Note the different scales. They were really floundering and never got up to anything like their intended altitude. They also continued the crazy-low altitude for over 5 minutes before final impact.
Looks like they climbed and maintained ~5000 feet after takeoff, presumably to figure out what was going on before returning to the airport. Wouldn't call that crazy low.
The interesting question is going to be: why didn’t the pilot abort the takeoff? Did the problem become obvious only in flight, or were the warning signs on the runway before it was too late?
Ah, a control issue would indeed be pretty much impossible to diagnose before V1. That makes sense.
I have heard of issues that were discoverable before V1. Famously there was the Russian hockey team that was killed because the pilot was riding the brake and didn’t abort in time.
The granular data from FlightRadar24 paints an especially grim picture: a descent of 30,000 feet per minute (fpm) at about 400 feet above the ground. That seems like it might be erroneous given how high it is, but -16,896 fpm at 2500 feet seems plausible.
That's not a particularly unrealistic speed for a plane that's flying straight into the water, especially if the engines were still producing thrust. The 400-ft altitude would have been recorded less than 1 second before impact.
Agreed, but it also had a groundspeed of 360 kts. Combined speed is then 463 kts. It's not impossible, but getting to that speed from 295 kts at a relatively steady 5000 feet...I don't know what to make of it.
Yeah, that's weird. Gravity alone is unlikely to be able to accelerate a plane like that in such a short time. If the data is anywhere near accurate, the engines must have been blaring until the last moment... Were the pilots desperately trying to go up, not knowing which way was up? (It happened before with AF447.)
The radio said the weather was clear and calm at the site of the crash. Rescue operations are already picking body parts and aircraft debris from the water.
The most likely scenario in my head is some sort of control surface malfunction. Given how quickly the debris was located I'm pretty confident that they'll get the black box and solve this mystery.
> Gravity alone is unlikely to be able to accelerate a plane like that in such a short time
Yeah, a quick (and very elementary) back-of-the-envelope energy calculation shows that gravity alone couldn't achieve that speed. [SEE EDIT]
> Were the pilots desperately trying to go up, not knowing which way was up?
We'll have to wait and see, but it was morning, and I think I heard that there was weather in the vicinity of the crash but not at its actual location.
EDIT: That calculation was wrong. The aircraft had more energy at 5475 ft than it did at 3200, 7.73 seconds before the last data point.
Pretty sure he was intellectually aware - all pilots have it drilled into them - just mentally frozen in a panic and hadn't made the kinesthetic leap of understanding.
While many aircraft have been lost due to what you're suggesting, we know from the investigation report that this is not what happened in the case of AF447.
As difficult as it is to believe for anyone who received their training in almost any other program, the crew of AF447 had never practiced a single stall recovery in an aircraft before that flight.
In addition, the transcript shows that they were not mentally frozen in a panic and unwilling to act, but that they were poorly-trained to correctly identify the problem, something compounded by terrible CRM as they argued about it such that even those who had correctly diagnosed the problem were overruled after the time to test their hypothesis had been wasted in argument.
Instrumentation issues also compounded the above, among other things.
Lastly, the pilot who attempted to apply correct control inputs to recover had his inputs negated by a dual-control input system so mind-boggling that it could only have been conceived by a company with such a culture of arrogance-driven ignorance as Airbus.
https://www.ainonline.com/aviation-news/2012-07-08/final-af4... indicates that the startle response played a major part in the accident. And in fact I don't think it could possibly have been otherwise, several minutes of failure to think rationally about the problem of dropping out of the sky even while trying to pitch up admits few other solutions.
There's an almost brilliant quality to the concept of a stall warning system that self-cancels when the angle of attack becomes too high, or the airspeed too low.
If all potential energy from an altitude of 5000 ft = 1500 m got converted into velocity, we'd talk about 170 m/s or about 330 knots (and a free fall from that altitude would take about 17 seconds, t = sqrt(2h/g)).
