Originally Posted by
Smythe
B 737 driver....In regards to the MCAS and AP, there seems to be some differences noted.
From Pilot reports:
Wind and mechanical turbulence was noted. Careful engine warm times, normal flaps 5 takeoff in strong (appeared almost direct) crosswind. Departure was normal. Takeoff and climb in light to moderate turbulence. After flaps 1 to "up" and above clean "MASI up speed" with LNAV engaged I looked at and engaged A Autopilot. As I was returning to my PFD (Primary Flight Display) PM (Pilot Monitoring) called "DESCENDING" followed by almost an immediate: "DONT SINK DONT SINK!"
I immediately disconnected AP (Autopilot) (it WAS engaged as we got full horn etc.) and resumed climb.
Another report:
After verifying LNAV, selecting gear and flaps up, I set "UP" speed. The aircraft accelerated normally and the Captain engaged the "A" autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink." The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful.
I haven't seen the original reports (would appreciate a pointer to the source if someone has it), but I saw this discussed elsewhere. It had been pointed out that this is likely two reports for one incident - one by the Captain and one by the FO. It is quite common for both pilots to fill out separate reports.
This does not appear to be a MCAS issue, since the A/P was engaged. It is more likely an autopilot issue. Not knowing the detail of how the crew had the A/P set up or the maintenance history, I couldn't really comment beyond that. I've seen A/P doing wonky things before on engagement which is why I keep my thumb near the disengage button when turning the ship over to HAL.