Twin engine or Single engine? (Dumb question)

So.... what about the stories I have heard about the tendancy of twins to flip over on take off if you loose an engine? Do we have any concerns about that?
 
hindsight2020 said:
Overwater solo? I'd probably still do it in a single. With the family on board? Hell no. Twin or nothing.
For that mission set, I see the value of a twin. For everything else over land? Not at $6/gal and engines at 30K+ a pop, I don't.
Click to expand...

It is a psychological concern. If your single has been flying just fine for 1,000 (well-maintained) hours, and you get nervous because you're crossing Long Island Sound or part of Lake Michigan, it is illogical. The odds are essentially the same. Thus, you should have been nervous for the past 1,000 hours, or you shouldn't be nervous now. But, we're not all capable of Spock's commendable control of emotion.
 
Scud_072 said:
So.... what about the stories I have heard about the tendancy of twins to flip over on take off if you loose an engine? Do we have any concerns about that?
Click to expand...

It is not a tendency, it is what it does when handled incorrectly.

A simplified situation is, if you're afraid of stalling and spinning on a base-to-final turn. When you operate the airplane correctly, it will not happen.
 
mtuomi said:
It is not a tendency, it is what it does when handled incorrectly.

A simplified situation is, if you're afraid of stalling and spinning on a base-to-final turn. When you operate the airplane correctly, it will not happen.
Click to expand...

Having just finished the multi engine rating, it is hard for me to imagine someone losing an engine, slowing all the way to Vmc, continuing to pull, and rolling.

If the same reaction were common in a single, we'd see a lot of stalls after an engine failure, but we don't see that. I wonder why?
 
Scud_072 said:
So.... what about the stories I have heard about the tendancy of twins to flip over on take off if you loose an engine? Do we have any concerns about that?
Click to expand...
That is why we train.

Unless you are flying something unique like the B-25 (VMC is ridiculously high) you should never be in a position (ie slow enough) for the airplane to VMC roll if one quits. Doesn't mean that people don't sometimes do it, but pilots also still run airplanes out of gas on a regular basis.
 
Piloto said:
Before Charles Lindbergh crossing of the Atlantic on a single two attempts were made on twins by other pilots, they were never found. Amelia Earthart crossed the Atlantic on a single but was lost on a twin.

On typical piston twin you have 12 cylinders. On a typical single you have four cylinders. Assuming a cylinder failure at 2000hrs for a 4 cylinder that will put the twin at a cylinder failure at every 700hrs.

Airlines prefer twins vs four engines or three engines because of the economy and dispatchability. FEDEX opted for the Caravan single vs a twin for the same reasons.

On take off at max power the probability of an engine failure is twice on a twin than on a single.

On a crash the single engine the engine provides a shield that is not on the twins.

To me there is no added advantage on piston twins but more maintenance and fuel costs.

There are singles like the Mooney Acclaim or the SR-22 that fly faster and cheaper than most piston twins.

José
Click to expand...

This is so poorly thought out I don't know where to start.
 
FloridaPilot said:
The article said: "History shows piston twins are no safer than afflicted singles. In fact, engine failures that result in accidents are more likely to be fatal in twins."
Click to expand...

This is often quoted, but leaves out the numerous twins that safely land on one engine following a failure. It also leaves out that many twins fly in worse conditions than many singles.
 
dans2992 said:
Having just finished the multi engine rating, it is hard for me to imagine someone losing an engine, slowing all the way to Vmc, continuing to pull, and rolling.

If the same reaction were common in a single, we'd see a lot of stalls after an engine failure, but we don't see that. I wonder why?
Click to expand...


The thrust is not asymmetric when you lose your engine in a single.
 
Aren't fatality rates higher in twins? Like 2 to 1 higher? So while, they should logically be safer, they aren't statistically.

But I'm sure there are reasons for some of that. Twins typically have more people in them if they go down. Pilots may fly into more dangerous conditions because they are in a twin. Complex aircraft are in general more dangerous, single or twin, and pretty much all twins are complex.
 
dans2992 said:
If the same reaction were common in a single, we'd see a lot of stalls after an engine failure, but we don't see that. I wonder why?
Click to expand...

We DO see a lot of stall/spin accidents in singles after engine failures on climb out.

