Comment by loverofhumanz 4 days ago
"I’m a little confused by what there is to investigate at all."
You're confused why they should investigate how everyone on that flight came within minutes of dying?
Something about the fuel reserves, procedures, or execution was clearly flawed.
> If this happens once every 100k flights, then it doesn't even beg the question of "why aren't we overfuelling to 4.5 hours".
- This does not happen once every 100k flights. That's once per day
- If this were happening once every 100k flights we would be adding another half hour to the reserve tomorrow.
Although credit is due to fuel reserve policies considering they landed after two diversions and three go arounds.
Why not? It's a factual report stating that the AAIB has opened an investigation into a potentially dangerous incident. There's not any editorial bias evident. See other extensive comments as to why this is not just a case of "it landed, so what's the problem?".
Or did it work as intended? The plane had multiple failed landing attempts, was re-routed, and had enough fuel to land safely. While no one wants to cut it this close, this was not a normal flight.
I’m not an expert in this field, but it would seem that the weight of extra fuel would increase operating costs, so it’s is effectively insurance. How much extra fuel should be carried to account for unplanned events like this, while not carrying so much that it becomes cost prohibitive.
Fuel depletion is risky, but not that risky; see the Gimli Glider for a case much more dangerous than this, which still worked out amazingly well.
Edit: Here is the Wiki on incidents... https://en.wikipedia.org/wiki/Fuel_starvation_and_fuel_exhau...
That example is so well known due to how exceptional it was, especially how the pilots handled it. Robert Pearson, the captain, was a very experienced glider pilot. That's something that not many commercial pilots have.
There were also two factors in the landing, that allowed for this to happen. You're going to be coming in really fast for a landing, when gliding in a commercial jet, and you don't have access to your thrust reversers to slow it down. There was a repurposed runway, that they used to land, that just happened to have been used as a drag racing track and had a guard rail. They were able to slow down by scraping across that. It also just so happened the nose gear didn't deploy fully so scraping the nose of the plane against the ground also helped slow it down.
Needless to say it was a bunch of very fortunate events that allowed it to not end in disaster. In any case I would consider it very risky.
And even with all that scraping damage they were able to fly the plane out, repair it, and put it back in service. Amazing.
I would hesitate to chalk it up to just theory, given it was in the NTSB report and they don't really mess around with throwing baseless stuff around. I'd be interested to take another look at it. They likely go into the material science and physics behind this very thing. They're usually filled with gems.
You also have to keep in mind, it wasn't just rubber against asphalt, it was rubber on a wheel that spins. I'm not sure if the front nose gear on a 767 has any brakes but even if it did, I can't imagine it would be sufficient at the speeds they were going.
Don't forget the surface area of contact...
Rubber likely grips much better than metal, however three wheels have massively lower surface area than the body of the plane, or even a small section of it like the head.
Of course we don't land tireless for other reasons (metal transfers heat exceptionally well unlike rubber, paint doesn't survive high speed impact, and it tends to deform upon impact with anything, making any future flights unsafe), but the fastest way to slow down if you don't care about safety or comfort would probably be to land tireless, if you could introduce some rotational spin, that might be faster (more force directed in multiple directions).
Also, on the note of "coefficient of friction", remember that this number is not just some innate property of a molecule - as the metal scratches the pavement and deforms, its coefficient of friction goes up as micro-deformities accrue.
You could've read at least the Wikipedia page on how miraculous Gimli Glider was.
From "all engine failure is never expected and not covered in training" to "Pearson was an experienced glider pilot familiar with techniques rarely needed in commercial flights" to the amount of maneuvers they had to execute on a barely responding aircraft
Depends largely on the altitude when fuel runs out. If it runs out when they're at 4,000 ft and it's windy, it's probably game over.
Fuel depletion is _not that risky_ is an interesting take. But hey, it won Chapecoense its first and only Copa Sudamericana, so maybe it isn't that bad after all?
I think the argument is that this is precisely the tail end of exceptional conditions overfueling is designed for. If it's typical to fill fuel for 4 hours on a 2 hour flight, and the flight took 4 hours. It seems like this is exactly why they overfuel to 4 hours. If this happens once every 100k flights, then it doesn't even beg the question of "why aren't we overfuelling to 4.5 hours".
This is just clarifying the question from the perspective of an outsider.
That said, an investigation would be pretty reasonable, even if only to confirm that the abornamlity were forces majeures