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Dallas air show crash

Old 19th Dec 2022, 00:03
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Originally Posted by ATC Watcher
I am not sure any of the 2 aircraft involved were equipped with ADS-B out , more likely the data you are talking about comes from F24 , and the data then coms from the transponders relayed via a few private antennas on the ground. It is not the certified ADS-B we talk about in ATC or Commerciall aviation.
As to using the vertical rates mentioined earlier , I persoally doubt the calculations and the figures posted . , FR24 is a great tool but is not exact science
You are referring to the MLAT feature used by FR24 for non-ADS-B equipped a/c, but this does not work for a/c at low level and is always too inaccurate for tracking a/c maneuvering sharply
And the Youtube clip from post #236 clearly shows ADS-B / UAT as Signal Source.
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Old 19th Dec 2022, 08:39
  #262 (permalink)  
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Originally Posted by DIBO
You are referring to the MLAT feature used by FR24 for non-ADS-B equipped a/c, but this does not work for a/c at low level and is always too inaccurate for tracking a/c maneuvering sharply
And the Youtube clip from post #236 clearly shows ADS-B / UAT as Signal Source.
Then I stand correted. I did not think a vintage aircrfraf such as a P-63 would be fitted with ADS-B-out /UAT, I do not know of any in Europe that would.be.hence my remark. My bad. .
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Old 26th Dec 2022, 02:04
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Originally Posted by SATCOS WHIPPING BOY
Sorry mate but I have to disagree here.
No problem, that's fine with me, we don't live in China or Russia.
Originally Posted by SATCOS WHIPPING BOY
The things you describe above are exactly what happens in a busy mixed-traffic circuit at any military airfield. I spent 6 years juggling metal at Boscombe Down which often had multiple aircraft types flying and landing in all directions. Is the Airboss a controller or just a mouthpiece?
The controller does seem to be the obvious answer to me.

However, the controller still assumes, the pilots do follow the instructions, etc.

Once the pilots don't follow the instructions, things will become challenging for an airboss. Especially, when the flight-path more or less still resembles the agreed path, though with deviations not immediately clear for the naked eye (things like airspeed, altitude/height, vertical speed, exact 4D position, etc). For these situations, the airboss is simply blind, no suitable real-time information available, other than just a judgement, provided the airboss' eyes are pointing in the right direction at exactly that moment in time.

Let alone, how a non-perfect situation is going to develop for the worse or just evens out without further consequences.

Not to say, when a pilot is already behind the aircraft, it is unlikely, the pilot will understand and comply with an airboss request/instruction. If the need for a pilot instruction is determined at all, since these things do unfold in just 10-15 seconds.

I really think, it is unrealistic to assume an airboss is able to micromanage the things you put on the airboss his/her shoulders. Humans aren't able to run a TCAS with their brain, let alone the sensory tool itself is already suffering from inaccuracy .....

That's what I (try to) say.

Originally Posted by SATCOS WHIPPING BOY
Anyone controlling aircraft is fundamentally aware that you do not make aircraft cross paths unless there is vertical, lateral or time separation.
Yep, I came across that one too, though my understanding is, the video showing this instruction, was from the 2021 briefing. Correct me, when I am wrong.

Originally Posted by SATCOS WHIPPING BOY
If that airboss told the fighters, who were on the inside of the turn radius, to come closer to the crowd than the bombers, thus crossing their paths without any height separation, screwed up by initiating what followed. BUT ultimately it was VFR flight and the responsibility lies wholly with the pilots.
Yes, the "IF", thought that was AFAIK the 2021 briefing. As long as there is sufficient separation of at least one parameter in 4D (x,y,z,time), things are OK. Typically, when a pilot does get behind the aircraft, bearing VFR responsibility becomes a burden.

