SecondLife

I have a Seneca II and considering using it for flight training. I know the conventional wisdom (mentioned here and that I have repeated myself) that having turbos on a training aircraft is a bad idea. I wonder though if anyone has practical experience with this? For example, would one expect the turbos' life expectancy to be cut in half? Or worse?

One bad thing with turbos is rapid power reductions where you have a fast spinning turbo with reduced oil pressure. You can't just yank an engine on climb out but otherwise I'm not sure how the turbos would be stressed by typical training scenarios. Granted its been a few years since I taught ME students so I may be missing something.

In some regards the Seneca II is not a bad twin for ME training. It has great performance when lightly loaded so it would keep a student on his/her toes. It also has a good single-engine service ceiling (12,000 ft) so you can actually do some flying on one engine.

sqwkvfr

I think that a carefully flown Seneca II makes a great ME trainer...if it is flown correctly. We use them for JAR/EASA students and I am impressed with their performance and forgiving nature.

However, I would NEVER lease my Seneca II (and to be clear, this is a hypothetical, since I don't own one) back to a flight school for fear that it would be a financial nightmare.

The biggest issues would be care and MX of the engines and landing gear. The fixed wastegate makes setting the MAPs a nightmare for the new ME student and the possibility of overboost very real. Doing stalls and the like are not conducive to good care of the turbochargers, and again we have the likely overboost issues. And last, but not least, the aircraft tends to land very heavy and very flat....a good landing requires a lot of practice, particularly for a new ME pilot...in fact, I was told by the examiner who did my CFI a few years back that when she instructed in the PA-34, they would NEVER use flaps 40 --even for short field landings-- in an effort to get more of a pitch up attitude for landing.

I suppose it can be done...we use them, but the FTO that I work for has fairly deep pockets and a full time MX guy (who doesn't work on the aircraft) monitoring issues with our fleet.

But, they still break all of the time....and I would think that there is no way that leasing back just one to a flight school would be anything short of a recipe for a financial disaster.

sqwkvfr

The only turbocharger failures that we've experienced haven't been of the catastrophic type.....the turbine blades, if cooled too quickly, evidently get brittle and eventually a small piece of one of the blades will break off, causing the turbocharger to vibrate and eventually break off of it's mounts.

We run 8 Seneca IIs, and I've had many failures, but what I've described above is the only type of direct turbocharger failure that we've experienced.

The turbocharger, however, creates many more "indirect" problems, some of which are described in my first post on this thread.

SecondLife

Thanks for the reply sqwkvfr. That is very helpful.

I would instruct in it myself and definitely not lease it back to a flight school. Mine also has the Merlin waste gate STC so the boost is easier to maintain. You are right about the stalls - power off/power on - that would be hard on the turbos.

sqwkvfr

If you're doing it yourself, hey, you might wanna give it a shot.

The technique that we use for "power off" (we call them "approach configuration") stalls is to not drop below 14" of MAP to prevent over cooling. The RPMS usually remain above 2K so the oil pressure problem that you (I think it was you) mentioned earlier should not be an issue.

We also let the engine idle for a minimum of 20 seconds before feathering the propeller in flight to prevent the oil from coking in the the passages of the turbochargers. We've never had a lubrication problem, but some of our instructors just don't take very good care of the aircraft, thus the problems that I mentioned above.

Other than the MX and other issues that we've already discussed, they're great aircraft....hell, we use them for single-engine go-arounds (don't try this at home, boys and girls) in the PHX summer heat, and they do quite well performance-wise.

Good luck with your decision.

One more thing: Have you added unfeathering accumulators (or is that even possible)? We have one come back about every month or month and a half single-engine because the instructor couldn't get the engine to re-start after an intentional in-flight shut down. I haven't had the problem because I prime the engine differently that what our checklist calls for, but every once in a while the starter kicks that engine over a lot slower than I'm comfortable with when I'm restarting in flight.

aeromike49

The Seneca 2 and probably most versions are very far forward CG with 2 persons in the front seats and nothing in the rear. I used to carry some ballast tied down in the rear baggage area and it helped a lot in the flare. This is a problem and there have been more than one nose gear failure in these aircraft. Do yourself a favor and put some ballast in the rear baggage area - tie it down well - and check out the difference. Use the ballast - don't need a lot - and make it easier to land and a little more gentle on the nose gear. Something I don't understand - if you are learning to fly a different type of plane - why not make it easy to learn - and then go for the challenge afterwards. No one is going to care if you have 10 hours in a 310, a Seneca, Seminole or Apache for that matter. Missing the point - get the rating - save a few bucks, and live to tell about it.

SecondLife

Regarding the use of a simpler/cheaper twin for the rating, that probably depends on what you want to do with the rating. One should also consider aircraft checkout and insurance requirements. My insurance policy, for example, requires 10 hrs dual in type. So even if you have a ME rating you would still need 10 hrs dual in the Seneca if you wanted to take it out solo. In light of restrictions like this it may make sense to get your ME rating in the aircraft type you plan to rent or buy.

MusDg

Going to drag out an old thread but this one came up on my search about turbos and multi engine trainers.

What do you all think about ME training out west at higher altitude airports. Been trying to rule out turbos and find something that will atleast keep it in the 7000' range at least for SE service ceiling. Average field elevation is 4-6000'. With that it brings me to a Twin Comanche C or CR and a C310R.

Have any of you all instructed ME out west in say a Duchess or Seminole? How was the SE work like? If not, what did you train in?

trip

I used a C310D, old and expensive but it got the job done. It could do 8000'msl and still climbing on one engine loaded lightly.
I see a lot of DA42's doing multi stuff out west, from what I hear they are gutless and cost in the millions but burn very little gas.
I'd look for a 4 banger like a Seminole/Seneca.

MusDg

Thanks for the input. I was looking at the DA42. Especially with the SE service ceiling being the same as the service ceiling (18,000'). That price tag though that comes with it. Plus I almost feel that it would be cheating to be trained in one with only having throttles and a toggle switch to feather the prop. They are safe and sip the gas though. Thinking the best option is going with a 310, PA30, or like you said. Finding a good four banger and keeping it on the light side.