I remember flying into Sardy Field for the first time. It was the summer of 2002, and the regional jet of choice for the hop from Denver to Aspen was the venerable BAe-146, a smallish regional airliner made by British Aerospace. I knew of the challenges flying into Aspen due to the high altitude, narrow surrounding mountains and unpredictable wind conditions, and I remember the sense of comfort provided by the “146s” visual similarity to the vertical takeoff capable Harrier “jump jet” fighter. Both planes had a short, squat appearance with their wings mounted from the top of the fuselage. Neither would win an airplane beauty contest.
Having previously flown mostly on larger planes between major commercial airports I was not prepared for more acute turns and elevation changes necessary to land at Aspen-Pitkin County Airport. But the BAe-146’s four small turbofan engines provided it with a very high thrust to weight ratio and it even had a large air brake mounted under its tail, to help control speed on the steep descents into short runway, high elevation environments of destinations like ASE. So, while the experience was new and a bit exciting, it was safe.
Most evident to me about the Bae-146 was the lack of arrogance in its design, intended for servicing more challenging destinations. Form definitely followed function. It was not built to be beautiful; it was built to get its job done, and it always felt as though the pilots were in complete control, which is as it should be with all airplanes.
I was reminded of the 146 last month when news broke of the second crash involving Boeing’s new 737 Max, which again occurred on take off in only a few months of service. Like the first crash, a Lyon Air flight, this one on Ethiopian Airlines, occurred overseas. Tragically no one survived either crash.
On its way to being the most ordered commercial airliner in history, the 737 Max provided better fuel efficiency and greater range than any of its predecessor 737 models. But as the news media zeroed in and started treating the second crash with the investigative vigor it merited, it became clear that things were not adding up. There is no end in sight to the FAA’s grounding of the entire 737 Max fleet, and future orders are in jeopardy.
Complete information about all of the issues contributing to these two crashes remains elusive. But we do know that by installing MCAS, the cryptically named “maneuvering characteristics augmentation system”, Boeing substituted a software program for inherent aerodynamic stability that was lost when the 737 Max’s larger engines were mounted further forward and higher than engines on previous 737 models. Even the lay reader like me recognizes that trusting software over fundamental principles of safe design means that arrogance has replaced diligence in the engineering process.
History tells us such engineering errors happen from time to time. Remember “Galloping Gertie”? Opened to traffic in May of 1940, the original Tacoma Narrows suspension bridge that connected the growing Tacoma, Washington area to the rural Kitsap peninsula, was designed to look light and delicate and beautiful, not to survive the sustained gusting winds that regularly race through the narrow passage separating the north and south sections of Puget Sound.
Those winds created mechanical resonance that matched the bridge’s natural frequency. The bridge deck became the physical manifestation of harmonic resonance. Seven months after its opening, a fall wind storm caused the bridge to tear itself apart, sending it to the bottom of the Puget Sound. In this case the arrogance was in prioritizing design beauty over rigidity to withstand the wind, because yes, even bridges need to be designed in consideration of aerodynamic principles. Fortunately, only a dog perished as a result of this tragedy of arrogance over engineering.
Then there was the 1981 Kansas City Hyatt Regency disaster. The new luxury hotel’s most notable visual feature was a four-story walkway designed to look like it was floating in mid-air. On July 17th of that year, the newly opened hotel was hosting a tea dance in its atrium. 1,600 people were on the atrium floor when that walkway suddenly collapsed, killing 114 and injuring 216. It was the highest death toll due to structural collapse in American history until the terrorist attacks on 9/11/2001 brought down the World Trade Center.
The subsequent investigation disclosed that fatal changes to the original design (that was itself subsequently shown to be insufficient to hold the required loads) were approved by supervising engineers over the phone rather than being subjected to standard load bearing tests. Again, arrogance in prioritizing beauty over strength led to a tragic disaster.
Today, the 737 Max twin tragedies show the terrifying danger of over-reliance on computerized control systems rather than properly engineered solutions. Software “fixes”, like those proposed by Boeing, do not repair the inherent flaws in the airplane’s aerodynamic stability that have now been widely reported and independently confirmed. I think it is safe to say that the Lyon and Ethiopian airline crashes would not have happened had the 737 Max been inherently aerodynamically stable on takeoff, because then Boeing’s MCAS system would not have been necessary in the first place.
History shows that Boeing’s substitution of software for inherent aerodynamic stability is just the latest example of engineering arrogance leading to tragedy. Unlike the BAe-146, the 737 Max will never fly into Aspen, but the truth is it should never fly again unless its inherent design flaws are corrected.