For this situation, both the flight path and the video (where the P-63 does head towards the camera) do show a trajectory not matching with this "at least one parameter in 4D" separation. And the "ADS-B" data does show what is going wrong.
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Old 26th Dec 2022, 02:14
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Originally Posted by Locked door
My understanding is that the Airboss is responsible for preventing the accident before any aircraft take off by creating choreography and a display sequence that ensures separation and makes an accident (almost) impossible.
Yes, but is still depending on proper cooperation/compliance from the pilots flying the aircrafts.

Originally Posted by Locked door
If the accident aircraft were performing a permitted manoeuvre and were both their permitted locations then the Airboss shares some if not most of the responsibility for the accident.
Provided sufficient 4D separation is build in, that would take the airboss of the hook. Don't forget EVERY maneuver with more than one aircraft around the same ground infrastructure will ALWAYS have crossing flight-paths. It just needs to have at least 1 of the 4D parameters to have sufficient separation. If one parameter gets a little "close-by", add another one to increase separation.

Originally Posted by Locked door
No pilot can keep full SA with respect to all the other aircraft in that busy display. Separation should have been ensured with differing altitudes and display lines and no crossover permitted.

A very sad set of events.

ATB
Yep & Yep, though, see my previous remark about the logic around this subject.
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Old 26th Dec 2022, 02:33
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Originally Posted by ATC Watcher
I am not sure any of the 2 aircraft involved were equipped with ADS-B out , more likely the data you are talking about comes from F24 , and the data then coms from the transponders relayed via a few private antennas on the ground. It is not the certified ADS-B we talk about in ATC or Commerciall aviation.
I do think, this is just Mode-C/Mode-S, using MLat to get the added details. Although MLat is "declared" to be only useful above 3000ft, it highly depends on the number of receivers with proper sky-view in that area. Given the trajectories and other parameters are not really looking ragged, I think, the accuracy of the (playback !) flight paths in the YT video is pretty good. Not to say, the collision location fits quite good with the factual wreckage location(s).

For real-time professional use, the "FR24" is not that suitable, insufficiently calibrated, unreliable, etc.

Though for replay, with the opportunity to remove obviously wrong data points, recalibrate, etc, this data is also used by the national safety boards to analyze the happenings.
Originally Posted by Locked door
As to using the vertical rates mentioined earlier , I persoally doubt the calculations and the figures posted . , FR24 is a great tool but is not exact science
I think, on the contrary. FR24 is an excellent data source to retrieve otherwise lost data. Of course, one needs to calibrate this data against other known sources.

The simple fact, none of the relevant parameters for this accident does show ragged playback, suggests, the data is pretty reliable. When you calculate a vs from subsequent altitude data points, and the vs does not show jumpy values, it is reasonable to assume, the altitude data points are reliable and accurate (in a row, of course, needing calibration).

Of course, it could be, the static pressure system / Mode-C measuring of the P-63 is completely off calibration, though for that, check the earlier circuits of the P-63 in the same display. I didn't, though, feel free to do so and report back. I have no reasons to assume, the final 30 seconds of data points would show erroneous, whereas the earlier ones would be OK. FR24 gives really powerful data, provided you know what you do.
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Old 26th Dec 2022, 12:14
  #266 (permalink)  
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The comments on this thread are all very interesting and very valid but seem to be missing one crucial fact (if fact is the right word) that all of the measures, distance, altitude, speed, air boss, atc, briefing, (add your variable here) mean nothing if the collision aircraft (and everyone else) doesn't perceive there is a conflict. Consider the following scenario. Air Boss orders that fighter stream to cross the bomber stream after checking that piece of air space is clear and that all fighters are in their respective air spaces. The P63 pilot looks at that piece of airspace where he will cross the stream and sees that it's clear (perhaps because the camo of the 17 hides the aircraft against the background) but understands that he will loose altitude in the turn. Again he checks those parameters, looks for conflicting traffic and sees nothing. The other aircraft are all checking their respective airspaces and they see everything as clear as do the safety persons and atc. Of course everyone is basing their decision on their own perception of what is happening at that time. Now you have a scenario where the perception, the speed of the closing aircraft, their flight profiles and angles of track, time compression and an element of bad luck all come together to create a tragedy. Accidents are normally a multitude of factors that come together and at the wrong time. I wonder how many times a similar scenario has played out and with just one parameter different there was no conflict and no tragedy.

