Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show • Hacker News Board

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#101

Post by Tsubasachan » Fri, Mar 15, 2019, 2:01 PM UTC

dubbel wrote: post #69

thedoctor79 wrote: post #52

The facts so far are that two new aircraft of the same model have crashed in a very short period of time, in the same stage of flight and exhibiting the same problem as evidenced by ATC recordings: loss of flight control. We should not focus only on the software aspect, even though a very questionable (and dangerous in my opinion) decision was made to not communicate to the pilots the existence and operation of the s…

> Even I, as a passenger sometimes look for the lowest price, so the pressure for cost cutting may come from us as well. Of course you do, and that is not your fault. This is why we have independent regulation organizations like FAA or EASA, to not have matters of security solely in the hand of the free market.

Reminds me of a story of a budget airliner cutting costs by buying used parts and patching them up. Now nobody had actually tried to do something so nuts/genius before so there weren't any clear cut regulations. Eventually there was an accident and the FAA started to put screws under the microscope and interrogate maintenance crew.

Thankfully the aviation industry nowadays out of self interest cares about safety.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#102

Post by jquery » Fri, Mar 15, 2019, 2:04 PM UTC

dang wrote: post #17

jquery wrote: post #2

Before the wild speculation, here's some words from an actual aviation expert, Greg Feith: It is sad to hear some of the “junior investigator” talking heads make a storyline out of factoids or no facts about the 737 MAX. They embellish their credentials to sound smart when in fact they have no clue and say things about analyzing data that doesn’t exist.... A good friend of mine who is a former airline captain and fli…

Your edit breaks the site guidelines, which ask: Please don't comment about the voting on comments. It never does any good, and it makes boring reading. Yes it can sting when one's comment is downvoted, but the guidelines ask all of us not to react in the usual tedious and sarcastic ways. A better approach is to take a moment to reflect on what in your comment might have attracted downvotes; if you notice anything to…

It’s boring to read HN wildly speculate on the crash and trash Boeing as if they know what went wrong. Historically speaking, early speculation has nearly always been notoriously bad at predicting what went wrong in a given crash scenario. Despite this happening twice it is still a sixth sigma event, there is no reason to think the exact same set of circumstances occurred twice, especially after pilots were well aware of the MCAS system post Lion-air. I’m sure Boeing deserves a large part of the blame in the end, but I’m also sure that unanticipated pilot error is at the nexus of both events. You can’t anticipate every pilot failure mode, and since this wasn’t lost at sea we have the luxury of waiting for the final report. For all we know it wasn’t a design defect, but an improperly maintained sensor, or pilots who failed to look at the logbook. I see people already talking about how “capitalism has failed” and “lets imprison Boeing execs” which sounds more like Chinese astroturfing than good-faith posting. It could even turn out the two events were independent, a statistical analysis across all jets probably shows the likelihood of two planes of the same type crashing within 6 months of each other is more likely than our intuition suggests, because the Pareto distribution applies to every plane type in the entire world.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#103

Post by Someone1234 » Fri, Mar 15, 2019, 2:16 PM UTC

neuronic wrote: post #96

gjtorikian wrote: post #89

Earlier quoted context omitted.

You have no idea what you’re talking about. Pilots already warned Boeing about the problem: https://globalnews.ca/news/5055894/u-s-pilots-warned-boeing-... Boeing ignored it.

I am just a passenger without aviation experience. Nonetheless, how does your link invalidate my comment? To reiterate, I see following issues: 1) Software issues (e.g. MCAS), hardware issues (e.g. AoA sensors) -> Boeing responsible 2) Little to no training for 737 MAX, shuffling of known UI and UX of other 737 models -> airlines and Boeing responsible 3) Certifications for 737 MAX granted despite lack of sufficient…

They must have misread your comment or similar, because their retort is a complete non sequitur. You said yourself you're a passenger and talking from that context/expectations, and their reply is:

> You have no idea what you’re talking about.

Plus you never blamed pilots themselves anyway. You said Boeing/FAA/Airlines which seems quite correct.

I'd just ignore that post.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#104

Post by sandworm101 » Fri, Mar 15, 2019, 2:29 PM UTC

neuronic wrote: post #57

Let's preface this by saying I am aware that cause of the accident has not been determined. Seeing reports of experienced pilots being assigned to 737 MAXs without prior flight experience of this precise model, prompts me to make this comment. As a passenger I expect pilots to fully know the plane they are flying and to previously have flown this exact type and model of aircraft in training sessions without any passe…

>> As a passenger I expect pilots to fully know the plane they are flying

Never going to happen. Modern aircraft are far too complex for anyone to have this sort of complete knowledge, let alone be able to use it properly in a crisis. This one reason, of many, that pilots work from checklists created by the manufacturer.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#105

Post by cjbprime » Fri, Mar 15, 2019, 2:38 PM UTC

CydeWeys wrote: post #84

cjbprime wrote: post #20

Earlier quoted context omitted.

I agree with you. I think in practise the feature choices are made per-airline, perhaps to avoid the pilot confusion you mention. "AOA disagree" specifically seems to have been purchased by only the North American airlines that use the MAX.

