All the stories about the two crashes of new Boeing 737 Max airplanes are still required, for reasons of caution and honesty, to say that no one knows for certain why the crashes, which killed 338 people between them, happened, or whether both crashes happened for the same reason. But every new development has been consistent with the theory that Boeing’s automatic anti-stall system, added to the Max model to compensate for its altered aerodynamic profile, reacted to malfunctioning sensors by forcing the planes’ noses down against the pilots’ wishes.



The latest news is that both planes could have had safety features that showed what the sensors were doing and would alerted the crew if there was a problem with the sensor readings. But Boeing had marketed them as add-on options, rather than basic equipment. The New York Times wrote:



Boeing’s optional safety features, in part, could have helped the pilots detect any erroneous readings. One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.



The “disagree light,” in particular, should be indefensible to charge extra money for. But the Times reported that Boeing treats all sorts of features that might seem essential as expensive add-ons:



Boeing charges extra, for example, for a backup fire extinguisher in the cargo hold. Past incidents have shown that a single extinguishing system may not be enough to put out flames that spread rapidly through the plane. Regulators in Japan require airlines there to install backup fire extinguishing systems, but the F.A.A. does not.



And:



Boeing declined to disclose the full menu of safety features it offers as options on the 737 Max, or how much they cost.

But one unredacted filing from 2003 for a previous version of the 737 shows that Gol Airlines, a Brazilian carrier, paid $6,700 extra for oxygen masks for its crew, and $11,900 for an advanced weather radar system control panel. Gol did not immediately respond to a request for comment.



Making oxygen masks a premium option seems almost unimaginable, at first—and yet, because the subject is air travel, it is unimaginable in a deeply familiar way. Boeing’s approach to selling airplanes is the same as the airlines’ approach to selling passenger tickets: bump up the profits by turning basic expectations into expensive upgrades.

An airplane needs a fully working fire-extinguisher system the same way a traveler needs to be able to bring a suitcase, or to sit with the people they’re traveling with, or to eat some food in the course of a five-and-three-quarters-hour flight. You need it badly enough to pay for it.