Weather won't affect that pattern much. Winds will affect ground speed but the air speed (aircraft relative to sorrounding air) will be very similar. Other factors such as rain and clouds also shouldn't affect climb rates much. So overall the upper, smooth, graph would be representative for departures at nearly every weather.
In this case, the very high speed at low altitudes could indicate that they had the expected amount of thrust but couldn't climb, maybe due to issues with controls.
I've only got the one data point, but I had a bit of a nightmare flying experience with Wings Air, a part of the Lion Air group. I was flying from Denpasar to Labuan Bajo and Wings was one of two airlines that I could've chosen. It started out as delays with no explanation of why. They finally called it for the night, explained that it was a mechanical issue and they needed to fly in a different plane which wouldn't arrive until the next morning. The put us up in a dingy hotel in Denpasar and told us it would be a 9am flight the next morning. So I went to sleep to wake up in time. They then delivered our luggage to the hotel without telling most of us. At about 2am, I got a knock on my door from another passenger that I'd become friendly with during the delay. She'd had difficulty sleeping and had gone down to the lounge to read only to hear that the flight was now scheduled for 3am and that we'd need to leave immediately. Had she not alerted me, I'd have been one of the many people in the hotel that were left there. As it was, only my luggage was left there and it took me calling the hotel 3 days later to have them search before the airline"found" it almost a week later.
The whole thing was a shitshow and I can't recommend strongly enough choosing any other airline if you've got the choice.
P/S, Pitot main issue (alt is more stable than speed > static is OK). Maybe.
OK, the DFDR will be telling, probably as much as the CVR. This plane was in distress from 300' AMSL, and has every indication of a longitudinal stability issue, e.g., stick force gradient deal. Immediately, forget about directional issues, this isnt an engine, TR, asymmetric slat, flap or other issue, look closely at the loadsheet, and the load control. The ADSB data is indicating an aircraft with negligible static stability, and that points towards a loading error, with a CG near neutral point. Should you ever have that happen, it is not fun; helicopter pilots get laughed at as that is what they are used to every day, which is why they are generally odd people. If you have an AP, the plane will do better on AP often than a driver at the wheel. If you have flaps, get the TE flaps out, or all flaps the Cp is shifted aft. Don't go to altitude, don't burn CWT gas, move pax fwd if needs be, but mainly, be very careful with your flight control inputs, planes that are unstable are fun to fly for very short times. Do not go fast, unless you have an ejector seat. As an AAI I normally would suggest awaiting data release before sprouting comment pointedly, but this is already shown in the data. Forget suicide etc, this plane had pitch instability from the get go.
I have investigated a number of aircraft loading events, and have also been on the receiving end of 2 of my very own. Have sympathy for the poor flight crew, unless they were form a flight test background it is unreasonable to critique their performance. Could an airline train crews to deal with load errors? I can say that is possible, in fact it is not even hard, and last count, I had investigated over a dozen events... need to dust off the confuser for an exact number, but I can recall 12 offhand. Will airlines train crew to handle such cases? highly unlikely, the industry is not after competency above that mandated by the regulator.
Yes, here it means the distribution of passengers and baggage in the aircraft. If the center of gravity after loading is too far forward or aft, you can end up with an aircraft that can take off just fine but then become unflyable.
There's actually a fascinating video if a cargo plane crashing just after a take off due to large cargo not secured properly and moving and changing the center of gravity: https://www.youtube.com/watch?v=M01RmcKsm2k
To be a little more descriptive, it's a dashcam video from a vehicle driving near Bagram Airfield, and you see the plane crash in a way that makes it clear that the entire crew are killed.
