Hindsight Bias and the M/V Dali

With regards to the actions of the pilots and crew of M/V Dali while in extremis

I can’t find it now but in Farwell’s somewhere is says that the courts will not pull out tape measures and stopwatches to judge decisions made at the time while in extremis,

Instead there is a standard called “objective reasonableness”.

This means that the circumstances at the moment of the incident, including the tense, uncertain, and rapidly evolving nature of the situation, are considered rather than evaluating the decision with the full knowledge of how things eventually turned out​ (Constitutional Law Reporter)​​ (Lexipol)​

Previous thread here:

So far, from what I have read, the bridge team did what I would hope my own team to do. I’m sure there are some small details that will come out that are questionable, but I am certainly not of the school that armchair quarterbacking or reveling in schadenfreude is productive in any way. I am more interested in the lessons that can be learned from incidents and I feel that most of us in the industry feel the same way.


I’m reminded of the adage that “The longest seconds in a pilot’s life is waiting for the rudder to come over.” This was said regarding steering gear design, and while illustrative in that sense it is clearly incorrect; the longest time in a pilot’s life is surely waiting for the lights to come back on. I think that doing anything correctly in that setting, be it letting an anchor out or getting the lights back on i a short time, speaks to ha high level of emergency perparedness.

I very much doubt that the interesting lessons in this case will be about the actions of the bridge team. Rather, we clearly have something to learn about robust system design, both in the sense of power distribution systems and organizational systems.


The scrutiny of Captain Sullenberger’s decision making process after he landed on the Hudson is a perfect example. The NTSB used flight simulators to test the possibility that the flight could have returned safely to LaGuardia or diverted to Teterboro.
The Board ultimately ruled that he had made the correct decision, reasoning that the checklist for dual-engine failure is designed for higher altitudes when pilots have more time to deal with the situation, and that while simulations showed that the plane might have just barely made it back to LaGuardia, those scenarios assumed an instant decision to do so, with no time allowed for assessing the situation.
Sullenberger’s decision proved to be the right one as there was high percentage of the probability that an attempt to reach an airport would have ended with loss of life of the passengers and people on the ground.


I agree, for one when the propulsion was restored the pilot couldn’t have known if it was going to stay or or not.

I do wonder, in hindsight, what sort of risk assessment was done wrt the bridge and these VLCS. Watching that huge ship approaching that bridge on the AIS replay it’s apparent there’s not much margin for error .

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I would assume so, since there was apparently a discussion about building a tunnel instead. I’m not sure how much use it would be though. A qualitative analysis would bring to light a number of low probability, high consequence events like the one we have just seen. Quantitative analysis is pretty much impossible due to the low incidence and significant environmental factors.

Passing bridges is far from the only situation in which a momentary loss of power can have disastrous consequences. The Viking Sky incident (which I’m still reading up on) is another example, and perhaps more pertinently the Bright Field allision very nearly became a 1000+ fatality accident. In the M/V Dali case it may or may not be that a higher level of redundancy could have prevented disaster, and this could give rise to the argument that it should be mandated. In the other two cases the cure would be to keep your ship in order, if only just a little bit.

This must also be seen in the broader light of goods transportation risk exposure. IMO the myriad road and rail bridges crossing inland waterways represent a far higher risk to human life because of the different nature of brown water operations. Statistics bear this out.


US Navy mustang here, commissioned in 1972 as a Surface Warfare Officer. Right after reporting to my first ship, I was sent to two one-week schools for Rules of the Road and Shiphandling.

We were taught that once In Extremis, the only only incorrect action is inaction. As we all know, hindsight is always 20-20…


When teaching people to fly, one of the hardest things to teach is engine failure right after takeoff. I always taught that below 500 feet you are landing on whatever you see ahead of you. A heroic turn back to the airport doing reversing steep turns to get lined back up with the runway can be done if you are a very good pilot and KNOW IN ADVANCE you will be doing it.
If you KNOW the engine is going to quit under the bridge, you would probably anchor before you got there. I hope no one tries to reverse-engineer the pilots into doing something wrong.


“This must also be seen in the broader light of goods transportation risk exposure. IMO the myriad road and rail bridges crossing inland waterways represent a far higher risk to human life because of the different nature of brown water operations. Statistics bear this out.”

Several years ago (a decade or more?), the APA had a paper on new road bridges and the gist of it was, “If you build it, it will be hit.” How many bridges in ports are not set perpendicular to the channel or have the approache/clearance run that involve reaching to the channel limits? We have ports on the Lakes with some bizarre bridge alignments and I am sure we are not the only place in the US with this issue. Fortunately, most of those bridges are bascule spans that at least have traffic stopped during transit but on a high river current day, they can be a challenge. Green Bay Wi always comes to mind!

I need to go back through my papers and try and find the article; it was very good. As ships and ATBs/tows get bigger, we all have to deal with infrastructure constructed decades ago when vessels were generally smaller/lighter and constantly adapt our passage plans to allow for smaller safety margins. As noted in multiple previous posts, the operational fall-out from the Key Bridge will likely mean increased attention to escort tugs and a deep dive to s/by power systems. We shall see…


Good article here:

Above all, by undertaking a risk-based consequence assessment every decade or so, authorities that are responsible for vital infrastructure can help visualize changing risks and prioritize their responses appropriately. In the case of river bridges, ever-increasing ship sizes, speedier turnaround times and higher cargo volumes have all increased the risks – and the costs of a catastrophic collision or collapse.

