REDUNDANCY

[teacher]

Engine failure crashes in light twin turbine aircraft actually have a lower survivability.

The stats are based on crashes attributed to engine failures. If we factor in engine failures that occured on light twins but resulted in a favorable outcome than the odds of having an engine failure in a light twin go up exponentially. Single engine failure crashes are more survivable. Most likely because the pilots are planning to put it down rather than limp it back to an airport. A controlled/planned crash is always better than an uncontrolled/unplanned one.

[photofly]

If you have an engine failure in a twin, you might not have a crash. But - if you do have a crash it's quite likely to be fatal. Why? higher stall speed and the crash is more likely to be because of a loss of control.

If you have an engine failure in a single, for sure you're coming down. But you can put it down slower so there's less energy to dissipate, and you're more likely to survive. (Stall speed of a PC12 is 65 knots vs 78 knots for a King Air. That's 45% more energy at stall speed for the twin, at the same weight.)

[crazy_aviator]

One very good pilot with a good plane is 4 times better than 2 poor pilots with a poor plane lol

[Doc]

If you have an engine failure in a twin, you might not have a crash. But - if you do have a crash it's quite likely to be fatal. Why? higher stall speed and the crash is more likely to be because of a loss of control.

If you have an engine failure in a single, for sure you're coming down. But you can put it down slower so there's less energy to dissipate, and you're more likely to survive. (Stall speed of a PC12 is 65 knots vs 78 knots for a King Air. That's 45% more energy at stall speed for the twin, at the same weight.)

Ah, but the subject of the thread is "redundancy", not pilot competence. Or pilot stupidity. Of course, if you lose control, it could lead to a dreary end. Of course, if you run out of gas, all bets are off. This does not speak to "redundancy" is speaks of poor pilot skill/decision making. The FACT remains. A second engine will take you home. B52's have EIGHT engines, but if you run one dry, it'll come down like a simonized piano! I will concede on point though. If I had to "dead stick" an airplane, I'd rather it be a PC12 than a B52!

[Doc]

Doc, I pasted this from the Ornge thread as it in my opinion gets closer to the facts than just personal opinions.

I suffer from having the ability to examine a subject and using the information I gather and learn from that information then I can come to certain conclusions that are based on logic.

Ornge lost me in the logic arena when they decided to choose single engine aircraft to transport patients on emergency evacuations where bad weather and other critical issues will be encountered because emergencies are not time wise manageable.

Money can not be the reason they chose to forgo the added safety of two engines because they do not seem to be lacking for money within their bureaucratic structure nor their offices so there has to be another reason why they chose to deny their clients the added safety factor of twin engine airplanes....ignorance on the part of those in the power structure maybe?

And yes, I may have a personal reason to be concerned in this matter because I may someday be unfortunate enough to require a medevac in Ontario.....this outfit is not a charter company one calls at their own initiative.

You know Cat, that one had me stumped for a while as well. Two things come to mind. Ornge came on the scene, almost "overnight" as far as a new air carrier goes. One thought is going with a single, there are WAY less hoops to jump through for an OC from TC. Second thought....they are a Hell of a lot easier to crew. You need one fairly low time pilot, and a right seat CPL. No real need to find guys with a pill of twin turbine time for the insurance company. And, while the do run two crew, the other guy can be very new, and therefore plentiful
Frankly, I was expecting them to show up with a new fleet of Beech 350's. The money IS there. The Ontario Ministry of Health would NEVER have accepted a "bid" using a single engine aircraft in the recent past. They HAD to be twins. Then they HAD to be twin turbines. Now, apparently a single engine airplane is just dandy. I just found that line of thinking to be bizarre.
Although the PC12 is a pretty fine aircraft, anyone who would seriously select it over a modern twin turbine for "all weather, go there, right now" capability is a complete moron! I can't believe "pilots" actually think two engines are not safer than one, for serious foul weather operations, over water operations, or inhospitable terrain operations?? You guys are funning with me, right?
That's the last Ornge related comment I want here. It's about redundancy....

[nimbostratus]

Many good points have been brought up in this thread. I am still leaning towards having two or more engines, I've got a family and I want to come home to them. End of story.
For a final definitive answer I have forwarded this thread to Transport Canada's "Department of Redundancy Department".

Flt safe all (on one or more engines)!

Nimbo

[photofly]

Ah, but the subject of the thread is "redundancy", not pilot competence.

If I'm the pilot then I'd naturally choose the aircraft with the lowest chance of a disaster assuming that I turn in a 100% textbook performance. The fact is, nobody estimates their own performance to be less than good. (The same way all drivers think their own driving ability is "above average".)

