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

nytimes.com

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

#121

Post by jcims »

stanski wrote: post #99
jcims wrote: post #64

Narrative from ASRS 1555013: I had my first flight on the Max [to] ZZZ1. We found out we were scheduled to fly the aircraft on the way to the airport in the limo. We had a little time [to] review the essentials in the car. Otherwise we would have walked onto the plane cold.My post flight evaluation is that we lacked the knowledge to operate the aircraft in all weather and aircraft states safely. The instrumentation i…

The problem is that if they had invested so much effort in training crews for the differences in the Max, it would be an admission that the Max and NG aren't so similar after all. Making it look like a quick and easy switch is only making the problem more serious. This is why corporations cannot police themselves and it's where the FAA dropped the ball.

I understand this but when our network team orders new gear they go through an extensive certification process before any packets are forwarded through them in anger.

I don’t see why airlines should be given a pass on trusting the vendor on hundred million dollar products that both employees and customers are literally entrusting their lives with.

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

#122

Post by cjbprime »

usrusr wrote: post #70
cjbprime wrote: post #16

Earlier quoted context omitted.

Two seems sufficiently airworthy as long as you warn the pilots that there's a failure they need to consider ("AOA disagree") and avoid control decisions based on the disagreeing system. It appears that the AOA disagree alert exists on the plane but is an optional paid feature (!).

A pilot might fire up that inference engine between his ears and make a very well educated guess when two sensors disagree, based on which one reacts more in line with how it should react to some exploratory control inputs or the recent control history. A control loop cannot do that, it is a stupid fact processor that we prefer to do one simple thing reliably than to venture off on inscrutably deep reasoning adventur…

It's mentioned briefly in: https://ad.easa.europa.eu/blob/2018-23-51_Emergency.pdf/EAD_..., and it's optional as a consequence of the entire AoA set of visual indicators being optional.

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

#123

Post by cjbprime »

concerned_user wrote: post #35
cjbprime wrote: post #16

Earlier quoted context omitted.

Two seems sufficiently airworthy as long as you warn the pilots that there's a failure they need to consider ("AOA disagree") and avoid control decisions based on the disagreeing system. It appears that the AOA disagree alert exists on the plane but is an optional paid feature (!).

It is optional on 737NG but not on a MAX.

I don't think this is true.

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

#124

Post by dang »

jquery wrote: post #102
dang wrote: post #17

Earlier quoted context omitted.

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 awar…

No doubt many people will turn out to be wrong about this. You simply need to make your points without breaking the site guidelines, as do we all.

You've unfortunately broken them again just now. It's explicitly against the guidelines to insinuate that people you disagree with are astroturfers. Would you mind re-reading https://news.ycombinator.com/newsguidelines.html and following them carefully when posting here? We don't need you to change your views, just express them within the limits specified. We have those limits because we're trying to preserve the commons for everyone.

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

#126

Post by towaway1138 »

ForHackernews wrote: post #86
exodust wrote: post #27

"You're in private mode" (no article for me). Is there another way to view the text?

Yes, one common way I've found to view the text is to pay money for the journalists' work.

Fair enough. But please don't post such links on HN.

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

#127

Post by VBprogrammer »

salawat wrote: post #119
acqq wrote: post #60

Earlier quoted context omitted.

As the plane "approaches a stall" the plane is actually in danger . Traditionally, the pilot is trained (on the simulator) to reflexively (every second matters) move the controls to avoid the danger in case of any problems (the different actual problems are simulated and separately trained for). But the new Boeing 737 Max planes exactly at that dangerous moment behave differently to the pilot's input than what the pi…

Excellently put. The 737 MAX is actually proof that even in the modern day, a basic grasp of philosophical principles is relevant. Namely, being able to identify when a redesign of a plane becomes substantially different enough to no longer be the plane it was based on anymore. The MAX blew past that line as soon as the system layout changed such that the pilot's mental models were no longer capable of accurately pre…

It literally went from a "steam gauge" aircraft to glass panels before. There are aircraft which are much more different and are on the same type rating, for example the 757 and 767. That's literally a widebody and a narrow body.

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

#128

Post by VBprogrammer »

cjbprime wrote: post #107
VBprogrammer wrote: post #54

Earlier quoted context omitted.

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 aerod…

I've seen that before. It certainly doesn't say it's impossible. I need to have look in the certification requirement but I'm pretty sure it would be uncertifiable if the trim couldn't be neutralised.

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

#129

Post by cjbprime »

VBprogrammer wrote: post #128
cjbprime wrote: post #107

Earlier quoted context omitted.

> 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 aerod…

I've seen that before. It certainly doesn't say it's impossible. I need to have look in the certification requirement but I'm pretty sure it would be uncertifiable if the trim couldn't be neutralised.

> It certainly doesn't say it's impossible.

What would it have to say? It says you might have to do X before Y, where Y is a thing that you need to do quickly while at low altitude to avoid dying and X is a thing that gives you even less time to do it in and makes the problem worse.

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

#130

Post by VBprogrammer »

cjbprime wrote: post #129
VBprogrammer wrote: post #128

Earlier quoted context omitted.

I've seen that before. It certainly doesn't say it's impossible. I need to have look in the certification requirement but I'm pretty sure it would be uncertifiable if the trim couldn't be neutralised.

> It certainly doesn't say it's impossible. What would it have to say? It says you might have to do X before Y, where Y is a thing that you need to do quickly while at low altitude to avoid dying and X is a thing that gives you even less time to do it in and makes the problem worse.

Ok let's look at it another way. Do you think it's even remotely likely that Boeing haven't had one of their 737 Max aircraft try this out at a safe altitude? They staked the future of the aircraft by saying they believe they are safe to fly.

I've never suggested having a trim runaway close to the ground is trivial. It's certainly going to result in brown trousers when it happens, but it should be within the abilities of a well trained crew to handle.

Following the outcry over Lion air I just don't believe a pilot on type wouldn't have known the procedures for getting the aircraft to a safe altitude and disabling the stab trim.

As a pilot your hands are on the controls. You notice pretty instantly that your having to pull the nose up. You instinctively reach for the trim control on the yoke. This disables the MCAS system for 5 seconds. You get the pitch forces under control. A few seconds later MCAS decides you've still got the nose too high because of a faulty sensor and tries to trim it back down once more.

How many times before you remember that fatal bug from that crash a few months ago. Maybe twice? Three times tops.

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