I wish the families, the CAF and all involved in this tragedy a merry Christmas. It's going to be a hard time for them.
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Old 29th Dec 2022, 14:58
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Originally Posted by uxb99
...... that all of the measures, distance, altitude, speed, air boss, atc, briefing, (add your variable here) mean nothing if the collision aircraft (and everyone else) doesn't perceive there is a conflict........
Actually, I do go one step further in my writing, that I seriously think all indications show, the P-63 pilot was that much behind the aircraft, that he didn't even get to the point, to being able to perceive there was an upcoming conflict (let alone conclude there was a conflict).

And, given the timing and rapid development of the situation, for any bystander, including the airboss, there was simply no opportunity to raise awareness for and/or correct the P-63 pilot.
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Old 13th Jan 2023, 22:07
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Audio has been released

https://www.star-telegram.com/news/l...fqWx1IpoYhjeik
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Old 13th Jan 2023, 22:59
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A sad, sad photo.


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Old 14th Jan 2023, 00:32
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Blancolorio's take on the audio transcript

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Old 14th Jan 2023, 06:55
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Let me drop some notes on this additional information:

- The audio gives me serious thoughts about a person micromanaging something that can not be controlled/guarded by micromanagement.
- The airboss is that busy with the speaking, this person is no longer mentally able to monitor for a discrepancy between the "instructions" given and the factual implementation of the given instructions.
- Let alone, interpret potential upcoming conflicts, let alone react on that. There is simply no monitor or mental interpretation/decision capacity left.
- I'd personally call this airboss style more suitable for a local fancy-fair event.
- Earlier on in this thread, a video was included, where a double display line, together with ground plane projected crossing flight paths, was an item briefed.
- Presumably, this video was of the last-years' briefing. If correct, this implies this year's show was, at least the second year in a row, these crisscrossing flight paths were used. Investigation needs to reveal the fine details of this aspect.
- One thing the audio shows, the whole situation is pretty chaotic.

Now back to the reality and lets get the paper sheets, scissors and glue. Let's create the intended flight paths for the bomber and fighter jets in paper objects. Place these objects in a 3D space (using the 1000ft and 500 ft display lines at both 500ft altitude) and it will become clear, the flights paths effectively do cross only in 2D dimensions of the 4D (x,yz,t) we have. Or so to say, these flight paths will not interfere, as long as all airplanes follow their trajectories.

So, yep, in 4D a complex maneuver, though doable.

In just a few words, the bombers do run a pretty flat circuity, with little altitude changes and the fighters do come in from higher altitude with a significantly higher RoD. This implies, that the fighters will have an altitude clearance of (roughly) 200ft with the bombers, when crossing the 1000ft display line. Not much, but there is also a separation in time.

The P-63 did hit the B-17 at (just above 500ft), while crossing the 1000ft display line. Or so to say, the P-63 was far too low at that moment, if its target had been the 500ft display line. Not to say, with the actual RoD and the heavy banking, when hitting the B-17, the P-63 would have ended up far below the 500ft display altitude, when it would have arrived at the 500ft display line (and 500ft further potentially hitting the crowd). All, when the B-17 would not have been there.

The strange thing is, the audio is about 2 display lines, whereas the radar plots do seem to indicate both bombers and fighters do follow (more or less) the same display line (be it 500ft or 1000ft). So, something strange is happening here.

All in all, several conflicting aspects (developing ???) in(to) a chaotic situation.

So, I'd say, the presumably used double display line with "crossings" as well the way the aircrafts are guided by the airboss aren't the "cause" of the accident, though certainly a hole in the Swiss Cheese model, contributing to the chances of this accident factually happening.

