regulatory oversight, testing and analysis—and testing continues. Recently, we completed a multi-day simulator evaluation with the FAA to ensure the overall software system performs as intended.

14. Why is it taking so long?

We have been working closely with global regulators who are conducting a rigorous review of the improvements to the flight control software and the associated pilot training. In addition, an independent board including experts from the FAA, NASA and the U.S. Air Force has provided input. We are proceeding deliberately to ensure that we have the right solution in place and that all these inputs have been fully addressed. It has taken this long because we are all focused on getting it right.

15. Does Boeing charge for safety features?

All primary flight information required to safely and efficiently operate the 737 MAX is included on the baseline primary flight display. This is true of all our commercial products. Boeing doesn’t put a price on required safety features.

16. What are you doing to improve the way Boeing itself works?

A specially appointed Boeing Board of Directors committee conducted a rigorous, five-month independent review of our policies and processes. We have adopted their recommendations. In late September, we announced a new Product and Services Safety organization. It will review all aspects of product safety and maintain oversight of our Accident Investigation Team as well as our safety review boards. We also have established a formal Design Requirements Program and enhanced our Continued Operation Safety Program. We are partnering with airline customers and other industry stakeholders to ensure that flight deck designs and general training anticipate the needs of future pilot populations, and we are expanding the reach of our Boeing Safety Promotion Center.

17. How do Boeing employees raise safety concerns?

Speaking up has always been encouraged and supported at Boeing, and we provide multiple ways for our employees to report concerns. Our new Product and Services Safety organization and our new independent Aerospace Safety Committee established within the Boeing Board of Directors now will oversee the review of all safety concerns raised by Boeing employees, including those raised anonymously.

18. What have you learned from the 737 MAX accidents?

We are focused on making the 737 MAX one of the safest airplanes in the sky. We updated the Maneuvering Characteristics Augmentation System (MCAS) on the 737 MAX by adding three additional layers of protection to prevent accidents like these from ever happening again. Additionally, we have taken several immediate actions to strengthen the company's enduring commitment to product and services safety. In addition to establishing a permanent Aerospace Safety Committee of the Boeing Board of Directors, Boeing is standing up a new Product and Services Safety organization that will further strengthen the company's safety-first focus. This organization will unify safety-related responsibilities currently managed by teams across several Boeing business and operating units.

19. What are you doing for the families of those affected by the accidents?

The Lion Air and Ethiopian Airlines accidents weigh heavily on us, and we have made a commitment to help rebuild the communities and families impacted by these accidents. To that end, we have established a $100 million relief fund, $50 million of which is in an independently run fund that has already begun providing near-term financial relief to the families of victims. We’re working with experts, governments, communities and families to determine how best to distribute the remaining funds.

More 737 MAX Resources

Here’s more information about our ongoing efforts in working with customers, regulators, pilots and airlines around the world to improve flying for everyone.

Resources