Piston twin safety

All light twins should be able to climb on one engine on takeoff, like higher level king air or multi's can. Just a thing that would boost safety IMO. Just came across this article and thought i would share my opinion.
 
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Ryanb said:
All light twins should be able to climb on one engine on takeoff, like higher level king air or multi's can. Just a thing that would boost safety IMO
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The PIC can assure that by loading light enough for the conditions. In the end of it, it's all a matter of cost/benefit ratio. None of the 6 cylinder twins with 500+ HP have trouble climbing out on one to several thousand feet as long as you mange your weight. At my typical flying weight in the 310 I could climb out to 7500' on one and still have some climb left. Even the Seminole today would climb 150fpm on one with two of us on a warm day.

It's just a matter of excess HP remaining on one, and horsepower costs money. If you want single engine performance in 4&6 seat planes, then you have to have enough excess horsepower, and that increases the cost of operations. The only thing pilots care about more than safety is money, so the trainer twins are built with the minimum HP to keep the costs down.
 
I've been following various conversations about baron P1&2 conversions on another forum.

Intriguing.

Crazy performance.

Seconds before you are at a safe altitude. (2000+ fpm climb will do that).

Assume if you fave a problem below 500' you just push the throttles forward and take what's coming ... It makes a good case for a twin. A chute isn't any better.


Gas prices stay where they are (as well as twin prices) I might just ... No that's just crazy talk...
 
Ryanb said:
All light twins should be able to climb on one engine on takeoff, like higher level king air or multi's can. Just a thing that would boost safety IMO. Just came across this article and thought i would share my opinion.
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And a Chevy Spark should be able to pull a 47' boat with no issue, right?
 
Ryanb said:
I came across this article.

http://ehfc.net/twin_engine_aircraft_safety-1.pdf

I personally say the 6000lb minimum for single engine operation on climb needs to be changed for GA safety.
Opinions?
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Having given dozens of MEL checkrides under the current regulation (and having written a book on MEL training), I'm not sure where you are coming from. The laws of physics are immutable, and I don't see how your proposed change would improve anything. The keys to multiengine safety are training, retraining, and proficiency. Every multiengine pilot should expect an engine failure on his/her next takeoff and be mentally prepared for it to happen. In my book I call this constructive paranoia. I have had not-quite-to-rotation failures and I have had initial climb failures and I am here to tell the tale because my mindset was to expect a failure and I was not disappointed.

BTW, that article was written by Richard Aarons for Business and Commercial Aviation magazine back in the day, and I have talked to him about it. He admitted that the concept of "keel effect" came from pilot lounge discussions, not from any kind of research or testing. The FAA Light Aircraft Directorate says that there is no such thing.

Bob Gardner
 
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Henning said:
The PIC can assure that by loading light enough for the conditions. In the end of it, it's all a matter of cost/benefit ratio. None of the 6 cylinder twins with 500+ HP have trouble climbing out on one to several thousand feet as long as you mange your weight. At my typical flying weight in the 310 I could climb out to 7500' on one and still have some climb left. Even the Seminole today would climb 150fpm on one with two of us on a warm day.

It's just a matter of excess HP remaining on one, and horsepower costs money. If you want single engine performance in 4&6 seat planes, then you have to have enough excess horsepower, and that increases the cost of operations. The only thing pilots care about more than safety is money, so the trainer twins are built with the minimum HP to keep the costs down.
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So it is possible to climb on one engine it just depends on how its loaded? One thing i thought about was the accident at KLAL yesterday involving a highly experienced CFI in an apache. During a training flight i would assume just the two of them it should be able to climb if one of the engines failed.
 
Ryanb said:
So it is possible to climb on one engine it just depends on how its loaded? One thing i thought about was the accident at KLAL yesterday involving a highly experienced CFI in an apache. During a training flight i would assume just the two of them it should be able to climb if one of the engines failed.
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Read FAR 23.67.

