Expert: software update will not help marriage in the Boeing glider

To place newer and larger engines on the plane, the Boeing decided to move them forward. This changed the aerodynamics of the aircraft. To compensate for this, a single sensor and a software update were added to Boeing: MCAS .

The Boeing saga of the 737 MAX model serves as a worthy example of both engineering incompetence and engineering ethics - or rather, its absence.

New details have emerged of how competitive the Boeing 737 engineers were due to the fact that the manufacturer was trying to prevent the departure of major US airlines to its competitor Airbus. In the European consortium, Boeing's flagship product competed with the new Airbus model, the A320neo. American carriers, for example, American Airlines, were preparing to switch to a model from Airbus with a longer range.

In response, Boeing released an updated, according to company claims, version of the 737th workhorse, equipped with larger CFM LEAP engines, giving longer range and greater efficiency. But due to enlarged engines, Boeing engineers had to push them further forward to the front edge of the wing so that the clearance of the device did not become too small.

And this decision meant that the 737 MAX would try to increase the pitch angle during acceleration or at a large angle of attack — the angle between the wing and the direction of flight. We decided to fix the problem with nose-lifting, which had to be solved for certification, using the MCAS software.

Critics considered that a different arrangement of engines makes the 737 MAX, in fact, a different aircraft, with different control characteristics, and this requires new control software and pilot training. As a result, the recertification process that Boeing sought to avoid due to competition would be too long and expensive.

In fact, critics say that in response to a threat from Airbus, Boeing reduced the level of passenger safety to an “average seat in the economy class”, and “raised it to the first class” for financial reasons. The company Boeing denied this.

Among Boeing’s critics is Gregory Travis, an experienced programmer and pilot with a PPP certificate, who controlled aircraft in simulators up to the Boeing 757. Travis published criticismrelated to the fiasco that the 737 MAX suffered last week. In conclusion, he wrote: “Most likely, MCAS, originally added to increase security, has already killed more people than it could save. It does not need to be “fixed” with the help of even greater complexity and an increase in the number of programs. It must be completely eliminated. ”

Confusing Solutions

In an interview, Travis said that “what confuses me most of all is how this could have happened” with a commercial aircraft manufacturer with a long history of safety and reliability, as well as an excellent engineering reputation.

Travis has no doubt in the evaluation of the Boeing 737 MAX. “This is an unreliable enclosure. It is necessary to fix the case, but it cannot be fixed without moving the engines back and away from the current location.

The main problem with the engines with forward engines is that “since he has begun to increase the pitch angle, he will want to continue further,” Travis said. “And this is very bad,” he continued, as the increased pitch angle increases the angle of attack.

This is where MCAS came from, implemented using software on the 737 MAX flight computer. Using a single sensor, MCAS had to correct what subsequently proved to be a fatal design error, dropping the nose of the aircraft based on data from this single sensor. Travis insists that the pilots of the two tragic 737 MAX flights could not overcome the operation of this system, regardless of how much they pulled the control knob. The only way to turn off the system was to activate the breaker, the button of which was to be visible on the 737 MAX control panel [ in fact, no one knew about this option at all / approx. perev. ].



The Boeing hung the engines from a hull whose size has not changed. And with this model, the engines almost hit the runway.

The company offered a single angle of attack sensor as standard equipment and took extra money for a second sensor along with a “cancel” indicator that would allow 737 MAX pilots to “check” the failed sensor. Describing such decisions, another observer noted: “Who is developing a system with a single point of failure?”

The EE Times sent a PDF to Boeing with an analysis of Travis and his conclusion that the manufacturer solved the hull problem in the cheapest way, suitable for obtaining federal certification.

A Boeing spokesman declined to comment on this analysis, citing the fact that investigations into the two disasters involving aircraft from Lion Air and Ethiopian Airlines are still ongoing. Instead, the publication pointed to several public statements about the accidents.

In fact, Travis regrets the “cultural laziness” that dominates the software development community, which is slowly penetrating critical systems such as flight computers. “By laziness, I mean that people are less and less trying to make the right and most simple design,” he wrote. “I believe that responsibility should begin to be borne where it arises.”

Incompetence or unethical?

Does the warning story of the Boeing 737 MAX relate to the ethics of engineering solutions - according to engineering ethics, everything needs to be done right the first time, to make sure that critical systems work with reliability of five nines (99.999%) and have excess insurance - this remains to be seen .

“The whole point may be the incompetence of the engineers,” Travis concludes.

Either that, or pressure from competitors forced Boeing to essentially hide the existence of the MCAS system in order to avoid a long recertification process, which requires careful re-training of pilots on new expensive simulators. All this would raise the cost of each instance of the aircraft by millions of dollars, Travis said, and would reduce the Boeing's chances of winning a competition with the Airbus 320neo.

The tragedies of the 737 MAX evoke engineering decisions that led to the disaster with the Challenger shuttle in 1986 and the fire on the Apollo 1 in 1967. Boeing’s rush in response to challenges from competitors reminded Travis and others of the curse of group thinking as “launch fever”, which during the development of the Apollo project led to the death of a team of three cosmonauts during ground tests at the launch complex. In that episode, teams were neglected for schedule compliance.

Engineering solutions of the Boeing company, in a hurry developing 737 MAX, led to the death of 347 people.

Travis expects the Boeing to now have two options. "I fully admit a scenario in which they will no longer sell these aircraft." But it is more likely that in the coming days we will hear an announcement that the manufacturer is correcting the MCAS software so that it processes the input data from several angle of attack sensors.

In any case, Travis concludes, "Now there are programs between man and machine."