Look up LOTOT (loss of thrust on takeoff) for more details.

Just like in a twin, training has everything to do with the outcome whether a single or twin. The big difference is that at lower altitudes, the twin will slow to below VMC before it stalls.
 
Last edited:
dans2992 said:
Having just finished the multi engine rating, it is hard for me to imagine someone losing an engine, slowing all the way to Vmc, continuing to pull, and rolling.
Click to expand...

A real life Vmc event is nothing like the watered down version we train during the ME rating.
 
weilke said:
A real life Vmc event is nothing like the watered down version we train during the ME rating.
Click to expand...

So very true. If a newly minted ME pilot thinks they understand VMC, they should watch some of the videos on YouTube of real life VMC rolls.
 
FloridaPilot said:
I'm a newbie, but the overall added expenses of owning a twin doesn't seem worth it to me. If it was a significant difference then I believe I would see different. Don't get me wrong, twins are beautiful but with that added expense I could fly more in a single to me it's all about getting in the air.
Click to expand...

It is worth it if you want to rely on a plane for transportation and are willing to spend the extra amount for a fully equipped twin with known ice and radar. There have been flights I had t scrub in the single that I would have done with either boots or on board radar.


The article said: "History shows piston twins are no safer than afflicted singles. In fact, engine failures that result in accidents are more likely to be fatal in twins."
Click to expand...

The data this conclusion is based on is garbage, the conclusion is invalid. It is based on accident reports. The great majority of engine failures in a twin end with a landing at an airport and are never reported to the FAA or NTSB. Even a single engine engine failure doesn't get reported unless there is an injury or substantial damage to the plane (there is a ntsb definition for what counts as such). If your underlying data is unreliable, so is your conclusion.

The equation is abit different with single engine turbines and jets. The engine itself is so reliable that failures dont make a big enough share to count. Still, the director of the Hawaii state dept of health died on a acheduled charter flight when the engine quit and they ended up in the ocean only a couple hundred yard from shore. Another Caravan full ofcpax landed on a public road at night in HI, lots of luck in that event. I believe that singles are safer when I get on board of a single engine commercial jet for a transatlantic flight the first time.
 
Fearless Tower said:
That is why we train.

Unless you are flying something unique like the B-25 (VMC is ridiculously high) you should never be in a position (ie slow enough) for the airplane to VMC roll if one quits. Doesn't mean that people don't sometimes do it, but pilots also still run airplanes out of gas on a regular basis.
Click to expand...
In the case of the pilot who shut down the good engine, on a go round, killing himself and family, it was a piper Cheyenne turbo prop. The CFI who trained him said he had about 500 hours in type and never missed a beat in a BFI or when he flew with him. He was a successful business owner, etc. but in a tense situation he made a fatal mistake. It's why military pilots are screened so carefully and so many wash out, still even then, a few make it thru. (The CFI said the Cheyenne 111 would easily do a go round on one engine. )
 
FloridaPilot said:
That is a good reason, especially if you get the same fuel burn. So if you were to get something like a Cirrus with the CAPS system wouldn't it be somewhat similar?
Click to expand...

I don't really want to be drifting down at night under a parachute knowing that I am likely going to impact some steep slope in the Sierras, or the like.
 
Since the comparison was being made with a twin, the alternative is pointing your twin with the failed engine down hill and landing at the nearest suitable airport in that direction. Compared to another single, then the parachute might be a better option, assuming the pilot is smart enough to glide away from dangerous terrain before popping the chute.
 
Jimmy cooper said:
In the case of the pilot who shut down the good engine, on a go round, killing himself and family, it was a piper Cheyenne turbo prop. The CFI who trained him said he had about 500 hours in type and never missed a beat in a BFI or when he flew with him. He was a successful business owner, etc. but in a tense situation he made a fatal mistake. It's why military pilots are screened so carefully and so many wash out, still even then, a few make it thru. (The CFI said the Cheyenne 111 would easily do a go round on one engine. )
Click to expand...

For every example of a twin pilot who screwed up I can find an accident report of a single engine pilot mistake.

