HEMS safety (?)

[Melclin]

I just came across a couple of flight articles a little while ago.

One was on Australia HEMS safety (includes stats for SAR, rescue winch etc, because alot of Australia HEMS choppers fulfill multiple roles).

It showed between 1992 and 2002 that there were 50,164 missions flown in the entire country, with 3 accidents occurring. Only one of them was fatal (a 5yr old boy, his mother, the pilot and two paramedics were killed).

All three of those accidents occurred in one state (QLD), in one community based service, and some controversy surrounds their flight rules, but I don't understand the aviation talk.

Minus that one service<_<, there were no crashes or fatalities in the entire country over a ten year period. Approx 42,000 missions, no crashes for rescue and HEMS.

Now my point here is not to brag, the thing the got me is that the above record seems pretty decent, especially if you take into account that the QLD accidents were probably caused by factors not affecting the other services so much, HOWEVER, the comparrison with US stats were as follows: AUS: 1.46 accidents per 100,000 flight hours, US: 1.69 per 100,000 hours.

That doesn't seem much different, and it doesn't seem commensurate with how dangerous everyone here claims American HEMS to be. What am I missing? Dodgy stats? Some kind of statistical oddity misleading me? What are the mission stats on American HEMS, do you just fly so many more hours that u get more fatalities?

This is the article in question, "Holland J & Cooksley D G. Safety of helicopter aeromedical transport in Australia: a retrospective study. MJA 2005; 182: 17–19"

 

[HNcorpsman]

just wait for usafmedic, he is the subject matter expert on this subject.

 

[usafmedic45]

I just came across a couple of flight articles a little while ago.

One was on Australia HEMS safety (includes stats for SAR, rescue winch etc, because alot of Australia HEMS choppers fulfill multiple roles).

It showed between 1992 and 2002 that there were 50,164 missions flown in the entire country, with 3 accidents occurring. Only one of them was fatal (a 5yr old boy, his mother, the pilot and two paramedics were killed).

All three of those accidents occurred in one state (QLD), in one community based service, and some controversy surrounds their flight rules, but I don't understand the aviation talk.

Minus that one service<_<, there were no crashes or fatalities in the entire country over a ten year period. Approx 42,000 missions, no crashes for rescue and HEMS.

Now my point here is not to brag, the thing the got me is that the above record seems pretty decent, especially if you take into account that the QLD accidents were probably caused by factors not affecting the other services so much, HOWEVER, the comparrison with US stats were as follows: AUS: 1.46 accidents per 100,000 flight hours, US: 1.69 per 100,000 hours.

That doesn't seem much different, and it doesn't seem commensurate with how dangerous everyone here claims American HEMS to be. What am I missing? Dodgy stats? Some kind of statistical oddity misleading me? What are the mission stats on American HEMS, do you just fly so many more hours that u get more fatalities?

This is the article in question, "Holland J & Cooksley D G. Safety of helicopter aeromedical transport in Australia: a retrospective study. MJA 2005; 182: 17–19"

There is a big difference between the two countries in terms of how the operations are pursued, the attitude towards safety, how the governments handle aviation regulation and oversight and that has a lot to do with why there are such dramatic differences in crash rates. I hate to say this, but a more detailed explanation from me is going to have to wait until this evening as I am about to leave for work. I am sure someone else with a good background (Rid, MSDeltaFlight, VentMedic, etc) will be able to hit the key points and I'll fill in the remainder or correct any misconceptions.

 

[Melclin]

Yeah I realize there are very large differences in approach, hence my expectation that the crash stats would be more different.

 

[usafmedic45]

Sorry, I was half awake this morning when I read and responded to your post so I apologize for misunderstanding what your were asking.

HOWEVER, the comparrison with US stats were as follows: AUS: 1.46 accidents per 100,000 flight hours, US: 1.69 per 100,000 hours

I find those numbers- at least for the US stats- incredibly suspect. It seems like they might have "cherry picked" the numbers by including only fatal accidents (which is actually a very poor indicator of aviation safety) and even then it seems like they parred the numbers down, perhaps by using a restrictive definition of what consititutes an HEMS flight.

The problem might be explainable by the Aussie flights being longer since most crashes occur during takeoff, approach and landing and thus there are fewer takeoffs and landing in that given number of flight hours so less exposure to risk. Perhaps a better measure in this case might be number of crashes per 100,000 miles flown to allow for the differences in the length of an "average" flight between the two countries.

It also might be a question of what years they looked at, since the explosive growth of the last few years in the US (mostly in the form of fly-by-night dash for cash operations such as AirEvac Lifeteam) has played a large role in the horrendous death toll. You are also looking at old data. The recent NTSB hearings cited a crash rate in the US of 4.56 crashes per 100,000 flight hours for the period of 1997 through 2001.


