5 ms·

Speed and altitude compared to the previous day. Immediate problems from the start. Pilot radioed a technical problem. Plane was delivered in August. https://c

Speed and altitude compared to the previous day. Immediate problems from the start. Pilot radioed a technical problem. Plane was delivered in August. https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1151x734/3_c4607b5fa54c9ce9d2ba78abc73c901bc9efc3a4.gif 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_aircraft_missing_off_jakarta/ https://www.reddit.com/r/aviation/comments/9s9752/indonesian...)

avip 8y ago
Is there some real-time anomaly detection observing that data? It looks like nothing is ok as soon as 90 seconds in.
matt4077 8y ago
I just noticed Safari went all the way from no favicons in tabs to animated favicons in tabs. And in this case, it's being used somewhat distasteful.
larkeith 8y ago
Does anyone know how the day's speed/altitude graph compare to a regular day of heavy weather and turbulence?
- dx034 8y ago
  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.
phumbe 8y ago
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. Source: https://www.flightradar24.com/blog/flightradar24-data-regarding-lion-air-flight-jt610/ https://www.flightradar24.com/blog/flightradar24-data-regard...
- kijin 8y ago
  30000 fpm == 540 kph == 292 knots 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.
  - phumbe 8y ago
    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.
    - kijin 8y ago
      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.)
      - FabHK 8y ago
        1/2 mv^2 = mgh, so v = sqrt(2gh). 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)).
      - jandrese 8y ago
        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.
      - phumbe 8y ago
        > 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.
RL_Quine 8y ago
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.
- village-idiot 8y ago
  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?
  - JshWright 8y ago
    Hmm... Why would that be an interesting question? It seems most likely that the issue occurred either during the climb out, or after V1 on the runway. https://en.wikipedia.org/wiki/V_speeds https://en.wikipedia.org/wiki/V_speeds
    - village-idiot 8y ago
      Because if the plane was down on power, the pilot might have had a chance before he hit V1. This is obviously speculative, but I’ll be curious to find out what happened.
      - JshWright 8y ago
        From the very limited telemetry available, it doesn't look like a power issue, it looks like a control issue. It's certainly not impossible that there was an obvious fault before V1, but it's _way_ down the list of likely scenarios.
        village-idiot 8y ago
        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.

avip 8y ago

Is there some real-time anomaly detection observing that data? It looks like nothing is ok as soon as 90 seconds in.

matt4077 8y ago

I just noticed Safari went all the way from no favicons in tabs to animated favicons in tabs. And in this case, it's being used somewhat distasteful.

larkeith 8y ago

Does anyone know how the day's speed/altitude graph compare to a regular day of heavy weather and turbulence?

dx034 8y ago
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.

phumbe 8y ago

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. Source: https://www.flightradar24.com/blog/flightradar24-data-regarding-lion-air-flight-jt610/ https://www.flightradar24.com/blog/flightradar24-data-regard...

kijin 8y ago
30000 fpm == 540 kph == 292 knots 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.
- phumbe 8y ago
  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.
  - kijin 8y ago
    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.)
    - FabHK 8y ago
      1/2 mv^2 = mgh, so v = sqrt(2gh). 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)).
    - jandrese 8y ago
      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.
    - phumbe 8y ago
      > 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.

RL_Quine 8y ago

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.

village-idiot 8y ago
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?
- JshWright 8y ago
  Hmm... Why would that be an interesting question? It seems most likely that the issue occurred either during the climb out, or after V1 on the runway. https://en.wikipedia.org/wiki/V_speeds https://en.wikipedia.org/wiki/V_speeds
  - village-idiot 8y ago
    Because if the plane was down on power, the pilot might have had a chance before he hit V1. This is obviously speculative, but I’ll be curious to find out what happened.
    - JshWright 8y ago
      From the very limited telemetry available, it doesn't look like a power issue, it looks like a control issue. It's certainly not impossible that there was an obvious fault before V1, but it's _way_ down the list of likely scenarios.
      - village-idiot 8y ago
        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.