What’s Up With The 737 Max?

[Jobe]

I see where two US pilots have experienced the plane wanting to go nose down a bit when the autopilot was engaged. Easy fix for the pilot by disengaging the autopilot and correcting. Still uneasy as there is a record of this issue during or after every flight and no feedback from Boeing. If you offer a pilot a "fly by wire" plane it should do what you say it will do. Experienced pilots can deal with glitches and that makes them great and the few I have met take great pride in 'flying' an aircraft. Throw a new plane out into the world with sophisticated tech and expect every Tom, Dick and Harry pilot to assume business as usual might be part of the issue. I don't know. But if I was a pilot I would want to know my plane. Inside out. The manufacturer should insist upon it. This 737 has many outstanding orders that will (maybe) account for a lot of Boeing's bottom line. They can say they have a good plane but refer to my first sentence. Gonna have to fess up and fix the glitches. May have nothing to do with the recent tragedy but you are on notice none the less.

[endpin]

I am surprised a ONE-TIME-INSPECTION of all the MCAS related hardware has not been issued (AIR DATA PROBE/A-O-A transducers etc.)

The advantages of this would be:

1) It might find something!

2) Cost would be trivial compared to red ink already being bled

3) Usual objection of plane down time irrelevant with operators unilaterally taking whole fleets out of service

4) Would show manufacturer as proactive and would take some pressure off the operators

Anyway, it would not surprise me if some type of interim corrective action is released in advance of the “scheduled” April software update

[Wadcutter]

Originally Posted by endpin

I think at this point, the public relations problem has overtaken the technical problem.

Yup. Boeing stands firm and released a statement that they have “full confidence in the safety of the 737 Max.” Yeah, well good for you Boeing, but the the problem is the flying public doesn’t have “full confidence” and are scared to death to board this aircraft.

[Pura Vida]

Well said, Wadcutter. Boeing has to solve both issues.

[Dru Edwards]

Well, both Canada and the US have grounded the 737. Huge news. Airlines are scrambling to find replacement jets. Air Canada has 24 Max 8 jets and fly 9,000 - 12,000 people daily. Not sure how they'll accommodate all that.

[valleyguy]

Boeing announced before this latest crash that it was rewriting the software code to not take only one instrument's readings as a sole source to counter a stall. The software was to be rolled out in April. Though why they don't go back to the way it was in the prior models where a stall warning would be given rather than nose diving the aircraft.

They could have been following Airbus' lead there. As you may recall, Air France had an Airbus crash into the Pacific because of the incorrect pitot tubes readings and the pilots not reacting properly.

I still believe since it was as easy as shutting off the auto pilot, the Ehtiopian pilot has a lot of responsibility in this crash. Jeez, even I knew of this problem, and I'm not a pilot. There were other U.S. airline pilots that had to do that.

[Wadcutter]

With the USA now grounding all 737 Max’s, we now have a world wide grounding of this aircraft. Would love to be a fly on the wall at Boeing Corporate HQ.

[valleyguy]

I'm sure a lot of software engineers are burning the midnight oil.

[Neil K Walk]

Wasn't it a 737-800 that crashed outside of Pittsburgh about 2 decades ago? One would think that they would just retire the 737 altogether and design an all-new aircraft. The following story claims that Boeing initially considered doing just that until Airbus upgraded the engines on the A320.

https://theaircurrent.com/aviation-s...n-the-737-max/

[valleyguy]

Originally Posted by Neil K Walk

Wasn't it a 737-800 that crashed outside of Pittsburgh about 2 decades ago? One would think that they would just retire the 737 altogether and design an all-new aircraft. The following story claims that Boeing initially considered doing just that until Airbus upgraded the engines on the A320.

https://theaircurrent.com/aviation-s...n-the-737-max/

The plane might look like an old 737, but the new ones are quite different. New wings and engines. In fact the engines are so large that the plane had to be raised to account for the larger diameter, it also moved the center of gravity forward. There is some conjecture that the weight balance change may affect its flying ability.

[unimogbert]

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[endpin]

1) I have heard some interesting discussions between dedicated flight control software engineers (old-school - most of which were EE’s who were brought up on assembly language coding by hand) and “regular” software people and there is a whole different mindset for sure. A lot of software people use the phrase “we’ll catch problems on REV A”.

2) A common problem you see in software is failure to handle all possible cases of a decision tree (complete truth table). You often see source code comments to the effect of “we don’t know how we would have got here, but IF WE DID…”

3) There has traditionally been a problem with lack of modern certified compilers for mission critical task such as flight control (REF: the whole "Ada" thing).


4) The FAA air worthiness directive referred to “erroneous AOA sensor inputs" - My guess is the AOA inputs passed to MCAS are fluctuating or have noise and need additional filtering (integrated) before committing to a single pitch down trim activation

[DenverSteve]

It's no where as low as it was in December. In fact March 1 it was at a 5-year high. This is easily an adjustment, not exactly tanking.

[Kerbie]

There was an excellent discussion this morning on C-SPAN's, "Washington Journal," which is a daily newshow that engages in current events with callers. The guest for the 45-minute segment was Mary Schiavo, who is a pilot and former Inspector General for the Department of Transportation.

https://www.c-span.org/video/?458743...airline-safety

[unimogbert]

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