5 ms·

The spinning ATR plane crash in Brazil

58 points by mhb 2y ago

samstave 2y ago
SO basically a quick-icing on one side/unevenly with the potential for pilot error is truly what caused it?
- dudus 2y ago
  At the end he says... "So… icing by itself likely cannot be the cause of the recent accident in Brazil."
  - pfdietz 2y ago
    Airline accidents almost always have multiple causes. Only when all the swiss cheese slices line up holes can the accident slip through. Mentour Pilot four years ago on superstall (deep stall): https://www.youtube.com/watch?v=Kg6jV5mkf-8&t=0s https://www.youtube.com/watch?v=Kg6jV5mkf-8&t=0s T-tail aircraft (like this one!) are at risk. ATR-72 specifically mentioned.
  - samstave 2y ago
    Thats why I specifically said with potential pilot error (I was going to say mechanical failure, but that is highly less likely given the age of the aircraft.) >"Right, it was that bolded "400'" climb that clearly is what hes pointing at - as the ice caused the drop, then the pilot sharply climbed, then ice-stall, causes plane to yaw pilot corrects the wrong direction causing spin - all in the course of what seems like ~30 seconds?" Is what my thoughts are.
- dcan 2y ago
  > "The plane had been cruising at 17,000 feet until 1:21 p.m., when it dropped approximately 250 feet in 10 seconds. It then climbed approximately 400 feet in about eight seconds." > The last sentence suggests that they were actively trying to get back to their assigned altitude of 17,000′. I believe the author is implying that if the pilots attempted to maintain speed rather than altitude, the aerodynamic stall wouldn't have occurred - if they descended below 12000', the icing would be reversible.
  - samstave 2y ago
    Right, it was that bolded "400'" climb that clearly is what hes pointing at - as the ice caused the drop, then the pilot sharply climbed, then ice-stall, causes plane to yaw pilot corrects the wrong direction causing spin - all in the course of what seems like ~30 seconds?
- k1w1 2y ago
  It seems that the pilot error here was to fly into severe icing, or to staying in icing conditions beyond what the aircraft was capable of handling.
  - pfdietz 2y ago
    Or to not recover properly from icing.
- quilombodigital 2y ago
  Its early to make assumptions, but the weather report confirms the theory, and at the plane previous flight, from the inverse route, a passenger filmed ice at the wings.
Jyaif 2y ago
> Captain Sully had the stick full back during his heroic single-pilot landing on the Hudson, just like a panicked student pilot Ouch!
- k1w1 2y ago
  I think the original author is drawing the wrong conclusion here. Sully may have had the stick all the way back, but that doesn't mean it was wrong. The lowest energy way to land is to try to prevent the aircraft from landing. So when you are in the flare, the technique is to pull back on the stick to keep the aircraft in the air a few feet above the runway, until you have no more elevator authority, and the aircraft will settle onto the runway with the least amount of energy. Exactly what you want in a off-field landing too. As my glider instructor put it: those last few seconds before touchdown are the prime rib of flying. Keep pulling back on the stick and make it last. In fact if you look at the Wikipedia article that the OP linked to it suggests that Sully was unhappy that the aircraft was not responding to his full back stick: > However, Sullenberger said that these computer-imposed limits also prevented him from achieving the optimal landing flare for the ditching, which would have softened the impact.
  - aftbit 2y ago
    My understanding is that transport-class aircraft (i.e. large passenger jets) are typically landed differently than smaller planes like a Cessna Skyhawk or a glider. In my brief flight training experience in a small plane, I was taught to stall the A/C just above the runway as you describe. However, I believe ATPs are taught to land at about 1.3x stall speed, then use the spoilers to dump the lift entirely and get full weight on the wheels in a very controlled way. I'm of course discussing typical on-field operations, not emergency dead stick ditchings. I don't know how those are supposed to go, but one might imagine that going to full stall just before impact would indeed result in the minimum energy state. The trick is to not accidentally do that too high!
  - Vecr 2y ago
    From what I read "the stick all the way back" is correct, because it's telling the computer your intent, "raise the nose of the plane". Airbus aircraft use flight laws to control the actual control surfaces, so there's no reason to make your intent less strong than it actually is.
tqi 2y ago
> The aspiration seems to be an LCD version of the gauges and dials that were in a B-17 bomber over Germany in World War II. The computers on board the aircraft had all of the information that they needed to warn the crew “you can’t hold altitude at this power setting” long before they came anywhere near stalling. I feel this way in cars as well - with a full LCD infotainment center why am I still forced to try and interpret inscrutable indicator lights?
- aftbit 2y ago
  My 2019 Subaru Outback will at least display things like "low fuel" and "low tire pressure" on the center display as well as on the drivers mini display. I haven't gotten into any check engine situations, or anything really scary like overheat or low oil pressure, but IMO even the data from a scan tool is somewhat inscrutable if you are not an expert.
- tomp 2y ago
  Because they don’t distract. Nothing I hate more than my Audi loudly beeping for non-critical infos/warnings. The only appropriate time for a car to loudly beep unprompted is if I need to stop immediately.
  - OptionOfT 2y ago
    This reminds me of the BMW 3 degrees C bling. Which is the same bling as parking sensors dirty and thus no longer reliable.
  - andrewinardeer 2y ago
    I agree. If I want to drive at 15km/h without a seat belt in an empty car park the car shouldn't be beeping at me at 50 decibels warning me of immediate death.
- nvy 2y ago
  Because if the automakers were left to their own devices, the infotainment display would need to show a loading bar before an ABS warning, and the speedometer would be buried there menus deep.
guerby 2y ago
https://www.youtube.com/watch?v=5zaRCbnMhFo https://www.youtube.com/watch?v=5zaRCbnMhFo ATR-72 EN VRILLE by ATE CHUET In French, a bit more information about ATR and icing as potential cause for this crash.
deleted 2y ago
[deleted]
deleted 2y ago
[deleted]