BUT - if I'm the passenger then I'll choose the aircraft with the lowest overall chance of a disaster factoring in the probability of the pilot screwing up, like pilots sometimes do, which includes failing to maintain control of a twin with one engine out.

Whose assessment of risk is more accurate? The pilot, or the passenger? I submit it's the passenger who's got it right.

Saying the same thing differently, the higher the level the skill that a piece of redundancy requires in order to ensure a successful outcome, the less valuable that redundancy is.

[Cat Driver]

I can't believe "pilots" actually think two engines are not safer than one, for serious foul weather operations, over water operations, or inhospitable terrain operations?? You guys are funning with me, right?

Reading a lot of these opinions regarding the two versus one debates it is difficult to understand how a lot of pilots come to the conclusions that the risk factors for single engine turbines are not a real problem and then go on to state that there is more chance of being killed in a twin because there are so many loss of control accidents in twins after losing an engine....the only conclusion I can come to is it has become acceptable to believe that there are so many incompetent pilots out there flying twins that you are just as safe in a single after an engine failure as you would be in a twin.

Frightening mindset isn't it Doc?

No one has yet explained to me why the ETOPS rules are so strict on the big jets if single engine turbine flight is so safe.

[photofly]

so many loss of control accidents in twins after losing an engine.

There may not be many, but there are at least some.

[Big Pistons Forever]

One day back in the 1990's I was at the flying club having lunch. At the table was a 59.5 year old Canadian 747 Captain with a single digit seniority number. He had started flying the bush in the 1950's and got on with CP in the 1960's. With close to 30 K hours he was truly a been there, done that pilot. A couple of young newly minted CPL's were peppering him with questions but one still stands out in my memory

Q. You must really love flying a jet with 4 big engines.

A. Well I guess it will do until somebody makes a 5 engine jet.

[Doc]

I don't get it Cat. I'm safer in a single, because I'm too much of a ham fisted twat to fly a twin with one feathered? Therefore nobody else could possibly have the skill level to actually survive an engine out scenario in said twin. OR.....I'd rather glide into whatever lies below me, than cage an engine, spin in a few degrees of rudder trim, select climb power on the running engine, and make it home to see the wife and kids?
News flash (from someone who has had a few) an actual engine failure in a twin turbine is "duck soup". Make sure you have the right one, go climb power on the good one (I know you train max power, but you'll reduce it later) shut down and feather the bad one, toss in the right amount of trim to pretty much centre the ball, turn off generator, etc on the bad side with your trusty check list. You can probably turn the bloody auto-pilot back on. It's NOT rocket science here. Monkeys really can do it. I know several. Sometines, I am one.

[iflyforpie]

[I can't believe "pilots" actually think two engines are not safer than one, for serious foul weather operations, over water operations, or inhospitable terrain operations??

Who here is saying that two engines aren't safer than one? For aircraft with the same capabilities and in the same category, generally more engines are better.

But you can't just arbitrarily say any two engined plane is better than any one engined plane. C'mon, is this plane.....?



....better than this plane...?




What most people (including myself) are arguing is that for planes of similar capabilities, the difference in safety is not as great as you think.

[FL500]

I don't get it Cat. I'm safer in a single, because I'm too much of a ham fisted twat to fly a twin with one feathered? Therefore nobody else could possibly have the skill level to actually survive an engine out scenario in said twin. OR.....I'd rather glide into whatever lies below me, than cage an engine, spin in a few degrees of rudder trim, select climb power on the running engine, and make it home to see the wife and kids?
News flash (from someone who has had a few) an actual engine failure in a twin turbine is "duck soup". Make sure you have the right one, go climb power on the good one (I know you train max power, but you'll reduce it later) shut down and feather the bad one, toss in the right amount of trim to pretty much centre the ball, turn off generator, etc on the bad side with your trusty check list. You can probably turn the bloody auto-pilot back on. It's NOT rocket science here. Monkeys really can do it. I know several. Sometines, I am one.

I think this is the best post on this thread Doc +1

[Stallspin]

Just ask yourself this question:

CYVR to CYYC
Low IFR condition along the route
2011 King Air 200 vs 2011 PC12

[Cat Driver]

On one of our ferry flights we were stuck in Wick Scotland for a few days due to adverse weather over the North Atlantic and we spent a lot of time taking to a ferry pilot who ferried single engine airplanes across the North Atlantic.

