Can we put the myth that singles are as safe as twins to bed now?

stratobee

stratobee

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stratobee
Stole this find from the Beechcraft forum: 93% of non commercial accidents are in singles, 7% are in twins. The FAA says that singles are flown 12.16 million hours per year and twins are flown 1.82 million hours per year. That means that singles have twice as many accidents per flying hours as twins.

Wherever that figure that we've heard bandied around for the last decades comes from, I don't know (Dick Collins, I'm looking at you), but they're not true according to these documents. First only deals with the amount of accidents, but the FAA one deals with flight hours:

http://www.aopa.org/-/media/Files/AOPA/Home/Pilot%20Resources/Safety%20&%20Proficiency/Accident%20Analysis/Nall%20Report/ASI%20GA%20Scorecard%202011_2012.pdf

General Aviation and Part 135 Activity Surveys - CY 2010

Interestingly, most accidents are in Day VFR, not IMC like is often mentioned.
 
So how many single engine plane crashes happened solely because they only had one engine? That's what you're looking for right?
 
and how many PPL students train in twins?
 
Not normalized for the single vs twin population or flight hours.

Just taking piston single and piston twin, I would speculate that there are about 4X single engine plane ops per twin. Similar for flight hours maybe.
 
Silvaire said:
So how many single engine plane crashes happened solely because they only had one engine? That's what you're looking for right?
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Exactly! I don't presume to know the answer but the stats quoted by the poster are misleading. For example I would expect a multi-engine rated pilot to have more experience and more ratings than Billy with 20 hours total time who flew into IMC with his 152 and never made it back. Perhaps a better question might be how many of those single engine accidents were caused by engine failure, where a second engine might have made a difference.


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You also have to take into account that people flying twins have had more instruction overall. A single as little as 40 hours. At minimum, by the time you are flying twins, you have your private and at least another 10 to 20 hours doing your complex and hp ratings. Then you have another 20 hours or so in getting your twin. So you would be at an absolute minimum of about 80 hours to get that rating.

Now you can even give more hours to the twin people. What percentage of twin certified pilots have their IFR as opposed to people flying singles? Remember, if you take the time to go to a twin your mission generally includes "higher risk" flying, so I bet IFR is much more common in those pilots. Since VFR into IFR conditions is a major cause of accidents in pilots not trained for IFR, it seems likely that if more twin certified pilots also have their IFR, then this would reduce this type of accident.

Plain and simple twin certified pilots on average have more training, more advanced ratings, and more experience. I do not know how to correct that accident rate for those variables.
 
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NTSB report for 2002
http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-data/ARG06-02.pdf
shows that piston twins are flown mainly by pilots with over 1000 hours experience, and (per hour flown) they are slightly less likely to have an accident but slightly more likely to have a fatal accident.

It also shows that fatalities due to loss of engine power for mechanical reasons are not numerous.

There are probably more recent reports, but that is the one I found first by google.
 
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drotto said:
You also have to take into account that people flying twins have had more instruction overall. A single as little as 40 hours. At minimum, by the time you are flying twins, you have your private and at least another 10 to 20 hours doing your complex and hp ratings. Then you have another 20 hours or so in getting your twin. So you would be at an absolute minimum of about 80 hours to get that rating.

Now you can even give more hours to the twin people. What percentage of twin certified pilots have their IFR as opposed to people flying singles? Remember, if you take the time to go to a twin your mission generally includes "higher risk" flying, so I bet IFR is much more common in those pilots. Since VFR into IFR conditions is a major cause of accidents in pilots not trained for IFR, it seems likely that if more twin certified pilots also have their IFR, then this would reduce this type of accident.

Plain and simple twin certified pilots on average have more training, more advanced ratings, and more experience. I do not know how to correct that accident rate for those variables.
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I bought my Travelair when I had 60hrs TT, received another 25 in my twin for the rating and insurance. I had a PP and no IR. Twins are not monsters. The higher risk I was looking at was flight over inhospitable terrain, much of it at night.
 
The best piece of safety equipment any airplane can have is a well trained pilot that understands his limitations as well as the limitations of the aircraft he flies.
 
drotto said:
Plain and simple twin certified pilots on average have more training, more advanced ratings, and more experience. I do not know how to correct that accident rate for those variables.
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that's what I'm thinking. You'd expect fewer accidents in twins b/c the pilots are more experienced.
 
How about this one: out of all accidents how do the rates compare between twins and singles as to fatality/non-fatality?
 
Henning said:
I had almost 4 hrs of BE-18 time towards mine, Danny Kaye did his whole PPL in an Aztec IIRC.
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Ok, so out of the how many thousand posters we have on this board, you are the only one. I've also never heard of anyone else doing it that way. It is not a common practice. One out of every what, 50,000-100,000?
 
drotto said:
You also have to take into account that people flying twins have had more instruction overall. A single as little as 40 hours. At minimum, by the time you are flying twins, you have your private and at least another 10 to 20 hours doing your complex and hp ratings. Then you have another 20 hours or so in getting your twin. So you would be at an absolute minimum of about 80 hours to get that rating.

