Piston twins, a case of love and serious airmanship

[youngskywalker]

Lucky guy I 'was', my former employer took away all my toys .

I'm the ultimate aviation coward, I get nervous just crossing a small river in a single engine piston never mind flying over the chanel or the Alps!

You cant beat that feeling of utter reliability that you get from sitting in the cruise and listening to those fantastic PT-6's growling away! In contrast everytime I got into a twin piston I fully expected to die horribly one day...only joking!

Trouble is that once you get a taste of flying something really special (in my opinion it was the King Air) then it becomes really hard to get enthusiastic about pootering around in something smaller again, god help me if I ever get near a jet!

Bose-x, fair enough, I know nothing about the more advanced piston singles.

[IO540]

I wouldn t like to cross a mountain range in the single

Statistically and practically, you are far more likely to die doing this by icing up (because you don't have the operating ceiling, so got stuck in IMC) and plummetting and hitting a mountain because the 0C level is below the terrain so you never got a chance to thaw out, than through a straight engine failure.

Enroute IFR flight is (or should be, unless you have balls of solid brass) done in VMC, and (especially in a non-turbocharged plane) the engine is running at quite a low power and thus under little stress. When I cross the Alps at say FL180 the engine is probably making only 40% power, and is cool as a cucumber. FL250 is the province of turbos but even then the power output should not be high; FL250 is the ceiling for most turbo pistons.

[youngskywalker]

Of course, chances are you will be perfectly safe doing so. It's just an attitude to risk, which is a very personal thing. I've lost a good friend after a water ditching in a single engine piston at night and my first instructor perished in a twin engine piston prang, I guess thats what plays on my mind and has made me very cautious, perhaps overly so.

[FlyingForFun]

I wouldn t like to cross a mountain range in the single, just a personal thing.

Out of interest, what's the single-engine ceiling of your Seneca? And how how are the mountains you're crossing?

FFF
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[BelArgUSA]

Singles and twins...

Having flown with airlines, I am just about to retire in a few weeks.
Throughout my aviation career, I am often around small private airfields.
Even own a Piper L-21C (a former military Super Cub).
And of course have acquaintances who own/fly light twins.
xxx
If flying a twin with powerful engines and good single engine performance, fine.
But beware of low-powered twins, and heavy payloads.
Besides all that, try to maintain adequate engine-out proficiency as pilot.
xxx
I have a preference for my little tail dragger. I can land it about anywhere.
Twins have double the engine failure rates than single engines.
Statistics - If engines fail every 4,000 hrs, twins will average one each 2,000 hrs.
I agree to the mention of system redundancy, i.e. generators, vacuum pumps.
De-icing, dont believe in it too much... and call it anti-icing.
If you enter icing conditions, your best procedure might be a 180º turn.
For me, lightplanes, single or twins remain restricted to VMC and blue skies.
xxx
I have a friend who owns an old PA23 Apache - 2 x 160 hp...
Last year, one engine failed, he had to land it on a road in the country.
Had 4 adults on board, could not keep it flying to the nearest field.
xxx
Have fun guys, if you can afford the extra gasoline. And fly safe.

Happy contrails

[Pace]

>Out of interest, what's the single-engine ceiling of your Seneca? And how how are the mountains you're crossing?<

Flying for fun

The single engine ceiling on Seneca twin is around 16500 feet without checking the manual I have over 2000 hrs in Seneca Five twins and they are a solid safe twin. The five is great at altitude. Crossing the Alps the lowest you will get airways is FL180.

Passengers especially if they are not aviation Knowledgable are not happy in a single. They see the twin engine as having a spare engine and in the cruise loss of one would make that the case as they are a doddle to fly one out in level cruise.

I also must admit that statistics or no statistics I feel far happier at Night solid IMC with a 300 foot cloudbase and 1000 metre viz in a twin. The same goes over fog or 200 miles out to sea when you know those white caps seen from Altitude would be 50 foot high moving brick walls close to in the event of a ditching.

So maybe statistics dont mean that much to me or my passengers its perception. Knowing sods law the 300 cloudbase at night is the time the single will decide to go bang anyway Or my single turboprop hot rod will choose to hit the only eagle flying in the skies and knock out my one and only prop.

Finally and this is a little known fact! if you collide at high speed on the ground into something solid, with a single the whole engine enters the passenger compartment and will smash the occupants into obliteration. No! aircraft deformable structures are non existant compared to the techology in cars.

The twin has those massive lumps of potential projectile metal on the wings and away from you or your passengers and the nose of a twin does act as a deformable structure.

Pace

[IO540]

Crossing the Alps the lowest you will get airways is FL180.

You can get a lot lower than that, an lower still from Austria IIRC. I recall filing FL140 from UK to Croatia, straight over the Alps.

But rarely can one do it without climbing to remain above cloud.

[Pace]

10540

I would imagine without checking charts for airways that it depends where you are routing maybe over the lower Alps?

Have you been into Lublijana LJLJ has to be one of my favourite destinations into really pretty countyside and high mountains.
I have flown into there in twins and business jets and it well worth a visit.

