Twins are No Safer Than Singles

[philiplane]

On 7/10/2021 at 7:58 PM, PMcClure said:

I think the math has already been done. Check the cost to insure a similar valued twin to the mooney.

A twin costs about 50 percent more to insure, but only because the most common claim is a gear up landing. In which case, a twin has two props and engines to repair.

You'd think insurance should cost double, or more, but it does not.

Edited July 12, 2021 by philiplane

[aviatoreb]

37 minutes ago, KLRDMD said:

I just got a text from a friend of mine who owns a Beech 58P (pressurized Baron). He had to shut down his right engine tonight and landed uneventfully at CHD. He would not have made the airport in a single engine. Would he have survived the landing, been injured, badly? Fortunately, we'll never know. There will be no accident/incident report.

He had a B55 Baron previously. In that airplane he also had to shut one down and landed uneventfully, this time at ABQ. That was less than 100 flight hours ago for him. Again, no accident/incident report was filed. In this case he would have landed out in the desert somewhere between Albuquerque and Phoenix. With his family onboard. If in a single engine would they have been injured, alive, who knows?

This was the last part of his text to me: "The guy in the tower at Chandler though was more frazzled than me because he was the controller when the Bonanza overran the runway yesterday. They had firetrucks out and everything."

Oh, and he is METICULOUS about every last thing on his airplane being perfect. No squawks ever. A completely open checkbook.

You can see the right prop feathered.

So you are arguing that twins are cheap and safer.

I don't buy that they are safer in average Joe-pilots hands and most of us here are average Joe pilot.  Sure if you or I have an engine in cruise flight then no question, I would sooner a twin.  If you are over hostile terrain, flying at night, etc then no question.  But you mentioned it - in a twin most of the risk is concentrated in the 1st 30 second or so of every flight.  Loose an engine when low and slow climbing out, and there is a procedure, but time and again, average Joe pilot has proved often to not be up to the task, and ends up flipping upside down and crashing into the flight safety building.

If I had a twin, I would fly at night and over more hostile terrain.  I do not, so I do not.  That is my small part in mitigating the cruise flight risk of a single.

I am just not convinced that in a years worth of operations, that I would be safer in a twin.   I think I would be less safe.  I would probably take on certain more challenging flights, and also I would hope to stay enough current on the emergency cage-the-correct engine quickly maneuver just in case on engine out on take off, but we can never be sure.  3 seconds.  stay current!  knock on wood.  Of course singles are dangerous too.  So no doubt and no second guessing here.  I am just very much unconvinced you have an open and shut case.

If I had need to fly at night, or carry more load, I would get a twin since those are great reasons to get a twin.  If I wanted a twin I would go get a twin.

Separate - do twins have engine failures more often than singles?  Anecdotally so many people seem to have engine loss.  Ok take that with a grain of salt since I too had an engine loss, a complete loss of power in cruise flight in my single, at 16,000 (by choice as a practice my theory being that altitude is the poor man's twin, and in day flight by choice as a practice I give up night flying in a single - so am I more, less or same safe in a single in day flight than twin in night flight?), and I thankfully found myself to an uneventful landing on a runway.  No damage, no ntsb report.

[philiplane]

1 hour ago, aviatoreb said:

Those seem nice - very fuel efficient.

how is climb performance at sea level with one engine?

Much better than a single with an engine out....

[philiplane]

I suggest everyone read the FAA daily accident reports each day for the next year. 

You will find lots of singles have off airport landings, with injuries, and fatalities, due to engine failures. Sometimes several per day.

You will also find that is is very rare for a twin to show up in these reports, with injuries and fatalities, due to an engine failure.

[aviatoreb]

3 minutes ago, philiplane said:

I suggest everyone read the FAA daily accident reports each day for the next year. 

You will find lots of singles have off airport landings, with injuries, and fatalities, due to engine failures. Sometimes several per day.

You will also find that is is very rare for a twin to show up in these reports, with injuries and fatalities, due to an engine failure.

Not systematic and doing that anecdotal study would have no relevance to me.

How many twins are there vs how many singles?  How many of those twins are flown by non professional operations pilots?  I imagine the number is much smaller, but I am only imagining.  I presume that is already all baked into whatever the actuaries did in making rates.

