police incident
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http://www.aviation.fs.fed.us/safeco...ne.asp?ID=3433
I wonder if that guy was happy he was in a twin...
Try that in a 205!
Mike
I wonder if that guy was happy he was in a twin...
Try that in a 205!
Mike
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There's lot's of conjecture about how much safer a twin is. So does anyone have any real numbers to show how much safer a twin is ?? I'm talking true engine failures that aren't related to fuel starvation, accessories, etc. I believe Rotor & Wing did one, and showed a 4% difference.
I wish people would stop trying to compare helicopter flying and driving a car. When everyone gets an a/c then we can compare them. You are far more likely to need a side impact airbag in your car than a second engine in a helicopter. Yes there are operations where twins do better. I won't go very far from shore in a single, and for constant work over a built up area they are preferred. With proper maintenance, and a good daily inspection a single is as safe as atwin, but if you feel safer in a twin then that's okay. I don't have a problem flying a single engined helicopter. I can count on one hand the number of people I know who've had an engine failure. I had a snow ingestion decel, but the auto re-light worked. I also know a similar number who have had serious problems in a twin.
It all ends up as what costs more, and twins do. We would all love to fly twins in all ops, heck what is an emergency in a single, isn't all that urgent in a twin. But is it worth a 50% premium ?? Only you can make that descision, oh and your client.
Cheers
I wish people would stop trying to compare helicopter flying and driving a car. When everyone gets an a/c then we can compare them. You are far more likely to need a side impact airbag in your car than a second engine in a helicopter. Yes there are operations where twins do better. I won't go very far from shore in a single, and for constant work over a built up area they are preferred. With proper maintenance, and a good daily inspection a single is as safe as atwin, but if you feel safer in a twin then that's okay. I don't have a problem flying a single engined helicopter. I can count on one hand the number of people I know who've had an engine failure. I had a snow ingestion decel, but the auto re-light worked. I also know a similar number who have had serious problems in a twin.
It all ends up as what costs more, and twins do. We would all love to fly twins in all ops, heck what is an emergency in a single, isn't all that urgent in a twin. But is it worth a 50% premium ?? Only you can make that descision, oh and your client.
Cheers
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Randy,
I was just trying to say that side-impact bags are additional saftey features that don't help in every situation - just like a second engine. The principal is the same, and that's all I was after.
Engines are still the most complex bits in a helicopter. They do fail. While other things do fail, and a helicopter sans engines is still more complicated than just the engine, having a second one can help. It is more expencive, more complex, and (in some cases) more difficult to operate - but when you think of the price of writing off a helicopter due to a heavy auto, botched auto over a city, or a forced landing into the abyss, the extra money looks like pocket change.
There are places where having a twin is an absolute necissity, such as on a CSAR mission behind enemy lines or when the helicopter gets too big for one engine to suffice, but I doubt there is any situation where having another engine couldn't help given one of numerous possibilities. It was realized that there aren't many places to safley set a jumbo jet down save an airport, so why do you think ALL airliners and commuter planes have at least two engines?
I have no problem when people say "twin engines cost more", cause they do, but it bugs me when people say "twin engines aren't safer". The margin isn't that wide, but there is a situation when an engine fails or must be shut down, and the landing options are pretty slim. In that case, having a second engine could be invaluable.
Mike
I was just trying to say that side-impact bags are additional saftey features that don't help in every situation - just like a second engine. The principal is the same, and that's all I was after.
Engines are still the most complex bits in a helicopter. They do fail. While other things do fail, and a helicopter sans engines is still more complicated than just the engine, having a second one can help. It is more expencive, more complex, and (in some cases) more difficult to operate - but when you think of the price of writing off a helicopter due to a heavy auto, botched auto over a city, or a forced landing into the abyss, the extra money looks like pocket change.
There are places where having a twin is an absolute necissity, such as on a CSAR mission behind enemy lines or when the helicopter gets too big for one engine to suffice, but I doubt there is any situation where having another engine couldn't help given one of numerous possibilities. It was realized that there aren't many places to safley set a jumbo jet down save an airport, so why do you think ALL airliners and commuter planes have at least two engines?
I have no problem when people say "twin engines cost more", cause they do, but it bugs me when people say "twin engines aren't safer". The margin isn't that wide, but there is a situation when an engine fails or must be shut down, and the landing options are pretty slim. In that case, having a second engine could be invaluable.