Reading this article it occurred to me that a lot of the shock comes from watching the video. No video of the collapse of the Skyway bridge in Tampa Bay.


The Dali allision involved approximately the same ship size, speed and outcome that Delaware authorities have been working to defend against at the Delaware Memorial Bridge since 2015. But even if Maryland transport officials had followed Delaware’s lead, it is not clear that they could have done anything, engineering experts told the Washington Post. The center span on the Key Bridge is narrow, and installing protective dolphins or fenders would make it even narrower.

"That’s a pretty tight channel,” a former state transport official told the Post. “You might actually create a hazard rather than mitigate one.”

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This epic tragedy with 6 lives lost and the economic impact that will cause a lot of suffering leaves many assumptions and theories as to why and how it happened.
I race sailboats offshore, so obviously I don’t stand at the level of expertise that most people have, but Rob Almeida, the founder of gCaptain was a student of mine and later worked with me in the Offshore Office at USNA. Still, I have no degree in the subject matter. I’ll leave my resume out of this.

First, the reaction of the professional crew with the bridge with the sudden loss of power at 4 ship-lengths away was based on their decades of experience that doing something was better then doing nothing. My heart goes out to them like the many leaders I’ve known who make decisions knowing there will be some loss of life no matter what.

Everyone here has scrutinized the AIS track & timeline from the moment of power loss and the turn to starboard and how the speed decayed from 8.7 knots to about 6.5 knots at the moment of impact with the bridge stanchion and have watched the video as the Dali made its fateful turn.

The engine on Dali: A professional mariner with a blog said this engine is a low RPM engine that does not have a gearbox other than maybe a reduction gear, and the engine and shaft rotation must come to a complete stop before restarting and rotating the engine and screw the opposite direction from forward to reverse.

Generators: Is the Dali equipped with an emergency generator that would power the essential lighting, steering control and air compressor for restarting the engine?

The tide was ebbing. The blogger said the current from the Curtis Bay Channel caused the ship’s stern to move to port to encourage the turn to starboard.
Before hearing that supposition, I had assumed that the engine was in reverse when the plume of smoke emitted, and transverse thrust then encouraged the turn.

For those of you who have done an emergency stop on a ship like the Dali, how much transverse thrust will you expect, and does the turn exhibited by the Dali meet that expectation?
If it is impossible to reverse this engine in that amount of time, then the point is mute.
Certainly support for the leadership on Dali’s bridge is needed, as no one would want to trade places with them and the heavy burden they must be feeling at this time.

I was thinking about that as well. There were two different perspectives on that. One was the public’s and the other the accident investigators of the NTSB,

As far as the public they saw Sully as a hero. I don’t know about the NTSB, in the movie “Sully” there was a lot of discussion about the fact that by simulator the aircraft could have made it back. Don’t know it that’s an accurate portrayal of the facts or not.

In this case, the Dali, from what I’ve seen the public apparently understands that there was a loss of propulsion / control that was not the fault of the pilots.

Likely somebody at some point is going to pull out the stopwatches and tape measures but I don’t think that’s going to shift the narrative much if it does happen.

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The word ‘hero’ is one of the most misused words in current parlance. Captain Sullenberger was competent pilot who followed his training and relied on his experience to successfully respond to an emergency. Calling him a hero, like calling the ditching a miracle, takes away from his accomplishment.
When asked about his successful water landing, he answered: “One way of looking at this might be that for 42 years, I’ve been making small, regular deposits in this bank of experience, education and training. And on January 15, the balance was sufficient so that I could make a very large withdrawal.”
When the public learns the details of how the Dali’s pilots saved lives by their actions as the ship drifted toward the bridge, they’ll probably be hailed as heroes when rightfully they should be commended for staying cool and exhibiting professionalism under fire.


Film makers’ liberal use of artistic license for dramatic effect.

Page 120, 15. The captain’s decision to ditch on the Hudson River rather than attempting to land at an airport provided the highest probability that the accident would be survivable:


I got interviewed by reporters after an engine out landing and they asked me if I felt like a hero.
I answered thusly: “Not really, I was in the plane too, I was saving my own skin along with the passengers. This is what I was trained for over and over, I was just happy to do the job right”.
To me I would have been a hero if I had parachute, could have jumped out and waved bye-bye, but didn’t :roll_eyes:


Turning back is going ALL IN, you either make the runway, stall in and die, or land short in a crowed city and probably die.
The river was a vastly better bet.


Did simulations really show that Sully could have made it back to the airport?

Also at the same link: How long did it take for the NTSB investigators to conclude that Sully made the right decision to ditch the plane?

Another term that might be applicable is “local rationality.”

Local Rationality | SKYbrary Aviation Safety.


OODA loop again. We all orient differently because we all have different experiences.