Private pilot dropout hours - US
Thread Starter
In a sense, we already have a fair qualitative idea of what kills pilots - flying into IMC; carb icing; engine failure at night; the impossible turn etc... One could also argue that it doesn't really make sense to worry too much about the proportions of most of those accidents, because whichever one we neglect is the one that will catch us out. One has to think about all of them.
The 'killing zone' asks a much more general question - what the time course of developing a reasonable general level of competence and judgement is. The problem it tries to address isn't so much people doing demanding and risky things, as people doing risky or stupid things through ignorance rather than intent.
The 'killing zone' asks a much more general question - what the time course of developing a reasonable general level of competence and judgement is. The problem it tries to address isn't so much people doing demanding and risky things, as people doing risky or stupid things through ignorance rather than intent.
Join Date: Nov 2007
Location: Europe
Posts: 46
Likes: 0
Received 0 Likes
on
0 Posts
I think there's too much obsession about the fatal accident.
As said before there are simply not enough fatal accidents to make a reliable statistics on. For an accident to be fatal it has to be a rather spectacular one such as the ones agbd mentions above. Most accidents don't actually have a fatal outcome unless it's a high speed accident such as loss of control or CFIT, or there might be the odd case of very unlycky circumstances making the survival prospects very small. An engine failure daytime, even if caused by gross negligence, is normally a very survivable accident. And the most frequent accidents are very rarely fatal. Such as the mishandled crosswind landing, or the continued landing in to a wet short grass strip with too much speed, etc.
A few years ago (in the 90's) there was a survey regarding accident rates with gliders but it did not focus on fatalities, but all accidents. Compared to the large variety of different private flying operations, gliding is somewhat more consistent. Most of the flights takes place in similar weather conditions, similar type of flying, not too much variety of aircraft complexitiy and performance. (Mountain flying was excluded). The conclusion was quite similar to the "Killing Zone", that there was an increased rate of accidents at a certain level of experience. But once again, this was statistics which could be questioned just as we have done here.
As said before there are simply not enough fatal accidents to make a reliable statistics on. For an accident to be fatal it has to be a rather spectacular one such as the ones agbd mentions above. Most accidents don't actually have a fatal outcome unless it's a high speed accident such as loss of control or CFIT, or there might be the odd case of very unlycky circumstances making the survival prospects very small. An engine failure daytime, even if caused by gross negligence, is normally a very survivable accident. And the most frequent accidents are very rarely fatal. Such as the mishandled crosswind landing, or the continued landing in to a wet short grass strip with too much speed, etc.
A few years ago (in the 90's) there was a survey regarding accident rates with gliders but it did not focus on fatalities, but all accidents. Compared to the large variety of different private flying operations, gliding is somewhat more consistent. Most of the flights takes place in similar weather conditions, similar type of flying, not too much variety of aircraft complexitiy and performance. (Mountain flying was excluded). The conclusion was quite similar to the "Killing Zone", that there was an increased rate of accidents at a certain level of experience. But once again, this was statistics which could be questioned just as we have done here.
Join Date: Dec 2010
Location: UK
Posts: 134
Likes: 0
Received 0 Likes
on
0 Posts
Crankshaft makes an excellent point.
IF there are many more non-fatal accidents than there are fatal ones, then those accidents could include horrendous injuries. Often, when considering safety we focus too much on whether we'll be killed or not.
A really irritating example of this are the muppets who take their seatbelt off too early / stand up on commercial flights. You can see them thinking "i'm hardly going to be killed if it stops abruptly", well that's true, but you could also lose an eye or have horrific facial scarring, etc, etc. Or worse still, these utter morons could cause the same to another innocent passenger.
Aside from that rant!
... You'd probably find that if you were able to look at all GA accidents, then once an accident becomes and accident it's only a matter of luck whether it ends up a fatal one or not. So ...
But abgd's last post says it all in my opinion :
It's pointless worry about the number of hours you've had as P1 as a safety factor, as you literally cannot affect that (except not to fly into the "killing zone" at all).. instead look at what causes people to crash, and work as hard as you can to avoid the causes.
Otherwise all you're doing is saying "hold on, I'm in the killing zone, so I better be a bit more careful for 100 hours or so until I'm out of it, and can then just fly around carefree".
IF there are many more non-fatal accidents than there are fatal ones, then those accidents could include horrendous injuries. Often, when considering safety we focus too much on whether we'll be killed or not.
A really irritating example of this are the muppets who take their seatbelt off too early / stand up on commercial flights. You can see them thinking "i'm hardly going to be killed if it stops abruptly", well that's true, but you could also lose an eye or have horrific facial scarring, etc, etc. Or worse still, these utter morons could cause the same to another innocent passenger.
Aside from that rant!
... You'd probably find that if you were able to look at all GA accidents, then once an accident becomes and accident it's only a matter of luck whether it ends up a fatal one or not. So ...But abgd's last post says it all in my opinion :
In a sense, we already have a fair qualitative idea of what kills pilots - flying into IMC; carb icing; engine failure at night; the impossible turn etc... One could also argue that it doesn't really make sense to worry too much about the proportions of most of those accidents, because whichever one we neglect is the one that will catch us out. One has to think about all of them.
Otherwise all you're doing is saying "hold on, I'm in the killing zone, so I better be a bit more careful for 100 hours or so until I'm out of it, and can then just fly around carefree".