Mike
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THM I was agreeing with the statement that twins are safer. My point is that singles aren't as dangerous as many like to think. How does one explain the many operators out there who run singles, and haven't had engine failures ?? Lucky ?? Maybe, but I bet they have great maintenance programs, and pilots who pay attention to limitations. Without those it doesn't matter how many engines you've got. With the reliability of modern engines is a twin really necessary. As I mentioned, there are ops when it is preferrable to use twins, but not for all ops. Do you need a 212 to lift an 350 kg (770 lbs) diesel engine ?? A 206, 500, AS350 will do just nicely for half the price (give or take). If you want to be ridiculous, one could ask why all helicopters don't have 3 (like the EH-101) or 4 engines. Just in case you know.
Oh BTW not all airliners have twin engines. The Pilatus PC-12, and Cessna Caravan have only one, and they are used quite frequently in remote areas. Airliners also have dual, sometimes triple systems redundancy. Something most helicopters do not have. Does your 212/412 collective have a redundant hydraulic system ?? What if you have a #2 hyd failure, and a bad batch of fuel, so that both engines flame-out ?? (I know it's far fetched) What would happen to your RRPM ??
My thoughts
Cheers
Oh BTW not all airliners have twin engines. The Pilatus PC-12, and Cessna Caravan have only one, and they are used quite frequently in remote areas. Airliners also have dual, sometimes triple systems redundancy. Something most helicopters do not have. Does your 212/412 collective have a redundant hydraulic system ?? What if you have a #2 hyd failure, and a bad batch of fuel, so that both engines flame-out ?? (I know it's far fetched) What would happen to your RRPM ??
My thoughts
Cheers
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Randy,
I guess we are on the same page then. I agree with you totally - singles aren't as dangerous as many think. However, twins do have a little edge in that one-in-a-million (figurativley) situation. While it's bad for people to forget that there is that advantage with the twins, it's equally bad for people to think that singles are dropping like flies. I apologize if what I said was misinterpreted.
As for that diesel engine, a 212 would indeed be quite overkill. But that's not to say that a 427 or 206LT (if there are any left) couldn't do it and still have that friendly little increase in options if the engine should go south. Say you are floating around about 100m from putting an air conditioner down on a roof when you get an engine chip light - with a twin, you might be able to coast the load down onto the roof in the general vicinity of the insertion point (say right next to the bracket) on 2.5 minute OEI power, rather than either setting the thing down in the mud in the best case or dropping it to it's death in the worst case if you were in a single. Or maybe continuing on the chipping engine while it destroys itself as you gently set the AC down on the roof and prepare to glide down to the parking lot and shut down.
Your comment about the EH's and 4 engined ships brings up a great irony for the pro-twin people. Pro-singles say "a second engine isn't worth the extra money", and I bet pro-twins will say 3 and 4 aren't worth it as well. The chances of an engine failure are out there, but the chances of two or three are down right silly. Plus, loosing 2/3 engines wouldn't be pretty unless you had a HUGE gap between OEI power and MCP AEO power. Going from 1134shp to 1025shp (in the case of my girl) isn't quite as big of a hit as going from 3x to 1x in the case of a double engine failure in a triple. A double failure would put me on the ground ASAP while that EH or 53E might be able to limp along a few miles before it runs out of altitude or 2.5 minute power.
Pilatus PC-12s aren't terribly popular as airliners as far as I know. They are primarily marketed as exec ships, and I don't think they are a smash hit there none the less. The Caravan is a rare specimen that runs along the lines of the Beaver and Otter, but it still has yet to find a place outside of very small scale operations (outside of FEDEX). I doubt the Boeing 787 and 797 will be powered by one mammoth GE90 sibling, nor will the EMB120s and Saabs be replaced by a caravan on steroids. I doubt the MI26's successor will have a single engine either - in the case of that and the airliners, they are too big to be able to auto or glide down into someone's backyard or onto the beach... but that doesn't mean I wouldn't prefer a 427 over 407 just because I can
Mike
I guess we are on the same page then. I agree with you totally - singles aren't as dangerous as many think. However, twins do have a little edge in that one-in-a-million (figurativley) situation. While it's bad for people to forget that there is that advantage with the twins, it's equally bad for people to think that singles are dropping like flies. I apologize if what I said was misinterpreted.
As for that diesel engine, a 212 would indeed be quite overkill. But that's not to say that a 427 or 206LT (if there are any left) couldn't do it and still have that friendly little increase in options if the engine should go south. Say you are floating around about 100m from putting an air conditioner down on a roof when you get an engine chip light - with a twin, you might be able to coast the load down onto the roof in the general vicinity of the insertion point (say right next to the bracket) on 2.5 minute OEI power, rather than either setting the thing down in the mud in the best case or dropping it to it's death in the worst case if you were in a single. Or maybe continuing on the chipping engine while it destroys itself as you gently set the AC down on the roof and prepare to glide down to the parking lot and shut down.
