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Old 26th Aug 2019, 22:45
  #121 (permalink)  
 
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Originally Posted by Lead Balloon
Did you read Angel Flight’s response to the ATSB’s analysis, printed in The Australian last week? Be worth your while, if you’re interested in facts.
As pasted earlier in this thread? I did. Have you read the full report?

Angel Flight complained that only the passenger carrying legs were included in the statistics, however the report is basically investigating the risk to Angel Flight passengers so that is 100% valid - there is no risk to passengers on legs where they are not present. The hypothesis is "That Angel Flights carrying passengers have a higher risk of a fatal accident than other private flights" so Angel Flight legs with passengers is the correct group to test.

They said they engaged their own statistician who found the numbers were not significant. However they don't tell you the number or tests they used, or their threshold for significance. We have dueling statisticians, but only the ATSB presented their data and methodologies. There's nothing there in the Angel flight information that you can use to evaluate it (and people are accusing the ATSB of hiding data - by putting it into a report people can't be bothered reading presumably).

They also complain about the use of occurrence data. I haven't looked deeply into that because the fatal accidents concern me more. My main impression from the occurrence data was that the pilots involved seemed to be operating in unfamiliar environments, which you might expect to raise stress and make poor decisions more likely. If Angel Flight want to focus on the fatal accidents only that's fine with me.
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Old 26th Aug 2019, 22:56
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Originally Posted by Sunfish
AndrewR, there is only one statistic that counts. The rate of VFR into IMC accidents per thousand hours flying or per cycle of Angel Flight vs. private ops and charter and airlines. That statistic didn’t show Angel Flight was anymore or less dangerous than normal GA ops.
They used rate of fatal accidents instead of VFR into IMC. Restricting it to VFR into IMC would include all Angel Flight but not all private accidents, so would look even worse for Angel Flight. I'm sure someone can do that statistic if you want it.

The statistic DID show angel flight was more dangerous than normal private flights. From the report, the probability that passenger carrying Angel Flight fatal accident rate is greater than other private flights: 96.8%.

And for Angel flight, who are claiming that non-passenger flight were excluded, that number is there too: the probability that the combined flights Angel Flight fatal accident rate is greater than other private flights: 82%

ATSB produced the statistics. The numbers and methodologies are documented. If you want to dispute the methodologies and produce your own numbers feel free - that is why it is important that the information is published. But you can't claim that ATSB didn't produce the numbers. If you do your own calculations, you should publish the workings as well so that people can see how you came to a conclusion.
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Old 26th Aug 2019, 22:57
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Originally Posted by Lead Balloon
But both ATSB and CASA failed to identify the most important and telling statistic: The pilots of nearly 100% of the community service flight aircraft involved in an ‘occurrence’ were male!
Fatal accident rates of male vs. female pilots might not be a statistic you want to see!
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Old 26th Aug 2019, 23:06
  #124 (permalink)  
 
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Let’s assume that the ATSB’s analysis is correct and your impressions are correct.

What is it in CASA’s response - the imposition of conditions on flight crew licences - that causally mitigates the risk of community service flight pilots being more likely to make decisions that result in fatal accidents? Which of those conditions would have prevented fatalities?

And why wouldn’t we want to see the statistics of male v female fatal accident rate? Surely there should be a regulatory response to the disparity. After all, there must be a causal connection, not mere correlation.
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Old 26th Aug 2019, 23:13
  #125 (permalink)  
 
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As others have said, “a little statistical knowledge is a dangerous thing”.

The occurrence data is irrelevant. Your argument about stress in unfamiliar environments is correct from my experience, I’ve been caught that way myself.

However that argument fails statistically because you would need to compare AF to other GA flights operating in unfamiliar airports, which ATSB could not do. Furthermore that issue can be fixed by training and mentoring anyway. In any case the AF accidents were not caused by unfamiliar airports.

Then you raise “passenger carrying”, you would again need to compare AF with GA flights carrying passengers from A to B, not just tootling around the circuit on a sunny day or doing a local scenic flight.

However, even without those tests, the basic poisson and normal distribution tests for the accident rates can’t produce significant results or ATSB would have trumpeted them.

What that means is that we DON’T KNOW if the two crashes are anything more than coincidence.

The same argument unfortunately applies to the RPT fatality rate in Australia. We cannot crow about how safe we are because the data is “lumpy”. You could go 40 years without an accident, then lose 500+ in a mid air over Sydney. If that ever happened, you can bet that the ATSB would be calling it an “isolated incident “ - statistically insignificant, random, etc. etc. They should afford the same latitude to Angel Flight.

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Old 27th Aug 2019, 05:58
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I bet there is an added layer of regulations for Angel Flights because some idiot exceeded his skills and his confidence by flying into IMC.

CASA are trying to regulate against stupidity. And because pilots keep on doing stupid things (like flying into IMC when not trained or qualified) then CASA will always have a reason to tighten the noose.

The pilot in command failed to act responsibily, safely, or even within his (limited) competency.