Bob Gardner
 
Ryanb said:
I came across this article.

http://ehfc.net/twin_engine_aircraft_safety-1.pdf

I personally say the 6000lb minimum for single engine operation on climb needs to be changed for GA safety.
Opinions?
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Pilots that are properly trained in light twins know that the second engine means more options in some situations... climbing after takeoff is not one of them. Basically in an engine out scenario where a safe climb can't be made, you treat a twin like a single and do an engine out landing.

It would be hard to make an argument to change this without arguing against the safety of single engine aircraft as well.

It is also worth noting that there are MANY cases where twins could have climbed on one engine, but do to poor technique, lack of training, or other factors the pilot failed to do so. More power isn't always a panacea.

Finally, with regard to the KLAL crash, we don't have enough facts to speculate much yet and due to the nature of the post-crash fire we may not get as conclusive of an answer as many of us would like to see.
 
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Ryanb said:
All light twins should be able to climb on one engine on takeoff, like higher level king air or multi's can. Just a thing that would boost safety IMO. Just came across this article and thought i would share my opinion.
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How do you propose to do this? If you increase the horsepower of the engines you will have more asymmetric thrust when one quits so you will need a higher Vmc or a bigger rudder. It might climb better but the handling characteristics might be worse.
 
Ryanb said:
I came across this article.

http://ehfc.net/twin_engine_aircraft_safety-1.pdf

I personally say the 6000lb minimum for single engine operation on climb needs to be changed for GA safety.
Opinions?
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Where would you stop? At "positive climb"? Up to what altitude? Maybe Part 25 minimum engine out performance? Or should they meet the 200 ft/mile climb required by TERPS and the AIM to clear "standard" obstacle surfaces? What about obstacles that require higher published climb gradients? What about obstacles at places like Aspen?

At some point, every multi engine airplane needs to reduce weight for engine out performance, or cancel a flight because it can't be met...and pilots who DO fly airplanes that meet obstacle performance will still die in engine-out situations.

The only way to make airplanes "safe" is to not make them at all. Judgement, training, and skill need to be applied.
 
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As im saying, this was jusy something I thought about. Not saying my opinion matters at all, just something talk about since i dont know much about twins. I would just think all twins should be capable of SE climb without issue as a safety question, much like a king air or some type.
 
Everskyward said:
How do you propose to do this? If you increase the horsepower of the engines you will have more asymmetric thrust when one quits so you will need a higher Vmc or a bigger rudder. It might climb better but the handling characteristics might be worse.
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From the 550 (300hp+ / side) baron drivers, you are talking seconds before you are above TPL and leveling off for a crazy fast cruise climb.

If you assume a failure in this case (below TPL) is a land straight ahead scenario, pushing the throttles forward and taking your licks is pretty much equivalent to a single or even a chute equipped aircraft.


Dang it... I'm buying the twin argument :(
 
MauleSkinner said:
Where would you stop? At "positive climb"? Up to what altitude? Maybe Part 25 minimum engine out performance? Or should they meet the 200 ft/mile climb required by TERPS and the AIM to clear "standard" obstacle surfaces? What about obstacles that require higher published climb gradients? What about obstacles at places like Aspen?

At some point, every multi engine airplane needs to reduce weight for engine out performance, or cancel a flight because I can't be met...and pilots who DO fly airplanes that meet obstacle performance will still die in engine-out situations.

The only way to make airplanes "safe" is to not make them at all. Judgement, training, and skill need to be applied.
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Very true, as im saying not trying to start any arguements, this was just a thought i had while reading that article.
 
Ryanb said:
So it is possible to climb on one engine it just depends on how its loaded? One thing i thought about was the accident at KLAL yesterday involving a highly experienced CFI in an apache. During a training flight i would assume just the two of them it should be able to climb if one of the engines failed.
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The Apache is THE worst performing light twin in use (the Champion Lancer likely takes the prize overall, but they aren't in use), it can get pretty marginal, but I agree, they should have been able to climb at the weight and condition they were likely at, and normally the Apache will fly one down low, so I think there was more involved than single engine performance. That he drilled a hole through the roof of a building with plenty of options that could have left them alive again points in that direction. I don't come to the obvious conclusion in that wreck, lots of little oddities makes me think there will be an oddity behind that one.