Your comment about the EH's and 4 engined ships brings up a great irony for the pro-twin people. Pro-singles say "a second engine isn't worth the extra money", and I bet pro-twins will say 3 and 4 aren't worth it as well. The chances of an engine failure are out there, but the chances of two or three are down right silly. Plus, loosing 2/3 engines wouldn't be pretty unless you had a HUGE gap between OEI power and MCP AEO power. Going from 1134shp to 1025shp (in the case of my girl) isn't quite as big of a hit as going from 3x to 1x in the case of a double engine failure in a triple. A double failure would put me on the ground ASAP while that EH or 53E might be able to limp along a few miles before it runs out of altitude or 2.5 minute power.
Pilatus PC-12s aren't terribly popular as airliners as far as I know. They are primarily marketed as exec ships, and I don't think they are a smash hit there none the less. The Caravan is a rare specimen that runs along the lines of the Beaver and Otter, but it still has yet to find a place outside of very small scale operations (outside of FEDEX). I doubt the Boeing 787 and 797 will be powered by one mammoth GE90 sibling, nor will the EMB120s and Saabs be replaced by a caravan on steroids. I doubt the MI26's successor will have a single engine either - in the case of that and the airliners, they are too big to be able to auto or glide down into someone's backyard or onto the beach... but that doesn't mean I wouldn't prefer a 427 over 407 just because I can
Mike
Randy,
Please flesh out your question....I am flying my trusty Bell 212/412 and my #2 hydraulic system packs its bags and goes home to mother....both engines then fail due to food poisoning.....and you worry I might have main rotor RPM problems? Are you implying...suggesting...stating that the dual engine failure has anything at all to do with the uninterrupted supply of hydraulic power to the collective system? You have me cornfused here laddy.....is my alcohol ravaged memory letting me down here....but from what sticks out from the vapors of last nights gin bottle.....is that both hydraulic pumps on the 212/412 are transmission mounted and as long as the floppy things up above continue to turn....one has "normal" control of both cyclic and collective controls.....depending upon which hydraulic system that fails....then maybe the pedals get kinda cranky but not the collective or cyclic. Now are you per chance confusing the unlikely event that you could simultaneously lose a hydraulic pump and Main Rotor Tacho generator and find yourself with cranky pedals, no rotor rpm showing on the big clock looking thing but with no change in noise or rpm and several lights marked #1 Hyd and a gauge showing zero pressure....and the low rpm audio and other gadgets doing their jobs? The Bell product does sometimes shear the shaft from the transmission to the #1 hydraulic pump with piggyback mounted main rotor Tacho Genny.....very similar concept to the Bell Jetranger....except you only have the one hydraulic system there.....thus revert to no hydraulics and no Main rotor tacho genny. More than one Hero has embarassed himself by ditching a perfectly good Jet Ranger after that has happened.
Please flesh out your question....I am flying my trusty Bell 212/412 and my #2 hydraulic system packs its bags and goes home to mother....both engines then fail due to food poisoning.....and you worry I might have main rotor RPM problems? Are you implying...suggesting...stating that the dual engine failure has anything at all to do with the uninterrupted supply of hydraulic power to the collective system? You have me cornfused here laddy.....is my alcohol ravaged memory letting me down here....but from what sticks out from the vapors of last nights gin bottle.....is that both hydraulic pumps on the 212/412 are transmission mounted and as long as the floppy things up above continue to turn....one has "normal" control of both cyclic and collective controls.....depending upon which hydraulic system that fails....then maybe the pedals get kinda cranky but not the collective or cyclic. Now are you per chance confusing the unlikely event that you could simultaneously lose a hydraulic pump and Main Rotor Tacho generator and find yourself with cranky pedals, no rotor rpm showing on the big clock looking thing but with no change in noise or rpm and several lights marked #1 Hyd and a gauge showing zero pressure....and the low rpm audio and other gadgets doing their jobs? The Bell product does sometimes shear the shaft from the transmission to the #1 hydraulic pump with piggyback mounted main rotor Tacho Genny.....very similar concept to the Bell Jetranger....except you only have the one hydraulic system there.....thus revert to no hydraulics and no Main rotor tacho genny. More than one Hero has embarassed himself by ditching a perfectly good Jet Ranger after that has happened.
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EGO favors the twin....
... more noise, buttons, switches, gauges, systems, pilots.
... more importance more PAY! - yup its a money thing!
