Some freeper stated the Boeing 737 Max is an inherently unstable plane due to design changes from previous Boeing 737s. That is why the plane relies so heavily on a a computer to fly straight. I understand many military planes are designed to be unstable so they can perform high G maneuvers on a dime or for reasons of the airframe is maximized for stealth. Are there other commercial jets with a design flaw like this?
All I could find is the larger engines and their different position can cause the nose to pitch up.
I don’t think automation and computer controls are a problem in general. Many aircraft cannot be flown any other way. It’s just in this case they have to figure it out.
Thanks PJ, for linking. C19fan, here’s the full text what I wrote:
The problem is with the overall design of the plane itself. The body profile has been out since the ‘60s, and hasn’t changed much except for length. When Boeing set out to make this variant, they stuck with the body design, but altered the wing configuration, changing the position of the engine nacelles to accommodate the new propulsion system. The plane now has a natural tendency to go nose-up, so the MCAS system was implemented to keep the flight path stable. It’s an inherently unstable configuration, but as long as the sensors are working properly, the plane will fly fine. But with a faulty sensor telling the MCAS that it needs to move the nose down, the pilots suddenly find their selves fighting the plane’s actions.
The pilots who fly MAX equipment are aware of the issue, but have not been trained properly to react to an MCAS failure.
The MAX configuration was released in mid-2017. Currently, there have only been about 340 delivered worldwide. Prior to the Lion Air crash, very few major US-based carriers even had simulation equipment specific to that model. To date, American, Southwest, and Delta have added MAX sims, but United has not. The installation of these simulators have been very recent, and with thousands of pilots to train, most have not been through hands-on training on how to react to the MCAS scenario.
Immediately after the Lion Air crash, pilots complained bitterly that they were not properly trained on how to react to this problem. Jon Weaks, president of the Southwest Airlines Pilot Association said that the pilots “were kept in the dark.” He also said “We do not like the fact that a new system was put on the aircraft and wasn’t disclosed to anyone or put in the manuals.” The move from the older 737 NG model cockpit to the new 737 Max system consisted of little more than a one-hour session on an iPad, according to Dennis Tajer, the spokesman for the APA.
These incidents are occurring at low altitude and with very little time to react. Decisions need to be made quickly while under duress — all the while at the same time fighting the aircraft’s actions. The Lion Air flight crashed within 13 minutes of takeoff. The Ethiopian flight within six. Both experienced issues only minutes at the tail end of those time frames, and both flights were at an altitude that is not very forgiving.
These planes need to be grounded all over until a definitive answer can be discovered, and proper training initiated on MAX-specific simulators. We have too many of these flying right now to take a risk otherwise.
Maybe a fighter plane should behave this way. An aircraft carrying people and freight for hire has no need for high G maneuvers or stealth. They need to be as stable and as predictable as possible.
Very good description of MCAS;
https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/
A caller on talk radio this am said there is a known-problem with the aircraft’s Angle of Attack indicator and autopilot. The indicator apparently can be inaccurate showing the plane is flying level when it’s heading slightly down. He said ‘skilled pilots’ or something like that know to disengage the autopilot and correct its flight path.