58 points by mhb 2y ago

samstave 2y ago

SO basically a quick-icing on one side/unevenly with the potential for pilot error is truly what caused it?

dudus 2y ago
At the end he says... "So… icing by itself likely cannot be the cause of the recent accident in Brazil."
- pfdietz 2y ago
  Airline accidents almost always have multiple causes. Only when all the swiss cheese slices line up holes can the accident slip through. Mentour Pilot four years ago on superstall (deep stall): https://www.youtube.com/watch?v=Kg6jV5mkf-8&t=0s https://www.youtube.com/watch?v=Kg6jV5mkf-8&t=0s T-tail aircraft (like this one!) are at risk. ATR-72 specifically mentioned.
- samstave 2y ago
  Thats why I specifically said with potential pilot error (I was going to say mechanical failure, but that is highly less likely given the age of the aircraft.) >"Right, it was that bolded "400'" climb that clearly is what hes pointing at - as the ice caused the drop, then the pilot sharply climbed, then ice-stall, causes plane to yaw pilot corrects the wrong direction causing spin - all in the course of what seems like ~30 seconds?" Is what my thoughts are.
dcan 2y ago
> "The plane had been cruising at 17,000 feet until 1:21 p.m., when it dropped approximately 250 feet in 10 seconds. It then climbed approximately 400 feet in about eight seconds." > The last sentence suggests that they were actively trying to get back to their assigned altitude of 17,000′. I believe the author is implying that if the pilots attempted to maintain speed rather than altitude, the aerodynamic stall wouldn't have occurred - if they descended below 12000', the icing would be reversible.
- samstave 2y ago
  Right, it was that bolded "400'" climb that clearly is what hes pointing at - as the ice caused the drop, then the pilot sharply climbed, then ice-stall, causes plane to yaw pilot corrects the wrong direction causing spin - all in the course of what seems like ~30 seconds?
k1w1 2y ago
It seems that the pilot error here was to fly into severe icing, or to staying in icing conditions beyond what the aircraft was capable of handling.
- pfdietz 2y ago
  Or to not recover properly from icing.
quilombodigital 2y ago
Its early to make assumptions, but the weather report confirms the theory, and at the plane previous flight, from the inverse route, a passenger filmed ice at the wings.

