Home Safety Analysis: Pilots right to ask why they weren’t told about MAX system

Analysis: Pilots right to ask why they weren’t told about MAX system

Boeing MAX 8

Sean Broderick

Since the crashes of two Boeing 737 MAX 8 crashes, and a continued focus on software designed specifically for that aircraft, it has become increasingly clear that many pilots are finding it hard to believe that they were not informed about that software.

In mid-May, almost two months after the second crash, of Ethiopian Airlines flight 302, Boeing announced that modifications were finished to a now-infamous flight control system that both investigators and Boeing acknowledge played a central role in both accident sequences.

The changes, put into motion by the first accident, Lion Air flight 610 in October, make—in Boeing’s words—a safe airplane even safer. The upgrades to the maneuvering characteristics augmentation system (MCAS) software make it less likely to activate at the wrong time and ensure pilots can override its commands—automatic horizontal stabilizer movement—more easily.

The MCAS, often described as an anti-stall system, is really about making the MAX feel like the 737 Next Generation to pilots during very rare flight profiles. When it works correctly, pilots don’t even know it’s there.

But the original version didn’t always work correctly. One bit of inaccurate data—overstated angle-of-attack (AOA) readings from one of the MAX’s two externally mounted AOA sensors—could fool the system into thinking that nose-down commands were needed to keep the aircraft from falling out of the sky. Instead, the aircraft was directed out of the sky.

Why wasn’t the system developed with more redundancy? The answer is: simplicity. Boeing determined that adding cross-checks to validate the AOA data could render the system inoperative and hamper coveted dispatch-reliability metrics. Instead, Boeing reasoned, pilots would recognize uncommanded MCAS inputs as runaway stabilizer—uncommanded movements of the large, tail-mounted horizontal flight control surface. If the nose pitching down didn’t clue them in, surely the spinning trim wheels on the center console would. After all, once airborne, a trained pilot is the best remedy to just about anything that goes amiss.

Boeing’s reasoning was reasonable, up until the point that it determined the MCAS’ role as a background system should carry over to the book that 737 pilots rely on to know all that they need to know to safely do their jobs. Rather than add a page or two about MCAS to the hundreds of pages in the 737 flight manual, Boeing determined that pilots need not know too much. Runaway stabilizer is runaway stabilizer—the cause is irrelevant, but the symptoms are always the same, and always recognizable.

But in at least two MCAS-related failure scenarios, it was not—and 346 people are dead.

There is no disputing that the pilots flying JT610 and ET302 were ill-prepared to handle anomalous MCAS activations. The question is, why? Some, including Boeing and FAA, cite basic airmanship. Plenty of data points from each aircraft’s flight data recorders support this.

But there is a large gap between incompetence and perfection. Is it possible that the Lion Air and Ethiopian pilots didn’t do everything they should have, but still couldn’t have done enough?

It’s impossible to know and the accident investigations are ongoing. But if the reactions from American Airlines pilots in a meeting with Boeing executives after the Lion Air accident—but before the Ethiopian crash—are any indication, no pilot was prepared for an MCAS worst-case scenario.

A recording of a meeting with Allied Pilots Association (APA) members provided to ATW by APA leaves little to interpretation. Their main concern, expressed with some shock and anger: How can we be the last line of defense if we are not even told a system is on the plane?

“We deserve to know what’s on our airplane,” one pilot tells the Boeing execs. “When the pilot is the last stop in the safety process, we need to understand what’s going on.”

APA president Daniel Carey summed up the level of concern this issue has raised. American Airlines pilots have been pressing Boeing for answers because we owe it to our passengers and the 346 people who lost their lives to do everything we can to prevent another tragedy. Boeing did not treat the 737 MAX 8 situation like the emergency it was, and that’s why we took swift legal action demanding years of records related to the model and are working with lawmakers in Washington to ensure proper oversight of Boeing, FAA, Airbus, American Airlines and all carriers.”

Manufacturers build the aircraft that airlines want to buy. Airlines want better fuel burn, more common training and lower operating costs. OEMs meet demand.

Airlines may buy the aircraft they operate, but pilots fly them. American’s pilots pushed for some features on its MAXs, including AOA Indicator displays, that most other airlines—including Lion Air and Ethiopian—didn’t buy.

In airline C-suites, pilots are often seen as obstacles to labor peace and financial success. Sometimes, they earn those labels. But they also have earned and deserve the benefit of the doubt when it comes to anything related to flight safety.

If keeping them out of the loop seems like a prudent decision, the pilots probably aren’t your most pressing issue. Re-examine the loop.



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