The content on Breitflyte Airline News Network will always be free and won’t require a subscription. is a participant in several affiliate advertising programs designed to provide a means for us to earn fees by linking to affiliated sites.  We may earn a commission if you click on or make a purchase through one of our links.  Thank you for supporting our affiliate advertisers. 

NOTICE: Due to the Impact of Hurricane Ian, We Expect to Experience Power and Connectivity Issues From Wednesday, September 28, 2022.  Thank You for Your Patience and Understanding.

  • Joe Breitfeller

Boeing CEO Dennis Muilenburg Testifies Before the U.S. Senate on Aviation Safety and Future of MAX

Updated: Jan 11, 2020

In a fiery congressional hearing Tuesday, Boeing President and Chief Executive Officer, Dennis Muilenburg, testified before the U.S. Senate Committee on Commerce, Science and Transportation.

Boeing President & CEO Dennis Muilenburg - Courtesy Boeing

Mr. Muilenburg was joined by John Hamilton, Vice President and Chief Engineer, Boeing Commercial Airplanes. A second panel included Robert Sumwalt, Chairman of the National Transportation Safety Board (NTSB) and Christopher Hart, Chairman of the Federal Aviation Administration’s Joint Authorities Technical Review (JATR), which was commissioned to evaluate the certification process of the Boeing 737 MAX. Although Mr. Muilenburg had an extensive prepared opening statement, it was summarized at the hearing in the interest of time. In both his written and spoken testimony, Mr. Muilenburg opened by expressing his “…deep sympathies to the families and loved ones of those who were lost in the Lion Air Flight 610 and Ethiopian Airlines Flight 302 accidents, including those who are in the room today.” In his written opening statement, Mr. Muilenburg said,

“While the Ethiopian Airlines accident is still under investigation by authorities in Ethiopia, we know that both accidents involved the repeated activation of a flight control software function called MCAS, which responded to erroneous signals from a sensor that measures the airplane’s angle of attack. Based on that information, we have developed robust software improvements that will, among other things, ensure MCAS cannot be activated based on signals from a single sensor, and cannot be activated repeatedly. We are also making additional changes to the 737 MAX’s flight control software to eliminate the possibility of even extremely unlikely risks that are unrelated to the accidents.”

Lion Air Boeing 737 MAX - Courtesy Boeing

In both his written and spoken opening statements, Mr. Muilenburg described the efforts Boeing has made in 737 MAX improvements and testing, including over 814 test flights with updated software. As part of the testing for return to service (RTS) for the MAX, Boeing has relied not only on their own team, but also 41 global regulators and 545 participants from 99 airline customers. Mr. Muilenburg further expressed his belief that when the Boeing 737 MAX returns to service, that it would be one of the safest airplanes ever.


While U.S. Senators delivered a barrage of questions that ranged in tone from subdued to accusatory and even to downright indignation, they stopped short of calling for Mr. Muilenburg’s resignation. Early in the hearing, U.S. Senator Roger Wicker (R-MS) Chairman of the Committee brought up the well-publicized November 2016 e-mail exchange between former Boeing 737 MAX Chief Test Pilot Mark Forkner and current Boeing 737 Chief Test Pilot Patrik Gustavsson, describing the e-mail chain as potentially “Jedi mind tricking regulators.” The e-mail exchange described “egregious” and “crazy” responses by the Maneuver Characteristics Augmentation System (MCAS) during simulator testing.

Later in the hearing, Senator Ted Cruz (R-TX) displayed the full text of the e-mails on a poster board, with Forkner stating, “MCAS is now active down to M .2 [200 knots] and it’s running rampant.” Later Forkner stated, “So I basically lied to the regulators (unknowingly),” to which Gustavsson replied, “It wasn’t a lie, no one told us that was the case.” Mr. Muilenburg maintained that it was still unclear whether that exchange was in reference to the testing of the flight simulator itself or was in reference to the actual MCAS software included in the accident aircraft. Senator Cruz expressed his incredulity over the fact that Mr. Muilenburg was only made aware of the e-mails over the last few weeks, when the Department of Justice has had them since last February.

Earlier, Senator Ed Markey (D-MA) took up a line of questioning regarding the option of one or two angle of attack (AoA) sensors and a cockpit “disagree light,” which would illuminate when the sensors were giving contradictory readings. Mr. Markey called this “a-la-carte add-ons for safety,” contending that there should be no difference between critical and non-critical safety features and insisting they should be free. Although they will be included on the aircraft when they are returned to service, Mr. Muilenburg pushed back on the idea that Boeing was “selling safety.” Basically, Boeing considered the equipment optional because they expected pilots to react to a runaway stabilizer event as trained, which was also reiterated by both Boeing and the Federal Aviation Administration (FAA), which issued an Airworthiness Directive (AD) after the Lion Air accident. Unfortunately, Mr. Muilenburg made an unforced error during the exchange by stating, “We don’t sell safety and that’s not our business model.” It should have been clear to anyone watching that he simply meant the optional MCAS features were not considered necessary to the safe operation of the aircraft. During his testimony Mr. Muilenburg agreed that Boeing had been wrong with their assumption that a failure of the MCAS system would result in pilots naturally treating it as a runaway stabilizer, taking appropriate countermeasures. Senator Tammy Duckworth (D-IL) then stated that Boeing had told her in a meeting that the 2018 Lion Air accident was the result of "pilot error" and concealed their knowledge of the faulty MCAS system.

Both Senator Jon Tester (D-MT) and Senator Marsha Blackburn (R-TN) later mischaracterized what Mr. Muilenburg meant by "not selling safety." The main line of questioning from Senator Tester was that the relationship between the FAA and Boeing was too cozy, with Mr. Tester stating, “Why don’t we just turn over the certification back to the FAA? Then, they would be sitting at this desk and not you.” Mr. Muilenburg maintained that the “Delegated Authority Process” had resulted in vast safety improvements over the past few decades, although the balance between government regulators and those with deep industry technical expertise might be reevaluated.

Most of the remaining questions revolved around why the MCAS system wasn’t detailed in the airplane flight manual and whether the MAX had evolved beyond the status of a derivative. Senator Jacky Rosen (D-NV) brought up an interesting point about how Brazil’s National Civil Aviation Agency (ANAC) added documentation and training to the airplane flight manual before certification in Brazil, and wondered why this information wasn't disseminated to other operators. Mr. Muilenburg explained that he respected each regulator's independent authority in the matter. On Wednesday, Mr. Muilenburg will testify before the U.S. House Committee on Transportation and Infrastructure.

Source: United States Senate