OK, forgive me, but it's rainy and drizzly and I'm bored. Rain or not, I'm going to eventually take a couple of the dogs to Troy for a walk, but before I go, a question bordering on "stupid".

When I started looking at twins and bought the A*, I really was attracted to the 685 Commander. Expensive 1200 TBO engines and what must be a horrendous fuel burn dissuaded me. Still, I find them to be a really appealing airplane.

So, considering the weather and my mood, anyone have any experience? Book says max cruise is 220, stall 75. No doubt they possess the legendary Commander stability and flying characteristics.

What would fuel burn be? 50 gph? Cost to overhaul $75k per side? Real TBO, would it make 1200 hours? I would love to hear from somebody who has owned and maintained one.

Jgreen

I know someone who will be along real soon to tell us about his new bird.

Come on out

Let's hear it!

Jgreen

Is the 685 the one with the GTSIO-540's?

Continental GTSIO-520's.

Jgreen

John

An air-ambulance company I used to work for ran C-421's and they had approval to run the GTSIO-520's to 1800 hours and they most of the time made it. We were flying them 75 hrs a month but still if you run right they will go and go.

Only 66 were built. The engines are GTISO 520K's that produced METO power of 435HP.
Very different than GTISO 520L's in 421C's that produce a lot less power at 375 HP.
435 HP was too much to ask of a GTISO 520.
Cruise was only 217 Kts and 9 passengers max.
GPH at cruise about 50 to 55

I'd stay away, John. I looked long and hard at them before I bought the Aerostar and spoke to the Commander gurus. Couple of things:

1. Rwy hoggers. Need close to 3000ft in ideal conditions. The props are too small for the plane and they'd have to change the gearing on the engines to be able to swing a bigger one. It's basically a 690 that's underpowered.

2. GTSIO engines will never make TBO without top end work. 435hp is just too much to ask from these. In the Cessnas they last longer because they only pull 380hp out of them, not 435. Also, they are perhaps the most expensive engines to overhaul at $55K+ per engine. Firewall forward you're looking at closer to $100K per side when the time comes. You can get a half time turbine replacement on a Turbo Commander for much less.

3. Since the share the same frame and construction as the Turbo Commander 690A/B, you're susceptible to all the AD's they have. That means the recurring spar inspection every 36 months unless you've done the STC (The STC to do the spar is $100K). The inspection is $14K each time, as the have to take the fuel bladders out. Then every 5 years you need to do the gear overhaul, that's another $13K. Don't think the 685 needs the aft pressure bulkhead fix, so at least that's a relief.

4. They'll guzzle 55gal/hr going 60kts slower than the turbine version burning 65gal/hr of Jet A-1. You'd be saving money on fuel in the turbine.

They are wonderfully big and roomy planes, they have great range and perhaps the most silent cabin of all twins. So I understand the draw. I really wanted one myself. But they were just made for a different time when Avgas and overhauls were cheap. They were marketed as an economic piston alternative to the turbine. That's changed today and you'd probably have the same operating costs as a turbine. In which case you might as well get the turbine.

As Michael alluded too, I just put a downpayment on a Turbo Commander. A 680V with the Century engine upgrades. You can read the thread here:

http://www.beechtalk.com/forums/viewtopic.php?f=49&t=97688

If you want to step up to the roominess of a Commander, look at the turbines. You can get into them for not that much money, many with the spar mod done so you don't have to deal with inspections. And if you chose the right model, you can stay clear of almost all the inspections and AD's (hint: 681 model).

But if you do decide to get a 685, you need to talk to the Commander genius Morris Kernick. He knows more about Commanders than anyone who's ever lived. PM me for his number.

So, $7k per year just to comply with AD inspections? One of them requires removing all the bladders? What is the draw to these planes again?

Would not a MU-2 make more sense?

Most of the turbines have had the STC done. And the pressure bulkhead fix is mandatory for planes over 4000hrs, so most have had them done as well. So, on one that's up to scratch you only need to do the gear overhaul every 5 years. Not that big a deal.