... more engine sales - more bread extracted from the MOD (lets try and sell THREE engines per helicopter!)
fine enjoy the twin - but just stop pissing on our single bonfire without just cause (15 seconds of takeoff exposure doesn't justify 'banning' singles! )
- extended exposure might (just) justify the twin in some cases sure.
If I were sonar dunking I'd rather be in the machine in which I was less likely to find myself in the water than the machine in which I could have an engine fail and stay dry.
The mil (army particularly) did well with the gazelle - they need more numbers of simply maintainable, reliable, versatile low logistical hassel machines.
There's a squared law of .......etc
... more importance more PAY! - yup its a money thing!
... more engine sales - more bread extracted from the MOD (lets try and sell THREE engines per helicopter!)
fine enjoy the twin - but just stop pissing on our single bonfire without just cause (15 seconds of takeoff exposure doesn't justify 'banning' singles! )
- extended exposure might (just) justify the twin in some cases sure.
If I were sonar dunking I'd rather be in the machine in which I was less likely to find myself in the water than the machine in which I could have an engine fail and stay dry.
The mil (army particularly) did well with the gazelle - they need more numbers of simply maintainable, reliable, versatile low logistical hassel machines.
There's a squared law of .......etc
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two engines but one pilot and one tail rotor, Hmm....
UKCAA, bless 'em: proposed twin engines thro' single gearbox and prop aeroplanes banned because failure of the single drive system ie prop, would lead to a forced landing. Same logic clearly doesn't apply to flying machines with a big propeller (one) on the top ( not to mention the stern propeller,eh?)
Anyway, 2nd engine is for girls.
UKCAA, bless 'em: proposed twin engines thro' single gearbox and prop aeroplanes banned because failure of the single drive system ie prop, would lead to a forced landing. Same logic clearly doesn't apply to flying machines with a big propeller (one) on the top ( not to mention the stern propeller,eh?)
Anyway, 2nd engine is for girls.
This is I know an argument - often visited - with no winners, but do not do down the humble plank wing in the process!
'... Pilatus PC-12s aren't terribly popular as airliners as far as I know. They are primarily marketed as exec ships, and I don't think they are a smash hit there none the less. The Caravan is a rare specimen that runs along the lines of the Beaver and Otter, but it still has yet to find a place outside of very small scale operations (outside of FEDEX) ...'
Both these types are replacing twins in law enforcement in the remotest of places - the wastes of Canada and Australia and undertaking sea patrols off Malaysia and others. In addition operators are pushing quite successfully to get such singles lugging passengers on overwater legs. They will go in - about a year ago a long distance PC12 had an unhappy ending after ignoring a rough engine around Russia someplace, but it is rare enough.
The magic formula for their success is that because where they put the 'rotors' most twin airplanes have dire one engine out performance - but I guess a Chinook with one stopped would be pretty much the same!
It is to toss a crooked coin whether it is better to dunk in a airplane or a helicopter ...... perhaps a rotor would be safer in most instances where you have height but at least it shows that in this 'progressive' world at least there is some reversal of the sinking fortunes of the single at the hands of the deskbound legislators!
'... Pilatus PC-12s aren't terribly popular as airliners as far as I know. They are primarily marketed as exec ships, and I don't think they are a smash hit there none the less. The Caravan is a rare specimen that runs along the lines of the Beaver and Otter, but it still has yet to find a place outside of very small scale operations (outside of FEDEX) ...'
Both these types are replacing twins in law enforcement in the remotest of places - the wastes of Canada and Australia and undertaking sea patrols off Malaysia and others. In addition operators are pushing quite successfully to get such singles lugging passengers on overwater legs. They will go in - about a year ago a long distance PC12 had an unhappy ending after ignoring a rough engine around Russia someplace, but it is rare enough.
The magic formula for their success is that because where they put the 'rotors' most twin airplanes have dire one engine out performance - but I guess a Chinook with one stopped would be pretty much the same!
It is to toss a crooked coin whether it is better to dunk in a airplane or a helicopter ...... perhaps a rotor would be safer in most instances where you have height but at least it shows that in this 'progressive' world at least there is some reversal of the sinking fortunes of the single at the hands of the deskbound legislators!
To expand a little on the comments on the Caravan, as this is an example of a technological advancement creating a complete re-think of the "traditional" operating and regulatory environment. It was ultimately successful in seeing a complete re-write of commercial operation of single engine operating regulations - a pretty significant achievement I think you would agree.