The things to consider when reading anything involving HEMS safety:
-What did they consider an "aeromedical flight" (did they count ferry flights where they were not either transporting a patient or responding to a scene?, etc)?
-What is/are the measures being used to yardstick the crash rate against?
-Were they solely looking at fatal crashes? If so, why?
-What was the source of the data? If they are using NTSB/ATSB data it is much more likely to be free of bias than data from a lobby like the AAMS (Association of Air Medical Services) that has an agenda to promote ahead of any concern for safety or efficacy?
-What role do the authors of the study play in HEMS? Are they safety researchers vs employees of an HEMS operator vs someone who has a lot riding on making HEMS look good (*cough* Robert Bass *cough* Tom Scalea *cough* Maryland State Police *cough**cough)? In other words, is there a conflict of interest?
-Where was it published? If it came out of the Annals of Emergency Medicine, Accident Analysis and Prevention, Aviation Space and Environmental Medicine, it probably should be looked at as carrying far more weither than something published in the Air Medical "Journal" which is nothing more than the industry lobby mouthpiece and is filled mostly with marginally conducted research (I've seen better experimental constructs on Mythbusters) and has a long history of printing numerous whitewash stories about the wonders of HEMS while ignoring for the most part the appalling loss of life in HEMS. Relying on anything published in the Air Medical "Journal" to assess HEMS benefit or safety is a lot like relying upon handouts from a political party about how great their ideas and candidates are.

 

[Melclin]

I find those numbers- at least for the US stats- incredibly suspect.
I thought so too, even given my limited knowledge. Hence my questions.

It seems like they might have "cherry picked" the numbers by including only fatal accidents (which is actually a very poor indicator of aviation safety) and even then it seems like they parred the numbers down, perhaps by using a restrictive definition of what consititutes an HEMS flight.

It didn't seem to be suggesting that it was only fatal crashes. The Australian stat wasn't and it would be awfully poor form to change the rules for the US stats. This is their reference for the American Stats:
Blumen IJ, UCAN Safety Committee, editors.
Air medical physician handbook, November
2002 supplement. Salt Lake City, Utah: Air Medical
Physician Association, 2002.


The problem might be explainable by the Aussie flights being longer since most crashes occur during takeoff, approach and landing and thus there are fewer takeoffs and landing in that given number of flight hours so less exposure to risk. Perhaps a better measure in this case might be number of crashes per 100,000 miles flown to allow for the differences in the length of an "average" flight between the two countries.

The average flight time, roughly, (hours/missions) was about 1.2 hours, I think. Is that long by American standards. I keep hearing about HEMS flights to suburban neighbourhoods for 10 min flights to trauma centres. That seem a special kind of dangerous and unnecessary to me.

It also might be a question of what years they looked at, since the explosive growth of the last few years in the US (mostly in the form of fly-by-night dash for cash operations such as AirEvac Lifeteam) has played a large role in the horrendous death toll. You are also looking at old data. The recent NTSB hearings cited a crash rate in the US of 4.56 crashes per 100,000 flight hours for the period of 1997 through 2001.

Both were for the same periods apparently: 1992-2002. Over the course of that time there was no increase in fatalities or crashes despite a tenfold increase in missions (in Aus I mean).

The things to consider when reading anything involving HEMS safety:
-What did they consider an "aeromedical flight" (did they count ferry flights where they were not either transporting a patient or responding to a scene?, etc)?
-What is/are the measures being used to yardstick the crash rate against?
-Were they solely looking at fatal crashes? If so, why?
-What was the source of the data? If they are using NTSB/ATSB data it is much more likely to be free of bias than data from a lobby like the AAMS (Association of Air Medical Services) that has an agenda to promote ahead of any concern for safety or efficacy?
-What role do the authors of the study play in HEMS? Are they safety researchers vs employees of an HEMS operator vs someone who has a lot riding on making HEMS look good (*cough* Robert Bass *cough* Tom Scalea *cough* Maryland State Police *cough**cough)? In other words, is there a conflict of interest?
-Where was it published? If it came out of the Annals of Emergency Medicine, Accident Analysis and Prevention, Aviation Space and Environmental Medicine, it probably should be looked at as carrying far more weither than something published in the Air Medical "Journal" which is nothing more than the industry lobby mouthpiece and is filled mostly with marginally conducted research (I've seen better experimental constructs on Mythbusters) and has a long history of printing numerous whitewash stories about the wonders of HEMS while ignoring for the most part the appalling loss of life in HEMS. Relying on anything published in the Air Medical "Journal" to assess HEMS benefit or safety is a lot like relying upon handouts from a political party about how great their ideas and candidates are.

Yeah it was published in the Medical Journal of Australia - its not 'Nature', but its not the Womens Weekly either. There was no conflict of interest statement, which I believe they are required to do - but who knows. The authors are both EM docs. All things considered its not the best of articles, but it was really intended for comparisons to other services.

Good info, I'll keep it in mind for future research.

http://www.scribd.com/doc/17834418/MJA-Safety-of-Helicopter-Aeromedical-Transport-in-Australia

This is the paper. If you can be bothered glossing over it.