He told us there was no reason to worry about the safety factor because he had been doing it for years.

Several months later I found out that on his next ferry flight in a light single he went missing somewhere between Iceland and Greenland, I often wonder what his last few minutes of life were like, I can see the area in my mind as clear as if I am there now and it is truly disturbing thinking of what it would be like in those last few minutes before you died.

[iflyforpie]

CYVR to CYYC
Low IFR condition along the route
2011 King Air 200 vs 2011 PC12

Maintenance and pilot training/skill being equal, which aircraft are you going to take?

How much of a budget do I have? If I don't have enough dough for the King Air, maybe I'll just sit tight and wait for better weather. Count my couple million extra dollars and check the CADORS for the King Air or MU-2 who had to get emergency vectors between peaks because of ice....

http://dsp-psd.pwgsc.gc.ca/collection_2 ... -05-5E.pdf

http://www.youtube.com/watch?v=Wbm8xzLVgQ4

[nimbostratus]

I feel I just have to add this... After 5 engine failures and one precautionary landing/diversion due to an oil leak (3 of which were in single engine aircraft below 500 AGL), the return to the airport on one engine in a twin jet was by far the least stressful.
I won't be flying a single engine aircraft for a living any more. I would however happily fly one for fun in good weather.

Nimbo

[Stallspin]

.

[flyinthebug]

I don't get it Cat. I'm safer in a single, because I'm too much of a ham fisted twat to fly a twin with one feathered? Therefore nobody else could possibly have the skill level to actually survive an engine out scenario in said twin. OR.....I'd rather glide into whatever lies below me, than cage an engine, spin in a few degrees of rudder trim, select climb power on the running engine, and make it home to see the wife and kids?
News flash (from someone who has had a few) an actual engine failure in a twin turbine is "duck soup". Make sure you have the right one, go climb power on the good one (I know you train max power, but you'll reduce it later) shut down and feather the bad one, toss in the right amount of trim to pretty much centre the ball, turn off generator, etc on the bad side with your trusty check list. You can probably turn the bloody auto-pilot back on. It's NOT rocket science here. Monkeys really can do it. I know several. Sometines, I am one.

Ive had two engine failures in a twin in my career. Neither were very "dramatic" and both ended happily for all involved. The one time I lost my engine in a single...it cost me 22 broken bones and my career. Ya, lets pick one engine over two...is that REALLY where our industry`s mindset is heading??? I hope the younger guys and gals reading this thread, take heed to what Cat, Doc and others with 1000`s of hours are telling us here. You can never have too much fuel or too many engines.

[The Weasel]

Just wondering, on a twin engine helo, how many transmissions does it have? Two engines dont do a whole lot of good when the transmission fails.

Only one transmission. True, but transmision failures are extremely rare. A lot less moving parts than an engine. It's much less a 'transmission' or 'gearbox' (in automotive terms) than it is a simple 90 (or whatever) degree change in drivetrain direction. Not much to it, much less to go wrong, and pretty much bullet proof.

[Expat]

The day twin pilots do their check rides, from take-off to landing, with one feathered, I will feel safe in a twin.

[teacher]

Obviously the odds of crashing due to an engine failure are higher in a single and I doubt anybody would argue against you. Hell, I flew a PC12 for 2 years and now multi turbine and of course I'm more confortable now. However some of you guys are making it seem like SEIFR is a death trap and shouldn't be allowed. That is very outdated thinking considering the advances in engine technology and the stats prove it.

[robertsailor1]

Not all engine failures are the same...Old timers will tell you that engine failures (the kind from mechanical failures) happen more often on the first power reduction on takeoff. There are some marginal twins out there when it comes to losing engines on take off so if I had the choice of losing an engine on a grossed out Twin Comanche/Apache or the like in Calgary in the summer or the same situation in a Cessna 172 I'd rather be in the 172...but that's just me.

[photofly]

Ya, lets pick one engine over two.

How about two ropey turbines over one good one? One turbine over two pistons? One piston over two piston?

[cdnpilot77]

Just wondering, on a twin engine helo, how many transmissions does it have? Two engines dont do a whole lot of good when the transmission fails.

Only one transmission. True, but transmision failures are extremely rare. A lot less moving parts than an engine. It's much less a 'transmission' or 'gearbox' (in automotive terms) than it is a simple 90 (or whatever) degree change in drivetrain direction. Not much to it, much less to go wrong, and pretty much bullet proof.

I may have my facts ass backwards, but wasnt/arent transmission failures the cause of several crashes involving the RCAF sea king helicopters?