Single vs. Twins?

Redundancy and saftey do not necessesarily run hand-in-hand.

Flying a twin with one engine can be far more dangerous that flying a single with no engine. I have often read that it simply gives a false sense of security. At least with the single, you "know" is going down. Just pick the best spot you can find, and go for it. The twin keeps you looking for better options, until the best one has likely passed you by already.

Then it's kind'a like trying to figure out where you are, or where you should be when you're lost, and your not quite sure how you got where you are, or where you think you are relative to where you think you should be. Which process goes something like this:

Of course, this is all just what I've read. I have no practical experience with any of this!

-the newbie in training that still hasn't solo'd.

"And always remember: Flying isn't dangerous. Crashing is dangerous!"

 

Rob,

First to address the safety of twins vs. singles. There is always the battle between those who profess the safety of having the second engine vs. having only one engine as being somewhat better. Suffice to say that the statistics singles vs. light twins is about the same. Most accidents are not due to engine failure and when they are, the challange of handling a twin with an engine out is greater than that of a single. Obviously, proficiency in emergency operations, especially engine out and double especially on takeoff is paramount. If you will be flying the aircraft frequently that is good. Infrequently, the issues of multi-engine proficiency become problematic.

One must also recognize that depending where you will be flying, the single engine service ceiling of most light twins is dismal at best. At worst, it is lower than the airport elevation (like here in Colorado). Single engine service ceiling is also dependent on whether the remaining engine condition has horses or "old grey mares" producing its propulsion.

Even in the simplest light twins, systems tend to become more complex. There are dual power busses to manage and understand the emergency procedures for as well as fuel systems of various degrees of complexity as far as numbers of tanks, valving, crossfeed, etc. Those emergency procedures must similarly be mastered. Some aircraft (the older Cessna 310's come to mind) have some of the most complex fuel systems in light twins known. They can easily become the source of a problem rather than the solution.

The cost of ownership and maintenance of a light twin vs. a single is not simply just a factor of 2. Any shop will tell you that it is, in fact, several-fold. This due to the additional complexity of an aircraft which is usually much more capable than a high performance single. Factor the costs and downtime into the equasion.

To that end, I might make some recommendations. Since there are not that many types to consider, the short list might look as follows:

At the very low end there is the Beechcraft Duchess and perhaps the Piper Seminole. These aircraft are the ones usually used as multi-engine trainers. They may not make the best cross country airplanes for the mission requirements you have previoulsy stated. Roominess, load-carrying ability and fuel quantity suffer.

Piper Aztecs (PA-23's), especially the later ones with larger engines are brutes of an aircraft. Well built, strong, roomy, good haulers, GREAT flying characteristics, but not very swift. A good all around aircraft to consider. Avoid the earlier models, especially the Apache, as they are likely not fitted out anywhere neare as well as they were on the earlier portion of the evolutionary timeline of the marque.

Piper Twin Comanche's make GREAT all around airplanes for comfort, speed, range, but not as good for load carrying. Not as docile as the Aztec but it will not bite you either.

The Cessna 300 series, starts at the low end 310, and proceeds to the 320's and 340's. The evolution in this series is profound. Early 310's will try and kill you every time you start one up, the 320's are a bit better but the 340's finally got it right. VERY good aircraft! There is also the oddball 303 Crusader
Excellent airplane, but not that many around.

Cessna's 400 series, i.e. 414 and 421 are business aircraft to the extreme and more suited to the professional pilot, rather than the weekend warrior.

Going on to Beechcraft, the B55 and B58 Barons are SUPERB all around twins with the B58 models fixing all the evolutionary issues with the 55's. GREAT handling qualities, range, speed, load, etc. Built like the proverbial brick-privy.
Prepare to pay top dollar for a good one and, as previously stated, become VERY friendly with your mechanic and banker.

Up Beech's food chane come the Duke (one of my personal favorites) and then the King-airs. The Dukes are kind of like the Cessna 303's in terms of scarsity. Youl'll need to find a shop which specializes in the type and who has the special tooling and handling equipment. (start tapping that oil well you have in your back yard)

King-airs are like the Cessna 421. Made for professional pilots as business aircraft. In that vein there is also the Piper Cheyenne.