Some more detail from the Wikipedia entry[0]:
"On 2 June 2013, investigators from the Ministry of Transport and Civil Aviation of Afghanistan confirmed the load shift hypothesis as the starting point: three armoured vehicles and two mine-sweeping vehicles, totalling 80 tons of weight, had not been properly secured. At least one armoured vehicle had come loose and rolled backwards against the airplane's rear bulkhead, damaging the bulkhead. This also crippled key hydraulic systems and damaged the horizontal stabilizer components - most notably the jackscrew, which rendered the airplane uncontrollable.[10] Control of the aircraft was therefore lost, with the abnormal pitch-up rotation, stall, and crash to the ground ensuing.[1] The damage made it impossible for the crew to regain control of the aircraft."
You measure up front and plan. Doing a weight and balance calculation is a standard (and critically important) part of flight planning. For light aircraft in particular it is _really_ important because there is very little margin for error. With light private aircraft you're weighing yourself, your passengers, your bags, and the fuel load and you're only taking off if you're within a safe envelope.
I'm not familiar with airline operations because I've never flown anything bigger than a Cessna 172, but from what I gather the airlines assume an average per-passenger weight, and account for number of bags and the ground crew will distribute in the holds accordingly. Ever seen flight crew moving passengers on little regional jets? It's to make the weight distribution safer. The smaller the plane, the bigger the effect of a few passengers.
FlightRadar24 has a more detailed chart of the telemetry with a link to the granular data: "We have processed the granular ADS-B data received from #JT610. Last signal was received at 23:31:56.030 UTC from -5.81346, 107.12698 at 425 ft AMSL. Final ADS-B data received from the aircraft indicates a high rate of descent."
(FlightRadar24: "A word of caution: ADS-B data can be incredibly useful, but to speculate on a cause at this point would be conjecture. The Flight data recorder and Cockpit voice recorder will play an important role in the investigation, as always. #JT610")
Given the erratic altitude and speed throughout the entirety of flight, and the fact the pilots radioed to turn back pretty early on, could it have been something similar to the Peruvian flight where the static ports were covered, leading to lack of basic altitude and speed data and causing a crash?
(The other possibility I can think of is icing, but since Indonesia is a tropical country, and the flight never got above 5000 feet or so, I'm guessing it wasn't.)
They don't have that info the day of a plane crash -- it requires the airline to release the list of victims, and then the families to release any photos on request, which is what you sometimes see several days later when a news org takes the time to collect the photos and stories. But that doesn't happen with all mass casualty incidents. Not just because it's resource-intensive, but because the news cycle moves so fast. We've just learned the names/ages of the 11 killed in the Pittsburgh shooting. How many people remember any of the names of the people who died 3 weeks ago in what was the U.S. worst transportation accident in a decade?
Same-day and day-after coverage is typically when most people are most focused on any given tragedy, and images are often what stays in people's memories. A photo of disaster workers picking up pieces of metal doesn't convey much of the human tragedy at all.
When MH17 was shot down, an Australian paper published a large picture on the front page which showed actual dead bodies tangled in the wreckage. No blurring or obfuscation. You could clearly see a young woman's arm held up as if to ward off an impact in the foreground. Highly distasteful and inappropriate IMO.
MH17 was shot down. Someone actually had to lock an anti-aircraft system onto a commercial airliner and give the order to fire. I don't disagree with putting something graphic on the front page in that case. The public deserves to know what happened and whitewashing it just serves to protect those who committed that crime. With a purely accidental tragedy I think it's a little different but not much. I don't see the point in trying to bubble wrap the world. Shit happens. Sometimes it will be messy and ugly.
The public needs to see graphic imagery of humans causing other humans to suffer. We need to know the harm we inflict and we need to turn the raw emotion of pain and disgust into action.
I don't think it's appropriate to show blood and gore when there's nothing at stake, but these are not such instances.
Bubble wrapping has a lot of value. There's nothing I can to stop accidental airplane crashes. It's not healthy for for many people to be surrounded by negativity and violence. It serves no purpose other than making me feel bad
Not reporting also limits backlash when preventable things happen. I don't see running a graphic picture to be substantially different than reporting the details on that guy the Sauidis sawed up. One man's bubble wrap is another man's sweeping things under the rug.
