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Crashed Boeing Planes Lacked Safety Features That Company Sold Only As Extras (apnews.com)
The recent Boeing 737 MAX crashes involving an Ethiopian Airlines flight and a Lion Air flight may have been a result of two missing safety features that Boeing charged airlines extra for (Warning: source may be paywalled; alternative source). The New York Times reports that many low-cost carriers like Indonesia's Lion Air opted not to buy them so they could save money, even though some of these systems are fundamental to the plane's operations. "Now, in the wake of the two deadly crashes involving the same jet model, Boeing will make one of those safety features standard as part of a fix to get the planes in the air again," the report says. From the report: It is not yet known what caused the crashes of Ethiopian Airlines Flight 302 on March 10 and Lion Air Flight 610 five months earlier, both after erratic takeoffs. But investigators are looking at whether a new software system added to avoid stalls in Boeing's 737 Max series may have been partly to blame. Faulty data from sensors on the Lion Air plane may have caused the system, known as MCAS, to malfunction, authorities investigating that crash suspect.
The jet's software system takes readings from one of two vanelike devices called angle of attack sensors that determine how much the plane's nose is pointing up or down relative to oncoming air. When MCAS detects that the plane is pointing up at a dangerous angle, it can automatically push down the nose of the plane in an effort to prevent the plane from stalling. 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 angle of attack indicator will remain an option that airlines can buy. Neither feature was mandated by the Federal Aviation Administration. All 737 Max jets have been grounded. "Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes," the report adds, citing a person familiar with the changes. "Boeing started moving on the software fix and the equipment change before the crash in Ethiopia."
Slashdot reader Futurepower(R) adds to the story: The FBI has joined the criminal investigation into the certification of the Boeing 737 MAX, lending its considerable resources to an inquiry already being conducted by U.S. Department of Transportation agents, according to people familiar with the matter. "The federal grand jury investigation, based in Washington, D.C., is looking into the certification process that approved the safety of the new Boeing plane, two of which have crashed since October.
The jet's software system takes readings from one of two vanelike devices called angle of attack sensors that determine how much the plane's nose is pointing up or down relative to oncoming air. When MCAS detects that the plane is pointing up at a dangerous angle, it can automatically push down the nose of the plane in an effort to prevent the plane from stalling. 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 angle of attack indicator will remain an option that airlines can buy. Neither feature was mandated by the Federal Aviation Administration. All 737 Max jets have been grounded. "Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes," the report adds, citing a person familiar with the changes. "Boeing started moving on the software fix and the equipment change before the crash in Ethiopia."
Slashdot reader Futurepower(R) adds to the story: The FBI has joined the criminal investigation into the certification of the Boeing 737 MAX, lending its considerable resources to an inquiry already being conducted by U.S. Department of Transportation agents, according to people familiar with the matter. "The federal grand jury investigation, based in Washington, D.C., is looking into the certification process that approved the safety of the new Boeing plane, two of which have crashed since October.
... on plane manufacturing safety and design... say it isn't so.
Well, in the situation how it was being sold, this is pretty much the truth.
Without the MCAS, the MAX handles fundamentally different in some pretty dangerous flight modes than the NG. This alone would require a new type rating. Type ratings for pilots are expensive and time consuming, Boeing wanted to avoid that, mostly as an economic argument. That's why they put in the MCAS. With a WORKING MCAS, the MAX handles sufficient close to the NG, that pilots with just the NG type rating can still fly "safely", until MCAS fails and potentially crashes the plane.
Boeing and/or the FAA could have skipped MCAS and made type ratings for NG pilots mandatory. Then, at least every pilot would know about the tendency to pull the nose further up than the NG when going to full throttle. Most pilots fly with some automation still enabled, even if they're flying "manual", so auto-trim could've easily have corrected for this.
This aspect of the MAX would have certainly not be one of its highlights, but if every pilot knew about those properties, it wouldn't be a safety problem, just part of normal procedures.
The alternative would obviously have been designing a different airframe, allowing for a higher, but more balanced placement of the engines. Maybe higher legs would've been sufficient though, since the MAX 9 does already feature higher legs.