I don’t have an allegiance to Cirrus. I’ve been flying lots of aircraft for lots of years.
I initially transitioned to twins because they fulfilled my mission profile more safely than one engine. I made a similar decision in choosing a parachute equipped tourer. If my aircraft still had two engines I would not require a parachute.
It comes down to logic, and physics – not marketing.
If you fly a piston single, the data demonstrates that there is a nonzero chance of an engine failure at some point. The data also demonstrates that if you have a forced landing there is a nonzero chance of a fatal accident as a result
If you have an engine failure and deploy a parachute within parameters, the current data demonstrates a zero chance of a fatal accident as a result.
The data set is 93 parachute deployments .
As I said previously, take the entire dataset of engine failures in an equivalent high performance single and randomly select any 93. How lucky do you have to be to find no fatalities in those random 93?This discussion isn’t really happening anywhere, except in some special interest groups. Most pilots (as in about 98%) know very well the Cirrus, with its chute, is a safer airplane in case of an engine out. And most people have no problem admitting that fact, even though they may not fly one.
Which may have a variety of reasons, the most important one being money, as the Cirrus’, even the earlier ones, are still comparably expensive compared to other, older, traditional single engine pistons.
It reminds me a lot of the discussion, back in the day, about safety belts becoming oblicatory to wear in cars. Lots of people, at the time, defended their not using them for lots of baloney reasons. If BRS would be easily retrofittable into Pipers, Bonnies, Mooneys, etc. this thread wouldn’t even exist.
Data shows that in a chute equipped plane like a Cirrus, there is also a nonzero chance of a fatal accident in case of engine failure.
There is no logic whatsoever, to compare all engine failures in non-chute planes with the special group of engine failures where the chute was deployed „within parameters“ and the pilot did not make any other significant mistake.
Comparing the 93 selected cirrus accidents where the chute was deployed and people all survived with a random sample of non chute accidents is as silly as comparing 93 successfull off field power off landings with 93 random Cirrus accidents (spoiler alert: in the latter case the non-Cirrus win).
If we compare something that should make sense, we need to compare a random sample of Cirrus accidents with a random sample of non chute equipped accidents – that is to compare the overall accident statistic for Cirrus with the overall accident statistics for similar performance planes. And, guess what, you suddenly see no significant difference…
LeSving wrote:
Buuut, pulling a chute in a perfectly well operational small little glider is not exactly the mark of an Aviator It’s a bit difficult to brag about your flying skills after such an event.
“The dirt is full of people who wanted bragging rights”
If you have an engine failure and deploy a parachute within parameters, the current data demonstrates a zero chance of a fatal accident as a result.
No. Using a binomial confidence interval calculator, that would indicate that the chance of a fatality is between 0% and 3.89%, using 95% confidence intervals. That’s good, undoubtedly much better than an old high performance spamcan but may not be better than some STOL aircraft that can crash slowly. I am certain that the chance of death is not zero.
Do those 93 deployments with no fatalities include the one where the pilot landed safely but the parachute didn’t come out?
https://statpages.info/confint.html
http://www.aero-news.net/index.cfm?do=main.textpost&id=da260970-3974-400f-95b1-c095ab971053
There was this one.
After Achim posted that, all those years ago, we got demands from several SR22 owners (in Germany, mostly) to remove it because it devalued their aircraft. We obviously didn’t – not least because it was already all over social media – and they left EuroGA in protest.
I think that if say most or all of the Cirrus chute pulls involved an engine stoppage, the advantage of the chute would be massive and quite obviously so. Forced landings are not something anybody wants to be doing, in general. But they don’t – see a list of the pulls posted some while back and with a discussion of each one. It doesn’t read all that great, actually…
Peter wrote:
But they don’t – see a list of the pulls posted some while back and with a discussion of each one. It doesn’t read all that great, actually…
And for the cherry-picking that will inevitably follow… I’ll have low-fat yogurt on mine please :-)
Snoopy wrote:
I never saw it that way, interesting. Thank you for the perspective.For me it’s still hard to understand how the PIC of AF447 can be responsible and held accountable for the crash when he wasn’t even at the controls. But, I get it, from the perspective highlighted by referring to ships and other vessels that have command hierarchy.
A lot of concepts in aviation have their roots in marine tradition. Nautical miles, anyone? In the case of AF447 it could be argued that knowing they were going to fly through the ITCZ on what apparently was a pretty bad night (several other airliners diverted) he should have been on the bridge, called cockpit in aviation. That’s why he’s called ‘captain’ and at sea any responsible captain will be on the bridge during difficult times. As he/she should be in an airliner.
The entire dataset
And for the cherry-picking that will inevitably follow… I’ll have low-fat yogurt on mine please :-)
I doubt anybody will want to do that lot again; it was done before around here.
But, yes, feel free 
I did type up a long itemised commentary a few years ago here and that whole thread is a good fun read too.
Playing with the numbers
93 chutes have been deployed. The total flight hours for the Cirrus fleet is (according to Cirrus) 11.6M hours. That means there are 0.80 deplyed chutes per 100k hours flown. Or, 1/lambda = 124731
According to this, Cirrus have had 86 fatal accidents up through 2018. So, subtracting 1M hours for 2019 and we get a fatality rate of 0.82 per 100k flight hours.
The world wide GA fatality rate for 2018 was 0.8 per 100k hours
This means the Cirrus fatality rate is about the same as world wide GA fatality rate. But – Cirrus has an additional 0.8 deployed chutes per 100k flight hours. One therefore has to wonder; why did they pull their chutes ?