Pace

[Pace]

BelArgUSA

The Apache is NOT a GOOD example of a twin single engine on takeoff or cruise. It has a diabolical record and performance capability.
The Apache is really a single with half its one engine on each wing

Many moons ago flying from the UK to France we shut down a Seneca engine and flew the whole 70 miles across on one. Restarted and landed on two Crazy thing to do looking back but ????

A twin will happily fly on one in the cruise.

The Seneca is approved into Light ice and does a pretty reasonable job of dealing with it although I agree you do not want to hang around in ice.

Pace

[englishal]

I don't fly a Twin in Europe, as frankly I don't own one and paying £300 per hour for the privilige of renting one doesn't appeal to me.

However, when in the USA (like now) I always rent a Twin Star, which I think is the best twin out there. It may not perform along the lines of the Seneca (yet), and only have 4 seats, but it is a great IFR platform and the benefits outweigh the extra 10 kts of the seneca . It performs great on 1 engine and of course being turbocharged has no problem with altitiude. The new version with ~170HP engines will cruise in the region of 190 kts+ ......

Nowadays I'd never buy an Avgas burning piston twin, for many reasons, not least operating costs. I just wish I had a spare $800,000 How much does one pay for a TS in the UK?

[IO540]

Pace,

Yes, LJLJ, been there and really loved it.

Re routes, here are some examples, validated for 0900 Z tomorrow, FL100 base level

-EGHH0900
-N0150F100
SAM R8 DVR DCT KOK L607 NEKIR/N0150F120 L607 RUDUS/N0150F100 L984 ASKIK/N0150F120 Z74 KOSEK/N0150F100 L603 UNKEN/N0150F130 L603 OBEDI/N0150F150 L172 VIW/N0150F110 L608 TELSI
-LJLJ0502

The above is FL150 max.

SAM R8 DVR DCT KOK L607 NEKIR/N0150F120 L607 RUDUS/N0150F100 L984 ASKIK/N0150F120 Z74 KOSEK/N0150F100 L603 TEGBA L605 ALMER L604 GRZ L141 ARLON

is FL120 max.

although I agree you do not want to hang around in ice.

And there is the crunch! Let's say you are doing a 5hr flight. Pottering along nicely at FL100, no oxygen, and ahead are clouds looming up to an estimated FL180.

What is the plan now?

There is no way to do this without "hanging around in ice" Regardless of icing forecasts (for what they are worth) being completely blank, I can guarantee that over some hours you will pick up ice. Also you cannot see where you are going anymore, so you could fly into something with "quite a bit" of ice inside it.

The only way is to either totally rely on your rubber boots, over mountains etc, or make sure the SAT is colder than -15C and preferably (if there is any lift, which over mountains is fairly likely) a lot colder than that.

VMC on top is the only way.

Englishal

A poor man's turboprop is $2M (Meridian) A Jetprop can be a lot less, depending on how beaten-up the Mirage it is based on was. And it is 1999kg

[Pace]

>170HP engines will cruise in the region of 190 kts+ ......<

Englishall

Can you detail that? are you talking about the Avgas version or some replacement diesel unit? for the 135 hp diesels.

Pace

[Fuji Abound]

Englishal

The new version with ~170HP engines will cruise in the region of 190 kts+ ......

Are you writing from experience? I have flown the single with the new engine and it doesnt add greatly to the performance - certainly nothing like that amount. I have not flown the 42 with the new engines however.

I guess you have flown the 42 at MTOW with a simulated failure after take off. Personally I would not have said on the critical engine the performance is all that great - reassuringly it does climb IF you are on the money, but plenty of margin to get it wrong if climbing away in IMC. In the cruise I would agree it is fine - and I speak from actual experience .

[sternone]

I flew a few hours in a Seneca and a few hours in a Twin Comanche. While both are fun, they will kill you in a second. Twin flying is much more dangerous than single engine flying.

Buying a new Seneca V for 1M$ doesn't work that good anymore these days. It's a bad business model.

I know some very good pilots who will never fly a twin over mountains. In case of an engine faillure (which you have more chance to happen than in a single) they will go down to SE ceiling and you won't be able to climb anymore in case you encounter something nasty like icing etc.

I tought I wanted to fly twins, but I don't buy it anymore. Give me a IO-550 anytime.

Could be a last hope of the original poster of this thread to get the prices or request up for his seneca since he before wrote he wants to stop flying because of the money. It must hurt for him filling up his Seneca tanks each time these days... and for what ? Not for speed that is... his Seneca is so nasty on the fuel burn compared to speed it simply doesn't make sence.

[Pace]

Sternone

I dont know where you are getting your information? You say you have has a few hours in a Seneca and a few in a commanche?

Any aircraft will kill you if mistreated single or twin the only difference is the twin gives you more options. The single in the event of an engine failure means you are going one place and that is down.

The twin gives you the option of possibly staying up but yes you do have to be current and on the ball and able to make the right choices.

I have had three engine failures in over 2600 hrs multi piston time. One was a full failure the other two partial so maybe in a position to offer an opinion?