No one is immune from making mistakes. All we can ultimately do is hedge our bets and mitigate risk. I have no delusions that when the crap hits the fan I won't make a mistake, but I do my best to be prepared and hopefully prevent fatal errors.
 
spiderweb said:
It is a psychological concern. If your single has been flying just fine for 1,000 (well-maintained) hours, and you get nervous because you're crossing Long Island Sound or part of Lake Michigan, it is illogical. The odds are essentially the same. Thus, you should have been nervous for the past 1,000 hours, or you shouldn't be nervous now. But, we're not all capable of Spock's commendable control of emotion.
Click to expand...

Oh come on, you don't need to patronize me. I believe you missed my point. We all know the engine doesn't know it's over water. I'm not nervous about losing an engine as a generality, otherwise I'd never fly. BTW, when I made the example I was referring to the Caribbean Sea and adjacent Atlantic Ocean, not piddly Long Island Sound. :rolleyes2:

At any rate, my point rather pertained to the the post-egress actions and responsibilities of a ditching with family versus crash landing. Having formal training in water and land survival, I am much more comfortable rolling the dice and being responsible for a post-crash rescue recovery in the semi-urban Central United States than managing a water survival situation hundreds of miles from the nearest US Coast Guard helo. That's not irrational fear, that's a calculated opportunity cost between two otherwise equal engine failures.

Over the land where I usually fly, help is one shout away or a cell phone call; hell I might just crash on top of help. Offshore over Milwaukee Deep or halfway between Curaçao and Hispaniola? Fat chance Jack. I don't want to be in that situation with my loved ones, not for an hour, let alone overnight. I rather crash on trees all day.

For that reason, I find the twin a dedicated superior choice for the overwater mission, whereas I'm not willing to say that for overland.
 
I still like my single engine, still drinks 100ll, but even slower than a twin, but the journey is important as the destination. I might go to a twin someday, but now I still like my single.
 
spiderweb said:
It is a psychological concern. If your single has been flying just fine for 1,000 (well-maintained) hours, and you get nervous because you're crossing Long Island Sound or part of Lake Michigan, it is illogical. The odds are essentially the same. Thus, you should have been nervous for the past 1,000 hours, or you shouldn't be nervous now. But, we're not all capable of Spock's commendable control of emotion.
Click to expand...
you have no concept of risk management. It's odds multiplied by consequences. If the consequence is death then the odds must be much longer to be acceptable.

Look at a construction site as an example. A worker might put down a board to walk over on a muddy area. The board is easy to walk on, the odds of falling off the board are small. If s/he does fall off then the severity is low (gets muddy but is uninjured).

Now but the same board bridging 2 platforms 100ft in the air. The board is just as easy to walk over. The risk of falling off is equally low. But the severity of falling off is high. Same board, same worker, but in this case a safety harness is required before walking across the board.

The chances of your single engine failing over lake michigan are indeed the same as that same amount of time over iowa. How does the severity compare ?

when we lived in IL i didn't fly across lake michigan in my twin. Severity of a failure is high and avoidance of the risk is easy (go around)
 
Last edited:
Fearless Tower said:
So very true. If a newly minted ME pilot thinks they understand VMC, they should watch some of the videos on YouTube of real life VMC rolls.
Click to expand...

What should be done to make it more realistic and, therefore, translatable to a real-world sudden engine loss?
 
hindsight, I did not mean to patronize you. I included myself in that statement. I wish all pilots could be as calm and collected in an emergency as a vulcan (theoretically) would be.

hindsight2020 said:
Oh come on, you don't need to patronize me. I believe you missed my point. We all know the engine doesn't know it's over water. I'm not nervous about losing an engine as a generality, otherwise I'd never fly. BTW, when I made the example I was referring to the Caribbean Sea and adjacent Atlantic Ocean, not piddly Long Island Sound. :rolleyes2:

At any rate, my point rather pertained to the the post-egress actions and responsibilities of a ditching with family versus crash landing. Having formal training in water and land survival, I am much more comfortable rolling the dice and being responsible for a post-crash rescue recovery in the semi-urban Central United States than managing a water survival situation hundreds of miles from the nearest US Coast Guard helo. That's not irrational fear, that's a calculated opportunity cost between two otherwise equal engine failures.

Over the land where I usually fly, help is one shout away or a cell phone call; hell I might just crash on top of help. Offshore over Milwaukee Deep or halfway between Curaçao and Hispaniola? Fat chance Jack. I don't want to be in that situation with my loved ones, not for an hour, let alone overnight. I rather crash on trees all day.

