4 ms·

Sounds like maybe a microburst?

by TylerE 4y ago

nsxwolf 4y ago
I hope it's something like that and not an unexplained mechanical or software issue. I'd have expected after an incident like that so close to the departure airport, you'd turn around and get everybody on a different flight.
- TylerE 4y ago
  In the event of weather like that you want to get as far away as you can as fast as you can. Don’t want to hit another on approach.
- sokoloff 4y ago
  In the event of a temporary/localized weather condition or a flight crew error, understood, corrected, and with no expectation of recurrence, I'd generally expect a continuation to the destination. This occurrence slightly exceeded the transport category load factor limit of 2.5g, but I doubt the flight crew was aware of the slight exceedance at the time of the flight.
freeqaz 4y ago
What is a microbust?
- arealaccount 4y ago
  Its a burst of strong updrafts or downdrafts, it’s very dangerous in aircraft. Video of some small airplanes attempting to fly in microburst conditions: https://m.youtube.com/watch?v=b_WmjWAGkLI https://m.youtube.com/watch?v=b_WmjWAGkLI
- TylerE 4y ago
  Powerful downburt. The air can be descending at thousands of feet per minute. A fairly recent incident that did result in a crash: https://en.m.wikipedia.org/wiki/Aeroméxico_Connect_Flight_2431 https://en.m.wikipedia.org/wiki/Aeroméxico_Connect_Flight_24...
- tjohns 4y ago
  A microburst is an intense column of descending air that sometimes occurs within thunderstorms. They are incredibly hazardous, and often produce downdrafts that exceed 6,000 feet per minute - well beyond even an airliner's climb performance. See: - https://en.wikipedia.org/wiki/Downburst https://en.wikipedia.org/wiki/Downburst - https://www.boldmethod.com/learn-to-fly/weather/microbursts-and-how-they-affect-your-airplane-and-performance/ https://www.boldmethod.com/learn-to-fly/weather/microbursts-... There's an entire list of disasters where an airliner inadvertently flew into a microburst and couldn't escape in time. Pilots are trained to avoid the conditions that create them, and some airports have LLWS warning equipment to help identify when they're occuring (such as the TDWR system, which shares the DFS spectrum used by 5 GHz WiFi).
- jacquesm 4y ago
  A lot of air moving down as one large mass. One happened a few km from here two years ago, just over a canal that carries a lot of shipping from Utrecht to Amsterdam. Along the side of that canal there are long rows of pretty sturdy trees. Over about two hundred meters they had all snapped like matchsticks, a few meters above the ground. The theory on why this happened is that the air has to go somewhere when it reaches the bottom, converting a large mass of air moving downwards into a large mass of air moving sideways and that happened to coincide with the treeline base. Here are some pictures of that event: https://www.parool.nl/nieuws/bomen-als-luciferhoutjes-omgeknakt-langs-amsterdam-rijnkanaal~b489d768/?referrer=https%3A%2F%2Fwww.google.com%2F https://www.parool.nl/nieuws/bomen-als-luciferhoutjes-omgekn... The way those trunks are splintered is interesting, normally a tree under wind pressure will topple as a whole, so this must have happened extremely quickly for the tree base not to have moved but the top to be snapped off.
cromka 4y ago
Why speculate when the article itself is quite clear on the cause? „(…) a formal internal safety report was filed by the pilots and the aircraft was inspected before its next flight. “ United then closely coordinated with the FAA and ALPA on an investigation that ultimately resulted in the pilots receiving additional training.”
- aflag 4y ago
  That’s not clear at all to me. Can you clarify?
- woodruffw 4y ago
  I think you're reading too far into that: that could mean anything from "the pilots needed more training to handle a microburst" to "we don't know what happened, so we're going to blame it on a lack of training."
  - mjevans 4y ago
    Training might be on Reporting the live observed incident in real time, for the benefit of others who might be in that same area soon.
    - TylerE 4y ago
      Probably not quite real time. Aviate, navigate, communicate. In that order.
      - mjevans 4y ago
        In the sense of after they'd recovered or were well in control again rather than waiting until after the entire flight.
    - deleted 4y ago
      [deleted]
    - aflag 4y ago
      Even if the training is due an error that caused the incident, it doesn't say what the error was. I'm sure they didn't confuse their plane for a submarine.
jaboutboul 4y ago
At first read this sounded like maybe a wind shear, but very curious that nothing was picked up by ATC about this, nor did the pilots say anything. Quite odd.
- sklargh 4y ago
  My first thought. Where was the PIREP if it was windshear? Obviously not mandatory but feel like that’s something you’d share earliest.
deleted 4y ago
[deleted]
mhandley 4y ago
According to FR24 [0], the decrease in altitude corresponds to an increase in groundspeed. If you're flying through descending air, the groundspeed generally wouldn't change, just the rate of climb decreases. Even if you increase thrust, you'll use this to arrest the sink rate, rather than increase groundspeed. Instead, it looks like they first traded altitude for airspeed, then airspeed for altitude, and ended up close to the original climb track. Sounds more like a straightforward dive to me. [0] https://www.flightradar24.com/blog/united-airlines-777-dives-after-departure/ https://www.flightradar24.com/blog/united-airlines-777-dives...