[philiplane]

Just now, aviatoreb said:

Not systematic and doing that anecdotal study would have no relevance to me.

How many twins are there vs how many singles?  How many of those twins are flown by non professional operations pilots?  I imagine the number is much smaller, but I am only imagining.  I presume that is already all baked into whatever the actuaries did in making rates.

There is no systematic way to do it, because there are no reports on how many twins suffer engine failures and land safely. But every single that loses an engine will end up in a report because in virtually all cases, it results in an accident with some injuries, or fatalities. And rates for insurance are based on claims, not on a feeling of what is or is not the safer plane. 

I've personally dealt with dozens of aircraft recoveries and rebuilds over the last 25+ years. At least a dozen fatalities. I've only witnessed two twins with injuries or fatalities in that group, and those two were take-offs with possible or known mechanical defects after unsatisfactory run-ups where the pilots took off anyway. One was a Cheyenne, the other a Cessna 335.

My personal experience includes 5000+ hours of multi engine time in about 30 different twins, from a Piper Apache, to Barons, 310's, Navajos, King Airs, and Cheyennes including the 400LS, And several Citation series jets. A loaded King Air 90 does not climb much better than a loaded Seneca on one engine, although you can do it in air conditioned comfort.

Everyone focuses on the engine out on takeoff, which is actually the least likely situation. Most engines fail enroute, due to lack of fuel, or oil, or a cylinder giving up. Those situations are easily handled, whereas in a single, they nearly always result in an accident. 

There are about ten to twelve singles for every twin. But, most twins fly much more than comparable singles, and fly in worse weather, so it is hard to compare apples to apples. 

If all the hyperventilating about how dangerous twins are were true, we would see a fatal twin accident every week. I think I've seen three so far this year. I've also seen dozens of fatals in singles this year though. 

My experience with insurance is that a twin does not cost much more than a comparable single to insure. Certainly not double, and not because it's likely to roll over and crash on every take off. It costs more because a pilot is nearly as likely to gear it up, as to gear up a single. 

[aviatoreb]

18 minutes ago, philiplane said:

There is no systematic way to do it, because there are no reports on how many twins suffer engine failures and land safely. But every single that loses an engine will end up in a report because in virtually all cases, it results in an accident with some injuries, or fatalities. And rates for insurance are based on claims, not on a feeling of what is or is not the safer plane. 

I've personally dealt with dozens of aircraft recoveries and rebuilds over the last 25+ years. At least a dozen fatalities. I've only witnessed two twins with injuries or fatalities in that group, and those two were take-offs with possible or known mechanical defects after unsatisfactory run-ups where the pilots took off anyway. One was a Cheyenne, the other a Cessna 335.

My personal experience includes 5000+ hours of multi engine time in about 30 different twins, from a Piper Apache, to Barons, 310's, Navajos, King Airs, and Cheyennes including the 400LS, And several Citation series jets. A loaded King Air 90 does not climb much better than a loaded Seneca on one engine, although you can do it in air conditioned comfort.

Everyone focuses on the engine out on takeoff, which is actually the least likely situation. Most engines fail enroute, due to lack of fuel, or oil, or a cylinder giving up. Those situations are easily handled, whereas in a single, they nearly always result in an accident. 

There are about ten to twelve singles for every twin. But, most twins fly much more than comparable singles, and fly in worse weather, so it is hard to compare apples to apples. 

If all the hyperventilating about how dangerous twins are were true, we would see a fatal twin accident every week. I think I've seen three so far this year. I've also seen dozens of fatals in singles this year though. 

My experience with insurance is that a twin does not cost much more than a comparable single to insure. Certainly not double, and not because it's likely to roll over and crash on every take off. It costs more because a pilot is nearly as likely to gear it up, as to gear up a single. 

You have put in some interesting data that I don't have/ is it correct?

-you said there are about 10 times as many singles as twins.  So that might make it seem like there are more accidents in singles even if there were less or maybe there really are more.

-you said many twins fly more, and indeed many or flying professional routes, mail, part 135 etc.  I presume those are more current pilots than average Joe pilot.  I consider myself average Joe pilot.

-the risk for singles is present in cruise and in take off.  The risk in twins is largely concentrated on take off.  And they do happen.