Now you can even give more hours to the twin people. What percentage of twin certified pilots have their IFR as opposed to people flying singles? Remember, if you take the time to go to a twin your mission generally includes "higher risk" flying, so I bet IFR is much more common in those pilots. Since VFR into IFR conditions is a major cause of accidents in pilots not trained for IFR, it seems likely that if more twin certified pilots also have their IFR, then this would reduce this type of accident.

Plain and simple twin certified pilots on average have more training, more advanced ratings, and more experience. I do not know how to correct that accident rate for those variables.
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20 hours is not a typical amount of training to get a MEL add on;however, more training is usually required for insurance for a twin checkout-owned or rented.
 
EdFred said:
Ok, so out of the how many thousand posters we have on this board, you are the only one. I've also never heard of anyone else doing it that way. It is not a common practice. One out of every what, 50,000-100,000?
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probably not common but it does happen. My first solo and first license were in a C-337
 
Good thing this is an aviation board and not a statistician board. If it were the latter, a few of you would have to be banned for statistical abuse.
 
If your engine dies in the clag your autopilot will fly you into the side of a mountain and you can watch it happen on the G1000.
 
Aside from pilot error, what is the rate of engine failure. How many pilots here have lost an engine? I have asked a/p, they say the rarely see or hear about engine failures.
 
RotorAndWing said:
If we're talking GA, I've lost 4. 2 in singles and 2 in twins.
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I can't find a reliable number for MTBF for a piston engine.

I'm guessing that it is around 5000 hours, based on the experience of one high-time guy I know. For complete failure for mechanical reasons in flight. Much higher if you include fuel problems and partial failure.
 
Safety of the airplane has to do with the skill and training of the pilot,not the number of engines he has.
 
I had posted this graphic on the board a while ago, always interesting to think about/discuss even though it's not multi-specific. Of the 3,107 accidents listed below, a fatality from engine failure only occurred in 2% of them.
defining_accident_events_2007-2009.png
 
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EdFred said:
Ok, so out of the how many thousand posters we have on this board, you are the only one. I've also never heard of anyone else doing it that way. It is not a common practice. One out of every what, 50,000-100,000?
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It's irrelevant to the point, people are searching for a way to rationalize a single being safer than a twin for them. It doesn't exist, quit rationalizing and just accept that. Rationalization is one of the hazardous attitudes, and once you start, you just keep on going.
 
Henning said:
It's irrelevant to the point, people are searching for a way to rationalize a single being safer than a twin for them. It doesn't exist, quit rationalizing and just accept that. Rationalization is one of the hazardous attitudes, and once you start, you just keep on going.
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You missed the point.
 
EdFred said:
You missed the point.
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Not at all, people are trying to say that the real statistics are not because a twin is safer, but because twin pilots are more experienced high time pilots which is pretty irrelevant because a twin is no more difficult to fly than a single.
 
C182P said:
Good thing this is an aviation board and not a statistician board. If it were the latter, a few of you would have to be banned for statistical abuse.
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frfly172 said:
Safety of the airplane has to do with the skill and training of the pilot,not the number of engines he has.
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(just posting a reply to the thread, not pick at on any particular poster)

Good thing this also isn't a safety board.

Safety is about managing all the risks/hazards.

A much faster aircraft can have higher risks due to higher landing speeds.

Complexity can bring additional risks

One highly reliable engine can have less risk than a twin with engines that have very low MTBF.

Safety analysis is waaaaaay more complex than counting the number of engines.
 
Who is saying that singles are actually safer? Arguing that the differential in accident rate is partly due to other factors isn't the same thing as saying that singles are safer to fly. For me, a twin is just out of the question for reasons of cost. If I could afford to fly one, I would.
 
No, I don't think you can put it to rest. In my case, I know you can't. I'd much rather have an engine failure on take off in a single than in a twin.

For one thing, I'd have a lot of runway left. For another, I don't know how to fly a twin!
 
tinerj said:
No, I don't think you can put it to rest. In my case, I know you can't. I'd much rather have an engine failure on take off in a single than in a twin.

For one thing, I'd have a lot of runway left. For another, I don't know how to fly a twin!
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Which makes your opinion based on lack of knowledge outside of myth.
 
tinerj said:
No, I don't think you can put it to rest. In my case, I know you can't. I'd much rather have an engine failure on take off in a single than in a twin.



For one thing, I'd have a lot of runway left. For another, I don't know how to fly a twin!
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Yes, but here's the thing...you don't get to choose if, when and where you will lose an engine.

Not saying that I'm safer because I fly a twin....just that what is really 'safer' is a lot more complicated than what some folks try to make it out to be.
 
Fearless Tower said:
A lot of people have been arguing that point on the internet and in several aviation magazines in the last 5-10 years.
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Maybe so, but so far, not in this thread, or on this board for that matter, at least in the threads I've followed.
 
I've dated singles and twins... The twins were definitely more dangerous, once they'd compared notes.

Oh... sorry, I thought this was one of the other threads.

yes this is sarcasm.
 
What to be safe...Go turbine and leave the piston engine on the ground.
 
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