Sounds like maybe a microburst?

by TylerE 4y ago

Sounds like maybe a microburst?

I hope it's something like that and not an unexplained mechanical or software issue. I'd have expected after an incident like that so close to the departure airport, you'd turn around and get everybody on a different flight.

TylerE 4y ago
In the event of weather like that you want to get as far away as you can as fast as you can. Don’t want to hit another on approach.
sokoloff 4y ago
In the event of a temporary/localized weather condition or a flight crew error, understood, corrected, and with no expectation of recurrence, I'd generally expect a continuation to the destination. This occurrence slightly exceeded the transport category load factor limit of 2.5g, but I doubt the flight crew was aware of the slight exceedance at the time of the flight.

freeqaz 4y ago

What is a microbust?

arealaccount 4y ago
Its a burst of strong updrafts or downdrafts, it’s very dangerous in aircraft. Video of some small airplanes attempting to fly in microburst conditions: https://m.youtube.com/watch?v=b_WmjWAGkLI https://m.youtube.com/watch?v=b_WmjWAGkLI
TylerE 4y ago
Powerful downburt. The air can be descending at thousands of feet per minute. A fairly recent incident that did result in a crash: https://en.m.wikipedia.org/wiki/Aeroméxico_Connect_Flight_2431 https://en.m.wikipedia.org/wiki/Aeroméxico_Connect_Flight_24...
tjohns 4y ago
A microburst is an intense column of descending air that sometimes occurs within thunderstorms. They are incredibly hazardous, and often produce downdrafts that exceed 6,000 feet per minute - well beyond even an airliner's climb performance. See: - https://en.wikipedia.org/wiki/Downburst https://en.wikipedia.org/wiki/Downburst - https://www.boldmethod.com/learn-to-fly/weather/microbursts-and-how-they-affect-your-airplane-and-performance/ https://www.boldmethod.com/learn-to-fly/weather/microbursts-... There's an entire list of disasters where an airliner inadvertently flew into a microburst and couldn't escape in time. Pilots are trained to avoid the conditions that create them, and some airports have LLWS warning equipment to help identify when they're occuring (such as the TDWR system, which shares the DFS spectrum used by 5 GHz WiFi).
jacquesm 4y ago
A lot of air moving down as one large mass. One happened a few km from here two years ago, just over a canal that carries a lot of shipping from Utrecht to Amsterdam. Along the side of that canal there are long rows of pretty sturdy trees. Over about two hundred meters they had all snapped like matchsticks, a few meters above the ground. The theory on why this happened is that the air has to go somewhere when it reaches the bottom, converting a large mass of air moving downwards into a large mass of air moving sideways and that happened to coincide with the treeline base. Here are some pictures of that event: https://www.parool.nl/nieuws/bomen-als-luciferhoutjes-omgeknakt-langs-amsterdam-rijnkanaal~b489d768/?referrer=https%3A%2F%2Fwww.google.com%2F https://www.parool.nl/nieuws/bomen-als-luciferhoutjes-omgekn... The way those trunks are splintered is interesting, normally a tree under wind pressure will topple as a whole, so this must have happened extremely quickly for the tree base not to have moved but the top to be snapped off.

cromka 4y ago

Why speculate when the article itself is quite clear on the cause? „(…) a formal internal safety report was filed by the pilots and the aircraft was inspected before its next flight. “ United then closely coordinated with the FAA and ALPA on an investigation that ultimately resulted in the pilots receiving additional training.”

aflag 4y ago
That’s not clear at all to me. Can you clarify?
woodruffw 4y ago
I think you're reading too far into that: that could mean anything from "the pilots needed more training to handle a microburst" to "we don't know what happened, so we're going to blame it on a lack of training."
- mjevans 4y ago
  Training might be on Reporting the live observed incident in real time, for the benefit of others who might be in that same area soon.
  - TylerE 4y ago
    Probably not quite real time. Aviate, navigate, communicate. In that order.
    - mjevans 4y ago
      In the sense of after they'd recovered or were well in control again rather than waiting until after the entire flight.
  - deleted 4y ago
    [deleted]
  - aflag 4y ago
    Even if the training is due an error that caused the incident, it doesn't say what the error was. I'm sure they didn't confuse their plane for a submarine.

jaboutboul 4y ago

At first read this sounded like maybe a wind shear, but very curious that nothing was picked up by ATC about this, nor did the pilots say anything. Quite odd.

sklargh 4y ago
My first thought. Where was the PIREP if it was windshear? Obviously not mandatory but feel like that’s something you’d share earliest.

deleted 4y ago

[deleted]

mhandley 4y ago

According to FR24 [0], the decrease in altitude corresponds to an increase in groundspeed. If you're flying through descending air, the groundspeed generally wouldn't change, just the rate of climb decreases. Even if you increase thrust, you'll use this to arrest the sink rate, rather than increase groundspeed. Instead, it looks like they first traded altitude for airspeed, then airspeed for altitude, and ended up close to the original climb track. Sounds more like a straightforward dive to me. [0] https://www.flightradar24.com/blog/united-airlines-777-dives-after-departure/ https://www.flightradar24.com/blog/united-airlines-777-dives...