The limited "below the aircraft" visibility for P-63 pilots is a nuisance, though, I don't think, this is a cause of the accident. The P-63 simply should not have been there at the flight path it followed, being able to see "below" or not. The P-63 simply violated the presumed aircraft separation, build into the (4D) display model.

An addition to the Swiss Cheese items: Probably, but only minor, since these accident items develop that fast, that a "see and avoid" simply doesn't work. (Which was in itself the reason the whole IFR airspace control model got worked out and implemented, after the 1956 Grand Canyon VFR accident).

Referring to my earlier writing, I still think, and further confirmed to me by the above items around the released audio and display flight paths' organization, the "behind the aircraft" of the P-63 pilot (with subsequent erratic P-63 flight path/profile) was the reason this accident happened. Though, the complex display configuration/guidance did provide little room for error on the part of the fighter aircraft pilots.

Last edited by Pilot DAR; 14th Jan 2023 at 13:21. Reason: Fixed typo
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Old 14th Jan 2023, 14:24
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In just a few words, the bombers do run a pretty flat circuity, with little altitude changes and the fighters do come in from higher altitude with a significantly higher RoD. This implies, that the fighters will have an altitude clearance of (roughly) 200ft with the bombers, when crossing the 1000ft display line. Not much, but there is also a separation in time.

The P-63 did hit the B-17 at (just above 500ft), while crossing the 1000ft display line. Or so to say, the P-63 was far too low at that moment, if its target had been the 500ft display line. Not to say, with the actual RoD and the heavy banking, when hitting the B-17, the P-63 would have ended up far below the 500ft display altitude, when it would have arrived at the 500ft display line (and 500ft further potentially hitting the crowd). All, when the B-17 would not have been there.
I don't know much about airshow management, other than what I have learnt from this thread and watching the Youtube videos. At no time did I hear any altitude separation being applied by the Airboss. The ADS-B data shows quite arbitrary altitudes being achieved during the course reversal (dog bone leg?). So how can you conclude there should've been an altitude separation between the fighters and bombers as they crossed path?

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Old 14th Jan 2023, 14:53
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TOO MUCH TALKING. That's just an awful way to run an airshow. Sorry, but that's my take having run some major displays in the UK.
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Old 14th Jan 2023, 15:25
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Originally Posted by Flying_Scotsman
TOO MUCH TALKING. That's just an awful way to run an airshow. Sorry, but that's my take having run some major displays in the UK.
Agree.
The Dallas incident is a comprehensive example of how not to do it.

UK CAP403/CAP1724:
Brief the show
Fly the show
Debrief the show

Minimal radio traffic: Call incursions or infringements.
Itís demanding enough flying the show without having to listen to all that blah.

Itís clear from the audio that calls werenít being heard, lots of Ďsay againí.

Total shambles and desperately sad.

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Old 14th Jan 2023, 16:14
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Originally Posted by 172_driver
I don't know much about airshow management, other than what I have learnt from this thread and watching the Youtube videos. At no time did I hear any altitude separation being applied by the Airboss. The ADS-B data shows quite arbitrary altitudes being achieved during the course reversal (dog bone leg?). So how can you conclude there should've been an altitude separation between the fighters and bombers as they crossed path?
Simply: The math, trigonometry.

As such, my suggestion to use paper, scissors and glue to create the flight paths of each the bombers and the fighters as a paper object and put these in 3D, to visualize that the fighter path is above the bomber path, at the 1000ft display line. Then, you can literally see, that the fighter path is not conflicting with the bombers path.

When the fighters do come in from a much higher altitude AND are expected to reach the 500ft altitude, at 500ft closer to the public, they will be higher than 500ft at the 1000ft display line (my estimate > 200ft). So, in 4D, there is no conflict between the bombers and the fighters.

The safety of this separation mechanism is unfortunately very sensitive to pilot mistakes, which happened in this 2022 Dallas situation.
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Old 14th Jan 2023, 16:28
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Originally Posted by WideScreen
Simply: The math, trigonometry.

