Downfall - Netflix

[virustalon]

Hello aviation community/mostly pilots.

I got my wings taken out during the COVID. I flew the 76 and the A320 for more than 10 years and now it's gone... Now I do some other stuff in life, however, my love for planes and aviation still remains. (if you ever think you don't know how to do anything else other than flying planes, think twice. You sure know!)

I just turned on Netflix and found "Downfall" which is a documentary about the 737 Max and the MCAS system.

I just have one single question for those people who know about it.

Is the plane safe to fly now? Was the fix mechanical or a software patch?

There are so many threads I didn't know where to read that simple answer.

Thanks!

[Less Hair]

MCAS is not starting over and over again. So it should be safe now. At least this is what the FAA thinks after test flying the current setup with MCAS on and off.
https://www.faa.gov/foia/electronic_reading_room/boeing_reading_room/media/737_RTS_Summary.pdf

[safetypee]

Aviation safety is required to confront and manage risk. The overall view is that the current processes provide a level which is acceptable to both the industry and travelling public. Trust is an important, although ill defined component in these interactions, and depends on knowledge and understanding of risk - actual risk, perceived risk, communication of risk (beware tabloid risk).
The Max challenged the actual risk for the 737, Boeing, and FAA; a loss of trust.

The aftermath involved rebuilding trust in a suspicious world muddied by other events and ill-informed media reporting.
From a certification and airworthiness viewpoint the 737 meets the same requirements as other aircraft - status quo. Flight crew trust is being resorted in the aircraft, but perhaps more slowly that in the manufacturer and regulator; best to believe actions rather than words.

The report below gives an interesting view of a small sample of how people in the industry perceive risk:-

‘Distress call from the flight deck: Cross-Cultural survey of aviation professionals reveals perception that flight safety is decreasing’. https://www.researchgate.net/publication/268271017

“… analysis of interviews with twenty-three aviation professionals from four European countries. According to these front-line operators, while aviation statistics may still portray a healthy industry, the operational reality is another matter altogether: the negative impact of economic scarcity and the ever-increasing focus on profits has reduced safety through changes in management practices, organisational structure, and regulations.”

“In response to the question “Do you think aviation is safe?” several people responded “yes…”, paused, seemingly conflicted, and then qualified their response with explanations like: “it is statistically safe” or “safer than all the other modes of transportation”. They generally described behavioural, procedural, and operational examples of “safety” in their daily work. This revealed a distinction between safety as the active experience of an activity (e.g. flying) in contrast to the “safety level” described by statistics reflecting the outcomes of that activity (e.g. fatalities or hull losses). A review of the interview data reveals that, with very few exceptions, safety was discussed as the qualitative, tangible experience of the risk involved in the activity, and this risk is compared to some cognitive or affective baseline – what could be considered the “comfort level” of the individual.”

The operational industry should be careful with understanding risk - a fear of fear alone; this is difficult in the current world situation. Beware misplaced initiatives after covid, lest they rock the boat.

The operational profession must retain confidence in itself; the means and assessment of this may differ from the theoretical regulatory view, but what ever is being done - keep calm and carry on safely.

[HOVIS]

Hello aviation community/mostly pilots.

I got my wings taken out during the COVID. I flew the 76 and the A320 for more than 10 years and now it's gone... Now I do some other stuff in life, however, my love for planes and aviation still remains. (if you ever think you don't know how to do anything else other than flying planes, think twice. You sure know!)

I just turned on Netflix and found "Downfall" which is a documentary about the 737 Max and the MCAS system.

I just have one single question for those people who know about it.

Is the plane safe to fly now? Was the fix mechanical or a software patch?

There are so many threads I didn't know where to read that simple answer.

Thanks!
Short answer is they fitted an additional AOA sensor and tweaked the software. Extra training for flt crew too.
Whether or not it still fits the criteria of a having the same flying characteristics as the NG is for others to answer.

[oceancrosser]

Curiously little discussion here about the Documentary. It opened my eyes to quite a few issues and I thought I was following things pretty well. Besides a chunk of money, Boeing and its management gets away scot free, with the possible exception of one low level scapegoat.

[DaveReidUK]

Short answer is they fitted an additional AOA sensor

I don't think they did.

[tdracer]

I don't think they did.
I'm pretty sure you are correct. There is an IOU to EASA (and perhaps others) to provide a 'synthetic' AOA that can be used to validate the mechanical AOA sensors (basically a 3rd source to allow voting if there is a disagree). However given the difficulty in developing and certifying the associated s/w, there was an agreed to timeframe before the synthetic AOA s/w needs to be certified and retrofit. I don't remember what that timeframe was though.

[MechEngr]

As far as documenting the technical aspects and/or the flight activities recorded by the FDRs, the movie gets an F. If one is looking at creating a movie that is to influence those who don't care about either of those factors, then it's as effective as any other that ignore the majority of the facts.

