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NOT FOR AMATEURS

The word “kludge” keeps coming up when pilots and engineers discuss Boeing’s 737 Max

By Tripti Lahiri

Again and again, in discussions of what has gone wrong with Boeing’s 737 Max plane in two deadly crashes within five months, an unusual word keeps coming up: kludge.

Merriam-Webster defines kludge—sometimes spelled kluge—as “a haphazard or makeshift solution to a problem and especially to a computer or programming problem.” Oxford defines it as, in computing, “A machine, system, or program that has been badly put together, especially a clumsy but temporarily effective solution to a particular fault or problem.”

More commonly found in 737 Max discussions on tech or pilot forums, the word has popped up in news reports, too (including a Quartz newsletter).

“My concern is that Boeing may have developed the MCAS software as a profit-driven kludge to mitigate the Max 8’s degraded flight characteristics due to the engine relocation required to maintain ground clearance,” commented Philip Wheelock on a New York Times story about the plane’s certification process this week. “Not convinced that software is an acceptable solution for an older design that has been pushed to its inherent aeronautical design limits.”

The roots of the word are possibly Scottish or Germanic, or even Danish. It appears to have come into common parlance—in the computer engineering and systems-design communities—with its use in a 1962 Datamation article by computer pioneer Jackson Granholm, who spent a large chunk of his life working for Boeing. He defined it as:

“An ill-assorted collection of poorly-matching parts, forming a distressing whole.”

….Today “kludge” forms one of the most beloved words in design terminology, and it stands ready for handy application to the work of anyone who gins up 110-volt circuitry to plug into the 220 VAC source.

 

“Kludge” on the 737 Max stage

With respect to the 737 Max, journalist Jeff Wise, author of a book on the disappearance of Malaysian Flight MH370, appears to have been among the first to use “kludge” after the March 10 Ethiopian Airlines crash that killed 157 people. Wise described the design decision Boeing was faced with when France’s Airbus in 2014 unveiled its A320neo, a more fuel-efficient narrow-body aircraft, in a piece for Slate March 11:

To maintain its lead, Boeing had to counter Airbus’ move. It had two options: either clear off the drafting tables and start working on a clean-sheet design, or keep the legacy 737 and polish it. The former would cost a vast amount—its last brand-new design, the 787, cost $32 billion to develop—and it would require airlines to retrain flight crews and maintenance personnel.

Instead, it took the second and more economical route and upgraded the previous iteration. Boeing swapped out the engines for new models, which, together with airframe tweaks, promised a 20 percent increase in fuel efficiency. In order to accommodate the engine’s larger diameter, Boeing engineers had to move the point where the engine attaches to the wing.* This, in turn, affected the way the plane handled. Most alarmingly, it left the plane with a tendency to pitch up, which could result in a dangerous aerodynamic stall. To prevent this, Boeing added a new autopilot system that would pitch the nose down if it looked like it was getting too high. According to a preliminary report, it was this system that apparently led to the Lion Air crash.

If Boeing had designed a new plane from scratch, it wouldn’t have had to resort to this kind of kludge.

A kludge, as Granholm notes, isn’t the work of amateurs—it’s a combination of complexity and “designasininity” that introduces errors in some unrelated, unexpected part.

In the case of the 737 Max, it’s the combination of how two separate problems interacted—a plane whose design introduced aerodynamics issues and what now appears to have been a poorly designed anti-stall system—that seems to be drawing many to turn to Granholm’s term. The problems were compounded in many ways, including by the fact that pilots were not told of or trained for the Maneuvering Characteristics Augmentation System (MCAS) before the Lion Air crash, which killed all 189 on board.

“Indeed, it seems the 737 MAX was a kludge to an existing design, and that MCAS was a kludge on top of that,” said a commenter on Hackaday.

Indonesia’s preliminary report showed that the anti-stall system repeatedly pushed the plane’s nose down in response to erroneous data about the angle of the plane from a single sensor. As pilots desperately tried to redirect it, the system responded by again pushing the nose down. A previous method of counteracting this action had been disabled.

The preliminary report on the Ethiopian Air crash—which Ethiopian and US officials have said shows similarity to the Lion Air crash—is expected within a month.

A word without friends

On the Professional Pilots Rumor Network, “kludge” appeared in a discussion on whether MCAS could be made more “fault-tolerant,” so it works properly even in the face of an instrument or other failure.

“The fact this kludge was implemented apparently against the basic & fundamental engineering principles and with great silence is highly concerning,” wrote a user. “There must have been substantial objections about the lack of fault tolerance from engineers who reviewed this fix. One has to wonder just how many were involved in the decision making process to implement this, and at what level.”

While the use of kludge might be more typical of computer science and design communities, more general words for the same phenomenon exist around the world. They include India’s jugaad, or Brazil’s giambarra, which can have the connotations of being nifty and clever in the face of scarcity.

Judging from Granholm’s definition, and its recent usage, a kludge doesn’t have any redeeming qualities.

“How did Boeing decide to kill the 757 and to continually delay the “New Midsize Airplane”, and to progressively extend and modify the 737 until it reached 757 size in the 737 MAX 9?” a user with the handle Merrill asked on startup accelerator Y Combinator’s Hacker News site. “I would bet good money that there is a wonderful book to be written about competing design teams, rival marketing plans, and mahogany row politics at Boeing about events resulting in the MAX kludge.”

Read more of Quartz’s coverage of the Boeing 737 Max crisis.