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by thoughtpeddler·4y ago·view on hn ↗
As the article points out: > causes for flight diversions can range from medical (related to crew and passengers), weather (unlikely), unruly activity (we would have heard about that), and mechanical (the most likely). Someone even mentioned solar flares.

But none seem to be the case with these diversions, from what is publicly known.

4 comments
Two of the Southwest flights are known to be mechanical related:

https://avherald.com/h?article=4fc19a3b&opt=0 https://avherald.com/h?article=4fcfe330&opt=0

AvHerald finally supports HTTPS!
Medical diversions (a passenger gets too sick) are by far the most common type. I find this interesting how the planes are so much more reliable than the passengers on board.
There are also a hundred or more passengers on a transpacific flight. If planes and humans were equally reliable, we'd expect to see medical diversions to outnumber mechanical ones by more than 100:1....
Also depends on whether you had the fish for the in-flight dinner.
I think this post is referencing a joke from the movie Airplane! https://www.imdb.com/title/tt0080339/
which is in turn referencing the plot of https://en.wikipedia.org/wiki/Zero_Hour!

Surely one of the great comedies.

They serve dinner?
Never been on a plane before? Yeah they serve meals and drinks at your seat.
That's outrageous. Think of the profit they're giving up for comfortable service.
Ah yes, I had lasagna.
Underrated comment right here.
That’s an interesting argument in favor of smaller and faster aircraft (for a given reliability…).
By quite a bit, right? Assuming passenger malfunctions were statistically independent, I guess passenger malfunctions would follow the binomial distribution.
The probability of any passenger malfunction should be exponential by the number of passengers.
Do you mean multiplicative? Or linear? Why would it be exponential?
Any one malfunctioning passenger is sufficient to fail the overall flight. Assume each is independently probable of malfunction. If we know nothing else about the passengers, we can only model them as having some average rate of successful flight without malfunction, say 99.9%.

Say there are 100 passengers. We roll the dice 100 times, once for each passenger.

The success rate for the overall flight would be 0.999 ^ 100 = 90.4% -> About a 10% chance of flight failure.

If there are 400 passengers, we get 67.0%, about a 33% chance of flight failure.

Given enough passengers per flight, few or no flights reach their destination.

I think they mean it's 1 - prob of any person getting sick ** number of people on plane
Shouldn't you multiply rather than add IID events?
Ratios are multiplicative.
It's because of the redundancies. I have heard "Master Caution/Alarm" blaring on (IIRC two of) my flights, mid flight, and nobody said anything.

We just continued undisturbed and landed as we should. I'm sure the plane went to technical hangar, tho.

Also that goes off pretty frequently. When the PIC switches off autopilot when coming in for landing, for example.
Yeah, many activities trigger it (the pilot will be expecting it coming out of autopilot, if he hears it at cruise because autopilot disengaged they'll investigate).
It was squarely mid-flight/cruising, international IIRC. We were nowhere near landing/approach.
I suspect you meant "the PF" not the PIC (where PF equals 'pilot flying').
Autopilot disconnect sound is distinct from master caution/warning.
Also, serious processes dealing with anomalies, anonymous incident reporting, strict maintenance rules, long term active government research...
If each passenger underwent a 35 point health inspection prior to takeoff like the planes do, the numbers might look different.
I'll vote for the politician that proposes this lol
Find a politician that would pass said test first.
Isn't that what the TSA is doing?
Once I was too tired on a long journey and made a rude comment when TSA was checking my green card for the third time in a 50 meter line. At that time my green card was expired for reasons outside my control so I also needed to carry some letters from DHS explaining why my green card was expired and that it was not my fault and I should be let back in.

Anyway, after the rude comment she just smirked and wrote XXX or something like that on my boarding card. I was like whatever, but when I got to the line at the gate and they checked my boarding card I got taken into a run for a "special" inspection. So unless you love body cavity searches don't be stupid and say things you are going to regret to TSA agents.

I mean, yeah, what else would you have expected?

You're lucky that it was only hand written. Some people get that printed on their boarding pass which means it will pretty much always happen to them.

I had a special sticker placed in my passport by Australia because I left my passport laying on the counter while having work gear inspected and paperwork. Didn't realize it until attempting to check in, and then left all of the gear with my coworker while I ran off to get the passport. When I returned with it, the official that was "helping" us with our gear placed the sticker in my passport. Everytime I returned to AU, I got the special screening minus cavity searches. It was my own damn fault, and I was never rude to anyone about it, but yeah, I probably did look a bit shady running off after leaving a stack of large pelican cases. Oh well, that passport has now expired and the new one is sticker free.

> TSA was checking my green card

I would expect immigration and customs to check the green card. Immigration has never checked my boarding pass for what would be a potential onward flight. TSA would be at different area in the airport.

Don't fuck with people who can fuck you harder.
What gave you that impression? They're looking for hidden water bottles, not hidden diseases.
I assumed that comment was so obvisouly dripping with sarcasm that the /s wasn't needed, but that's what happens when on assumes
Well the people don't get regular maintenance and inspections before every flight where the planes do for starters. It'd be concerning if a random group of a few hundred people were more reliably well than a given mechanical system their lives depend on.
Most people don’t even get a yearly inspection lol
I was on Sydney to LA and we diverted to Hawaii because a passenger died and was taken off. I found it curious that they wouldn’t just wait until LA as the person died in the air so it’s not like they needed immediate attention.

We all stayed on board and we’re maybe down for 20 minutes.

I would guess they diverted out of:

- respect for the dead: a person has just passed on. Many people want at least the illusion of deceased people being at rest, and would think it's undignified to bring the body all the way to the destination when it could be allowed to be taken off and "rest".

and

- the comfort of surrounding passengers: there's not a lot of free space on a passenger plane. I don't know if there are any procedures for moving a body to someplace more convenient to the other passengers, but doing so would kind of fly in the face of the previous point.

As others have pointed out, redundancy. Consider rather the likelihood of say 3 of 3 passengers falling ill - it's basically zero. (unless, as someone else pointed out, they all had the fish).
Why would you say none of those reasons seem to be the case? We literally don't know, and there's not really any other reason (that's reasonably possible) other than those three.
I may have overstated my case there. Absence of evidence != evidence of absence, after all. Curious to see what the HN community makes of this though. Maybe it's a nothingburger.
LiveATC has archives of air traffic control comms in many places, it's possible that these flights are included. If we know the exact time, it might be possible for someone dedicated enough to check and see what the reported reason was.
If it's not a mechanical emergency (or even a caution) ATC often won't be informed; only if they need emergency equipment to meet, need priority, or have a security issue.

In other words if it's an airline policy diversion ATC may just see a plane requesting deviation from flight path.