-twins are often rightly deployed on more challenging flights.  So if a person in their single thinks they can do the same challenging flights for sure I would expect the singles on average to come out badly.  On the other hand if singles avoid those challenging flights because they have a single. they may well come out safer because of the reduced mission.

-I think the study can be done.  Not on an hourly basis, but on an annual basis.  What fraction of airplanes o the registry in each category are involved in incidents.  Yes, many singles fly less than many twins, yada yada.  I do think the actuaries and insurance companies are already doing this work.

[aviatoreb]

...and let us all affirm, this is surely one of the great tit-for-tat arguments of ga.  Right up there with canguard.   No evidence exists to prove one side definitely.

I firmly think a twin would be less safe in my hands and many are pilots like me.  Concientious, well meaning, reasonably current, but I know my limits and my time to train.

[EricJ]

3 hours ago, philiplane said:

But every single that loses an engine will end up in a report because in virtually all cases, it results in an accident with some injuries, or fatalities.

I don't think that is even close to true.   There are a number of known failures among this tribe that made it back to a runway without a report.    I've personally had three.     There are additional that end up in off-airport landings without damage, and some that end up in off-airport landings with damage but no injuries or fatalities.

 

[Urs_Wildermuth]

8 hours ago, aviatoreb said:

..and let us all affirm, this is surely one of the great tit-for-tat arguments of ga.

 

It is and I am quite sure the main reason for that is sour grapes and armchair experts who have never flown a twin but heard from a friend of a friends 2nd cousin that they are dangerous.

And you know, some of this is true. Yes, they are dangerous in those few first minutes of flight and they WERE more dangerous than now when Vmca demonstrations while in training were still forced and killed quite a lot of people.

The fact is, that the twin fleet operates quite safely in capable hands. If you are not capable, then clearly the airplane does not belong into your hands. That is why we have a MEP rating, which includes quite a lot of training and includes a lot of single engine flying. In my experience, when I started flying twins I was initially horrified and uncomfortable, because the actual training is gruelling. It is only once you get to fly the thing enroute when you get to experience what it is to actually fly normal ops, and quite some folks are sitting in quiet wonder why they have not had that critical engine failure after the first few months of flying... the large part of twin pilots see failures only during training or recurrency checks.

 

8 hours ago, aviatoreb said:

I firmly think a twin would be less safe in my hands and many are pilots like me

Have you ever actually done a MEP training? Or how do you come to this conclusion?

If you can fly a SEP safely, if you have the presence of mind to figure out an engine failure scenario in your SEP to the point where you know what to do if it happens, then you can learn to fly a twin. But clearly, if you are convinced that all twins are flying death traps and you are incapable of flying them, then you will most probably go into a twin transition training with so much negative expectation, that it won't work out for you.

 

Where I agree is that Twins need serious training and serious recurrency training to actually profit from the increase in safety that 2nd engine brings. Most folks do this with their IR recurrency flights, where they also refresh their OEI skills. But then, twins definitly can provide a level of safety which as SEP per definition can't reach.

 

 

[afward]

20 minutes ago, Urs_Wildermuth said:

Have you ever actually done a MEP training? Or how do you come to this conclusion?

If you can fly a SEP safely, if you have the presence of mind to figure out an engine failure scenario in your SEP to the point where you know what to do if it happens, then you can learn to fly a twin. But clearly, if you are convinced that all twins are flying death traps and you are incapable of flying them, then you will most probably go into a twin transition training with so much negative expectation, that it won't work out for you.

 

Where I agree is that Twins need serious training and serious recurrency training to actually profit from the increase in safety that 2nd engine brings. Most folks do this with their IR recurrency flights, where they also refresh their OEI skills. But then, twins definitly can provide a level of safety which as SEP per definition can't reach.

I think the point is mostly that a typical "weekend warrior" pilot isn't going to be consistently sharp enough to ensure proper and timely reaction to EFATO in a twin.  I know I personally am not flying enough to feel comfortable operating a twin...

End of the day, in the hands of a proficient pilot a twin will be safer (if noticeably more expensive).  I'm still keeping my single.

[aviatoreb]

48 minutes ago, Urs_Wildermuth said:

 

It is and I am quite sure the main reason for that is sour grapes and armchair experts who have never flown a twin but heard from a friend of a friends 2nd cousin that they are dangerous.