In the case of the plane that was shot down, you can lobby your government to actually give a shit and do something about it. But hey, it happened to them and not us, so why should we care, right? Graphic imagery showing that they are humans too might help people understand that it's not a 'us vs. them' thing.
I don't think it is appropriate to put it on the front page of a newspaper though, because there is no control over who can see it.
If your husband/wife/son/daughter/parents were killed in that crash, would you want your young child walking past a news stand in the street to see their mangled bodies in a field displayed for all and sundry to gawk over? Would you want the rest of the world to see and remember your kin like that?
Somewhere in the mix, there has to be an element of basic human dignity and respect towards deceased people, and their loved ones who have to come to terms with that fact.
That's a good point. In general, aviation safety is amazing, and an emotional response to an accident (as after MH 370) doesn't help. In Indonesia, on the other hand, corruption and lax attitudes to safety seem wide spread, and political pressure to rectify the situation might improve things.
the bodies depicted in such images are not capable of caring about how they are treated anymore, though. i agree that often relatives get upset about images of their loved ones bodies being used in newspapers or tv, but sometimes the journalists have to weigh the public interest value of showing the image against potential distress. for example, the famous vietnam 'napalm girl' photograph. i'm not suggesting a return to 'if it bleeds, it leads' shock-value journalism, just pointing out that sometimes distasteful images have real value and should not be censored.
Agreed, but I think for the most part aviation safety is well under control, and there's not need to shock people into action. However, Indonesia might well be an exception.
Note also, though, that this only works if shocking pictures are used very sparingly, and only really to make an important point.
I regularly travel to Jakarta - and I try to avoid the low-cost Indonesian airlines like Lion Air because of their very poor safety record. For example, AirAsia didn't think it needed to give its pilots upset recovery training until flight 8501 crashed:
In the wake of the Air France crash, the [Australian] Civil Aviation Safety Authority required that pilots receive upset recovery training, although it was long a standard practice at Australian airlines. The AirAsia Indonesia crash report said Indonesia's Director General of Civil Aviation has no such requirement and neither of the pilots were trained in upset recovery on an A320.
All things considered -- and remember, these airlines are flying in poor countries where a lot of the infra for air traffic control, airports etc is not up to scratch -- AirAsia has a reasonable safety record: the only major crash suffered by the entire group (not just Indonesia AirAsia) was Flight 8501:
Last I checked, AA uses Lufthansa Technik for its maintenance, so there's good third-party oversight. You can't say the same for Lion Air, which seems to write off its planes on an alarmingly regular basis:
I’ve flown multiple times within Vietnam and in Thailand with AirAsia, always a great experience. I think it’s the Australian-run branch though.
Edit: oh, ok, did some research. There’s no Australian Air Asia, no idea where I picked that up.
Leaving it here in case anyone had the same misunderstanding.
Vietnam Airlines has the most aggressive flight profiles I have ever ridden on. On my two domestic flights they took off and landed like it was roller coaster.
It's interesting that my gut reaction here is that Lion Air probably wasn't at fault, and that it had something to do with the plane. Otherwise if Lion Air messed up AGAIN a few years later, then that's just unthinkable.
Airplane crashes almost never have single fault. It's always something like "modest maintenance issue combined with incorrect pilot action combined with unusual weather pattern". Ultimately the pilot takes the blame in the situation, but the actual problem is systemic.
"human errors" is rather vague. Does that include pilots violating standards? Bad guidance from ATC? Making a poor call during an emergency? Letting a plane go into service with maintenance violations? Doing maintenance incorrectly?
There will be some significant scrutiny on the plane( it’s both a new plane and a new model of plane) even though lion air has a pretty bad reputation. The carrier is blacklisted in the EU for example.
International air investigation is usually get things right. Every now and then politics will interfere, but the process doesn’t change that much based on carrier and plane..
