Leaning towards a 700 superstar but am also interested in the 421. I know the 421 has more room inside and geared engines but what are pros and cons between the two? Mission is 760nm trips with occasional 350nm trips. Want to make the 760nm trip without a stop.

Kilometers (km) or nautical miles (nm)?

This is what we saw in our 421.
It held 262 gallons (2 nacelle tanks).
ROP was around 45 gph, so almost 5 hr range with an hour reserve.
LOP was 35 gph/6.5 hr range.

viewtopic.php?p=2989091#p2989091

You require a C501 or MU2. Paging Mr. Tarver…

Edited post, too much Christmas festivities last night I guess.
Jack, thanks for that info it’s very helpful. Do you happen to have any flight experience with an Aerostar 700 to compare?

I don't, never been in an Aerostar.

When I was shopping for a twin I went and got in a Aerostar. Oh man was it small. Would not work for me so I got the 421.

I think Aerostar can be great for a smaller pilot and family. I had a friend that had one and loved it.

After flying and maintaining my 421 I decided it wasn’t worth it and went to a 501sp.

Look at fuel trip cost with 100LL and a piston twin starts getting expensive.

That being said after 5 years in a 501sp maintenance can be all over the place and some
Years it’s bad. But I also had a bad maintenance year on my 421.

Mike

Looking at Jack's numbers, an F model MU2 would be 40-50KTAS faster burning 56-58GPH. Since Jet A is less expensive, sometimes much less expensive; the cost per mile is similar. If you have a newer than F model MU2, 300KTAS is available on 75GPH. The MU2 will need less maintenance and will be much more reliable than a pressurized piston twin. The 421 is larger inside than an MU2, but not by much and I bet it is quieter inside as well. My largest maintenance expense in any year was $20K, and three years were less than $15K including tires, batteries and other wear items. Only one unscheduled maintenance event is almost 5 1/2 years of MU2 ownership. Not knocking 421s or Aerostars, but if you are looking at that class of plane you owe it to yourself to look into MU2s as well. That is where I was 6 years ago and haven't regretted my choice. A lot of former Aerostar owners now fly MU2s.

Jeff Axel
N54PC

Comparison of Aerostar 700 and Cessna 421C (1976 – 1979)
Note: The C421 data is derived from our own experiences. The Aerostar data is derived from interviews and posted articles.

Purchase Price:
Aerostars appear priced between $450,000 to $600,000
Cessna 421C prices vary from $250,000 to $450,000

Market Size:
Aerostar – Approximately 1,200 were built, of which 25 model 700 were built.
Cessna 421C – Approximately 2,200 were built, of which 568 were this model year group.

Service and Support:
The much larger size of the C421 market means greater parts support and supply of knowledgeable mechanics.

Operational costs:
Both aircraft are similar in variable costs, fixed costs, maintenance costs, and engine overhaul costs. The geared engines of the C421C are not an issue.

Performance:
Aerostar – The Aerostar is faster, but the actual number depends on who is responding. TAS at 75% power varies between 235 – 255 Kts.
Cessna 421C – TAS is solid at 225 Kts at 75% power and 215 kts at 65% power.
Fuel consumption is comparable. The C421C has a shorter runway requirement.

Limitations:
Aerostar – Limited to 25,000 feet by certification unless certain mods are made. Altitude is then limited to 30,000 feet. Some operators report difficulty when operating in icing conditions.
Cessna 421C – Is certified under CAR-3 and is certified without an altitude limitation. Instead, it has a service ceiling of 31,000 feet at gross weight.
Both aircraft are routinely operated at FL250. The Cessna 421C has about 250 Lbs more useful load.

Cabin:
Aerostar – Cabin is much smaller, has six seats, and has a difficulty in getting through the cabin door into the aft passenger seats.
Cessna 421C – This is the most important point. It is just more comfortable. It has a much larger cabin with eight seats and a much larger area for baggage. Cabin entry is through an aft airstair door. The sound levels are lower because the propeller RPM is lower due to the geared engines. The C421C has a much larger instrument panel, more space to add things.

Accident History:
Both aircraft have similar accident record. Both have about the same accident rate as a percentage of aircraft built and the same percentage of accidents that are fatal.

