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MCAS Certification Flawed: Report |
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Russ Niles
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The Maneuvering Characteristics Augmentation (MCAS) system at the center of investigations into two fatal crashes of the Boeing 737 MAX 8 was misunderstood and mischaracterized in a flawed certification process as Boeing and the FAA rushed to bring the new jet to market, a Seattle Times investigation published Sunday alleges.
Citing named and unnamed sources, the Times’ Dominic Gates says the final certification of the system, which was intended to give pilots a control feel on the aerodynamically different MAX similar to that of previous iterations of the 737, not only gave “unlimited authority” to the stabilizer for nose-down trim, it literally fought the pilots’ attempts to correct the condition possibly to the point where they were physically unable to fight the stabilizer down force any longer.
“It had full authority to move the stabilizer the full amount,” Peter Lemme, former Boeing flight controls engineer, told the Times. “There was no need for that. Nobody should have agreed to giving it unlimited authority.”
The Times story said the profound ability of the system to take over a key flight control action should have resulted in close scrutiny in the certification process.
But the original specifications of the system called for MCAS to limit its ability to move the horizontal stabilizer .6 degrees at a time. By the time deliveries began, it could pitch the stabilizer 2.5 degrees, about half its total travel, in one movement, the result of flight testing tweaks aimed at finessing the flight control feel.
The system would also pivot the stabilizer that much repeatedly as long as data inputs indicated the aircraft was about to stall, regardless of the pilots’ strenuous efforts to overpower the system. In the October Lion Air crash, which killed 189 people, the flight data recorder counted the captain countering the system 21 times with the first officer taking over for few tries before the captain’s final futile efforts to arrest a 500-MPH dive. The data indicated the nose-down yoke forces peaked at a little more than 100 pounds.
The newspaper’s investigation said that engineers involved in the safety assessment of MCAS were not aware the system could move the tail five times more than the original specs called for. The certification documents should have been amended to reflect the final configuration but they apparently were not, according to the Times report. If they had been, the seriousness of a potential failure of the system would have required it to receive data from at least two sources.
MCAS gets data from only one of two angle of attack indicators on the MAX and the flight data recorder on the Lion Air airplane showed the AOA feeding MCAS was malfunctioning. “A hazardous failure mode depending on a single sensor, I don’t think passes muster,” said Lemme.
The newspaper is reporting that Boeing’s software fix will wire MCAS to both AOAs and only allow the system to move the tail feathers once, instead of repeatedly battling manual control inputs. It will also require additional pilot training and operating manual changes, both of which were called for by pilots unions following the Lion Air crash.
Boeing’s position, endorsed by the FAA, has been that because MCAS is only supposed to trigger in extreme circumstances—high angles of attack and accelerated stalls—that additional pilot training was not necessary. The company has also said that it assumed that based on their existing training on earlier models pilots would recognize the erroneous nose-down commands and hit cutoff switches that would disable the system. This is a standard runaway trim scenario for all aircraft.
“The assumptions in here are incorrect. The human factors were not properly evaluated,” the Times quoted an unnamed FAA safety engineer as saying.
The story also suggests that due to budget cuts the FAA’s certification managers were under increasing pressure to delegate more and more of the safety assessments to Boeing itself. The unprecedented levels of self-certification in the MAX were compounded by the urgency to get the airplane into service because of competitive pressure from Airbus’s new A320neo series. “There wasn’t a complete and proper review of the documents,” the former FAA engineer is quoted as saying. “Review was rushed to reach certain certification dates.”
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Our Friend Mary Grady |
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AVweb Staff
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Perhaps it’s my imagination, but I think long-term relationships in the workplace aren’t as common as they once were. Because of the work we do at AVweb and the predilection of our management, we tend to attract and retain marathoners rather than sprinters. One of those was our dear colleague Mary Grady, who died this week after a long illness.
That Mary was a stalwart is evidenced by the fact that she joined AVweb not too long after it launched in 1995 and despite the physical challenges of illness, she wrote regularly until just a few weeks ago. She wrote when she felt poorly and she wrote when she had to cover another editor traveling for a week. She hauled her laptop into the clinic and covered news cycles under the mirthless drip of chemotherapy. Courage and determination are the overused currency of the eulogy, but I can apply no better words than those.
