Originally Posted by
gums
Salute!
I shall stick with my interpretation of the reason MCAS was implemented.
It was to counter a nose up pitch moment.
If all it had to do was stiffen or increase back stick, there would not have been two crashes where the stab trimmed so far down that recovery was a big problem. Oh yeah, then the 5 sec pause and here we go again.
I would love to have Driver or another 737 jock fly the MAX with no MCAS and pull until the stall shaker. Let us know if the stick got lighter and if it was a problem. Real plane, not a sim.
PLease see the other forum where the pitch versus AoA charts are shown/discussed. and somewhere here we have the same chart.
Gotta see the dentist. So later..
...
Gums...
I think your interpretation is wrong.
My understanding is that MCAS was implemented ONLY to satisfy FAA Section 25.173
25.173 Static longitudinal stability.
Under the conditions specified in § 25.175, the characteristics of the elevator control forces (including friction) must be as follows:
(a) A pull must be required to obtain and maintain speeds below the specified trim speed, and a push must be required to obtain and maintain speeds above the specified trim speed. This must be shown at any speed that can be obtained except speeds higher than the landing gear or wing flap operating limit speeds or VFC/MFC, whichever is appropriate, or lower than the minimum speed for steady unstalled flight.
(b) The airspeed must return to within 10 percent of the original trim speed for the climb, approach, and landing conditions specified in § 25.175 (a), (c), and (d), and must return to within 7.5 percent of the original trim speed for the cruising condition specified in § 25.175(b), when the control force is slowly released from any speed within the range specified in paragraph (a) of this section.
(c) The average gradient of the stable slope of the stick force versus speed curve may not be less than 1 pound for each 6 knots.
(d) Within the free return speed range specified in paragraph (b) of this section, it is permissible for the airplane, without control forces, to stabilize on speeds above or below the desired trim speeds if exceptional attention on the part of the pilot is not required to return to and maintain the desired trim speed and altitude.
This link provides some good information.
737 MAX Maneuvering Characteristics Augmentation System (MCAS)
"MCAS is a longitudinal stability enhancement. It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and give a steady increase in stick force as the stall is approached as required by regulation."