For that reason, I find the twin a dedicated superior choice for the overwater mission, whereas I'm not willing to say that for overland.
Click to expand...
 
I fail to find where my statement and yours diverge.

We are essentially saying the same thing. The airplane will react how it reacts exactly the same (given, of course, the same atmospheric conditions)--the only difference is the psychology of the pilot.

One may think they are perfectly fine flying over a flat area, having picked a perfect spot for a forced landing, only to run through some previously invisible wires, killing all involved.

JHW said:
you have no concept of risk management. It's odds multiplied by consequences. If the consequence is death then the odds must be much longer to be acceptable.

Look at a construction site as an example. A worker might put down a board to walk over on a muddy area. The board is easy to walk on, the odds of falling off the board are small. If s/he does fall off then the severity is low (gets muddy but is uninjured).

Now but the same board bridging 2 platforms 100ft in the air. The board is just as easy to walk over. The risk of falling off is equally low. But the severity of falling off is high. Same board, same worker, but in this case a safety harness is required before walking across the board.

The chances of your single engine failing over lake michigan are indeed the same as that same amount of time over iowa. How does the severity compare ?

when we lived in IL i didn't fly across lake michigan in my twin. Severity of a failure is high and avoidance of the risk is easy (go around)
Click to expand...
 
N747JB said:
He did fine up until it really counted, real shame.
Click to expand...

I would actually say he did a bad job from the moment he declared an emergency (which the report says was for a rough engine) and shut it down. From FL210 he could've gone about 80 nm E, NE, or NW and gotten to a towered airport (two of which were class C, and then two military airports), any of which would have emergency services. From FL210, that would've been an easy, controlled descent in a 421, as you well know. Instead he chose an airport 10 nm away with a 5000 ft runway on a hot day with 7 people in the plane. Any of the other options with emergency services also would've had an 8500+ ft runway - 12,000 ft at BHM or CBM!

From a rapid descent, he ended up doing a visual approach (which did not set him up for a stabilized approach like an ILS would have), put drag out too quickly, and then wasn't able to maintain glide path on one engine, which a 421 won't do. If he suspected the engine was on fire, it'd be one thing. Otherwise, no reason to be in a hurry down.

I would suggest the following would have been a better approach:

1) Evaluated the nearest airports with services
2) Since they were about equidistant, pick the one with the longest runway that's pointing about into the wind. If calm, just go longest
3) Vectors to an ILS (controlled descent)
4) Kept the flaps and gear up, put the gear down approaching the runway. If runway is of sufficient length, don't bother with flaps
5) Request assistance! You never know when you might need it

Whole point is to not rush (we're not in a hurry here) and make it as easy on yourself as possible, with as many outs as possible, and make sure the trucks are there.
 
Fearless Tower said:
For every example of a twin pilot who screwed up I can find an accident report of a single engine pilot mistake.

No one is immune from making mistakes. All we can ultimately do is hedge our bets and mitigate risk. I have no delusions that when the crap hits the fan I won't make a mistake, but I do my best to be prepared and hopefully prevent fatal errors.
Click to expand...


THIS,

I believe it all comes down to the pilot, plane and circumstances!
 
Fearless Tower said:
For every example of a twin pilot who screwed up I can find an accident report of a single engine pilot mistake.

No one is immune from making mistakes. All we can ultimately do is hedge our bets and mitigate risk. I have no delusions that when the crap hits the fan I won't make a mistake, but I do my best to be prepared and hopefully prevent fatal errors.
Click to expand...

I would think there are many more singles flying than twins, especially currently. More chances for mistakes. As for screwing up when the chips are down , an excellent example is the sad tale of Clarence , N.Y. When a pilot was in charge who never should have been there, much less faced with an emergency which he and the co- pilot not only did everything wrong but killed many others while they were at it. A completely avoidable accident. Clutch city.
 
hindsight2020 said:
Oh come on, you don't need to patronize me. I believe you missed my point. We all know the engine doesn't know it's over water. I'm not nervous about losing an engine as a generality, otherwise I'd never fly. BTW, when I made the example I was referring to the Caribbean Sea and adjacent Atlantic Ocean, not piddly Long Island Sound. :rolleyes2:

At any rate, my point rather pertained to the the post-egress actions and responsibilities of a ditching with family versus crash landing. Having formal training in water and land survival, I am much more comfortable rolling the dice and being responsible for a post-crash rescue recovery in the semi-urban Central United States than managing a water survival situation hundreds of miles from the nearest US Coast Guard helo. That's not irrational fear, that's a calculated opportunity cost between two otherwise equal engine failures.