And you know, some of this is true. Yes, they are dangerous in those few first minutes of flight and they WERE more dangerous than now when Vmca demonstrations while in training were still forced and killed quite a lot of people.

The fact is, that the twin fleet operates quite safely in capable hands. If you are not capable, then clearly the airplane does not belong into your hands. That is why we have a MEP rating, which includes quite a lot of training and includes a lot of single engine flying. In my experience, when I started flying twins I was initially horrified and uncomfortable, because the actual training is gruelling. It is only once you get to fly the thing enroute when you get to experience what it is to actually fly normal ops, and quite some folks are sitting in quiet wonder why they have not had that critical engine failure after the first few months of flying... the large part of twin pilots see failures only during training or recurrency checks.

 

Have you ever actually done a MEP training? Or how do you come to this conclusion?

If you can fly a SEP safely, if you have the presence of mind to figure out an engine failure scenario in your SEP to the point where you know what to do if it happens, then you can learn to fly a twin. But clearly, if you are convinced that all twins are flying death traps and you are incapable of flying them, then you will most probably go into a twin transition training with so much negative expectation, that it won't work out for you.

 

Where I agree is that Twins need serious training and serious recurrency training to actually profit from the increase in safety that 2nd engine brings. Most folks do this with their IR recurrency flights, where they also refresh their OEI skills. But then, twins definitly can provide a level of safety which as SEP per definition can't reach.

 

 

I don't think twins are death traps.  I would happily buy one if my mission demanded it - for night flying, regular mountain flying, or the extra useful load.  I would not buy a twin because I think it is much safer.  I don't think it is much safer.  But that doesn't I think they are death traps.  Not at all. Everything I have read over the years suggest they are roughly similar on a per year basis as a single.  All thinks baked in.

Actual stats are hard to come by.  I have seen something, and being a mathematician that is what I look at, but I cannot find it again.

All I could find today was general statements like from this: https://www.avweb.com/ownership/do-you-really-want-a-twin/

"The overall accident rates of high-performance singles (like Bonanzas or 210s orMooneys) and light twins (like Aerostars or Barons or Commanders or Cessna 310s) areastonishingly close. Twins have a slightly higher accident rate per 100 aircraft and aslightly lower accident rate per 100,000 hours, but for all practical purposes theaccident rates are the same. The same is true if you consider only "serious"accidents that involve death, serious injury, or substantial damage. For bothhigh-performance singles and light twins, approximately one-third of all accidents areclassified as serious."

So yes, generally I think they are more or less the same, but yes quite desirable and appropriate to choose for specific and typical missions.  But not as a panacea that we will be dramatically safer as a population owning twins.

I am being a little dramatic in the previous posts deliberately taking the opposite side of the debate for sake of discussion. I have flown 5 hours of twin dual in my book with cfi-friends over the years.  Mostly a twin Comanche and a king air c90.  Not as lessons per se, but just going along for the ride but in left seat and doing a little air work on the way.  Including once the cage - the engine drill.  It didn't scare me in the least.

 

 

[steingar]

If I had to shut down at 12K feet I don't think I'd be sweating that hard unless I was over the Atlantic Ocean or the Rocky Mountains.  Our Mooneys can really glide.  I suspect any of us can make it to either to a usable field or a soft landing spot given that kind of altitude.

[Scott Dennstaedt, PhD]

11 hours ago, philiplane said:

I suggest everyone read the FAA daily accident reports each day for the next year. 

You will find lots of singles have off airport landings, with injuries, and fatalities, due to engine failures. Sometimes several per day.

You will also find that is is very rare for a twin to show up in these reports, with injuries and fatalities, due to an engine failure.

Not specifically engine failure related, but a study was done and published in 2015 and found that "Accidents in twin-engine aircraft carry a higher risk of fatality compared with single engine aircraft and constitute 9% of all general aviation accidents."

[A64Pilot]

You  have to be careful with stats, when I lived in Germany my neighbor told me that German’s have a saying, “Statistics are like a lady of the evening, if your paying, you get what you want”

Plus many defy logic. when anti-lock brakes for cars first came out, they were hailed as a significant safety improvement, insurence companies gave discounts for anti lock brakes.