From the article: "Established in 1999, it has had issues of safety and poor management in the past and was banned from flying into European airspace until 2016."
This is an eyewitness statement watching the plane arount at 6.25 est time:
1. The plane was tilting left side that the letter LION was clearly visible.
2. The nose cockpict was pointing UPWARDS.
3. There was BLACK SMOKE coming out from near the wheels.
4. There was a hole on the plane (?)
5. The engine noise was some one not loud and strangely "broken"
What does this tell us if it were true?
Simple: Turbine failure cause by shattered blades!
1. Any blades fracture would disintegrated the whole engine into pieces at about 20K RPM.
2.Some of the catastrohic debris might hit the body plane itself and cause punctured.
3. The black smoke would confirm such hypothesis, a hydraulic failure would never cause any smoke.
4. Pilot tried to balance the doom plane by pointing the plane upwards but the thrust was not available.
5. Electrical short circuited cause by the catastrophic turbin blade failure would make the whole electrical,electronic and hydraulic dead as well.
6. It is very likely that only one turbine is remaining but the whole system was lost to control the descent.
7. At such low altitude which less than 5000 feet, the estimated 70 ton plane would not have the time to do any meaningful repair.
8. Pilot and crew would prioritize saving the plane and passenger instead of radioing a may day.
The actual statement is 4 sentences, and hardly needs a tl;dr:
> The Boeing Company is deeply saddened by the loss of Lion Air Flight JT 610. We extend our heartfelt sympathies to the families and loved ones of those on board.
> Boeing is providing technical assistance at the request and under the direction of government authorities investigating the accident. In accordance with international protocol, all inquiries about this accident investigation must be directed to the investigating authority in charge, the National Transportation Safety Committee of Indonesia.
Well, ICAO rules establish who runs the investigation, namely the civil aviation authority of the state of occurrence. Other states (state of registry, operator, manufacture) might participate, or the state of occurrence might choose to delegate to them. But the official responsibility for the investigation lies with Indonesia for now.
I didn't say the statement wasn't factually accurate. It's just a little cold, throwing "thoughts and prayers" [1] in with a statement effectively saying don't call us, call someone else.
Yeah, and I didn't mean to imply that your summary was inaccurate or tone-deaf; just trying to explain why Boeing basically says "don't call us, call them".
Your (and Jeselnik's) criticism of the "thoughts and prayers" cliché is apt, though note one big difference: some of those senators and members of the house that offer "thoughts and prayers" after yet another fatal shooting take NRA money and/or actively block anti-gun legislation, while Boeing and Airbus are genuinely doing all they can to avoid plane crashes, I'd think.
So the aircraft manufacturers are much less cynical and hypocritical in offering up that cliché than politicians (faint praise, indeed).
NRA has donated a maximum of $9,990 to any politician[1], a rather small amount considering the huge cost of running a campaign. In 2016, the total political contribution of the NRA was roughly $1.1 million[2]. In the meantime, gun control proponent Michael Bloomberg alone has contributed $20 million to Democrat senate candidates[3] in 2018 and is planning to contribute $80 million to house candidates[4] for the midterms. Even if you hate the NRA and what they stand for, claiming that they are buying up politicians with money seems far from the truth.
Sounds like Boeing all right (source: I work at an MRO and deal with them regularly).
They don't do nice and fuzzy but they will get to the bottom of the technical aspect of the investigation.
Out of cynicism, however, I'll keep my eyes peeled for "free upgrade" Service Bulletins and configuration options being offered to new customers in the near future (like they did with the Short Field Performance on 737NG).
Would you prefer the alternative, "Sorry about the crash. Allow us to run our mouths about things we are not competent to comment on given the presently available information"?
More like “We are available to answer technical questions about this model of aircraft, however specific questions about the crash itself should be directed to the appropriate authority”.
Their sales organisation is always available to answer technical questions about the model of aircraft, but nothing of that is relevant to any of the journalists who might enquire in light of the crash, unless they are trying to play armchair accident investigators.
