Not nearly as much as the rest of the airplane, both forward and aft of the CG, which also impart mass and have a longer moment-arm than the engines which are relatively close to the CG.
The first class cabin alone can vary in weight (passengers and bags) by 4,000 pounds, or more, from flight to flight and has a significantly longer moment-arm than the engines. Are you suggesting that it is a bad idea to fly with a full first class section? I don't think you are.
The airplane must be in its CG envelope for takeoff, flight, and landing. If it isn't, you can't takeoff until it is. That is true of all airplanes, not just the MAX. If the MAX engines put more weight forward of the CG then either the design or loading of the airplane has to counter that with more weight aft of the CG. The result is a balance airplane around the lateral axis both in weight an rotational inertia.
Static stability is the initial reaction after a displacement. Dynamic stability is the stability over time. A pendulum has positive static and dynamic stability. If displaced, it initially returns toward the start point. That is positive static stability. As the pendulum continues to swing back and forth the oscillations will reduce in magnitude over time. That is positive dynamic stability.
Airplanes tend to exhibit weak positive static stability in roll at shallow bank angles which degrades as bank angle increases. At higher bank angles the static stability is negative as the airplane will continue to roll into an increasingly steep spiral. Airplanes don't always have positive stability and that isn't necessarily a bad thing.
That would be an example of static, not dynamic, stability but what you say is true for all airplanes with under-wing engines. The MAX is no different. The airplanes, including the MAX, still have positive static pitch stability.
An unscheduled MCAS activation does not make the airplane uncontrollable. The DFDR data from all three flights shows that the airplane is completely controllable when proper procedures are followed. See the following article for an in depth technical explanation of that.
https://seekingalpha.com/instablog/...GNHUU4mmx-Y_gSkFBWDEgSikRvXo1Lz7NODddBu5xB358
I've been an airline pilot since 1990. I have never flown an airliner that had an AoA display. They are used primarily on aircraft which use a HUD, instead of autoland, for CAT II and CAT III approaches.
As a current 737 pilot I can say that you are wrong.
An unscheduled MCAS activation PRESENTS as a runaway stabilizer. There is no way to diagnose the cause of a runaway stabilizer in flight. Trying to do so would be a dangerous waste of time as demonstrated by the accident crews. The key to a successful outcome is recognizing that the trim keeps trimming nose-down on its own and accomplishing the runaway stabilizer procedure. It doesn't make any difference if the cause of the runaway is an unscheduled MCAS activation, a failure in the Speed Trim System, or a shorted wire in the primary trim system. The solution to every runaway stabilizer situation is to maintain control of the airplane and accomplish the runaway stabilizer procedure.
I've flown the 737-9 MAX and 737-900 and agree completely.
It is in Boeing's own description of the system. At certain high-AoA conditions the MAX's elevator pitch "feel" is lighter than that of the 737 NG models. MCAS introduces a nose-down pitch bias through the introduction of stabilizer trim to produce a pitch "feel" that is more similar to the 737 NG.
It is in the name of the system itself;
Maneuvering
Characteristics
Augmentation
System. It is not a
Stability
Augmentation
System, which some other airplanes have.
Why do some airliners require a stick-pusher, which aggressively pushes the nose down with more force than a pilot could counter, in order to pass stall qualification but the 737s, including the MAX, do not? Airplanes are different. Engineering is about compromises. To get what you want you have to give up something somewhere else. Different ways to get to the same result which is a 14 CFR 25 compliant airplane.
I also want to address the issue of a single data input.
Single source inputs are common in airline design. Each airplane has multiple autopilots and flight directors. The 737 has two, the larger Boeings have three. Each autopilot and flight director receives input from a single Air Data Inertial Reference Unit (ADIRU), a single AoA, a single pitot tube, a single static source, a single Flight Control Computer, etc. One set of data sources is always what is being used to fly an airliner (except on an autoland). When there is a failure in one, you switch to the other(s). Tying MCAS to the active Flight Control Computer is in line with how most of an airliner's systems work.
Simply changing the master to the other side should also stop an unscheduled MCAS activation. That isn't a procedure, of course, because there is no way for you to verify an unschedule MCAS activation in order to know to do it. Instead you use the runaway stabilizer procedure which also stops it.