As such, my suggestion to use paper, scissors and glue to create the flight paths of each the bombers and the fighters as a paper object and put these in 3D, to visualize that the fighter path is above the bomber path, at the 1000ft display line. Then, you can literally see, that the fighter path is not conflicting with the bombers path.

When the fighters do come in from a much higher altitude AND are expected to reach the 500ft altitude, at 500ft closer to the public, they will be higher than 500ft at the 1000ft display line (my estimate > 200ft). So, in 4D, there is no conflict between the bombers and the fighters.

The safety of this separation mechanism is unfortunately very sensitive to pilot mistakes, which happened in this 2022 Dallas situation.
.

I’m sure you are quite possibly right but to be honest if the situation was that unforgiving to a single point failure then maybe it’s time to go back to the sort of basics Waltzer describes…KISS and all that.




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Old 14th Jan 2023, 16:56
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WideScreen,

But there were no defined points or lines in space from which you could build your geometry. The fighters happened to be higher during the course reversal, due to agility and performance I presume, but nothing (I heard) would guarantee that any single fighter wouldn't already be at 500 ft when crossing the path of the bombers?



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Old 14th Jan 2023, 19:35
  #278 (permalink)  
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After listening to the Blancolirio audio it's seems to me very clear what happened.
A lack of a pre-defined briefing which all pilots adhere to, without deviation. An overloaded Airboss that positioned aircraft into a conflict.
I haven't listened on my airband radio at a UK airshow for a few years now but when I did the airwaves during a display were very quiet and limited to display leaders giving instructions to their team and occasionally ATC.
The audio for this show sounded confused.
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Old 15th Jan 2023, 07:03
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Originally Posted by 172_driver
WideScreen,

But there were no defined points or lines in space from which you could build your geometry. The fighters happened to be higher during the course reversal, due to agility and performance I presume, but nothing (I heard) would guarantee that any single fighter wouldn't already be at 500 ft when crossing the path of the bombers?
Yes and no, there are some figures, to at least give you an understanding of the 3D positions in time. Earlier on in this thread, there was the YT video, showing the flights paths as well as the relevant details like altitude/speed/RoD from ADSBExchange.

Of course, this is not "hard data", though when it looks like a duck, squawks like a duck, walks like a duck, it's probably a duck, unless other circumstances strongly suggest otherwise. When needed, use cross-reference data to "calibrate" the ADSBExchange data. Use the data points from that YT video, make a plot assuming the 1000ft and 500ft display lines, and you have the trigonometry.

The relevance is, that, despite the PP critics, the figures of the bombers and figures do only "cross" at the same altitude, when plotted perpendicular on the ground. And there is no crossing at the same altitude, when the plotting is, for example, perpendicular to the plane in which the fighters fly (taking into account that the "altitude" reference will change also and is then relative to the plane of the fighters). IE a translation/rotation of the reference from ground to the plane, the fighters fly in.
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Old 15th Jan 2023, 09:28
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Of course, this is not "hard data", though when it looks like a duck, squawks like a duck, walks like a duck, it's probably a duck, unless other circumstances strongly suggest otherwise. When needed, use cross-reference data to "calibrate" the ADSBExchange data. Use the data points from that YT video, make a plot assuming the 1000ft and 500ft display lines, and you have the trigonometry.
Isn't that a bit like speeding through an intersection without looking - there is only a probability I will hit someone? Sure, if you're using the data plots after it happened, you can construct something which doesn't involve two aircraft at same point in space. Or am I not following you?

Now it so happened that probability positioned two aircraft at same spot in space, at the same time, and that probability could've been reduced to almost zero by better coordination of lateral and vertical profiles to be flown. Yes, the direct cause so happened to be the P63 (or the B17, but arguably the P63 was late) was at the wrong spot at the wrong time, but there was a good chance of that happening with the way it was set up.
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