‘Fast forward a few years and the stats show no difference at all in safety in cars equipped with anti lock brakes, I can’t explain it, logically there should be fewer crashes and less injuries. Many have postulated that people know they have anti lock brakes and drive more aggressively, I don’t believe that as the average driver doesn’t know what kind of brakes they have,

In 1993 when Chevy came out with the then new Camaro, according to the crash test data, it was the safest US built car in its class, a few years later when the accident statistics came out, you were more likely to be killed in a Camaro than any other US built car.

Volvo’s have forever had about the best safety ststistics than any other car, and yes they are a well built safe car, but it’s the way they are driven that makes them so safe, Volvo drivers are more often in the right lane going the speed limit and driving safely and the phrase hold my beer and watch this is almost never uttered in a Volvo, but likely heard very often in a Camaro.

Personally I never got my multi as I have no desire, and I know if I had one, I couldn’t afford to fly it as often as I can a single, and I like to fly.

Years ago my Father bought brand new C-210, very nice airplane but as it was only him and my Mother he didn’t need a 210 and as it cost more to fly he bought a C model Mooney, and my Mother learned to pack in pillow cases as they conform to the shape of the airplane, so yes they lost baggage space and useful load, but flew more often.

A friend used to fly the air show circuit in his Pitts, he learned very quickly that you could ship your clothes etc to the next Motel you were staying at, which lessens the “need” of a cargo carrying airplane, just ship the stuff your Wife bought on vacation home, and fly a smaller more efficient airplane, the cost savings of doing so far exceed any shipping charges.

[Hank]

22 minutes ago, A64Pilot said:

You  have to be careful with stats, when I lived in Germany my neighbor told me that German’s have a saying, “Statistics are like a lady of the evening, if your paying, you get what you want”

Plus many defy logic. when anti-lock brakes for cars first came out, they were hailed as a significant safety improvement, insurence companies gave discounts for anti lock brakes.

Look up Risk Homeostasis. As cars get safer, people's risk.tolerance remains the same, so they change their driving habits to maintain the risk level they are comfortable with. Safer car means riskier driving, and that's why we lost our ABS insurance discount. 

[A64Pilot]

1 minute ago, Hank said:

Look up Risk Homeostasis. As cars get safer, people's risk.tolerance remains the same, so they change their driving habits to maintain the risk level they are comfortable with. Safer car means riskier driving, and that's why we lost our ABS insurance discount. 

 

By that line of logic, then any safety gesture will be negated by riskier driving habits, but safety belts and air bags, crumple zones etc haven’t been negated, but anti lock brakes were.

I can’t explain it, other than to think that maybe locked brakes weren’t as unsafe and didn’t contribute all that much to accidents to begin with.

Either way, the possibility exists, although many will argue, but if there is the perception of greater safety, that pilots will make riskier flights.

‘For example when I was a kid we visited Newfoundland, my Father wouldn’t make that overwater flight due to water temps and expected survival time, so we made that leg Commercial and left the 210, if he had a twin he may have taken it.

[thinwing]

I went from a Baron D55 (285 hp a side) to a Bravo.The Bravo being much newer than a similar twin ,was definitely better equipped for the flying I was doing,Low time ,engine,fiki and the turbo gave me options I never had with the twin.I gave up the second engine with its cruise redundency,at least 800 lbs of useful load and picked up 10 gals less fuel burn in real world conditions...since my flying is only the wife and my self ,the bravos useful load has worked out fine...with most of our trips average 3 hrs at 200 kts.Fortunately the only engine shut down ive had , was due to alternator failure to perserve the Barons continental from debris from alternators drive coupling.A failure on takeoff close to vme was another matter...my go to plan if I couldnt stop on the runway,was to pull back the good engine and land straight ahead same as the Bravo.I dont typically fly at night,and over mountainous terrain..im a big fan of being within gliding distance of lakes and meadows.Obviously there are times I miss the Baron...but not at annual time.

[steingar]

Had a friend awhile back who lost an engine on takeoff in his Aztec.  Pulled the good one and crashed straight ahead.  Used to money to buy a Twinkie that he crashed with me in it.

[aviatoreb]

7 minutes ago, steingar said:

Had a friend awhile back who lost an engine on takeoff in his Aztec.  Pulled the good one and crashed straight ahead.  Used to money to buy a Twinkie that he crashed with me in it.