Aerodynamics:
Aerostar – Is regarded as difficult to fly with sharp stall and Vmc characteristics.
The rotation of the propellers is reversed with the top blade moving away from the fuselage (like a P-38). That puts the downward blade further from the fuselage centerline, increasing the Vmc speed.
Cessna 421C – Is extremely easy to fly with no bad characteristics. (We have transitioned a pilot with 350 hours total time safely to a 421C.)

Systems:
Aerostar – Has some unusual configurations of systems. The fuel system sometimes does not feed as expected and requires monitoring. The landing gear system is a combination hydraulic-mechanical. Alternators may produce less that total output. Fuel system is 166 – 220 gallons. CG has a narrow range and must be carefully managed, especially when the fuselage aux tank is used.
Cessna 421C – Has much simpler systems and do not require managing just to operate normally. The air conditioning system and landing gear are hydraulic, not electrical. Fuel system feeds without managing. Fuel system is 206 standard, normally 226, and can be expanded to 276 gallons. Managing CG is not a problem and is easily managed through passenger and baggage loading.

Flight Training:
Both aircraft require initial transition and recurrent training. The supply of qualified instructors for the training is much larger and less expensive for the Cessna 421C.

Refer to sabriscorporation.com for more information.

Thx David, good comparison list. Appreciate it.

Differnt than the multiple errors in David's post... Here is my experience.

I owned a 1976 Aerostar 601P with the Machen Superstar 700 upgrade. I had the 44 gallon aux tank. At the exact same time, I managed a 1976 421C, non strake, non-winglet. It's the airplane that Jimmy's World now owns with lots of information about it on his videos after the following owner did poor maintenance. I own a 414 for the moment, but it's scheduled to close the on the sale in the next two weeks and I am in the market for a 421C of my own.

For the Aerostar to make the requested 760nm flight, it will require the aux tank, preferably the larger one. Depending on the passenger load, you will want the gross weight increase. I suggest doing an inventory of the items required for the upgrade before purchase. Mine had the largest fuel system available, with 209 gallons usable. You could "trick" the fuel system into holding 230 gallons usable. Mind had a 1662# useful load without the 500# GW increase. Subtract 209 gallons of fuel, and you have a 462# payload. With the GW increase, I would have had a 962# payload.

The 421C will require at least one nacelle tank. 234 gallons usable is what you will have with the factory tank in the left nacelle (and factory air in the right side). If you are a fuel whore, you can stuff 298 gallons in the 421C. Most 421C's have a 2100-2300# useful load. Subtract 234 gallons and you will have a payload of roughly 800# payload. You can get a little more with the VG's/GW increase, and removing dead weight in the cabin such as bulkheads, cabinets, potty, and not installing extra crap like strakes, winglets, spoilers, etc.

The stock Aerostar has a 4.25 PSI/differential cabin. That's a 10,000' cabin around FL230. There is a fairly simple modification to increase that to 5.5 PSI. The 421C has a 5.0 PSI cabin. That will give you a 10,000' cabin around FL260.

The 421C has much better short field takeoff performance. It'll go into airports that you would not go near with the Aerostar.

Rough numbers, the Aerostar will beat the 421C to its destination buy a big handful of minutes. The Aerostar will make 260 KTAS at FL250 if you want to feed it 50 GPH. That makes the 760nm trip (no wind) about 3 hours on about 165 gallons of fuel. Pull the power back slightly, and it will be much more efficient. At higher weights, the Aerostar is most efficient at 75% power. At lighter weights, it does very well at 60% power. I've done 990nm in 150 gallons of fuel with a very slight tailwind. TAS increases about 2 KTAS per 1000'. You can almost always see a ground speed that starts with a 2 in an Superstar.

The same trip, the 421C will true about 230 KTAS at FL250 on ~45 GPH. 3:20 for the same trip on roughly 170 gallons of fuel. Run LOP, and it'll cost you another 45 minutes and save about 30 gallons of fuel. TAS increases about 1.5 KTAS per 1000'.

