Good afternoon, Mr. Chair, vice-chairs and committee members.
My name is Gilles Primeau, and I want to thank the committee for inviting me to appear today as an individual, professional engineer and private pilot.
Flight controls problems are the dominant factor in the Lion Air and Ethiopian Airlines 737 Max crashes. This is where my expertise and experience reside. Early on, I simulated them and spent hundreds of hours, notably in 737-300 level D full-flight simulators. Later, I worked for several aircraft types on the design, testing and certification of actual flight controls and on the horizontal stabilizer trim system, HSTS, in particular.
This is probably the most important of all aircraft systems. If its actuator breaks, or if its controller acts abnormally and the situation cannot be contained, you lose the aircraft. This happened before the 737 Max crashes. Alaska Airlines flight 261 crashed in 2001 because of the system's actuator, and in 2011 a Falcon 7X was almost lost because of the system's controller.
One year ago today, the second 737 Max crash took place. On that day, I started my independent, neutral and voluntary study into what caused those crashes. Contributing to the prevention of similar tragedies in the future became for me a professional and moral obligation and the best way I could ensure that the 346 victims have not perished in vain.
To prepare for today, I read the transcript from the February 25 hearing with Transport Canada certification leadership, and I can agree with their assessment of the high quality of regulatory oversight and the enviable safety record in Canada. I also agree with the spearheading by Canada of the need for high-quality simulation training, especially regarding MCAS. My experience as a pilot from three separate flights with specific difficulties encountered, one of them being during my first solo flight, has me absolutely convinced that in front of the unexpected, good training is your best ally.
I also agree that the level of international harmonization of regulations should be improved. The changed product rule, CPR, is a good example. This may also apply to regulation 25.1309, the most important regarding aircraft systems.
I now wonder whether there might be merit in having every national certification authority that oversees airframers in its own country dispatch permanently some of its own representatives to each of the other countries in the same situation. If everyone acts in good faith, new developments could be made more robust from the contribution of all stakeholders.
Also relative to the aircraft certification process, almost nine months ago I concluded that there exists the potential to introduce the following two new regulations.
First, regarding the CPR and the associated so-called “grandfather clause”, no grandfathering privilege should be granted if anything is interfaced, new or modified, to a previously certified critical system. The latter then needs to be recertified. With this rule, the introduction of MCAS would have forced the modernization of the HSTS.
Second, regarding testing—and this ties to a key recommendation from the JATR, the Joint Authorities Technical Review—testing for any critical system should be forced, maybe under regulation 25.1309, to be performed integrated with all its interfacing systems. Some call this aircraft-level testing. In other words, testing of critical systems individually or in silos is insufficient. With this rule, the simple test of a faulty AOA sensor would have easily uncovered its multiple effects, forcing architecture changes upon the 737 Max.
The MCAS software changes will make the 737 Max safer; however, the HSTS will then have become the next weakest link in the chain, and no chain is stronger than its weakest link. I have identified nine technical reasons to justify the need to modernize the 737 Max HSTS.
Another key finding was that a faulty AOA sensor, in addition to causing erroneous MCAS activation, has also caused a large increase of the control column forces due to the erroneous stall detection. High column forces, along with high manual trim wheel forces, a long-known problem, made it extremely difficult for the ET302 flight crew in particular to raise the nose of the aircraft, to trade airspeed for gaining altitude, which they had to do to avoid colliding with local peaks. Google Earth near Addis Ababa reveals why the ET302 crew requested from air traffic control a 14,000-foot altitude. That's what they were struggling to achieve.
The conclusions of my study have been compiled in a 44-page document, which was recently sent to Boeing. It notably contains 24 main technical questions, makes suggestions for rebuilding trust in Boeing and gives a synopsis of what likely occurred in each accident flight, based on the findings from my study. Because of the ties to regulations and the pre-cited incentive to harmonize internationally, the FAA and Transport Canada were also put in distribution of this document.
Thank you for your attention, and I am now prepared to answer your questions.