I believe there are 2 AOA sensors/vanes (left and right), with multiple sources of input data. Still, only one side/FCC is "active" at a time, and it switches sides for each flight.

There have been other instances of MCAS-related issues on MAX A/C as well, including the previous flight on the ill-fated Lion Air MAX-8. That crew experienced virtually the same thing and dealt with the problem properly by initiating runaway trim procedures (activating stab. trim cut out switches). They flew the remainder of the flight with manual trim and had no further issues (why it was not grounded after that flight is another matter/question).

So, while I think there is little question that the MCAS system needs to be reexamined and scrutinized/tested further, there is still an element of adequate experience and adequate training that also needs to be addressed, IMO.

For instance, there are systems/procedures on that aircraft that were required to be memory-items previously, that are no longer requirements today, primarily due to increasing complexity. Over the years, there have been a number of items added to what amounts to a troubleshooting "quick reference guide". That's all well and good if you have an issue at FL30, but at the more critical phases of flight (take-off & landing), you probably don't have time to be digging for a guide. You'd better have the experience and the applicable procedure should be a second-nature memory item, IMO.

I think there are already 2 on the MAX (left and right)?
Not only that, but I believe it's only "active" when flying manually, and/or with flaps up, and/or with extreme pitch/bank angles. It can also be temporarily overridden via elec. trim switches on the yoke, or manual trim wheels.
Further, it would seem that the standard procedure for runaway trim is applicable to faulty MCAS, albeit a bit updated now.

I can't imagine how/why a pilot would attempt to "fight" a problem like that for any lengthy period of time before initiating runaway trim procedures, all the way to stab. trim cut-out. However, that appears to be a possibility with the Lion Air crew, and maybe even the Ethiopian flight (alt. oscillations noted). As mentioned, the previous crew on the Lion Air A/C had essentially the exact same problem. They dealt with it appropriately and continued their flight without issue.

That said, I still think the big problem is the lack of training/awareness of the new system, and the differences in the initial runaway trim procedure.
As I mentioned previously, one could halt runaway trim on the "old" 737 by simply pulling back on the column (break-away). That won't work on an MCAS equipped A/C. You have to disable the trim altogether (cut-out).
While that was always the final step in the "old" 737 runaway trim procedure, the initial step of pulling back on the yoke no longer works with a faulty MCAS system. Sort of counter-intuitive, IMO.

Yep. Probably just waiting for prelim. info as they had to have help with the data gathering.

The same prelim info from the Lion Air crash is already out there.

I saw on the news tonight (ABC World News) that the Ethiopians wouldn't be doing any examination of the data recorders until the crash site was cleaned up. Sounds pretty flaky to me.

The 737 Max8 Type has been grounded in China, India, Indonesia, United Kingdom, the EU, Australia, New Zealand....about two thirds of the Max8 fleet worldwide is not flying. North American airlines and regulators have declined to ground the aeroplanes.


Several Pilots repeatedly warned federal authorities of safety concerns over the now-grounded Boeing 737 Max 8 for months leading up to the second deadly disaster involving the plane, according to an investigation by the Dallas Morning News. One captain even called the Max 8's flight manual "inadequate and almost criminally insufficient," according to the report.

https://www.zerohedge.com/news/2019-03-12/pilots-complained-about-boeing-737-max-8-months-deadly-crash

Didn't see/hear that. Only that one of the boxes was damaged.
Both Boeing and NTSB go-teams are en-route (or already there) to assist, so I am sure info will come out as soon as humanly possible.

Eric, you could be right. I did not work on 737's, so I'm really not sure. Looking at photos, it does appear to have a pair of pitot tubes and an AOA sensor on both sides.

A lot of what ATC says is repetitive and most of it can be anticipated. You should know what to expect especially if you have been to that airport in the past. My favorite airport to fly into was O'Hare in Chicago. It was the busiest but everyone there was professional and knew where they were, where they were going and what do to when they got there. I use to hear this a lot, "keep 'em spooled up UPS 'cause your next". (for take off) LOL And you had better be ready to go.

The original 737-100 had a long narrow "low bypass ratio" engine that was mounted almost directly under the wing. The newer versions of the 737 had an engine (CFM56) with a very high bypass ratio with a huge fan in front. The diameter of the large fan increased the over all diameter of the engine cowl that wouldn't fit directly under the wing and had to be mounted further forward to clear the ground. The CFM56 accessory package was moved from the bottom of the engine to the side and if you look carefully, you can see the bottom of the engine cowl looks somewhat flat. Here are some pics that might help.
http://forums.pelicanparts.com/uploa...1552454106.jpg
http://forums.pelicanparts.com/uploa...1552454135.jpg
http://forums.pelicanparts.com/uploa...1552454161.jpg
http://forums.pelicanparts.com/uploa...1552454179.jpg

Here's a better side view. http://forums.pelicanparts.com/uploa...1552454356.jpg

I am amazed at the breath of experience we have here on PPOT. If you want to know something, this is the place to come.

When I was an engineer our lab was tasked with investigating material failures on aircraft. There was also an electronics support lab in our building, but no big lab to investigate software failures. I'll bet there is now!

About 40 countries' civil aviation authorities disagree with you.

