I’ve owned my 601P since 2007.
And, except for the last year, I have flown over 200 hours a year.
Minimal unscheduled maintenance.
I got over 2000 hours out of my first set of engines and am over 1000 hours into the second set. No cylinders removed/replaced.
I’ve done up grades over the years (5.5, avionics, winglets).
It’s been a reliable airplane.
And a joy to fly.

Maintence done in a shop that specializes in Aerostars has been straight forward.

Maintenance done in shops that weren’t experienced with Aerostars (or other complex piston twins) has been frustrating.

I think potential turbo charged Aerostar owners should evaluate whether they can access a shop that can fix Aerostars.

I suspect a lot of Dr. Bienz’s unhappily experiences with his Aerostars can be attributed to his choices in maintainers.

All that said, in the last year I have suffered from the extreme supply chain issues at Lycoming (engine parts) and Hartzell (turbo charger parts).

Bottom line after waiting (grounded) months for promised new parts, in both cases, I ended up tracking down (or begging for) used parts to get the repair process back on track.

I’m not selling.

I am hoping the supply chain issues improve.

But, if I NEEDED a plane that would fly on demand, it wouldn’t be a turbocharged piston of any brand.

It can be difficult to know where to obtain maintenance for an aircraft as you can only go with reviews and word of mouth. I tried my best and spared no expense. When I built up my Superstar, I had Western Skyways do fresh overhauls with new turbos, hoses & servos, new interior with a reputable shop in Denver, new paint, and every annual as well as most scheduled & unexpected maintenance was accomplished by The Flight Shop in Utah which was one of the longest operating Aerostar specialty shops in the nation. Winglets were installed at AAC in Idaho, and AAC did some additional structural work as well; I did the gross weight upgrade, and a glass panel.
The airframe (with the exception of the nose gear and hat section) was bullet-proof. Mr. Smith's design is beautiful, and it handles like a fighter jet. The weak spots were the engines & 4 turbos (which IMO are being asked to do too much with 350hp, pressurization, ice protection etc.) and the general systems (which, oddly, were much more failure prone than our turbine planes [King Airs and Mitsubishi] despite the fact that they seemingly have similar elements).
Despite that, just off the top of my head, I had cracked hat sections, cracked doublers with loose rivets, fuel leaks under wing boots, hard starting when hot, voltage regulator and alternator issues, autopilot failures, broken shear pins on landing resulting in shimmy and loss of steering, magnetometer failures, heater issues, door seal issues, fuel servo malfunction multiple times causing sudden decrease in fuel flow during climb-out and detonation risk, two fractured wastegates resulting in "rich-out" engine failures right at rotation or during takeoff roll, cracked block requiring engine tear-down (3 mos down), cylinder separation during flight (4 mos down), frozen breather during ice flight causing case pressurization and ejection of dipstick with loss of oil and engine shut-down, frozen oil cooler (ground temp -35) with overheating requiring engine shut-down in snow storm and 100nm flight in icing to shoot ILS at nearest airport above minimums, snow impacting nacelles of both engines to such a great extent that they overheated while in hold during snowstorm requiring diversion to another state hoping to stay above the mountain peaks at night without burning up the engines. It became really difficult to feel comfortable flying in the Wyoming weather at night as I was always wondering what was going to fail and create the next emergency.
In contradistinction, the TPE-331's churn out twice the horsepower that my Lycoming 540's produced and they eat snow and ice for breakfast without complaint. Aircraft systems virtually never fail and when something does go wrong, finding the problem and fixing it has been very easy as the whole plane seems to have a modular set-up with well-designed, huge access panels and factory/service center support such that the part is in the mail overnighted the next day and installation is an easy task. Expert maintenance providers for my Aerostar took two people most of a day to remove my damaged piston engines. The maintenance shop for the MU-2 can get an engine off in 40 minutes and have it back on again at the end of the day. Aerostar annuals had the plane gone for 3-4 weeks if nothing bad was found, 3 or 4 months when engine issues were found. That's simply not acceptable for a working aircraft. The Mistubishi's scheduled service visits usually take about 5 business days, so I just schedule it when I have a week without travel clinics or away surgery, bring it on the weekend, pick it up the next weekend and it's back to work the following Monday. The "U" in MU-2 is for "Utility"...aptly named.

Wow! You must have nine lives like a cat. I’m not sure if you posted it elsewhere, but over how many years/hours were all these Aerostar experiences?

I flew my Aerostars for about 12 years...not sure on the total hours, but I flew quite a bit. They were my first twins and I now have about 4200 hours single & twin.

Were those wastegates AAC wastegates?

I have a little over 1600hrd in MU2s. The only, in-flight failures (at least I only noticed them in flight) were one outer tank transfer pump and one shut off valve.

I've got just over 500hrs in my Aerostar.