Thread Starter
A few years back, my obsession was cycling accidents rather than flying accidents, and there was pretty much the same problem. There are just over 100 deaths a year, versus 14 fatal accidents for GA.
At least for cyclists, it's almost impossible to infer anything from 'seriously injured' data, because this includes so much, from people rendered paraplegic to things that might spoil your day but which are not life changing. Rather a lot of 'seriously injured' people don't feel that they are 'seriously injured' enough to bother going to hospital, as an example.
You end up finding that your average cycling injury happens to a younger person (child, teenager) who is doing something dumb, but who probably gets away with a trip to A&E and no lasting harm. However, your average cycling fatality is an older person, possibly cycling to work after dark and often hit from behind - an almost vanishingly rare type of accident that is also exceedingly likely to prove fatal.
In the end I realised (as had some academic researchers) that fatal accidents were a much better proxy for 'life-changing' accidents, than 'serious' accidents were. I guess that's my bias coming to aviation statistics. But now you mention it, I can see it may have less justification in aviation.
On the other hand, the example you gave of a forced landing is one that may or may not affect both inexperienced and experienced pilots equally (somebody posted the other day that 80% were due to engine mismanagement) but where I would argue that experience would tend to swing things very much in your favour, all else being equal.
I wonder what proportion of forced landings do so little damage to the plane, that it's not notifiable as an accident? If it were a low proportion, one could search the NTSB database by type (e.g. C172, PA28) and chart the proportion of engine failures that were survived, by pilot hours. This might give some indication of how pilot experience affects manoeuvring skills.
At least for cyclists, it's almost impossible to infer anything from 'seriously injured' data, because this includes so much, from people rendered paraplegic to things that might spoil your day but which are not life changing. Rather a lot of 'seriously injured' people don't feel that they are 'seriously injured' enough to bother going to hospital, as an example.
You end up finding that your average cycling injury happens to a younger person (child, teenager) who is doing something dumb, but who probably gets away with a trip to A&E and no lasting harm. However, your average cycling fatality is an older person, possibly cycling to work after dark and often hit from behind - an almost vanishingly rare type of accident that is also exceedingly likely to prove fatal.
In the end I realised (as had some academic researchers) that fatal accidents were a much better proxy for 'life-changing' accidents, than 'serious' accidents were. I guess that's my bias coming to aviation statistics. But now you mention it, I can see it may have less justification in aviation.
On the other hand, the example you gave of a forced landing is one that may or may not affect both inexperienced and experienced pilots equally (somebody posted the other day that 80% were due to engine mismanagement) but where I would argue that experience would tend to swing things very much in your favour, all else being equal.
I wonder what proportion of forced landings do so little damage to the plane, that it's not notifiable as an accident? If it were a low proportion, one could search the NTSB database by type (e.g. C172, PA28) and chart the proportion of engine failures that were survived, by pilot hours. This might give some indication of how pilot experience affects manoeuvring skills.
Join Date: Jan 2008
Location: London UK
Posts: 517
Likes: 0
Received 0 Likes
on
0 Posts
Going back to abgd's original post, there is another way of judging the significance of Fig 1.2 in Paul Craig's "The Killing Zone", and I have always meant to do it, but never got round to it till now.
In simple terms:
Dropout Rate + Accident Stats -> Conclusion
Sadly we don't know the drop-out rates, but why don't we try it backwards?
Assumptions + Accident Stats -> Dropout Rate
With suitable assumptions we can start with the accident numbers and work out the drop-out rates they imply. Then we can judge how reasonable the drop-out rates are.
I had a stab at this, and there certainly seems to be a "safety zone" during pilot training, and then there might well be some kind of a "risky zone" for the next 250 hours or so.
Here is a link to what I found (you have to scroll past the flying pig):
TwoDodecaCarrot
PS For anybody who liked the Monty Hall problem, try googling: "boy born on Tuesday"
In simple terms:
Dropout Rate + Accident Stats -> Conclusion
Sadly we don't know the drop-out rates, but why don't we try it backwards?
Assumptions + Accident Stats -> Dropout Rate
With suitable assumptions we can start with the accident numbers and work out the drop-out rates they imply. Then we can judge how reasonable the drop-out rates are.
I had a stab at this, and there certainly seems to be a "safety zone" during pilot training, and then there might well be some kind of a "risky zone" for the next 250 hours or so.
Here is a link to what I found (you have to scroll past the flying pig):
TwoDodecaCarrot
PS For anybody who liked the Monty Hall problem, try googling: "boy born on Tuesday"
Thread Starter
The first graph shows two drop-out profiles: The dashed "Raw Data" line shows the dropout rate if pilot safety is completely unrelated to pilot experience. It is obviously wrong. The initial negative drop-out rates show only 40% of pilots starting with no experience, another 40% starting at 50H experience without ever having been in the sub-50H category and a final 20% start in the 100-150H category!
One thought is that 50 hours is a minimum for getting the ppl, so many people may still be working towards their licence at 50-80 hours, presumably remaining under instructor supervision for some time further after that.
In the USA you need 250 hours for a CPL - it would be interesting to take that into account too. I saw some training figures (on paper, not the internet) showing that in the UK, the annual number of fixed wing CPLs is now not very much less than the number of PPLs awarded each year, so despite the existence of straight-to-cpl programs, I think this is likely to be a big 'timed' effect.
I'll see if I can find the data (or ideally, USA data) again.