I wonder how pilots feel reading stuff like this. It must be tough.. As a mere passenger whose nearest flight will be in ~3 months, I am scared to death.
As another poster mentioned above - most pilots tend to study accident reports to file them away in their memory for later possible reference. Any instance of crew communication breakdown or wrong decision making can happen again, and knowledge that it did happen before will lessen the chances in the future.
I see a lot of comments on Twitter today along the lines of "What is happening in aviation these days??", and the answer is really "Nothing really". Commercial flying is safer than it ever has, and it is telling that an accident such as this is garnering so much attention because they don't really happen all that often, so air crashes seem worse because they are not always in the news as they were decades ago.
You have to consider the fact that these days, at any particular second of any day, there are more than a million people who are airborne at the same time. That is a city load of people who are not in contact with the ground at any given time. Given that - the low number of fatalities is remarkable indeed.
That may be true on average or in wealthy countries, but Lion Air has a pretty bad safety record. The portion of Lion pilots who end up in crashed planes may be only 1% or something, but still quite high compared to other airlines/nations.
I read accident reporting and investigations ravenously. Even a scrap or an anecdote may help me one day.
As a pilot who has been forced to land a plane off-airport, you would be amazed at how the brain, trying to save itself, can pull any tiny potentially helpful bit of information from memory and present it for your consideration and use. I collect aviation accident factoids like a magpie collects shiny folderol. :)
For a pilot, it might feel similar to how you, as a driver, feel reading about car crashes. Maybe you’re like me, car crashes don’t normally bother me, while airplane crashes usually do. I don’t know why.
I used to skydive in the US, and a subscription to the US skydiving magazine was required for an active license. In that magazine was a breakdown of every single fatal skydiving accident in the US, and an analysis of what went wrong. Those were sometimes pretty freaky to imagine, in the same way a plane crash is freaky to imagine, but at the same time, reading the reports made me feel overall safer. Seeing and understanding every single report and the specific situations that lead to them, and being aware that the community and equipment manufacturers were paying attention and taking action to make the sport safer whenever possible, knowing those things was informative and comforting.
I’ll echo the other commenter’s responses. I view accidents like this with deep curiosity. Any little bit of information that might help me not make similar mistakes or missteps in the future is worth so much.
In addition to learning about potential traps and how to react, each accident comes with a grave reminder not to become complacent. There is lots of discussion about a mechanical write up in the leaked aircraft logbook page on this accident. Some are questioning if the crew read that logpage and was aware of the earlier mechanical discrepancy. Any professional pilot will tell you that sometimes all you do is open the book and just make sure the mechanic’s signature is there signifying the aircraft is airworthy. This incident may reveal just how valuable it can be to go back a few pages and see what has been written up recently. Things that we normally do when we’re at the top of our game and have lots of extra time but will let slide when we get complacent.
Don't worry much about it, I've a 5 1/2hr flight in less than a week on a 737. The only thing that keeps me sane is that as a technical person, I know that airplanes wants to fly and that the prob/stats of safety are on my side. But then as a software guy, that understands complex systems, ha!
To be honest, there are very few plane crashes every year. People just find them more shocking because lots of people are involved and the media always refers to other incidents when reporting on one.
Well this is a pretty heartless way to refer to a disaster involving 188 people. (Title currently: "Lion Air's brand new Boeing 737 MAX8 crashes into sea")
I don't know that there's a good way to be both concise and informative about disasters like this without being somewhat heartless, especially when the event is so recent. Having a less-editorialized title would definitely help, though - there's something particularly callous about implicit speculation so soon.
> Given this is a near brand new aircraft, structural failure caused by a explosive device is certainly possible :(
Don't be daft, read the information presented rather than just making things up.
