Home Forums Hunting & Shooting Hunter's Campfire Question about the 737 Supermax 8 crashes

They failed to disconnect the system, either at the on/off switches just under the throttle quadrants or failing that, pull the offending circuit breakers. Apparently US airlines had the same incidents occur to them and they handled it with no problems.

Came out today, info from the so called black boxes had the pilots doing exactly what they were suppose to. Low altitude didn't give them a chance.l

Came out today, info from the so called black boxes had the pilots doing exactly what they were suppose to. Low altitude didn't give them a chance.

Phil

I have several friends who flew military and commercial. The agree that low altitude limits your options (time to recover); one friend stalled at 72,000', but had time to recover!

Well, reading the link, it appears that they turned it back on because it was impossible to trim manually.

It has two aoa probes. The MCAS only reads from the port (pilots) side.

It seems a pretty simple fix with a software update , a cutoff switch , and a little pilot training. MACS needs to be limited in its trim range and able to be permanently disengaged with a flick of a switch so power to the trim isn’t cut. Pilots need to be trained to recognize the issue and cut MACS off. Boeing screwed the pooch by giving MACS too much ability to trim , not providing a MACS cutout that didn’t cut power to the stabilizer , and hiding the systems nature from the pilots.
All this talk about how the aircraft is unstable and therefore unsafe is ridiculous. The slight nose up from the forward engine mounting means little as long as you are aware of this. Pilots need to trim their aircraft due to weight distribution and atmospherics every flight and compensating for the natural forward lift is no different than trimming the aircraft for weight and atmospherics.
The killer in this situation is that the pilots cut the power back on to the stabilizer to be able to get the stabilizer down but were unaware that MACS was going to throw it back up again in ten seconds. If they had turned the power back on for only a few seconds to get the stabilizer down and then cut it off again before MACS could intervene again they probably wouldn’t have crashed. MACS made it so the pilots couldn’t fly the aircraft by hand.
It’s Boeing’s fault but the MAX8 is a good platform that was made unsafe by Boeing trying to make it seem exactly like the 737NG when it wasn’t.

My question would be why did the MACS system decide that the aircraft was approaching a stall condition. Or was it just a bad reading from the AOA probe (which IIRC was written up in the maintenance log on a prior flight).

Another bad decision by Boeing to use only one AOA indicator instead of two and a warning of conflicting AOA readings. The entire MACS is a bad idea born out of regulation avoidance. If they weren’t trying to avoid pilot certification training costs for airlines and aircraft recertification costs and time there wouldn’t even be a MACS.

Pitch (& roll) trim are independent of the MCAS. The problem is, with the MCAS engaged, available pitch trim is very limited. I wasn't in the cockpit so we really won't know until the full report comes out AND vetted by the FAA and Boeing, but ostensibly, with pitch trim disconnected, you can manually trim with the big trim wheels on the side of the throttle quadrant. The huge turd in the punch bowl with MCAS, if you wait too long and the system (MCAS) has trimmed nose down and at low altitude, you're screwed (From what I saw nose down pitch was at 6 degrees which is YUGE and your trim tab only gives you ~1 degree. In the airplane I flew pitch trim was electric only, so it the pitch trim failed, you could still fly the jet with no issues, although coming aboard, could get a bit sporty. Suffice it to sa, if they kept turning it back on and every time it came on it kept trimming nose down, well we know the rest.