I've had one real failure (Lifter spit in half made lots of metal and trashed engine, turbos prop, governor etc...)

One failure with root cause caused by me...
Going to Alaska, Bellingham said cleared for immediate take off or wait an hour for your clearance. I got rushed on that take off and was too lean... cooked a cylinder.
Had to change the cylinder in Alaska....
Did not realize that the wrong cylinder was sent as a replacement and it failed over
port hardy Canada on the way back to the mainland.
(Short reach plug cylinder, should have been long reach plug)


Aerostar flies well on one engine.
It requires eternal continuous vigilance to mange the high strung motors.

Were those wastegates AAC wastegates?
[/quote]

No. The plane had Kniesly Welding (possibly called something else now) wastegates. The arms broke in half. I replaced them with AAC wastegates. I think AAC got the FAA to force them to stop supplying wastegates for Aerostars but when I just did a Google search it looks like they still offer “exhaust services” for Aerostars. Not sure if that still includes wastegates.

Hello Forrest,
I would like to ask what performance improvements you saw with the winglet installation?
I am considering or kicking around, may better summarize my interest, in purchasing a 1975 600A that has had the winglets added to it, not all that long ago. The owner, who is a very experienced pilot, says that they made a very substantial difference in speed as well as in climb performance at altitudes of 10,000 MSL and above. I have never owned or flown anything with winglets but I really like the added “sex appeal” but I am not sure that they add $35K of sex appeal only. He said that the winglets also lowered his over the fence speed from 120 down to 100.
What is your opinion on the new style props? The shorter version?
Thanks, Frank

When the winglets came out they were 15,000$.

They add 3kts and ‘feel better’, I would argue they make a bigger difference at high altitude in a 601P, adding a little climb rate and about 3kts when you level out. If you have a 700, I really doubt they do anything, you got mega horsepower.

If you have got them enjoy it! If you don’t, not sure if I would spend 35K on them, I’d rather buy 7000g of 100LL

Winglets:

They look nice and the work as advertised (capturing the energy lost at the end of the wing).

Here’s the deal:

They are most effective (@ reducing drag) at high angle of attack.

S/E

Low IAS

After rotation.

LOP at altitude (or normally aspirated at altitude)


Short props:

Quieter

More ground clearance

Higher RPM for a bit more power.

I heard turbo overhauls doubled in 2024 (from one of the two turbo overhaul
Shops), when I did my turbos in 2022 they were 4300$ each, standard overhaul is now 8,200$.

W.T.F.

I was told in the late 80s turbo OH was 750$ ($2200 in 2024)

I bet Hartzell is taking a big inventory adjustment, sucking all the money out, and we will be left with a shell of a company, which they will probably sell off what is left (the intellectual property).

Here’s a reality check:

At those prices:

No availability.

I got lucky and a fellow Aerostar guy had some scrap turbos with serviceable housings that ATC was able to use to get my turbos done.

I am still waiting on the two new (spare) turbos I ordered, and paid for, a while back.

The fellow who answered the phone at Hartzell was nice enough.

Their story is that they are waiting on housings from whoever does their casting.
Once they receive them, Hartzell does the machine work, and then they either get assembled into turbo chargers or the housings get sent off as parts.

They have customers who have been back ordered for over a year.

To put winglets on a 600 you first have to install the wing extensions. That's why it costs us twice as much.

If you fly your 600 MGW out of short fields you'll see the greatest payback. If you're expecting fuel savings to pay for the upgrade, you'll be waiting a very long time.

I'm trying to recall anytime I ever spent "3 to 4 months" in maintenance. A pandemic era panel upgrade, yes. But routine maintenance? Never. Even the annual early on in my ownership when both engines were found to be making metal and both overhauled -- it was ten weeks start to finish. That's what life was like before pandemic supply chain problems.

I'm trying to think of a maintenance issue (other than the obvious turbos and door seal) Bienz mentioned that I haven't dealt with at least once. Cracked case is the only one I see.

Maybe there's something about Wyoming winter weather that really benefits from the extra 750 HP. I fly the 600 in -40C winter weather without issue. But I'm based in the NE so turbo / pressurization is a "luxury." Were I ever going to upgrade from the 600, first place I'd look is a short body MU-2. But I'm already 200 knots @ 30 / hr with a total cost of ownership way less than triple that burn. (But I account for capital improvements separately while Forrest lumps them with expenses.) A single TPE331 overhaul would cost more than my 600? It's hard to justify that upgrade economically.

I do:

I’m a long time owner (17 years).

The way I look at avionics and other upgrades, and most everything I’ve done, is either it’s something that is going to have to be done again (like avionics or paint) or if I ever do sell, I am unlikely to recover my “investment” in 5.5 pressurization, hat section upgrade, winglets, HF Radio, Max Viz Camera, Oregon Aero Interior, etc.

Assuming the stars align, this fall I am looking at paint (again) and a windshield.