The difference is that the turbines were normally taken care of on part 135 certificate and it makes sense to do the STC's and upgrades for a higher value, working plane. For the 685 that's less the case - who wants to spend $100K to upgrade the spar when the plane is worth only $100K? So it's less likely they've been upgraded.

I'll add my .02 for whatever it's worth. If you like your A*, the step up is a Mits, not a Commander.

I agree with Adam's analysis about the turbine being a better deal, but I can tell you for sure that you won't be seeing a 65gal/hour fuel burn in a turbine commander unless you are RVSMed and you're up in the low 30's. More realistically you should expect a -10 to burn 75gals/hour at FL270, and that running it conservatively. Expect to be burning over 100gals/hour until you get high. Good luck with that in heavy traffic areas.

Commanders are fantastic airplanes. I love the way they look, and I love the way they fly. I don't own a commander because they scare the hell out of me. I know that I'm a chicken. I understand that plenty of people fly them all the time and they are easier to fly than an MU2. My beef with the Commander (and the reason I didn't buy one) is that the Va is 137 indicated. That sucker is pow-er-ful, especially a -10 Commander. That means you're up high in thin air indicating 190 knots or more in cruise at FL280 and if you get into some bad bumps you've got a lot of slowing down in a big hurry. I've read too many reports of Commanders shedding their wings. I'm not saying it's happened much, but over time the airframe just keeps generating ADs as the airframes get more hours on them. No thanks. Ted Smith may have designed both A*s and Commanders, but they are not the same ruggedness. The A* is way tougher, Va is 166 indicated. They may have some visual similarities, but the A* and the Mits are street brawlers, the Commander is a petty noble. You can't mix it up with the WX in the Commander the same way you can in a Mits. Yeah, I know: in a Commander you're up above all that most of the time. Guess what? You have to come down sometime.

The impression I get is that MU2s kill pilots who don't train train train because they have some unique characteristics, some of which are completely counterintuitive. Once you understand how to properly fly a high wing loaded bird with spoilers for roll control you're in really good shape. Run one through a thunderstorm by accident and you're probably going to survive it provided you're good at flying an MU2. Turbulence is a joke for an MU2. Don't let the thing get slower than 130KIAS and you're golden. It's basically an A* on steroids. The impression I get is that Commanders kill pilots who think their airplane is more stout than it is. I'll say it again: the Va is 137KIAS.

I love my MU2, but if I had my first choice it would have been John's Merlin. That sucker has a Va of 197; you aren't breaking that thing without a backhoe. The MU2 short body has a Va of 182 indicated, the long body 191 indicated. If I were you and looking at turbines (and I was for the past year) I'd get a ride in a Mits.

Excellent post. My Glasair has a Va of 187 with the yellow arc starting at 245 knots indicated. At 12k I'm indicating about 165 knots tops. Throttles all the way forward for all weather. If my Va was 130ish I would look for another airplane. The MU2 makes a lot more sense to me - especially when you want to sell it.

Holy crap Todd, that's a stout bird. I had no idea that thing was that tough; my kind of airplane.

Of course, I'm one of those guys who will sit in cruise nervous as hell with less than two motors, lol. I really am a coward.

Trust me, if I could afford it, I would love to have your airplane instead.

As far as piston airplanes go it is hard to beat the Glasair III IMO. 300 knot redline and +9/-6 G limits. 220 knots cruise on roughly 13 GPH. Just too much fun to fly and with a 30:1 wing loading bumps are not an issue. Now, lose an engine.... Well, let's just say that you leave the gear up and look for somewhere to land immediately. There has never been a Glasair break up in flight and some of them are running 50 knots OVER redline speed in Reno turning laps. You will break your body before you will break the plane.

Truly great posts here. My curiosity is truly academic, I think. The 601P Aerostar has met all my expectations and then some. I have used the same shop now for almost 15 years and they had some Aerostar experience so the learning curve for them was not too steep. I budgeted $18,000/year for maintenance and now realize that this was way high.

It's hard to argue with 210 knots in the mid teens at 30 gph. I am certainly not wealthy, but the fact is that I can own the Aerostar with almost no noticeable dent on my bank account. That's a nice feeling.

Like a lot of guys on here, I "almost" never met a plane I didn't want to own.

Jgreen