And we will all have to suffer increased regulations and oversight as a result.
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Old 27th Aug 2019, 07:19
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I bet there is an added layer of regulations for Angel Flights because some idiot exceeded his skills and his confidence by flying into IMC.
The experience & currency requirements for Angel Flight pilots is already higher than that required for single engine VFR charter pilots (ie most tourist flights).

CASA just don't like non-airline operations carrying passengers. They like dealing with large organisations with airconditioned meeting rooms and tea lady's. Full stop.
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Old 27th Aug 2019, 11:20
  #128 (permalink)  
 
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Originally Posted by Sunfish
However that argument fails statistically because you would need to compare AF to other GA flights operating in unfamiliar airports, which ATSB could not do. Furthermore that issue can be fixed by training and mentoring anyway. In any case the AF accidents were not caused by unfamiliar airports.

Then you raise “passenger carrying”, you would again need to compare AF with GA flights carrying passengers from A to B, not just tootling around the circuit on a sunny day or doing a local scenic flight.


You are suggesting that private GA has a higher accident rate for passenger carrying flights than non passenger carrying? It's certainly possible, the numbers would be interesting.

What you compare depends on the question you are trying to answer. It seems likely there was an expectation that the level of Angel Flight safety could be predicted by looking at the private GA accident rate. In that case you need to compare with the group you used to make the prediction.

Originally Posted by Sunfish
However, even without those tests, the basic poisson and normal distribution tests for the accident rates can’t produce significant results or ATSB would have trumpeted them.


You really need to read the report. The data is there, even if it hasn't been trumpeted to your satisfaction.

Originally Posted by Sunfish
What that means is that we DON’T KNOW if the two crashes are anything more than coincidence.

The same argument unfortunately applies to the RPT fatality rate in Australia. We cannot crow about how safe we are because the data is “lumpy”. You could go 40 years without an accident, then lose 500+ in a mid air over Sydney. If that ever happened, you can bet that the ATSB would be calling it an “isolated incident “ - statistically insignificant, random, etc. etc. They should afford the same latitude to Angel Flight.
One might be an isolated incident. 2 is more significant, if the expected rate is low. ATSB provide the numbers you can do the maths yourself if you want to. No need to speculate about hypothetical RPT accidents.

Don't get me wrong - I actually support the concept of Angel Flight. However, it appears they have a problem. One more similar accident and they are finished, I reckon. Denying the problem won't help them - they need to figure out how to stop it from happening again.
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Old 27th Aug 2019, 11:31
  #129 (permalink)  
 
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Let’s just save everyone the time and effort. Ban it now! It appears they have a problem. 2 incidents. Count them: 2!

Shut this **** down, now.
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Old 27th Aug 2019, 11:53
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Originally Posted by Lead Balloon
What is it in CASA’s response - the imposition of conditions on flight crew licences - that causally mitigates the risk of community service flight pilots being more likely to make decisions that result in fatal accidents? Which of those conditions would have prevented fatalities?
I would say that nothing in CASA's response will make any difference.

Pilots have been making bad decisions since before the Wright brothers, and will continue to make bad decisions until they are completely replaced by computers. We know how to mitigate that.
  1. Have standards and procedures that keep pilots away from areas where a bad decision will be catastrophic.
  2. Have someone e.g. Chief Pilot, business owner etc. who will be on the hook if something does go wrong so they will be looking over the pilots shoulder, second guessing them etc (supervising) at least until they are satisfied with their decision making.
Angel Flight does not do that - they place all responsibility on the pilot.

Angel flight needs to work out how to reliably cancel flights when the weather is unsuitable. We know from 100 years of experience that you can't 100% rely on the pilot for this. Angel Flight are not going to change that, even with a web education module.

What I believe they need to do:
  1. Set conservative standards for day VFR flights, e.g. ETA no later than 1 hour before last light, cancel the flight if destination requires an alternate etc.
  2. The pilot phones Angel Flight before taking off, Angel Flight have the weather for the flight plus a report and ETA information from the pilot, and Angel Flight cancel if the weather is not up to standard.
These procedures would have almost certainly have meant that both accident flights would have been cancelled and Angel Flight would have an excellent safety record, instead of what is currently a very poor one.

I suspect Angel Flight resist this because inserting themselves in the decision making creates a liability problem. Perhaps they wouldn't be able to get insurance at all. It would be ironic, but not surprising, if insurance was preventing an improvement in safety.

No commercial pilot, not even the most experienced A380 captain, operates with the autonomy given to Angel Flight pilots.
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Old 27th Aug 2019, 20:51
  #131 (permalink)  
 
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AndrewR:
Pilots have been making bad decisions since before the Wright brothers, and will continue to make bad decisions until they are completely replaced by computers. We know how to mitigate that.
  1. Have standards and procedures that keep pilots away from areas where a bad decision will be catastrophic.
  2. Have someone e.g. Chief Pilot, business owner etc. who will be on the hook if something does go wrong so they will be looking over the pilots shoulder, second guessing them etc (supervising) at least until they are satisfied with their decision making.
Angel Flight does not do that - they place all responsibility on the pilot.

Angel flight needs to work out how to reliably cancel flights when the weather is unsuitable. We know from 100 years of experience that you can't 100% rely on the pilot for this. Angel Flight are not going to change that, even with a web education module.

