Last time I checked it was about 10,000 more for GTISO520 engines .

I almost bought a 421C. The straight leg 421C is a great deal, the trailing link gear is coveted by some, but not worth it IMO. Extra weight, extra maintenance.

As to the engines, I became convinced the GTSIO-520 is a great engine and can provide reliable operation (to the extent any piston engine can). Given a choice between the highly stressed TSIO-520 in the 414 or the much lesser stressed GTSIO-520 in the 421, I would choose the 421.

That all being said, there are turbine options which operate about the same cost per mile as the 421, and ultimately, that is what I did and don't regret it.

Mike C.

Based on 100 hours per year or Less I believe the 421 is cheaper per mile.
If you’re flying more than 250 hours per year some Turbine’s are cheaper. The MU2 is an excellent example.

I look at total dollars spent per year rather than per mile.

Costs per mile are a great way to get yourself into trouble.

Per year is the only reasonable way to look at it. Almost every pilot who steps up, at any level, will fly more miles per year in the more capable plane.

Starter adapter problems are common to to 520s and 550s.

Gear box metal is GTISO specific.

I have 500 hours in on my 421C and have never been AOG GTSIO engines are very reliable and still being installed today.

https://continental.aero/news-events/ne ... 0_Engines/

It is the only reasonable way to make a comparison, what value are you getting for your money?

It gets worse for slower airplanes when you realize two thirds of your flight time will be in headwinds, too. This factor is often neglected in the comparisons.


That's more value so it has to be accounted for.

If you fly the same exact missions with 421C and MU2, the MU2 will cost you roughly the same per mile, maybe less, and will be a far more capable airplane.

The fact you can and want to fly more is a testament to the faster airplane delivering more value.

Mike C.

This is how i look at it. The new under warranty turbines I fly have little out of pocket maintenance expense, we send it to the service center for most everything. Initial cash outlay is more though.

I’ve run this exercise several times, the GTISO engines don’t receive much praise, a lot of pilots/owners tell the same tale.

Very experienced friend of mine went through 3 GTISOs in 1 year. RAM covered nothing.

What was wrong with the 3 GTSIO engines? Other than the same pilot flying behind them.

There is a difference between a pilot experienced at flying planes and a pilot experienced at operating GTISO520 engines.

Un-balanced prop installed and rebalanced by RAM. Pilot/Owner insisting it was not balanced. Turned out he was correct.

I agree and their in lies the problem. Fix the engines, pilots are a lot harder to fix.

Just one data point, but we are going on year 3 of 421C ownership. We had some catch up from deferred maintenance from the prior owner, but the geared engines have been reliable. They are quiet, make great power on take-off and climb out, and run so cool they don't even have cowl flaps. We did require a turbo overhaul that grounded us for a while during covid due to supply chain issues, but now those parts are available again since production has resumed. We installed a JPI monitor to really be aware of the health of each cylinder which gives me more comfort and confidence in the engines. Overall we are very pleased with our 421.

Guy,

Thanks for the information. Who does maintenance on the aircraft? Is it a “twin Cessna” specialty shop? I only ask because I’m looking for a new shop and am wondering if I should go to one of the specialty shops or guys that have done maintenance on my other aircraft before. I’ve had good luck from both.

My co-owner is an A&P IA with twin Cessna experience and he does the maintenance. We did have a specialty shop do some work and I frankly wasn’t impressed.