Jyaif 2y ago

> Captain Sully had the stick full back during his heroic single-pilot landing on the Hudson, just like a panicked student pilot Ouch!

k1w1 2y ago
I think the original author is drawing the wrong conclusion here. Sully may have had the stick all the way back, but that doesn't mean it was wrong. The lowest energy way to land is to try to prevent the aircraft from landing. So when you are in the flare, the technique is to pull back on the stick to keep the aircraft in the air a few feet above the runway, until you have no more elevator authority, and the aircraft will settle onto the runway with the least amount of energy. Exactly what you want in a off-field landing too. As my glider instructor put it: those last few seconds before touchdown are the prime rib of flying. Keep pulling back on the stick and make it last. In fact if you look at the Wikipedia article that the OP linked to it suggests that Sully was unhappy that the aircraft was not responding to his full back stick: > However, Sullenberger said that these computer-imposed limits also prevented him from achieving the optimal landing flare for the ditching, which would have softened the impact.
- aftbit 2y ago
  My understanding is that transport-class aircraft (i.e. large passenger jets) are typically landed differently than smaller planes like a Cessna Skyhawk or a glider. In my brief flight training experience in a small plane, I was taught to stall the A/C just above the runway as you describe. However, I believe ATPs are taught to land at about 1.3x stall speed, then use the spoilers to dump the lift entirely and get full weight on the wheels in a very controlled way. I'm of course discussing typical on-field operations, not emergency dead stick ditchings. I don't know how those are supposed to go, but one might imagine that going to full stall just before impact would indeed result in the minimum energy state. The trick is to not accidentally do that too high!
- Vecr 2y ago
  From what I read "the stick all the way back" is correct, because it's telling the computer your intent, "raise the nose of the plane". Airbus aircraft use flight laws to control the actual control surfaces, so there's no reason to make your intent less strong than it actually is.

tqi 2y ago

> The aspiration seems to be an LCD version of the gauges and dials that were in a B-17 bomber over Germany in World War II. The computers on board the aircraft had all of the information that they needed to warn the crew “you can’t hold altitude at this power setting” long before they came anywhere near stalling. I feel this way in cars as well - with a full LCD infotainment center why am I still forced to try and interpret inscrutable indicator lights?

aftbit 2y ago
My 2019 Subaru Outback will at least display things like "low fuel" and "low tire pressure" on the center display as well as on the drivers mini display. I haven't gotten into any check engine situations, or anything really scary like overheat or low oil pressure, but IMO even the data from a scan tool is somewhat inscrutable if you are not an expert.
tomp 2y ago
Because they don’t distract. Nothing I hate more than my Audi loudly beeping for non-critical infos/warnings. The only appropriate time for a car to loudly beep unprompted is if I need to stop immediately.
- OptionOfT 2y ago
  This reminds me of the BMW 3 degrees C bling. Which is the same bling as parking sensors dirty and thus no longer reliable.
- andrewinardeer 2y ago
  I agree. If I want to drive at 15km/h without a seat belt in an empty car park the car shouldn't be beeping at me at 50 decibels warning me of immediate death.
nvy 2y ago
Because if the automakers were left to their own devices, the infotainment display would need to show a loading bar before an ABS warning, and the speedometer would be buried there menus deep.

guerby 2y ago

https://www.youtube.com/watch?v=5zaRCbnMhFo https://www.youtube.com/watch?v=5zaRCbnMhFo ATR-72 EN VRILLE by ATE CHUET In French, a bit more information about ATR and icing as potential cause for this crash.

deleted 2y ago

[deleted]

deleted 2y ago

[deleted]