You quote a failure over mountains? The Seneca will maintain 16500 feet engine out! Are you referring to the Himalayas? As 16500 feet should keep you above most. The single will NOT keep you above any so I dont see your arguement?

>In case of an engine faillure (which you have more chance to happen than in a single)<

Yes but get this straight we are not talking about a twins engines being less reliable than a single but the pure fact that you have two engines and the greater mathematical chance that one will fail.

Pace

[sternone]

I have had three engine failures in over 2600 hrs multi piston time

First of all, I DO NOT WANNA FLY WITH YOU, you are completely MESSING UP THE SATISTICS!!! each 900 hours you get an engine faillure ?

The twin kills you faster, most who get killed while lost of trust on one engine is because they let the plane go below VMC or they feathered the wrong engine. While it doesn't happen with you it happens with other GA ME pilots alot. Why is that ? In a real partial loss (and you know that) it isn't THAT easy to feel what side has failled...the plane just goes from left to right...

The twin gives you more options to mess it up. And that's where it goes wrong with the GA pilot.

Most light twins don't go as high as the seneca. Ever checked if your seneca keeps altitude on SE ? I would love to see you can hold that 16500ft i doubt it.

Ever checked what the SE ceiling is of a baron ? 7000ft...

The fact remains that you are LESS prone in a single than in a twin to get into problems above mountains.

Don't get me wrong, i love twins, i just had to get the training and the flight expierence in them to know it's a bad business model.

[S-Works]

Don't get me wrong, i love twins, i just had to get the training and the flight expierence in them to know it's a bad business model.

My, you have done well. Only a couple of months ago you were doing your PPL and telling us the Mooney was the best thing in the world. Now you are an expert on twin flying. I am impressed indeed.

As pace points out the twin does have some advantages over a single in certain circumstances and does require currency. I only have around 700hrs of multi time so can't compare to his experience but my limited experience agrees with his.

Notwithstanding this I will take the Mirage over any of the twins based on speed and economy!!

[Contacttower]

You quote a failure over mountains? The Seneca will maintain 16500 feet engine out! Are you referring to the Himalayas? As 16500 feet should keep you above most. The single will NOT keep you above any so I dont see your arguement?

Which Seneca is that Pace?....I assume it's one of the later ones since I was under the impression that Seneca I single engined ceiling is something like 3000ft.

Certainly when it came out in 1963 the Twin Comanche was a major departure in terms of performance with a single engine ceiling of 5800ft service and 7100ft absolute. Which is fine for UK mountains at least.

The one thing that constantly bothers me about twins is engine failure on take-off.....one needs a nice long runway to ensure that if you get a failure below Vmca one is not going to have any problem with shutting the throttles and stopping/landing ahead.

[Fuji Abound]

Twins have double the engine failure rates than single engines.
Statistics - If engines fail every 4,000 hrs, twins will average one each 2,000 hrs.

I wanted to point out this is a commonly held view - which is incorrect. The single engine failure rate of twins is significantly lower than that for singles. Many factors combine to make this so.

Here is a few exercises to try for those here that think they know how to fly twins.

Climb to 3,000 feet and set up a descent of 500 fpm, 10 % below best SE rate of climb. Continue this to say 2,200 feet anticipating a landing at 2,000 feet and simulate a single engine go around. What do you think happens?

Can any one come up with a twin that doesn’t lose more than 80% of its climb performance on one engine - I can think of only one. It would be the one I would buy if I were in the market and have had the pleasure of flying for a few hours.

You can debate it all you like but twins offer a safety advantage during the en route phase in many circumstances and also generally during the approach and departure BUT in both cases, and especially the second, the skill of the pilot AND a proper understanding of what is and isnt possible is critical.

The last engine failure I had was in a twin. Had it been in a single I would have landed in a field. I would have hoped to have suffered little personal injury (based on the statistical evidence and my own experience) but as grateful as I would have been for that outcome, the aircraft would almost certainly have suffered some to considerable damage, the cost of recovery would have been significant and I and my passenger would have been inconvenienced. As it turned out the twin suffered no damage at all as a result of the landing (at the airport), no charge was incurred (the airport waived all costs) and personal inconvenience was minimal.

Some will tell you the extra engine in a MEP is to enable you to complete your journey. So far as I am concerned it is an emergency. At the point of losing an engine I have lost more than 80% of my performance.

I am still grateful when the transport picks me up it is from the nearest airport and not from the nearest muddy field.

[mixture]

asymetric flying

This is the double edged sword of twin flying.

Having that second engine can, in some pilots, incite a great deal of arrogance.

There are a number of crashes that could have been avoided by the pilots reluctance to do the right thing and shut off that second engine and go back to the good old SEP days of gliding.

Your multi is not a Boeing/Airbus. Different performance class althogether. Its probably not a wise idea to to extended runs on the good engine and you certainly won't get the same climb performance !

Twins are great, but in the right hands and the right circumstances. As others have pointed out, sometimes you're just better off with a good SEP !