What I believe they need to do:
  1. Set conservative standards for day VFR flights, e.g. ETA no later than 1 hour before last light, cancel the flight if destination requires an alternate etc.
  2. The pilot phones Angel Flight before taking off, Angel Flight have the weather for the flight plus a report and ETA information from the pilot, and Angel Flight cancel if the weather is not up to standard.
These procedures would have almost certainly have meant that both accident flights would have been cancelled and Angel Flight would have an excellent safety record, instead of what is currently a very poor one.

I suspect Angel Flight resist this because inserting themselves in the decision making creates a liability problem. Perhaps they wouldn't be able to get insurance at all. It would be ironic, but not surprising, if insurance was preventing an improvement in safety.

No commercial pilot, not even the most experienced A380 captain, operates with the autonomy given to Angel Flight pilots.

Congratulations! You trolled me! You aren’t a pilot and you still don’t understand statistics.

Last edited by Sunfish; 27th Aug 2019 at 22:15.
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Old 27th Aug 2019, 22:46
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Originally Posted by Sunfish
You aren’t a pilot
Why do you say that? Because real pilots believe you can eliminate VFR into IMC accidents if only you do enough education?

Originally Posted by Sunfish
and you still don’t understand statistics.
Maybe, but I think in this case we are trying to answer different questions with the statistics.

You are asking whether Angel Flight itself increases the danger of the operation. Yes, that question requires you to find the most similar private flights (or at least control for the differences). That would probably be not just private flights with passengers, but private flights with passengers where there were specific plans to be somewhere. And if you are that specific there might be no difference. There are plenty of examples of regular private VFR flights into IMC under those circumstances e.g. VH PXD. But is it useful to compare Angel Flight with some of the more dangerous private flights?

Why compare with other private flights at all? What we want to do is to understand the risk associated with the flights. The comparison with private flights suggests that private flights overall are not an accurate reflection of the risk of Angel Flight - which I think is the same as what you are saying, but approached from the opposite direction.

Other questions you could try to answer with statistics:
  • Is Angel Flight more dangerous than private flights (the original statement)
  • Is Angel Flight more dangerous than private flights carrying passengers
  • Is Angel Flight more dangerous than charter
  • Is Angel Flight more dangerous than RPT
  • Is the Space Shuttle more dangerous than Angel Flight (just to show that yes, you probably can draw valid conclusions based on only 2 accidents)
For each you select the data that best reflects what you want to compare, not the subset where the 2 groups are most similar.

Have YOU read the actual report yet? What statistics in the report do you disagree with?
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Old 27th Aug 2019, 23:18
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I shouldn’t feed the troll but, You don’t understand statistics. Look up hypothesis testing. We cannot tell if Angel Flight is more prone to vfr into imc accidents using ANY statistics. There is not enough data because the chances are vanishingly small. As I said, if ATSB could have claimed that, they would.

The occurrences data is just straight BS.

Do you also have a scheme for winning Lotto?
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Old 27th Aug 2019, 23:30
  #134 (permalink)  
 
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2 incidents. Count them: 2!
Lead Ballon, I usually find you very exacting in what you say, so this surprised me a bit.
I think you’ll find they were most definitely “accidents”.
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Old 27th Aug 2019, 23:36
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The Insurance Companies will be the main influence on the government agencies - no matter what statistics say or indicate - and we all agree that accidents will happen no matter what. Stats and trends help to make management decisions but are tools and simply assist in the process. The Insurance industry has the ability to shut down any industry or endeavour if they don’t like what they see so clearly they don’t agree with the ATSB and consider AF as safe enough for their purposes.
On the face of it I would suggest that a 400 hr pilot with a Class 2 Medical would have the skills and ability to provide this service for AF. I would also suggest that, by that stage, he/she would also have had plenty of previous experience of opting for prudence by making decisions that would disappoint others.

AF is an incredible organisation from a regional Australian viewpoint. Their critics appear to live in metropolitan areas and may have difficulty in understanding the impact of a 16/20 hour car journey undertaken on a frequent basis. The people that use their services are, by definition, resident in regional areas and some actually do drive 8- 10 hours on a fortnightly basis. These patients don’t have to avail themselves of an AF but they continue to do so and only then on medical advice. I also suggest that the vast majority do so because a stressful visit to a specialist that may have taken a number of days is, in some cases, reduced to a day out allowing them to sleep in their own bed that night.

Angel Flight is a true Australian icon and embodies the true essence of “Care in the Community”. It is not above criticism but when the alternatives are considered it stands up to scrutiny. I’m quite proud to be involved with their endeavours and long may they continue.
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Old 28th Aug 2019, 02:02
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Originally Posted by josephfeatherweight

Lead Ballon, I usually find you very exacting in what you say, so this surprised me a bit.
I think you’ll find they were most definitely “accidents”.
I’m aware of the counter-intuitive definition of “accident” in the ICAO convention and laws giving effect to it.

I was responding to this from AndrewR:
One might be an isolated incident. 2 is more significant...
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