Glad you are ok.

I love the twinkies.  What happened in that one?

[Scott Dennstaedt, PhD]

7 hours ago, A64Pilot said:

You  have to be careful with stats, when I lived in Germany my neighbor told me that German’s have a saying, “Statistics are like a lady of the evening, if your paying, you get what you want”

That's why I only read peer-reviewed journals for this kind of stuff.  It's more objective and there's typically no axe to grind.  Although the ASI's Nall Reports are pretty darn good.

[jaylw314]

3 hours ago, steingar said:

Had a friend awhile back who lost an engine on takeoff in his Aztec.  Pulled the good one and crashed straight ahead.  Used to money to buy a Twinkie that he crashed with me in it.

What?? Wait, we're not talking about the little industrial angel food cake thing, are we? 

[jaylw314]

32 minutes ago, Scott Dennstaedt, PhD said:

That's why I only read peer-reviewed journals for this kind of stuff.  It's more objective and there's typically no axe to grind.  Although the ASI's Nall Reports are pretty darn good.

Readers of peer-reviewed journals should look critically at who is publishing that research.  It's becoming clear that the power of academic bias (the desire to produce positive findings) is even stronger than financial bias--worse yet, unlike financial bias, there has not been a systematic or cultural way of mitigating that bias.  We demand researchers disclose financial conflicts-of-interest, and hold them accountable when they fail to, but no such mechanisms exists for academic bias yet.

[smwash02]

14 minutes ago, jaylw314 said:

What?? Wait, we're not talking about the little industrial angel food cake thing, are we? 

Twinkies are Twin Comanches

10 hours ago, aviatoreb said:

"The overall accident rates of high-performance singles (like Bonanzas or 210s orMooneys) and light twins (like Aerostars or Barons or Commanders or Cessna 310s) areastonishingly close. Twins have a slightly higher accident rate per 100 aircraft and aslightly lower accident rate per 100,000 hours, but for all practical purposes theaccident rates are the same.

Interesting data point. I wonder how the flight path/weather decisions plays into this. I am more conservative in the terrain / time I'll fly in my Mooney than I would be in a twin. If I had a twin with real weather radar, this would change my decision making and path choices.

9 hours ago, Scott Dennstaedt, PhD said:

Not specifically engine failure related, but a study was done and published in 2015 and found that "Accidents in twin-engine aircraft carry a higher risk of fatality compared with single engine aircraft and constitute 9% of all general aviation accidents."

Adding to my comments above, I wonder if the situations a twin pilot finds themselves in have fewer 'outs' than singles from being able to and entering situations that would be beyond the risk tolerance for most in a single. I would be curious to see that data overlaid with if it was weather/terrain related.

Edited July 12, 2021 by smwash02

[EricJ]

22 minutes ago, jaylw314 said:

Readers of peer-reviewed journals should look critically at who is publishing that research.  It's becoming clear that the power of academic bias (the desire to produce positive findings) is even stronger than financial bias--worse yet, unlike financial bias, there has not been a systematic or cultural way of mitigating that bias.  We demand researchers disclose financial conflicts-of-interest, and hold them accountable when they fail to, but no such mechanisms exists for academic bias yet.

Uh, that's the peer-review part.   Believe me, the desire to shoot down flaws in somebody else's research is strong among academia, and most academic or society journals have a reasonable blind review process populated with both academic and industry reviewers.     I've been on both sides, as an author and as a reviewer, and while it's certainly not bullet proof it generally produces good results.   When it doesn't produce good results, the likelihood of somebody else publishing a follow-up pointing that out is pretty good.

Some journals do this better than others, so like anything, one must consider the sources.   The reputable journals put a lot of effort into keeping the process working in order to maintain the reputation and attract quality papers. 

All that said it is getting harder for many journals to stay relevant or functional given the crazy ways that information flows these days.   Authors, reviewers, and editors are generally not compensated in most journals, and if a journal makes access and distribution difficult by limiting access through restrictive fees, etc., the system starts to shrink in relevance.   A bad thing on the horizon may be the loss of a lot of peer-reviewed publication organizations, just under the weight of maintaining the system.

Anyway, just another 0.02.