The 310 operated as a business man's special, solo or two up taking off full fuel has significant enough SE performance, that below 4000', you can count on having reasonable SE climb. There is an extra hazard point on take off where you are still below Vyse and need to clean up drag very quickly, but you can use ground effect to your advantage if you have enough clear space, or you can chop throttles and shed as much energy as you can before the stop.

Where you do the greatest benefit to safety in a light twin is in the preflight brief. That is really where the big difference between SE operations and ME operations lies. Having two engines opens more options, and the options are moving targets as energy changes. So to maximize your safety, you have to analyze more factors and make determinations where through the take off you need to meet performance goals, and what option you should chose if it doesn't happen. You have to figure out your course of action ahead of time what you will do if various conditions do or don't exist at certain points; and you have to do this for every takeoff.
 
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brian];1677912 said:
From the 550 (300hp+ / side) baron drivers, you are talking seconds before you are above TPL and leveling off for a crazy fast cruise climb.

If you assume a failure in this case (below TPL) is a land straight ahead scenario, pushing the throttles forward and taking your licks is pretty much equivalent to a single or even a chute equipped aircraft.


Dang it... I'm buying the twin argument :(
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What is TPL? Something about the traffic pattern?

In a land straight ahead scenario you are usually at a disadvantage in a twin because it has more momentum and energy to dissipate. That is unless you are flying an Aircam or one of those Diamond twins that looks like a glider. And why would you push the throttles forward when you were getting ready to crash? :confused:
 
Everskyward said:
And why would you push the throttles forward when you were getting ready to crash? :confused:
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I was wondering the same thing. If you have an engine failure just after takeoff, pulling both throttles back and a controlled crash landing straight ahead is the only option...

If you push both forward and "take your licks" that means you're going to roll it and auger in
 
I did not know that, thanks for the insight. This is why i post these topics on here so i can get educated by people who have more knowlege about these things than I do:D
 
Ryanb said:
As im saying, this was jusy something I thought about. Not saying my opinion matters at all, just something talk about since i dont know much about twins. I would just think all twins should be capable of SE climb without issue as a safety question, much like a king air or some type.
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The King Air is a few million dollars and around $1500hr to operate. For a Baron it costs over a million dollars to add that level of assured performance. As I said before, climb is a matter of excess HP available over drag. C=EHP/D so, to increase C, we can either increase EHP or degrease D.

Increasing HP is expensive, decreasing drag is free by leaving useful load unused and unloaded, that costs utility though.

So you can get the single engine performance you want in even a 4cyl twin, however you will have a single seat plane with 2 hrs fuel+ reserves. My Travelair with a pair of 180hp engines (the older brother of that turbine Baron that performs like a KA for $1.3MM and 50 gph)had very respectable single engine performance at that weight, and had very low cost of purchase and operations.

The more utility you want than that, the more horsepower you have to buy, maintain, and feed, or the more limitation and reduced options you have to accept. It's all a matter of what you need, and what you can afford. If I could afford it I'd have the excess HP of a Citation X, but I can't, nor can I afford a King Air. But I can afford a 310 or a Baron, and they have enough excess utility for my mission, I can trade that utility for the climb performance it would cost me a million dollars to buy in horsepower, and end up with an acceptable level of SE performance.
 
brian];1677912 said:
From the 550 (300hp+ / side) baron drivers, you are talking seconds before you are above TPL and leveling off for a crazy fast cruise climb.

If you assume a failure in this case (below TPL) is a land straight ahead scenario, pushing the throttles forward and taking your licks is pretty much equivalent to a single or even a chute equipped aircraft.


Dang it... I'm buying the twin argument :(
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Hmm, I'm gonna assume you mean pull the throttles...

I'm also assuming TPL is traffic pattern level? If so, the critical altitude is typically far below that. Typically I'm fully cleaned up by 25'. The danger zone is really while the wheels are cleaning up which is why I leave it in ground effect until the gear is clean. If I have a failure during gear transition I have both a better attitude for pulling power and letting it settle in ahead, or I can prevent the wing tip vortices from forming until the gear is up keeping the drag down and allowing for better acceleration and control.
 