The Caravan is hardly a rare specimen. It has become the backbone of thin commuter services in remote (and some not so remote) areas, due to its excellent safety record, reliability, economics and operability. It is in use Worldwide and has undoubtedly been proven one of the finest commercial aircraft ever manufactured. Perhaps uniquely (?) it has never had a single FAA Airworthiness Directive issued against it, unlike just about everything else that comes from that factory!
Some facts:
CARAVAN TOTAL FLEET HOURS Over 4 Million
CARAVANS DELIVERED Nearly 1,200
DISPATCH RATE RELIABILITY 99.86%
COUNTRIES OPERATING CARAVANS 66+
1,000th CARAVAN DELIVERED November 1998
REPEAT ORDERS FROM OPERATORS 70%+
HIGHEST TIME AIRCRAFT 20,000+ Hours
HIGHEST TIME AMPHIBIAN 20,000+ Landings
HIGHEST UTILISATION 250+ Hours a month
A/C DEDICATED TO FREIGHT USE 450 +
A/C IN SCHEDULED PASSENGER USE 160 +
SCHEDULED PASSENGERS CARRIED IN 1999 4.1 Million
A/C WITH WIPLINE FLOATS 100 +
A/C IN SPECIAL MISSION OPERATIONS 60 +
For example, the number one regional airline in the world, based in Brazil, currently operates 40 Caravans. In Central America, a large conglomerate of regional airlines started with four Caravans and has just purchased eight more.
There are over 1000 Caravans operating in 66 countries today, and the Cessna Caravans have gained over 50% of the world-wide market share in the utility/small commuter category.
Leading the way in safe, single engine technology - According to the Final report On 135 Single engine IFR Operations in IMC by the U.S. F.A.A The C208 Caravan is the only single-engine airplane that has achieved a substantial and extensively documented operating history providing the information necessary to make detailed safety and reliability assessments. This is primarily the result of a computer-based maintenance program developed by the manufacturer and used by most operators. The experience of this airplane serves as a model for others seeking to expand the operating privileges of their aircraft, and its accident record can provide a first approximation of the level of safety that is attainable with current technology single-engine airplanes operating in IMC."*
This is not to say that this machine is perfect for every application or type of operation, simply that in the choice of equipment an unfettered view will let you understand why your competitor is operating a Caravan and why technological advancement needs to be a continually reappraised.
The Caravan is hardly a rare specimen. It has become the backbone of thin commuter services in remote (and some not so remote) areas, due to its excellent safety record, reliability, economics and operability. It is in use Worldwide and has undoubtedly been proven one of the finest commercial aircraft ever manufactured. Perhaps uniquely (?) it has never had a single FAA Airworthiness Directive issued against it, unlike just about everything else that comes from that factory!
Some facts:
CARAVAN TOTAL FLEET HOURS Over 4 Million
CARAVANS DELIVERED Nearly 1,200
DISPATCH RATE RELIABILITY 99.86%
COUNTRIES OPERATING CARAVANS 66+
1,000th CARAVAN DELIVERED November 1998
REPEAT ORDERS FROM OPERATORS 70%+
HIGHEST TIME AIRCRAFT 20,000+ Hours
HIGHEST TIME AMPHIBIAN 20,000+ Landings
HIGHEST UTILISATION 250+ Hours a month
A/C DEDICATED TO FREIGHT USE 450 +
A/C IN SCHEDULED PASSENGER USE 160 +
SCHEDULED PASSENGERS CARRIED IN 1999 4.1 Million
A/C WITH WIPLINE FLOATS 100 +
A/C IN SPECIAL MISSION OPERATIONS 60 +
For example, the number one regional airline in the world, based in Brazil, currently operates 40 Caravans. In Central America, a large conglomerate of regional airlines started with four Caravans and has just purchased eight more.
There are over 1000 Caravans operating in 66 countries today, and the Cessna Caravans have gained over 50% of the world-wide market share in the utility/small commuter category.
Leading the way in safe, single engine technology - According to the Final report On 135 Single engine IFR Operations in IMC by the U.S. F.A.A The C208 Caravan is the only single-engine airplane that has achieved a substantial and extensively documented operating history providing the information necessary to make detailed safety and reliability assessments. This is primarily the result of a computer-based maintenance program developed by the manufacturer and used by most operators. The experience of this airplane serves as a model for others seeking to expand the operating privileges of their aircraft, and its accident record can provide a first approximation of the level of safety that is attainable with current technology single-engine airplanes operating in IMC."*
This is not to say that this machine is perfect for every application or type of operation, simply that in the choice of equipment an unfettered view will let you understand why your competitor is operating a Caravan and why technological advancement needs to be a continually reappraised.