Editorial operations like ours have a manic pace—weeks of routine news and content production, leavened by breaking news and the pressure cooker of show coverage. While the rest of us cycled through phases of blown gaskets, Mary was the steady hand who could generate just the right amount of excitability to soldier through a difficult deadline. And she always did.
Those of us who grew up in the news business, who spent time street reporting and who had heard the clatter of wire machines and labored in chaotic news rooms, can always recognize others of our ilk. News sense is part of it and so is the stamina to chase stories, but mainly it’s the writing and Mary could bring it. Boy, could she bring it. Crisp, precise and quick. Always quick.
Of the past few years, Mary couldn’t travel much so she supported our show coverage with what we call outside news—stuff that’s happening beyond the fence at AirVenture or Sun ‘n Fun. She could bury us in copy if we needed it and we often did. She did so without drama, without complaint and never a hint of strain.
Others will speak for themselves, I’m sure, but I secretly think all of us long to be as kind, as decent and just plain gentle as Mary was, if we could just imagine how. For me, Mary Grady was the sort of colleague and friend you could always count on and who would always be there. And one day, she wasn’t. Goodbye is hardly sufficient. -- Paul Bertorelli
I knew Mary for 20 years, in that way you “know” someone you interact with mostly online, mixed with sleep-deprived, deadline-fueled meetups at OSH. Mary was a senior editor; I was just the lowly copy editor. It didn’t matter: Mary treated everyone she met with kindness and respect. She brought out the best in all of us, mentoring new journalists who’ve joined us over the years.
Mary shepherded me around the field my first trip to AirVenture and managed to wrangle my newbie enthusiasm (“Look at all the airplanes!”) with a patient but disciplined focus on our work. And she made it look effortless. I recall her walking up to a booth manned by Tuskegee Airmen, chatting and jotting a few notes, and suddenly there was this fully drawn story with nuance and character and history I wasn’t even aware I’d overheard.
She was a pro, sure—but I also think she had a deep, abiding curiosity about the world and people’s stories. We are all richer for it.
She filled in as executive editor during a staff transition in AVweb’s early days. She had final responsibility for the publication, but I don’t know that that was an ambition; I think there was simply a job to be done and Mary, as always, rose to the challenge. She and I would trade tips about how to strip out rogue characters from redlined Word files, because back in those halcyon days the Flash had to be plain text with a maximum of 72 characters per line.
Technology marched on (only to fail in spectacular new ways). Mary remained unflappable. Our go-to gal. Our conscience. Our anchor.
She and I talked some about her illness. Ever the optimist, she talked about the luck still on her side, thanked her family and friends, and joked about finally having some deadline-free time to enjoy the city, the ocean, the kayaking, her lavender farm. She earned it.
Thanks, Mary. I miss you. -- Jennifer Whitley, AVweb copy editor
Mary was one of AVweb’s first journalists, and one of the best. She brought her long experience as a newspaper reporter to our fledgling internet news service, together with her love of aviation. It was a wonderful combination. -- Mike Busch, AVweb founder
So sad. She was so nice and always a pleasure to speak with. I’m sorry for your team. -- Mike Goulian, Red Bull Air Race pilot
Mary was an old-school journalist, careful, methodical, fair and balanced but she had her eye on the future. She loved covering the innovators, inventors and fresh talent in aviation to put a spotlight on their passion.
She was kind, tough, even-handed and while she looked for the best in everything and everyone, she never shied away from calling out injustice and dishonesty. It was an honor to work with her and she and her gentle and confident influence will be missed. -- Russ Niles, AVweb contributing editor
Mary played a small but critical role in preparation of IFR Magazine, and was almost completely unrecognized for her part. Mary provided a regular monthly one-page overview of important aviation news items that appeared as a general part of the magazine.
Her material was always first rate and required no copy editing at all. I often mused that I wished I could bottle her professionalism, enthusiasm, respectful cooperation, and general excellence and use it to teach my other contributors.
Mary is missed, and we’re all saddened and a bit worse off for her passing. -- Frank Bowlin, IFR Magazine Editor
She did so many interesting things apart from, and in addition to, the aviation world. She was one special lady and will be sorely missed. -- Crystal Loonsfoot, former colleague
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