There's nothing about a very wobbly assent that suggests a sudden failure, from take off they're struggling and changing air speed dramatically. There's numerous graphs posted in this thread comparing the take offs with the previous days which shows the stark difference. Clearly, radio contact was lost "suddenly" because it was doing 550 KM/h straight into the water. The last transponder ping would have been a couple of seconds before impact with the ground.
One of my other comments on this thread includes a link to data that suggests that the aircraft's ADS-B transmitter was working until the end. The vertical speed transmitted by the ADS-B makes in-flight breakup believable, but how likely is it that the ADS-B would continue transmitting in that case? Not very, I'd guess.
Fun fact: Flight Levels are really only used at 18000 feet and above. That's where local barometric pressure is ignored and aircraft use the standard value. I believe it's a global standard to use local barometric pressure below 18000.
> Fun fact: Flight Levels are really only used at 18000 feet and above. That's where local barometric pressure is ignored and aircraft use the standard value. I believe it's a global standard to use local barometric pressure below 18000.
I don't know if there are any fun facts in this particular conversation. May the crash victims rest in peace, and may their families, friends, and colleagues somehow find peace after this tragedy.
In any case, what you're referring to is the Transition Altitude, where pilots switch from local altimeter settings to a standard setting of 29.92. In the US and Canada, this is 18,000 feet, but it varies in other countries. In Australia, for example, the transition altitude is 10,000 feet. The transition altitude in any country is supposed to be above the highest elevation of any point in the country.
That's the theory anyway: the highest elevation in Australia is 7,310 feet, but the highest elevation in North America is Denali (Mount McKinley) at 20,310 feet - which puts it up in the flight levels.
Leaving that aside, the idea is that when you're flying at lower altitudes, you not only want to know your altitude relative to other aircraft to avoid collisions, you also want to know if you will clear any obstacles on the ground. So you set your altimeter to reflect current local air pressure to get an accurate altitude above mean sea level, which also lets you determine your altitude above ground level.
But once you're well clear of any terrain, this isn't helpful. It simplifies things to have all aircraft use a common altimeter setting, even if it doesn't truly reflect local conditions. In the Flight Levels, you are no longer worried about the ground, you're only worried about other aircraft. (And Denali!)
How does this work in practice, since I can imagine a situation where using the local air pressure value, altitude is measured at 18k feet - then, switching to the standard setting of 29.92, it turns out that this converts to an altitude of 17.5k feet - so, now the system switches back to using the local air pressure for calculations - and so on... Is there some form of hysteresis or rounding used, or would this never happen in practice?
Interesting observation! You could easily imagine an automated system going into some kind of oscillation if it didn't handle this properly.
Here is why it doesn't happen: whether you are climbing, descending, or flying level, you always have a specific target altitude or flight level. This target determines the setting you use, and you know which kind it is.
For example, you may be flying level at an altitude of 8000 feet and Air Traffic Control instructs you to "climb and maintain flight level 240" (roughly 24,000 feet).
You start a gentle climb and then change your altimeter to 29.92 because you're going up to the flight levels. You don't need to fiddle with the altimeter when you cross the transition altitude, because the target altitude/flight level is the only one that counts.
Excellent rejoinder. FWIW, GP reflects this tendency I've seen more than once to assume that specific US aviation rules or conventions apply everywhere.
"What to Submit
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic"
Indeed, once the cause is in it may be interesting (things like frozen pitots, invisible volcanic ash, etc). Until then it's just another speculation into yet another shoddy carrier crashing.
Hacker News guidelines are summarized by this statement: "anything that gratifies one's intellectual curiosity."
I'd agree that if it was an article about a Cessna 172 crashing, it wouldn't belong on Hacker News, but in this case, the interesting fact about this aircraft accident is that it's a brand new airliner model, one that has never been in an accident before. Furthermore, we have some basic flight data, so perhaps a bored hacker might decide to debug what they think happened using this data.
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1151x734/3...
(Credit to a comment on Reddit here https://www.reddit.com/r/aviation/comments/9s9752/indonesian...)