Over the land where I usually fly, help is one shout away or a cell phone call; hell I might just crash on top of help. Offshore over Milwaukee Deep or halfway between Curaçao and Hispaniola? Fat chance Jack. I don't want to be in that situation with my loved ones, not for an hour, let alone overnight. I rather crash on trees all day.

For that reason, I find the twin a dedicated superior choice for the overwater mission, whereas I'm not willing to say that for overland.
Click to expand...

Sorry, I had to Google Hispaniola. I had no idea where that was. On another note, suppose you were flying around just tall buildings and had no where to land in an emergency. Your fate is pretty much sealed

IMO, I prefer a water landing, it's a BIG place to land and I would come prepared with an inflatable raft and some flares in the plane. My fate might be sealed as well but it's possible someone would find me alive rather than crushed in a building.
 
Jimmy cooper said:
I would think there are many more singles flying than twins, especially currently.
Click to expand...

For personal use, I would say you're right. But many of the twins flying out there are used for business purposes and thus fly more regularly than their single engine counterparts. That's also part of why you see them flying in worse weather frequently - "Gotta go, boss is here."
 
My Columbia is perfect for a 3 member family. Fast, efficient and capable. But what if we want to take friends, or we lose a cylinder 500' over Miami Beach, or we want to fly to Cozumel? So I started looking at twins.
Darn you Ted...darn you!
 
mvirg said:
My Columbia is perfect for a 3 member family. Fast, efficient and capable. But what if we want to take friends, or we lose a cylinder 500' over Miami Beach, or we want to fly to Cozumel? So I started looking at twins.
Darn you Ted...darn you!
Click to expand...

You can always rent a twin, especially if they don't fly with you frequently!

:) Just trying to help
 
Ted DuPuis said:
For personal use, I would say you're right. But many of the twins flying out there are used for business purposes and thus fly more regularly than their single engine counterparts. That's also part of why you see them flying in worse weather frequently - "Gotta go, boss is here."
Click to expand...

The numbers on 100ll use support that. Twins burn a substantial percentage of all 100ll in the market. From living at the airport fence, it has been my observation that no matter how crummy the weather, thecourier twins will still land.
 
mtuomi said:
Caravan is a turbine, hardly comparable.

Engine failure in a single on takeoff means 100% probability for a forced landing. On a twin, not so. Not a valid argument.

Single engine provides a shield? No it doesn't. It just means your firewall is pushed against your face with more force.
Click to expand...

Still FEDEX opted for a single instead of a King Air.

I would rather takeoff on plane that has half the possibilty of an engine failure.

A wood spear will easily penetrate the radome and structure behind on a twin reaching the pilot chest. Try that with an engine in front.

José
 
Piloto said:
Still FEDEX opted for a single instead of a King Air.

I would rather takeoff on plane that has half the possibilty of an engine failure.

A wood spear will easily penetrate the radome and structure behind on a twin reaching the pilot chest. Try that with an engine in front.

José
Click to expand...
hardly. fedex contractors opted for caravans in place of DC3's. I lived through that changeover. Dispatch reliability went through the roof. But that was not really a single vs twin issue.
 
spiderweb said:
I fail to find where my statement and yours diverge.

We are essentially saying the same thing. The airplane will react how it reacts exactly the same (given, of course, the same atmospheric conditions)--the only difference is the psychology of the pilot.
Click to expand...
quite the opposite. If you view this as psychology then you have completely missed the concept
 
JHW said:
hardly. fedex contractors opted for caravans in place of DC3's. I lived through that changeover. Dispatch reliability went through the roof. But that was not really a single vs twin issue.
Click to expand...

If fedex found a way to fly MD11s on one engine they would do it.
 
You must log in or register to reply here.
Back
Top