Divided loyalties: the 737 Max warning light glitch

Boeing 737 MAX airliners have been grounded since March 2019 after two fatal crashes

In the sixth chapter of the Gospel of Matthew, Jesus is quoted as saying "No man can serve two masters; for either he will hate the one and love the other, or he will be devoted to one and despise the other." The context is the impossibility of serving both God and mammon (money). But one does not have to be a Christian to recognize the shrewdness of Jesus' observation that divided loyalties sooner or later lead to trouble.

A report from Bloomberg News this week makes this saying particularly relevant to the ongoing woes of Boeing Inc., whose 737 MAX airliner is still grounded after two fatal crashes led to investigations revealing serious problems with the plane's software. Now it appears that a warning light which could have helped mechanics fix the problem that contributed to the crashes wasn't even working, again due to software problems.

As we have mentioned in this blog before, both the Indonesian Lion Air crash in October 2018 and the Ethiopian Airlines March 2019 crash occurred when problems arose with the angle-of-attack sensors. Specifically, one of them malfunctioned, and as a result, the defective software responded by essentially flying the plane into the ground, despite the pilots' efforts to stay aloft.

The warning light in question would have illuminated if the two angle-of-attack sensor readings disagreed, showing that one of them had a problem. An alert pilot might have gotten a mechanic to fix the problem, which would have avoided the issue that led to the two fatal crashes.

But due to a separate software glitch, the warning light turned out not to work unless the customer also asked for an optional display showing each angle-of-attack sensor reading independently. And 80 percent of 737 MAXes sold did not have that option, and so also had a defective warning light.

It's a little like if you ordered a car and found out that unless you also asked for optional fog lights, your brake lights wouldn't work.

By itself, the sensor disagreement warning light's malfunction was not a safety violation. But in a letter written to Congress last July, the US Federal Aviation Administration (FAA) acting head Daniel Elwell said, "A manufacturer cannot alter the airplane’s features after it has been certified." The FAA is contemplating assessing fines against the company, and such fines can range up to the tens of millions of dollars.

That is a comparative drop in the bucket in relation to the estimated US$18 billion that the firm has lost so far in the 737 MAX debacle since that fleet was grounded last year. But the details of how Boeing discovered the warning-light glitch back in 2017 and decided not to fix it immediately reveal the glaring defects in a practice that the FAA decided to halt last November: allowing Boeing-paid engineers to act as FAA inspectors for certain aspects of the certification and approval process.

Regardless of the details, the intended relationship between the FAA and private airplane manufacturers such as Boeing is inherently adversarial, to the extent that the point of having a regulatory agency is to ensure that the entity regulated doesn't get away with murder, or its corporate equivalent.

A simple example is the state of food manufacturing and sale in the US prior to the establishment of the US Food and Drug Administration, the history of which can be traced back to 1906. Before then, it was perfectly legal to sell candy coloured with arsenic-containing dyes to children, or fruit with traces of the arsenic-containing insecticide Paris green.

Once laws were passed against such abominations, the laws had to be enforced, which meant that chemists and inspectors paid by the government went out, collected samples, and tested them for harmful ingredients. If found, the government used the evidence to levy fines and other penalties against the firms, and the US food supply took a notable turn for the better.

But note that the integrity of the inspectorate—those charged with checking the output of the private manufacturers—owed their livelihood not to the manufacturers directly, but to the government. This is a sound principle to ensure against corruption and divided loyalties, but one that was neglected when Boeing convinced the FAA to allow some of its employees to do inspections that the FAA would normally undertake.

According to the Bloomberg report, one such "inspector"—a Boeing employee authorized by the FAA to decide such matters—chose to let the warning-light glitch go until a future software update rather than issuing an immediate order to repair all the defective planes. A clearer case of letting the fox watch over the henhouse would be hard to find.

This lax procedure is probably not unrelated to the fact that Boeing is the only US maker of large commercial aircraft. Its only serious global competitor is the European combine Airbus. If there were three or four viable US airline manufacturers, the FAA would be in a stronger position to levy serious and even firm-threatening penalties against Boeing, the reason being that the other hypothetical firms could take up any slack and still allow the US airline manufacturing business to function.

But both Boeing and the FAA know that is not the case, and that whatever Boeing does, the FAA isn't going to do anything on its own that would threaten the company's existence and put the US out of the international airliner business.

There are many bad things about monopolies, and one of the worst is that they encourage laziness, both on the part of the monopoly itself and on any agency charged with keeping an eye on it.

In surrendering some of its authority to Boeing employees, the FAA preserved the appearance of vigilance while relinquishing the reality. When it ended such cozy arrangements last November, it took a step in the right direction of putting a respectable distance between itself and the industry it is charged with regulating.

But cultures and perceptions do not change overnight, and both Boeing and the FAA have a long way to go before they recover some of the public trust that went down in flames in the 737 MAX crashes.

Karl D. Stephan is a professor of electrical engineering at Texas State University in San Marcos, Texas. This article has been republished, with permission, from his blog Engineering Ethics, which is a MercatorNet partner site. His ebook Ethical and Otherwise: Engineering In the Headlines is available in Kindle format and also in the iTunes store.


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