That may be, although I think the effective number is higher than that, but that doesn’t make them right. We don’t know what brought down the second jet; as for the first one, I think you’d have a hard time blaming Boeing. There were mechanical problems that were not properly fixed, I suspect you’ll find that the pilot training was inadequate and I think you will also find that these Third World Airlines don’t spend the money that the US airlines do, to outfit the jets with the options that would make this problem fairly moot.

Boeing is happy to supply these jets with the angle of attack indication in both the captains’ and first officers’ displays, as well as the HUDS unit. Companies like SW Airlines avail themselves of these options. They also spend quite a bit more money on pilot training, which produces more competent pilots.

I'm not sure this came out all that well in the news coverage, but Lion Air is notorious within the industry for their shoddy maintenance practices. They have been caught on many occasions with "aftermarket" parts on their aircraft. Cheap ass, Chinese made knock-off parts of vastly inferior quality that are not certified by any major regulatory agency, like our FAA. As a matter of fact, their aircraft have, at times, been barred from certain airspaces. The whispered, behind the scenes consensus is that that practice is what led to their crash.

I'm not sure that any avionics, particularly safety of flight type stuff, or pilot aids, are "optional" in any way. They save money with cheaper interior components, like lavs, galleys, and seats, I have seen that. But as far as a downgraded cockpit or pilot/copilot interfaces, that I'm not so sure about. I would be surprised to learn any such equipment is "optional".

https://www.reuters.com/article/us-indonesia-crash-boeing-aoa/optional-warning-light-could-have-aided-lion-air-engineers-before-crash-experts-idUSKCN1NZ0QL

https://theaircurrent.com/aviation-safety/southwest-airlines-is-adding-new-angle-of-attack-indicators-to-its-737-max-fleet/

As for the fake parts, that's been an issue for a while. Hopefully the manufacturers do a good job of weeding those out before they make it onto a plane. What's worse to me is that some airlines outsource their maintenance to companies operating in what I'd call third world countries and I see no way to keep that crap off of those planes.

I'm getting to the point that I pick the carriers I use as much as I pick the planes I fly on.

Thanks for the links. I have to say, even having been around this stuff for awhile, I am surprised to learn something like this "warning light" is optional. Of course it is not the only warning system, but more of a feature to bring your attention to the real warning system, but still...

Looking at the cost of one of these aircraft, I cannot believe this was a financial decision. In other words, its omission was not to "save money" on the purchase of the aircraft. That, and the articles kind of overstate its importance, I'm sure. If properly trained pilots are monitoring systems as they should be, this additional warning feature becomes redundant and unnecessary.

There is a PR angle to this as well. We all know that. Southwest, for example, is not going to ground its fleet and immediately retrofit every one of their Maxes. I would be willing to bet they are still flying many of these aircraft years from now sans this retrofit. This modification will likely be performed "while they are in there" at some upcoming major service interval. Kind of like we would do on our cars.

Let's make sure we are clear about one thing - the manufacturers are not the ones installing "fake parts". That is happening in service, and it's the airlines along with the MRO's (Maintenance, Repair, Overhaul) facilities that are installing them.

And yes, the Third World carriers and MRO's are the culprits here. I would go so far as to say that anything that does not fall under FAA, EASA (Europe), JTSB (Japan), CASA (Australia), and similar First World regulatory bodies are suspect.

I spent most of my time in the field in the Third World. It's the nature of the business - they are the ones least likely to have their own engineering and mechanics staffs. This is all maintenance and what we call "Service Bulletin" (equivalent to automotive "recalls") work. We were obligated, if our mechanics or inspectors found non-OEM parts during the course of their work, to effectively ground the aircraft until replacement OEM parts could be obtained and installed. It got pretty testy at times, to say the least. Lots of money at stake...

Me too, those threads are very interesting (though I regret they exist at all, very sad) and I am impressed by the collective knowledge.

However, having followed all aviation threads and more recently the AF447 threads, the malaysian airlines flight, the "head fake A380" fight thing and this, it's kinda interesting to me from a somewhat impartial distance how the "if it ain't boeing I ain't going" crowd is playing defense this time around, when Boeing is most likely going to be called for the exact same thing that Airbus has been panned for on these pages (computers taking over, based on erroneous sensor readings or not, software fix making up from a questionable design change, not enough training for pilots to override computers, etc)... Hmm...
Kinda silly of the FAA not to ground the plane too (though I understand there needs to be an "ungrounding" criteria and it's hard to see what that will be yet) but travellers are voting with their feet big time at the moment, so they might as well.

I wasn’t saying that they were intentionally using fake parts, as the dirtbags in Third World countries will do, I was saying that it’s becoming more difficult to keep them out of the supply chain. It does happen.

https://www.washingtonexaminer.com/chinese-counterfeit-parts-found-on-raytheon-boeing-systems

March 12, 2019
Mitt Romney joins Democrats urging FAA to ground Boeing's 737-8 MAX
https://www.washingtonexaminer.com/business/mitt-romney-joins-democrats-urging-faa-to-ground-boeings-737-8-max

I did not realize this got into the political mainstream.

The vultures are circling.

Justt announced that the US is grounding them immediately