What has struck me most is the casual acceptance of false stall warnings. Without this defect in the ADIRU, MCAS would not have operated as it did. What was also uncovered by the investigation, but not dealt with, was the acceptance that there is something called "trim runaway" but without any defining characteristic. If a loose fragment of wire was loose in a trim switch it too would produce a random trim change, but not necessarily be continuous - is that considered "runaway?" What clear indication is there to a pilot to use the trim cutout switches?

[john_tullamarine]

What clear indication is there to a pilot to use the trim cutout switches?

I have a suspicion that, for old school 737 pilots, if the trim starts doing something, anything, that

(a) is contrary to what you command or expect, and

(b) you can't control it sensibly and appropriately, then

(c) the switches are used before the head scratching might commence.

I can recall a few odd ball situations contrived in the sim where this was emphasised as being a suitable response by the pilot.

Then, again, perhaps training standards and emphasis, these days, are a little different to days of yore ?

.. and ... that was back in the days where hand flying and raw data were valued as being of routine importance from a skillset consideration. I don't know that I would have liked to face the situation as a routine autopilot man .... routine hand flying put the pilot much more in the loop, in this dinosaur's opinion.

[Matey]

The system now compares left and right AoA outputs and if they differ by more than a set amount the MCAS function is disabled for the remainder of the flight

[tdracer]

What clear indication is there to a pilot to use the trim cutout switches?

I have a suspicion that, for old school 737 pilots, if the trim starts doing something, anything, that

(a) is contrary to what you command or expect, and

(b) you can't control it sensibly and appropriately, then

(c) the switches are used before the head scratching might commence.
<snip>

John, shortly after the second MAX crash, I attended a big fund raising event at the Seattle Museum of Flight. In addition to running into a few old Boeing friends who'd been involved in the MAX certification (and told me things that I didn't feel comfortable repeating at the time), I ended up sitting at a table with a high-power rocketry buddy who was a former Alaska 737 pilot - along with several other retired Alaska 737 pilots. Naturally the MAX was a major topic of discussion at the table - and one thing all those 737 pilots agreed on was that if the stab trim started doing something you didn't want or understand, the first thing they would do would be to turn it off.

MechEngr, I've not bothered to watch the Netflix movie, but I did watch a different TV program (I want to say it was on Smithsonian, but it might have been History). It was so full of factual errors and gross simplifications I found it hard to watch. Thanks for letting me know not to waste my time on the Netflix version.

[lederhosen]

I have thousand of hours in command on the 737 and I cannot remember in fifteen years flying it, ever needing to use the cutoff switches in real life. Sure it was a regular simulator drill and I certainly hope that I would have immediately done the right thing. But honestly do I think that the average pilot on takeoff at o dark hundred would have reached down for them like some Wild West gunslinger? I am pretty sure not all of them would have. I respect the views of a number of contributors above and I loved flying the 737. But honestly I do not think you can paint the whole MCAS business as anything other than some very poor decision making on the part of Boeing.

[Jwscud]

I found the documentary very perfunctory.

The sort of associated book “Flying Blind” however was very good indeed.

[washoutt]

As Safetypee said, there is no such thing as safety. There is however a set of design requirements, build since the 1930's by industry and by regulators on the basis of study of accidents and incidents (Car 4b, FAR's and JARs 25 and CS 25) which is continually upgraded with new insights by working groups and panels. The MCAS problems and resulting events are part of this proces and will eventually find their way in the regulations. IMHO the regulations are the pinnacle of human knowledge (so to speak) but the real effort is in the compliance finding to these regulations, by the regulator and airworth8iness authority.

[HOVIS]

I don't think they did.
You are absolutely correct. My apologies. I assumed they had added a third like Airbus have as standard. My mistake.

From Wiki....

The new flight control laws now require inputs from both AOA sensors in order to activate MCAS. They also compare the inputs from the two sensors, and if those inputs differ significantly (greater than 5.5 degrees for a specified period of time), will disable the Speed Trim System (STS), which includes MCAS, for the remainder of the flight and provide a corresponding indication of that deactivation on the flight deck.

[BBK]

Tdracer

I’ve just watched the documentary and I think it did a good job explaining a highly technical issue to the lay person. The film lacerates Boeing as having gone from one that valued excellence in engineering, rightly so, to one that was pursuing profit at any cost. There are contributions from several pilots from the US, including Sully, who are highly critical of Boeing’s conduct.

On the subject of trim runaways like lederhosen I’ve practised that in the sim but never with an accompanying false stick shaker and the confusion that would inevitably cause. Anyway, why not watch the film and judge for yourself. I realise that the technical data might be a little light for someone of your background.

One last fact that the film presented, which I’m unable to verify, is that the FAA conducted an investigation which I think was referred to as a TARAM.? In it the conclusion was that without modification one Max would be lost on average two years making it the most dangerous airliner ever.