Aviation Antipatterns Thread
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One commenter notes that (in the context of aviation) "the rules are written in blood." Sad to say, but this is true in all areas of transportation, and many other industries. All those rail system rules about blocks and ATC (er, Automatic Train Control) and air brakes on all wagons instead of manual screw-down brakes on a couple of vans in different parts of the train, and steam pressure safety valves, and ... and ... and ...,? The rules about seatbelts and working brakes and working lights and ... and ... and ... in your car? And your bus? And that guy's eighteen-wheeler?
Every single one of those rules was written because someone was killed, frequently lots of someones all at once.
Red For Danger by L.T.C. Rolt should be required reading for anyone working on safety-critical systems.
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@Steve_The_Cynic As we say in Dutch: "Als het kalf verdronken is, dempt men de put". Or, approximately, "After the calf has drowned, the pit is filled in".
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@PleegWat said in Aviation Antipatterns Thread:
@Steve_The_Cynic As we say in Dutch: "Als het kalf verdronken is, dempt men de put". Or, approximately, "After the calf has drowned, the pit is filled in".
This is the special case of the general definition,
A policy is a general statement meant to prevent a specific situation which has already occurred.
. It's special because it's the non-useless* case.* Note that this can lead to unchecked risk-inversions even in the critical case.
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@Gribnit yep. I like to say that every rule has a story.
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See also the tale of Chesterton's Fence. You don't get rid of a rule just because you don't like it or you don't see the point. Find out why the rule was created in the first place. You might just discover that it was for a very important reason. You might discover it was an arbitrary whim. Even in the former case though you might also discover that the reason no longer applies, in which case yes: it can be got rid of.
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@boomzilla And sometimes the rule would not have prevented the instigating event.
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@jinpa Some rules exist not to prevent events from happening but to lessen the severity of them when they occur.
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I always found it nuts that in the US you'll get landing clearance for a runway that's still in use by another plane. This is just the logical result of that.
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@dkf said in Aviation Antipatterns Thread:
@jinpa Some rules exist not to prevent events from happening but to lessen the severity of them when they occur.
And sometimes the rules would not have prevented the instigating event from happening nor lessened its severity.
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@Deadfast said in Aviation Antipatterns Thread:
I always found it nuts that in the US you'll get landing clearance for a runway that's still in use by another plane. This is just the logical result of that.
(I finally took the time to watch the video.)
Except that in this one, the landing clearance happened before the other plane was cleared to use the runway.
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@boomzilla That involved a lot less stalling than I though it would.
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@boomzilla Looks like one of the short landing competition planes.
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A) funny
B) people have to stop complaining about Ryanair. Their CEO has said you get what you pay for often enough.
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@DogsB Wizz, is that what they do on their customers?
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@DogsB said in Aviation Antipatterns Thread:
people have to stop complaining about Ryanair
Agreed. Now, people that fly Ryanair, on the other hand...
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@Carnage Indeed, combined with a careful approach in a strong headwind, which is almost cheating.
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@boomzilla said in Aviation Antipatterns Thread:
I just flew from San Francisco to DC
and boy are my arms tired.
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Confronted with several alerts in the cockpit of the Bombardier jet, pilots followed a checklist and turned off a switch that “trims” or adjusts the stabilizer on the plane’s tail, the report said.
The plane’s nose then swept upward, subjecting the people inside to forces about four times the force of gravity, then pointed lower before again turning upward before pilots could regain control, the report said.
Oof.
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@boomzilla
https://www.youtube.com/watch?v=Oc_71HNJZhUforces about four times the force of gravity, then pointed lower before again turning upward
+3.8g to -2.3g to +4.2g
There were a bunch of things that went wrong, starting with failing to remove a pitot tube cover during the pre-flight inspection. This caused a mismatch in reported airspeed between the pilot's and co-pilot's instruments during take-off. They aborted the take-off, discovered the cover, removed it, and continued. However, it appears they probably did not fully reset (the aircraft and themselves) and start over, but resumed from where they left off. They got another problem message (not directly related to the later incident) before taking off again, which should have caused them to cancel or postpone the flight, but which they wrongly believed was only advisory (QRH item #2 — no-go), and they continued anyway. During the second take-off, they noticed that the speeds that had been programmed into the flight control system for the first take-off were no longer programmed, but the copilot remembered them and continued from memory. They got 3+ more caution/warning messages preceding the in-flight upset event. They responded to the relevant message using the wrong checklist (Primary Stabilizer Trim Failure vs. Autopilot Stabilizer Trim Failure) and so failed to "have all passengers seated and belted prior to any action as there can be abrupt changes in control force once the autopilot is disengaged." All of these problems may have been caused by not shutting down completely and resetting the autopilot following the airspeed mismatch caused by the pitot tube cover.
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@boomzilla That made me think of an announcement one evening at London's Paddington station, the terminus for trains to and from the western part of England and the southern parts of Wales. The train I wanted was late, and the explanation given over the tannoy ("PA") was that the train had been hijacked by sheep.
