Boeing 737 MAX Debacle Continues

This is a very detailed reproduction on a graphical flight simulator program of the Ethiopian Airlines 737 MAX crash. It seems to have been produced using some data from the black box flight recorders. A significant factor in the crash is the fact that the aircraft was flying overspeed at several points.

Recently issues have been raised about the speed at which pilots can affect a recovery in certain conditions being limited by the system's overall response time to changes in trim controls.

The flight control system is made up of a large number of interoperating subsystems. This diagram shows some of those directly involved in trim adjustment, but these are not all of them.

Other links exist between the subsystems such as the Auto Throttle and the Autopilot, mediated by the Air Data Computer, which integrates Air Speed and Angle of Attack sensor data for input to the Auto Throttle, for example, which in certain modes adjusts engine thrust to maintain a constant air speed. From https://www.reuters.com/article/us-ethiopia-airplane-procedures-explaine/explainer-ethiopia-crash-raises-questions-over-handling-of-faults-on-boeing-737-max-idUSKCN1RG2PP

The 737’s air data computer also uses angle-of-attack (AOA) information to adjust airspeed readings. If it mistakenly thinks the angle of attack is high, it can trigger pilot warnings that airspeed and altitude data are unreliable on one of the pilot’s controls, according to former Boeing engineer Peter Lemme.

In addition to these direct electronic links between subsystems there are physical couplings through the airframe, engines and control surfaces, through which the various electronic subsystems respond to and influence each other's operation. These coupling's effects are a significant factor in the pilots' everyday experience of flying the aircraft. One such example is called Pitch Coupling. From http://www.flaps2approach.com/journal/2014/9/2/b737-autothrottle-at-normal-and-non-normal-operations.html

The autothrottle is designed to operate in conjunction with the autopilot, to produce a consistent aircraft pitch under normal flight conditions.  If the autopilot is disengaged but the autothrottle remains engaged, pitch coupling may develop.

Pitch coupling is when the autothrottle system actively attempts to maintain thrust based on the pitch/attitude of the aircraft. It occurs when the autopilot is not engaged and manual inputs (pitch and roll) are used to control the aircraft.

The systemic failure in Boeing's whole engineering operation is the failure to properly integrate the design and testing of these numerous interdependent electronic and mechanical subsystems. The 737 MAX 8 MCAS failure is just one symptom of a much more fundamental problem, which very likely affects all modern aircraft  manufacturers. It's the same problem NASA engineers had with the Space Shuttle programme.

I am not going to to say any more on this while I am left starving on the street. See update here: Another Boeing 737 MAX Problem which is actually this problem, but some people seem to think that this is a software bug. See also this post which raises another issue with the 737 MAX 8. Al Jazeera Investigating the Boeing 767 crash in 1999.