- I strongly recommend watching/reading the entire report, or the summary by Sal Mercogliano of What's Going On In Shipping [0].
Yes, the loose wire was the immediate cause, but there was far more going wrong here. For example:
- The transformer switchover was set to manual rather than automatic, so it didn't automatically fail over to the backup transformer.
- The crew did not routinely train transformer switchover procedures.
- The two generators were both using a single non-redundant fuel pump (which was never intended to supply fuel to the generators!), which did not automatically restart after power was restored.
- The main engine automatically shut down when the primary coolant pump lost power, rather than using an emergency water supply or letting it overheat.
- The backup generator did not come online in time.
It's a classic Swiss Cheese model. A lot of things had to go wrong for this accident to happen. Focusing on that one wire isn't going to solve all the other issues. Wires, just like all other parts, will occasionally fail. One wire failure should never have caused an incident of this magnitude. Sure, there should probably be slightly better procedures for checking the wiring, but next time it'll be a failed sensor, actuator, or controller board.
If we don't focus on providing and ensuring a defense-in-depth, we will sooner or later see another incident like this.
[0]: https://www.youtube.com/watch?v=znWl_TuUPp0
by psunavy03
10 subcomments
- Although I was never named to a mishap board, my experience in my prior career in aviation is that the proper way to look at things like this is that while it is valuable to identify and try to fix the ultimate root cause of the mishap, it's also important to keep in mind what we called the "Swiss cheese model."
Basically, the line of causation of the mishap has to pass through a metaphorical block of Swiss cheese, and a mishap only occurs if all the holes in the cheese line up. Otherwise, something happens (planned or otherwise) that allows you to dodge the bullet this time.
Meaning a) it's important to identify places where firebreaks and redundancies can be put in place to guard against failures further upstream, and b) it's important to recognize times when you had a near-miss, and still fix those root causes as well.
Which is why the "retrospectives are useless" crowd spins me up so badly.
by tialaramex
2 subcomments
- Note that "Don't make mistakes" is no more actionable for maintenance of a huge cargo ship than for your 10MLoC software project. A successful safety strategy must assume there will be mistakes and deliver safe outcomes nevertheless.
- Only tangentially related but the debate over whether the Francis Scott Key bridge is or was a bridge got so heated on Wikipedia that the page had to be protected, and I finally have a reason for bringing this up
Edit wars aside, it's a nice philosophical question.
https://en.wikipedia.org/wiki/Francis_Scott_Key_Bridge_(Balt...
by caminanteblanco
0 subcomment
- >The seven highway workers and inspector on the Key Bridge at the time were not
notified of the Dali’s emergency situation before the bridge collapsed. We found that,
had they been notified about the same time the MDTA Police officers were told to block
vehicular traffic, the highway workers may have had sufficient time to drive to a portion
of the bridge that did not collapse. Further, we found that effective and immediate
communication to evacuate the bridge during an emergency is critical to ensuring the
safety of bridge workers.
by DamnInteresting
1 subcomments
- Video explanation: https://www.youtube.com/watch?v=bu7PJoxaMZg
by caminanteblanco
0 subcomment
- Here's the attached report, it has a lot of additional helpful information: https://www.ntsb.gov/investigations/Documents/Board%20Summar...
- The big problem was that they didn't have the actual fuel pumps running but were using a different pump that was never intended to fulfill this role. And this pump stays off if the power fails for any reason.
The bad contact with the wire was just the trigger, that should have been recoverable had the regular fuel pumps been running.
- This is a great example of why “small details” matter. How many times do you think an apprentice has been corrected about this? What percentage of the time does the apprentice say “yeah but it’s just a label”. Lots of things went wrong in this case, but if the person that put the label on that wire did it correctly then this whole catastrophe could have been avoided.
- Worth noting: The MV Dali is a 1000-foot-long ship, weighing 50% more than a nuclear aircraft carrier, with a total crew of twenty-two.
That's everybody - captain, bridge crew, deck crew, cook, etc.
So - how many of those 22 will be your engineering crew? How many of those engineers would be on duty, when this incident happened? And once things start going wrong, and you're sending engineers off to "check why Pump #83, down on Deck H, shows as off-line" or whatever - how many people do you have left in the big, complex engineering control room - trying to figure out what's wrong and fix it, as multiple systems fail, in the maybe 3 1/2 minutes between the first failure and when collision becomes inevitable?
by buildsjets
3 subcomments
- In a well engineered control system, any single failure will not result in a loss of control over the system.
Was a FMECA (Failure Mode, Effects, and Criticality Analysis) performed on the design prior to implementation in order to find the single points of failure, and identify and mitigate their system level effects?
Evidence at hand suggests "No."
by comeonbro
3 subcomments
- A label placed half an inch wrong on misleading affordance -> 200,000 ton bridge collapse, 6 deaths, tens of billions of dollars of economic damage
Instant classic destined for the engineering-disasters-drilled-into-1st-year-engineers canon (or are the other swiss cheese holes too confounding)
Where do you think it would fit on the list?
- It’s been noted that automatic failover systems did not kick in due to shortcuts being taken by the company: https://youtu.be/znWl_TuUPp0
- We should have federal legislation requiring tugboat assist adequate to recover from complete loss of power and steering, through shipping channels that go under bridges supported by mid span support columns. The mechanism should be that if the Coast Guard catches you without a tug, the ship is permanently banned from the port under threat of seizure and repossession by the US federal government, or your vessel just gets immediately seized and held in port under bond.
Insurance providers insuring ships in US waters should also be required to permanently deny insurance coverage to vessels found to be out of compliance, though I doubt the insurance companies would want to play ball.
- My rule for a couple decades: any failover procedure that only gets run when there's a failure, will not work.
by kylehotchkiss
0 subcomment
- When shipowners are willing to cut costs with sketchy moves like registering with a random landlocked African country, why should we believe they'll spend any time or effort reading/implementing NTSB guidelines? It isn't like there's some well respected international body like ITAO calling the shots
- I know a little about planes and nothing about ships so maybe this is crazy but it seems to me that if you're moving something that large there should be redundant systems for steering the thing.
- If anyone was curious what is happening with the replacement, I just found this website: https://keybridgerebuild.com/
by 1970-01-01
3 subcomments
- So there were two big failures: Electrician not doing work to code; inspector just checking the box during the final inspection.
by taco_emoji
0 subcomment
- I was very confused by the word "contact" in the headline, which apparently means "crashed the fuck into and killed six people"
- Non redundant fuel pump that doesn't even restart on power failure. Main engine shutting of when water pressure drops, backup generator not even starting in time AND shoddy wiring that offlines the whole steering system. Thats what i call GOATED engineering. props to Hyundai HI
by nacozarina
1 subcomments
- I predicted 10yr & $20B to replace it and stand by that forecast.
- "Contact" is a weird choice of words.
by fluorinerocket
1 subcomments
- I still hate screw terminal blocks. Spring terminals + ferrules are still the way.
- The older I get , the more I trust people over rules.
by ocdtrekkie
2 subcomments
- "and WAGO Corporation, the electrical component manufacturer"
Sucks to be any of the YouTubers influencers today telling everyone they should use WAGO connectors in all their walls.
Seriously though, impressive to trace the issue down this closely. I am at best an amateur DIY electrician, but I am always super careful about the quality of each connection.
- The date for bridge completion was bumped from 2028 to 2030 already. I assume it won't be done until 2038. It is absolutely murdering traffic in the Baltimore area, not having a bridge. I would be super interested in seeing where every single dollar goes for this project, I assume at least 1/3 of it will be skimmed off the top.