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Engine failure on takeoff in an 80 year-old P-51D (WW2 fighter), with a perfectly executed recovery — no damage, or at worst, maybe a little too much stress to the right landing gear:
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A guy who's lucky to be alive:
https://www.youtube.com/watch?v=hEBLxD5oQYc
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You remember that guy who crashed his plane in California, the one who just happened to be wearing a parachute (with a fire extinguisher strapped to his leg under his pants), and jumped out of his plane as it was crashing, and posted video of it to YT? It was analyzed by every aviation channel on the planet, and I'm pretty sure at least one of those was posted here someplace. New development in the story:
https://www.youtube.com/watch?v=WNERrZ4yZo8
TL;DW: He's pleaded guilty to felony obstruction of justice, admitting he lied to investigators and destroyed the wreckage so the NTSB couldn't examine it. Obstruction of justice carries a maximum sentence of 20 years in federal prison, but he'll almost certainly get much less than that because he's pleading guilty. I'd guess maybe 2–3 years, but I'm just an internet rando; what do I know?
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@HardwareGeek There was one other case that also smelled like a publicity stunt/insurance fraud, the guy who sank a Bonanza just short of Half Moon Bay, with his girlfriend apparently wearing neoprene socks. Perhaps we'll see something about that one day too.
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@Bulb said in Aviation Antipatterns Thread:
with his girlfriend apparently wearing neoprene socks.
Hey! No kink-shaming!
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@DogsB said in Aviation Antipatterns Thread:
A) funny
B) people have to stop complaining about Ryanair. Their CEO has said you get what you pay for often enough.It has probably been posted, probably by me, but it bears repeating, those flights for 50p:
https://www.youtube.com/watch?v=ZAg0lUYHHFc
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@HardwareGeek said in Aviation Antipatterns Thread:
You remember that guy who crashed his plane in California, the one who just happened to be wearing a parachute (with a fire extinguisher strapped to his leg under his pants)
You forgot about his best friend's ashes in a ziplock sandwich bag, and a Ridge wallet.
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@LaoC said in Aviation Antipatterns Thread:
It has probably been posted, probably by me, but it bears repeating
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@HardwareGeek said in Aviation Antipatterns Thread:
A guy who's lucky to be alive:
I don't care about listening someone talks without pictures so I wanted to see if there was footage of the crash (there usually isn't, but this time there is) and skimmed the video without even properly reading the title first.
If you're like me, just watch the crash from this point of the video, and tell me what you think happened. It looks like the plane broke physics and just decided to fall like a stone.
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@remi If you want the raw footage without talking, go to
… the plane did fall like a stone—after it was rapidly slowed down by the power line. And fortunately for the pilot it fell tail-first, so the tail absorbed most of the energy of the impact.
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@dkf said in Aviation Antipatterns Thread:
@jinpa Some rules exist not to prevent events from happening but to lessen the severity of them when they occur.
It's good to remember this. I like to think of safety as having two parts: making it hard for things to go wrong, and reducing the damage when something goes wrong anyway. Both are important.
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@Bulb said in Aviation Antipatterns Thread:
@remi If you want the raw footage without talking, go to
… the plane did fall like a stone—after it was rapidly slowed down by the power line. And fortunately for the pilot it fell tail-first, so the tail absorbed most of the energy of the impact.
If I'm judging this correctly, it appears to have actually caught on the wires as it flips over which actually helps slow its descent a little bit, as well as causing the ultimate attitude to be tail-down. All told, it was probably the luckiest shitty situation you could find yourself in.
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@Bulb said in Aviation Antipatterns Thread:
the plane did fall like a stone—after it was rapidly slowed down by the power line.
What amused me is that the power line is barely visible on the video, especially if (like me) you had not read the video's title and didn't know what caused the plane to fall. It made the fall look very cartoon-ish.
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@remi Honestly, it still does even when you know what's happening.
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@HardwareGeek Even apart from the interference he mentioned, the rate of speech is very fast for such important information. I guess the pilots just know that they have to pay very sharp attention to what the controller says so they don't miss it.
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Deserves at least two s.
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@Bulb The circumstances are not at all clear from the video itself, unless you read the comments. It was a very long, 12+ hour flight, and they needed a certain minimum crew size so that they could get mandatory rest breaks (2x the normal crew, so a relief crew member for each position). What probably happened is that some scheduler messed up, and they didn't have the necessary spare crew aboard.
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@HardwareGeek Or a crewmember had the shits from eating airport food and missed the flight and someone didn't triple-check the manifest.
That's my best theory anyways.
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@HardwareGeek said in Aviation Antipatterns Thread:
What probably happened is that some scheduler messed up, and they didn't have the necessary spare crew aboard.
That's quite possible. But it took them quite long to realize it. I'd expect they notice there is not enough of them in the briefing room already.
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@Bulb It's my understanding that, yes, the pilots brief their flight before going to the plane (and multiple times during the flight), but the cabin crew isn't briefed until they're aboard. Although that's certainly no excuse; they still should have noticed there weren't enough of them.
Edit: Another possibility just occurred to me. For flights shorter than X amount of time, they need a cabin crew of N people, based on the number of seats on the plane. For flights of X ≤ duration < Y, they need a crew of N*1.5, and for flights ≥ Y, they need a crew of N*2. Maybe someone realized that the flight had been planned to be < Y, but something changed — maybe weather, maybe there was already a delay in leaving that was going to put them over the on-duty hours limit — and they now needed additional crew that hadn't been planned.
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@HardwareGeek Well, it might be on board, but doesn't it need to be before boarding passengers? They need to divide the work for boarding too after all. So they may be meeting on board or at the gate rather than briefing room, but it should still be well before they start to taxi out.
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@Bulb said in Aviation Antipatterns Thread:
it should still be well before they start to taxi out.
Yes, even my hypothetical should have been noticed before leaving the gate.
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