Here's Boeing's fix to its 737 MAX problem

Before Boeing's prized 737 MAX can start carrying passengers again, engineers will have to update one of the plane's automation systems.

[cabc]

We in IT use to design systems that are much less critical than a plane with the "no single point of failure" restriction. Meaning that the failure of a single component should not break the system. How can Boeing design a plane that relies in a single sensor an if that sensor fails the plane crashes?

[ericzhang]

The problem is not only MCAS, is the reason why they put such a system in! Boeing "upgrade" the engine which is larger in diameter and not able to fit under the wings so they simply move the engine forward and upward consequently reduce the aerodynamic performance of the plane and also increase the chance for the plane to get in to the stall situation. 737 is not initially designed for such a big engine, the plane needs to be re-designed rather than patch everywhere and hope it works! typical money vs safety.

[James-szhr]

Should have explained why the MCAS was installed in the first place.

[jameswaters]

Wait a minute here. I think I heard that the reason for the MCAS is to avoid a stall because the Maxes engines are so powerful that they can create an excessive nose-up condition. A pilot knows to drop the nose and throttle back if the climb rate is excessive. Are they saying that the airplane is out of balance as far as the mean aerodynamic cord right off the assembly line?

[raymondyee]

If it looks like BS and it smells like probably BS.

[mrmsmcgill]

What happened to the good old stall warning horn?

[neilmacleod]

Number of MCAS systems installed in the old 737, mmm zero . And did any stall at take off and crash ? They screwed with a proven airframe . Made the plane so unstable they had to add HAL to the cockpit crew, and gave him (it) full control. But they will save 10-15% in fuel .

Angle of attack IS NOT THE SAME AS THE plane's pitch angle. It's the angle between the wing's chord line to the relative airflow.

[aky]

Listen a plane is supposed to be balanced and a glider first and foremost. If a plane needs electronical computers to keep it's nose from shooting up, because the plane wasn't designed properly then it's a serious flaw! the center of balance is not set properly due to larger body and engines. Could you imagine if the plane that landed in the hudson river in NYC had the same issue as boeing, the nose would shoot straight up and crash immediatly due to a complete loss of power. Come on.

[mig]

I am a computer programmer.
I would never allow the computer to take preference over the pilot.
We can react to any unexpected situation, a computer program cannot.

[gregmcintosh]

All this emphasis on the MCAS system but the real problem this much deeper than that. The real problem is Boeing violated the laws of fluid mechanics by configuring an unsafe airplane and justifying it by attempting to compensate the change with an equally or more hazradous "autocorrect" MCAS system. Layers of fault inherent in the design. Two negatives don't make a positive in this case. They did this to save money at the expense of 300 live so far. You can't change the laws of nature. Be created an unstable design that was at risk of stalling compared to designs that match aerodynamics such that even if there is a better working MCAS system and correctly working angles of attack sensors the margin of error is now reduced leaving pilots less time to correct for any stalling or nose-diving which depending on the altitude problem start will end up being hazardous no matter what. The only responsible thing to do is reconfigured the plains back to the original configuration

[PHOENIXAHELO]

Still not wouldn't fly a 737 Max, before or after this "fix"

[kidssongssupersimple]

I don't want fly Boeing 737 Max 8. Please make a video of Airlines still using this killing machine

[Mackenzieadventures]

As a pilot anything controlling my horizontal stabilizer on climb out would be OFF! That is the most critical phase of flight.

[SlyGoesMeow]

Engineer: A plane with has aerodynamic flaw design.
Boieng: no problem mcas and software will fixed the problem.

[lightbox]

Software and hardware. Boeing could have fixed this or just given airlines and their pilots more and appropriate training. Boeing worked hard to describe the MAX series as not a new plane but as a modification of an accepted model. They did that to avoid FAA scrutiny. It was a gamble and they lost. I hope they have to pay up and learn something from it

[tylerfb]

This video is a little off. MCAS wasn’t designed to prevent a stall. It was designed to make MAX 737s feel to the pilot like all other 737 models.

Because of the more powerful engines, at certain combinations of angle of attack and power settings, the control forces to keep the nose up in a MAX are less than in other models. In those situations, MCAS commands pitch trim nose down so that control forces are higher than they normally would be.

We know almost nothing about the Ethiopian crash. In the Indonesian crash, a malfunction in the Angle of Attack system gave a faulty reading to the MCAS computer and caused MCAS to malfunction. But MCAS uses the normal electric pitch trim system to function. And in a situation where you have uncommanded pitch trim (called runaway pitch trim), there are three solutions: turn the electric system off; physically hold the trim wheel, located right next to both pilots’ knees, with your hand to keep it from moving uncommanded; or simply push or pull harder on the control yoke, albeit in some situations it will be much harder.

MCAS may not be perfect and is probably in need of an upgrade, but the problem is pilot training, not the aircraft.
And certainly not a faulty aerodynamic design.

[Komputar]

Solution : MCAS remains disabled while in take-off mode then activates itself at a certain 'safe' altitude, let's say 8000 feet?

[MANMETR]

Whatever the solution they find do you think airlines and more specially passengers, will have confidence in flying again on the Max? I am not sure.
And I won't fly a Max whatever any rational explanation that it is safe.

[Nikola]

Your video is all wrong.
MCAS is not stall protection system, it just augments handling characteristics. AoA sensor doesn't measure air pressure, but relative flow of air. Angle of attack is literally NOT angle of pitch. Horizontal stabilizer doesn't control pitch, it simply balances forces. MCAS cannot move the horizontal stabilizer in the opposite direction of the pilot's attempted corrections, it's not the same control surface. If just one AoA sensor is wrong, the MCAS will not put the nose down anyway, it depends on aircraft configuration, and FCC in command and possibly some other parameters.