Ryanb said:
Very true, as im saying not trying to start any arguements, this was just a thought i had while reading that article.
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Just remember how old that article is (1973), and that it was written for a commercial publication...the FAA used it with permission of the copyright holder. Many of Richard's assertions have been shot down over the years.

Bob Gardner
 
Even the insurance actuaries don't really agree amongst themselves the best way to treat it. It's bookmaking really, and different bookies assign different value to the same functions/statistics when they run the numbers. Insurance actuaries are scary smart, if they can't agree on all this stuff, I'm not going to really bother to try because it means the race is too close to call and can go either way. Best to just keep good karma, do the best you can regardless what you're in or what you're facing, and not worry about it.
 
Ryanb said:
All light twins should be able to climb on one engine on takeoff, like higher level king air or multi's can. Just a thing that would boost safety IMO. Just came across this article and thought i would share my opinion.
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While we're at it lets require that you can take off on one! Think of the fuel savings! :rolleyes:

All this is idle speculation since the light twin market is effectively dead.
 
TUPilot said:
Should read "cannot be made"
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Ah. I wasn't sure it wasn't a Fruedian slip. Some folks are so scared of twins, I think they'd actually do what you wrote, but then again they probably wouldn't get in one in the first place I guess.

dtuuri
 
RyanB, you need to take a few hours of multi engine training.

In general, a twin flies better on one engine than a single on no engine.
This ability comes with technical issues that you have to understand for the couple of critical phases of flight caused by asymmetric thrust . At those few moments you have to proceed the same way you would pet a grizzly bear - carefully.

Now, the bashing of the 150 hp Apache is more a reflection on the abilities (or lack thereof) of the pilots making them than of the airplane. Mine spent the majority of its 57 years hauling air taxi passengers, freight, doing ME training, and flying in nasty weather at night, at times well above the certified gross due to icing. It has no crash or damage history. One has to assume that the multiple pilots who have flown in it for over a half century all understood their flying machine and made good decisions. The loose nut on the yoke causes 98% of crashes. The other 2% should have stayed in bed that morning.
 
Henning said:
Hmm, I'm gonna assume you mean pull the throttles...

I'm also assuming TPL is traffic pattern level? If so, the critical altitude is typically far below that. Typically I'm fully cleaned up by 25'. The danger zone is really while the wheels are cleaning up which is why I leave it in ground effect until the gear is clean. If I have a failure during gear transition I have both a better attitude for pulling power and letting it settle in ahead, or I can prevent the wing tip vortices from forming until the gear is up keeping the drag down and allowing for better acceleration and control.
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Yea - pull.. wife was hollering...

Admittedly, rolling over due to an engine fail on takeoff is something that still scares me (I don't have a multi rating yet), but the idea of an engine fail in IMC seem to be a higher probability (due to the amount of time one spends in that configuration) and something that would be scarier if you only have one ...

... then again, we seem to be better at killing ourselves ...
 
Dr. O said:
In general, a twin flies better on one engine than a single on no engine.
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I haven't seen this stressed for OP's benefit yet, and it bears repeating. Even an overloaded light twin, flown right, is only going to sink a few hundreds of fpm and give more options than a similarly overloaded single of similar make.

I'm sure the argument can be pulled apart a dozen ways, but it's what ME drivers are banking on -- the idea that if their lack of skill doesn't kill them (which it can, in more ways than in a single -- particularly if they're overloading their twin), their par-or-better skills will enjoy more options with an engine out.

<3 my colemill Baron, glad to see it mentioned. To quote one of my favorite people, "with 600hp, I can even make a toilet fly." ... too much is just right. :D
 
Well, I guess sue me too, I thought it was a good article, but then again, I like math. If his conclusions are wrong or no longer valid, it would be nice to hear the more correct version rather than some cryptic "I know better, cuz I am better" kind of mischigoss. Not that we don't learn things along the way, but the physics are pretty well founded and haven't changed since the 70s much. Human reaction, and training methods sure - but physics are the same.
 