I'm still trying to wrap my head around the fact that an error warning can be an optional paid extra, even when the error being reported is that sensors are malfunctioning in a way that will cause the plane to override stick input and fly itself into the ground.

There is some complicated explanation: the AOA disagree alert requires the presence of the visual AOA indicators, and it's those indicators that are the paid upgrade, and the alert comes along for the ride with them.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#106

Post by CydeWeys » Fri, Mar 15, 2019, 2:45 PM UTC

cjbprime wrote: post #105

CydeWeys wrote: post #84

Earlier quoted context omitted.

I'm still trying to wrap my head around the fact that an error warning can be an optional paid extra, even when the error being reported is that sensors are malfunctioning in a way that will cause the plane to override stick input and fly itself into the ground.

There is some complicated explanation: the AOA disagree alert requires the presence of the visual AOA indicators, and it's those indicators that are the paid upgrade, and the alert comes along for the ride with them.

Why would AOA indicators be a paid upgrade? Isn't that a pretty fundamental display needed to safely fly the plane? And wouldn't having disparities here between planes create more confusion among pilots?

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#107

Post by cjbprime » Fri, Mar 15, 2019, 2:45 PM UTC

VBprogrammer wrote: post #54

cjbprime wrote: post #37

Earlier quoted context omitted.

I think both end up with blame on Boeing. If a discussion in world news isn't enough to prepare an experienced 737 pilot (ten years!) to counteract spurious MCAS, then nothing is, at least to the level of safety expected in airline travel. A plausible explanation for (1) that I've seen discussed is that, after disabling the auto trim, it may be impossible to manually re-trim while the yoke's pulled back, without firs…

I think it's unlikely that this crash will be attributed to the same set of circumstances as the lion air crash. I don't find it credible that an experienced pilot would fail to catch what, in essence, is a trim runaway event. There is a reason trim runaway is a memory item on almost all aircraft. Even in the Lion air case the previous flight experienced difficulty with the system and dealt with it. This was before t…

> I don't find 1 particularly compelling, it would have been noted by now if it was impossible to trim the aircraft using the manual trim wheels.

It has been noted:

737 Flight Crew Training Manual, chapter Non-Normal Operations/Flight Controls, sub heading Manual Stabilizer trim:

"Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the air loads to allow manual trimming. Accelerate or decelerate towards the in-trim speed while attempting to trim manually."

In this case the excessive air load would be caused by the yoke control pulling the elevator up while the trim controlled stabilizer is doing the opposite.

Like you say, it's hard to know whether this actually happened.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#108

Post by CydeWeys » Fri, Mar 15, 2019, 2:47 PM UTC

VBprogrammer wrote: post #93

CydeWeys wrote: post #79

Earlier quoted context omitted.

You don't do non-revenue training flights on full-size jetliners. It's way too expensive. You learn to fly (period) on small planes that can't hold passengers at all, then you train in simulators for a specific model, and then finally you're paired up with a more experienced pilot once you start flying it for real. They definitely did not do the proper training that was merited here, but the proper training is not an…

Funny enough, I remember seeing a 737 doing circuits at Prestwick airport. I believe there is (or used to be) some requirement for an airline to do a minimum number of circuits on a new type. Kinda fun to see. Apparently a lot of fun for pilots to do.

Yeah, each time a new type comes out, or a new plane is manufactured, you do empty test flights. But you don't do that just to train up a pilot.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#109

Post by amyjess » Fri, Mar 15, 2019, 2:48 PM UTC

Tsubasachan wrote: post #101

dubbel wrote: post #69

Earlier quoted context omitted.

> Even I, as a passenger sometimes look for the lowest price, so the pressure for cost cutting may come from us as well. Of course you do, and that is not your fault. This is why we have independent regulation organizations like FAA or EASA, to not have matters of security solely in the hand of the free market.

Reminds me of a story of a budget airliner cutting costs by buying used parts and patching them up. Now nobody had actually tried to do something so nuts/genius before so there weren't any clear cut regulations. Eventually there was an accident and the FAA started to put screws under the microscope and interrogate maintenance crew. Thankfully the aviation industry nowadays out of self interest cares about safety.

The usual way I've heard aviation regulations described is that every single regulation is written in blood.

That is, every one of these regulations exist because somebody died as a direct result of that regulation not existing.

Re: Boeing 737 Max Hit Trouble Right Away, Pilot’s Tense Radio Messages Show

#110

Post by dingaling » Fri, Mar 15, 2019, 2:51 PM UTC

alfalfasprout wrote: post #15

tyingq wrote: post #8

Earlier quoted context omitted.

It's not that weird for technical people to wonder why, when there are 2 AoA sensors, Boeing didn't consider the readings from both of them as input for the MCAS. We probably don't assume that was malicious. But we might assume deflecting away from that as an issue to be malicious. Similar for the fact that the system wasn't well described in the manual.

It's bewildering how even 2 would be sufficient. You'd expect some kind of 3 way setup where a single sensor failure is detected via majority quorum. Especially for anything that directly has the ability to alter control planes on the aircraft.

Yes, all Airbus aircraft have at least three AoA sensors.

Boeing standardised at two, even on the 787. And one of those is located where it is vulnerable to damage from a jetbridge.