I'm not real sure as to how the new crop of "plastic" twin engine aircraft as in the Diamond series stack up, so you're on your own in that regard. On the surface they lookk like the trainer type in the same category as the previously mentioned Duchess and Seminole.

Diverging just a little bit here, I thing one of the best kept secrets in the high performance single market is the (I don't know who makes them now) Rockwell Commanders, the 114 being my choice. VERY comfortable, Built tough, (the landing gear looks like it came off a fighter aircraft) Great looks! (I love the cruciform tail [applies to the Cessna 303 twin too!]) but rather sluggish in the speed category for its 260 horsepower lycoming. The older ones have had some serious airworthyness directives on wing spar cracking but I think that is all taken care of by now.

D'd'd'd'd...... That's all folks.

Planeflyr

 

You are correct. Cessna does not manufacture any piston twins any longer. For about 10 years they weren't manufacturing any piston singles either!

I for got one Cessna aircraft which has a rather loyal following. That is the Cessna 337, a.k.a known as the Skymaster [less affectionately known as the mix-master, bug-smasher, push me-pull you, etc.] What is somewhat unique about this airplane is that it is a centerline thrust configuration. This is to say that it has an tractor engine in front and a pusher engine at the rear. On the one hand it has an inherent safety factor as there is no critical engine meaning that with one engine out there is no yaw tendency to be concerned with as with conventional twins. [with conventional twins one engine out is worse than the other (I forget which) due to torque and p-factor. The "critical engine" issue is eliminated by some twins having counter-rotating propellers where each engine turns in the opposite direction thereby only having the yaw to contend with. Some examples are the later Piper PA-39 twin Comanches, the Beechcraft Duchess and maybe the Piper Seminole (not sure of that one)] The down side of that is if you acquire your multi-engine rating on a C-337, you have a restriction on your license limiting your multi-engine operations to centerline thrust aircraft only. Getting your multi in a conventional twin whether with counter rotating props or not qualifies you for any multi-engine airctaft not requireing a type rating.

C-337's have a great reputation as comfortable, fast, and as having excellent flying qualities. The rear engine is a nightmare as it tends to run very hot and overheat, made worse by the turbocharged version of the breed. It also comes in pressureized versions.

Should you chose to look into this type, beware the turbo and pressurized versions. Lots of downtime and maintenance bucks.

As I said thay have a very loyal following.

A side note... They were used extensively in VietNam as forward air control aircraft under the designation of O-2.

Planeflyr

 

I'm partial to the Pa-44 but that's just because thats what i got my twin license in. But in no way is it a big hauler of a plane. you lucky if you can take full tanks and 3 people, but i guess thats a light twin for you.

As for the bigger twins and singles. I would think a good single would cost you a bit less, overall. But with the twin you get some what of a redundancy factor you don't get in a single. You need also to take into account what you will be taking with you, ie the useful payload of the AC.

 

I believe the only NEW piston twins currently available are the Barons and the DiamondStar. That probably should tell you something (and the only NEW turboprop twins are the King Air series, which also tells you something).

Statistically, you are probably better off, or very close, in a single versus a twin. A friend of mind and I were just having this discussion, and he had done a study for his customer comparing turbine twins and turbine singles (the PC-12, specifically). The PC-12 had zero fatalities due to engine failure, a statistic which simply can't be replicated by any turbine twin flying today (except maybe the Beech Starship, but there are so few of those and they fly so few hours that it's not a fair comparison).

I don't know how the piston comparison would shake out, but I imagine the overall stats would be similar.

All that said, in weather or over the mountains, I still much prefer having two engines! Just less stress, as far as I'm concerned.

BTW, the accident stats for light twins generally dwell on the engine failure after takeoff scenario, because that's where most of the accidents occur. You don't hear that often about engine failure at cruise, because those usually result in a successful on-airport landing. Engine failure in a single at cruise usually results in an off-airport landing, at best.