Yes, have to agree with you Docmirror. A couple of comments have been made that this article is somehow flawed but without any references or arguments with facts. That is fairly typical for an internet forum though. :rofl:

"In general, a twin flies better on one engine than a single on no engine except for the leading causing of engine stoppage in flight (fuel exhaustion) where in general a single flies better than a twin".

What I don't understand is if having a piston twin is such a no-brainer from a safety point of view, why is it that the accident records shows us that piston twins are no safer than piston singles? :confused:
 
sixpacker said:
What I don't understand is if having a piston twin is such a no-brainer from a safety point of view, why is it that the accident records shows us that piston twins are no safer than piston singles? :confused:
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Because after getting the AMEL on their cert, most twin pilots don't practice engine outs. The twins are safer, the pilot's aren't.
 
brian];1679844 said:
Yea - pull.. wife was hollering...

Admittedly, rolling over due to an engine fail on takeoff is something that still scares me (I don't have a multi rating yet), but the idea of an engine fail in IMC seem to be a higher probability (due to the amount of time one spends in that configuration) and something that would be scarier if you only have one ...

... then again, we seem to be better at killing ourselves ...
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Study the issue a bit more in depth. Vmc and the corresponding roll issue is a multi variable equation that is based on several factors. If you vary any one of them, you change the outcome. One of the factors is drag, for Vmc that is assumed as flight out of ground effect. Lift is another factor, again, Vmc assumes out of ground effect. In ground effect you reduce if not eliminate the roll potential.

Second off, in a twin you never rotate off below Vmc, typically I will get half way to Vyse before I rotate, and it doesn't take long to accelerate above Vyse in ground effect without the wingtip vortices and gravity slowing you down, Vyse+10 the gear is home and I'm around 40' and pitching up climbing 2500fpm and have no worries making it around the pattern one from this point on unless I have some really serious constrictions from weight and terrain/obstacles.

Some planes Vmc can be made irrelevant. All the Twin Cessna series that have Vortex Generator STC, the Vmc is brought below stall speed, so not an issue. Doesn't keep you from stalling and screwing it up, but it's not going to roll over on you either.
 
sixpacker said:
Yes, have to agree with you Docmirror. A couple of comments have been made that this article is somehow flawed but without any references or arguments with facts. ...
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The article has long been cited for its merits by many experts. I'll continue to recommend it in spite of minor criticism.

sixpacker said:
What I don't understand is if having a piston twin is such a no-brainer from a safety point of view, why is it that the accident records shows us that piston twins are no safer than piston singles? :confused:
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My guess is people who buy them expose themselves to riskier flights. More night and IMC flying (TRWs & icing), for instance, and more marginal takeoff stopping distances on each flight. The safety benefits don't outpace the expanded risks, they mark time with them. Bottom line? You get to do more with the same level of safety.

dtuuri
 
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Another thing I've heard of before which bears repeating is the avoided accident where an engine is caged in flight, and no emergency was declared, or the flight was an emergency flight but came to a successful landing at an airport, thus no statistic was generated. This is an anomaly that is very hard to quantify, but represents some part of the twin-is-safer mantra. Maybe it's balanced out by the riskier flight profile though. Sometimes stats don't account for real life, and empirical evidence must be accommodated.
 
I know this....it sure was nice last night when my left vacuum pump ate itself and I was able to safely continue my night IMC flight to my destination.
 
EdFred said:
Because after getting the AMEL on their cert, most twin pilots don't practice engine outs. The twins are safer, the pilot's aren't.
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So excluding those who just got the AMEL and then never use it, for the twin pilots who use it is there any supporting data that shows that they are not practicing engine outs? Sometimes I wonder if this argument (which is used often) is a reaction to twin accidents and trying to rationalize why it happens by saying "oh it's the pilots fault he wasn't proficient enough". "That would never happen to me I practice all the time".

One of the outcomes of this article, from what I can see, is that in certain circumstances a light piston twin on one engine has such marginal performance that the probability of making a fatal error is high. It is all very well to practice emergency situations in non-emergency conditions but having something happen suddenly in a bad situation like IMC with a high workload could be quite a different situation for most people. In something like a KA with good climb performance on one engine and auto-feathering you not so close to the edge.
 
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