Boeing 787 Suffers Rare Dual Engine Failure on Landing • Hacker News Board

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#261

Post by outworlder » Wed, Jan 30, 2019, 9:39 PM UTC

laretluval wrote: post #2

I hope people are beginning to understand that the presence of software in any system is a liability.

> I hope people are beginning to understand that the presence of software in any system is a liability.

I do not understand this point of view.

If you don't have software, you are going to replace it with something mechanical. Or with people. Or lose the functionality entirely.

Do you want to bring back a 'flight engineer' to operate airliner engines?

Do you want to bring back mechanical autopilots? Analog computers? Let's ditch GPS while we are at it (GPS failures can cause deaths, specially under poor visibility).

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#262

Post by mav3rick » Wed, Jan 30, 2019, 9:42 PM UTC

philjohn wrote: post #249

jshap70 wrote: post #202

Earlier quoted context omitted.

there's a really interesting story around Lauda Air flight 004 where Boeing attempted to write it off as pilot error but Niki Lauda basically threatened to go fly one himself and recreate the conditions as proof it was not. Eventually Boeing conceded and he didn't have to actually risk himself or another of his planes, but still an interesting anecdote.

That's just the kind of person Lauda is. He was severely burned in a Formula 1 race at the Nurburgring, and despite still suffering badly scarred lungs and weeping wounds he was back in the seat before the end of the season and only lost the championship that year because he refused to go out in the pouring rain to race the Japanese Grand Prix as he decided it would have been foolhardy.

He lost the championship by one point. The movie Rush on this story is also amazing.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#263

Post by jshprentz » Wed, Jan 30, 2019, 9:43 PM UTC

Aviation professionals discussed this incident on the Aviation Herald website. http://avherald.com/h?article=4c2fe53a

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#264

Post by slavak » Wed, Jan 30, 2019, 9:46 PM UTC

esemor wrote: post #189

I think the auto shutdown of engines in flight, in case it senses reverse thrust, is a great design. The 787 is a replacement for my 767 (currently a pilot on the aircraft) and in 1991 a Lauda Air 767 suffered a failure in one of its thrust reverser and it became activated during cruise. The aircraft was destroyed in flight. The thrust reversers should not activate during flight (a air/ground sensors prevents that) b…

TCMA, the system the article refers to, doesn't actually shut down the engines in flight. In fact, one of the explicit conditions for its activation is the aircraft being on the ground:

> The EEC commands shutdown of the affected engine when the: > • airplane is on the ground, and > • thrust lever is at idle, and > • engine is above idle speed and not decelerating normally > The EICAS caution message ENG FAIL (L or R) is displayed with an aural beeper once the engine falls below idle speed.

https://quizlet.com/27148021/engines-apu-787-ge-engine-flash...

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#265

Post by Keloo » Wed, Jan 30, 2019, 9:51 PM UTC

focom wrote: post #200

esemor wrote: post #189

I think the auto shutdown of engines in flight, in case it senses reverse thrust, is a great design. The 787 is a replacement for my 767 (currently a pilot on the aircraft) and in 1991 a Lauda Air 767 suffered a failure in one of its thrust reverser and it became activated during cruise. The aircraft was destroyed in flight. The thrust reversers should not activate during flight (a air/ground sensors prevents that) b…

There is Airplane pilot on HN? I am surprised, did you make a career switch from IT?

Yes, some of my software engineer colleagues are pilots as well. You never know who you are talking to, especially now-days.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#266

Post by inferiorhuman » Wed, Jan 30, 2019, 9:51 PM UTC

t0mas88 wrote: post #142

cbhl wrote: post #139

The Boeing 787 is now about nine years old. I wonder how much of this is operator proficiency triggering latent bugs (aka, "pilots got too good at pushing buttons quickly"). The bugs in the Therac 25 were only discovered after the machine had been in production for a while (you had to be typing "too quickly" in order to get the software to trigger the bug with the safety interlock).

It's not very typical for pilots to push buttons quickly. Especially not the thrustreversers and engine and flight controls. But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do. A bit like opening your car door while still driving 60 mph... Nobody does that in normal operation.

> But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do.

That's overstating the case a bit. I'm 100% a layman here but I'd agree that the behavior seems like some sort of bug. But…… some planes (typically not commercial, although the Concord is one notable exception) call for reversers in flight under certain circumstances. Additionally there are definitely circumstances where a pilot might deliberately think reversers before touchdown are a good idea.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#267

Post by CodeSheikh » Wed, Jan 30, 2019, 9:51 PM UTC

collyw wrote: post #90

CodeSheikh wrote: post #42

Earlier quoted context omitted.

Correction: "I hope people are beginning to understand that the presence of poorly-tested software in any system is a liability."

Well tested software still has bugs. Ones that haven't been tested for.

So it makes it a not Well tested then if scenarios have not been tested. My point.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#268

Post by inferiorhuman » Wed, Jan 30, 2019, 9:53 PM UTC

bunderbunder wrote: post #243

weaksauce wrote: post #230

Earlier quoted context omitted.

I am not sure there is a perfect solution here. you have competing issues that you need to resolve. If it gets pulled in normal flight you would lose both engines but that's fine because you can glide and restart the engines. if the altitude sensor/ground sensor was broken and you want to override the reverse thrusters you have a conflicting goal there. If you accidentally pull it during the approach you lose your en…

Well, I thought that the design was that they would not engage if it gets pulled in normal flight. If it's on the approach, I'd be worried. I imagine that that, at an airport like ORD, that might result in more risk than anyone really wants of the plane unexpectedly touching down on an interstate highway or something like that. If it's like what Boeing described in the bulletin, where the engines only get shut down a…

With most types loss of engines on approach is FAR less dangerous than engaging your reversers in flight.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#269

Post by anderspitman » Wed, Jan 30, 2019, 9:53 PM UTC

whizzkid wrote: post #228

anderspitman wrote: post #196

Oh Dreamliner, still[0] making me look bad 12 years later. [0] https://news.ycombinator.com/item?id=9477941

I have never ever thought avionics software development would be in such a condition that you described in the link. I am surprised to say the least. I have always imagined avionics developers in a different way. Like having a thick rulebook to go through to add a new line to codebase etc.

Keep in mind my experience was almost exclusively with communications systems, which are important but nowhere near as vital as things like autopilot. Things could very likely be better there, or at a different company. And even many of the things I worked on were like you describe. There is a lot of red tape and testing to make certain changes, and the industry documents are often strict. But it wasn't always clear how much of that actually made things better/safer and how much was just fluff.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#270

Post by lallysingh » Wed, Jan 30, 2019, 10:00 PM UTC

mhh__ wrote: post #203

noir_lord wrote: post #143

Earlier quoted context omitted.

Make me think about could we use a robot to fuzz physical inputs.

Probably not cost effective as opposed to either making the software more resilient or just letting some monkeys/interns loose in the cockpit and pressing everything (With some focused searches obviously)

..or not requiring physical hardware to test?