Operationally, the biggest question is going to be which size cabin do you want. The Aerostar makes a great four place cabin, and an ok five place cabin. Six seats are more hassle than it's worth. My primary reason to move from the Aerostar was the cabin size. I own that class of airplane for charity flights, and now for an 800nm flight to see my daughter at college so the larger cabin is much appreciated and easier for recipients to get into.

Maintenance wise, the short answer is they both are exactly the same cost. There are a few differences, but it's a wash.

The Aerostar is built like a tank. The systems are as dependable as any airplane. The problem areas are fuel leaks, especially under the boots, rigging of the turbos and cracks in the nose gear tunnel. I highly recommend the upgraded tunnel. I never got my wastegates rigged right. Jim Christy tried to help me and I still couldn't get it. At the prebuy, I sent it to Juliet Delta Aviation, one of the best shops on the east coast in my opinion and Joel still didn't get it rigged right. The core engine is relatively bullet proof. The fuel system is only an issue if you don't understand it. It's core design makes it a very simple system, but if you don't know what you are doing, you can get yourself in a world of hurt and run out of options during a flight. Don't make it harder than it is. Overall, maintenance is fairly simple on it. Parts and technical support is 10X better than Textron. Jim Christy and John in parts are names to know if owning one. I've had John go pull original drawings from the vault to verify the installation of something.

The 421C also has relatively simple systems, almost similar to every Twin Cessna. The simplified fuel system with the wet wing makes it brain numbing, unless you don't listen to the 100 times I've said to add IPA or Prist and you freeze the crossfeed lines (and they are almost guaranteed to freeze). Then you have fuel in the aux tank (assuming one) that are only usable for one engine and you are SOL. Guess what, they have fuel tank leak issues also. The GTSIO engines are great engines. If you treat them well, they will blow past TBO like it doesn't exist. The cylinders run 100 degrees cooler than a TSIO520. They run LOP very well, and very smooth with the downdraft intake system. If you abuse them, you will join the club of owners that has had their lunch eaten. You'll stand on a podium and bitch about how horrible they are and how they fail often. In my experience at a large 135 operator, we proved that major engine issues are almost 100% pilot error. First run cases are idea, and cracks commonly develop on the third overhaul. In my opinion (and Twin Cessna Flyer), any aircraft with the factory nacelle tank needs the cover removed during prebuy for corrosion inspection of the structure under the tank and the spar. There is a good video that Jimmy's World did shows it on the airplane I managed.

In my opinion, one of the greatest benefits of the Aerostar are the ability to ala cart almost any modification. If you want FIKI, write the check and you can have it. No serial number specific BS like Cessna's. If I were looking today, I'd look for one with the large aux fuel tank, the cabin heat upgrade, AC, GW increase which includes the nose gear tunnel upgrade and boots.

As I said, I'm in the market for a 421C. The preferred things I'm looking for are first run cases, no spoilers, no corrosion under the nacelle tank, at least one nacelle tank and FIKI. Most are, but there are a few without the heated windshield. Additional nacelle tanks are readily available today, 18 gallons each for around $9000-11,000 installed and up to four on an airplane with no aux tanks (278 gallons total). The 1980 and newer with the trailing link gear makes nice landings, but is about 200# heavier and cost around $80k more.

All things considered, a well maintained airplane of either type wouldn't scare me. The Twin Cessna will have more common shops to work on them, but there are still good Aerostar shops out there. There are also big name shops, self proclaimed experts per say that I would avoid. At least one was recently mentioned in the Aerostar thread.

Right now, there are about 25-30 421C's publically listed on the market. 14 of them were listed 12 months ago. Several have had $100k+ price decreases. I counted about 19 that have either been sold or have been removed from the market in the last 10 months. There are several that are still $100k+ above a comparable airplane.

You guys are amazing. That’s some of the best comparisons i have read. Well done.

I will add that the systems on the 421 are very similar to the 501sp. It made for an easy transition for myself and the insurance company. If you ever think you will move up to a 501sp I would add that to the list advantages to the 421.

Mike

Yes and no. That was what I convinced myself with as well , but the reality is that on a Garrett turbine, if the Woodward fuel controller packs up, or you run out of adjustment to increase FF (even worse if it's a Bendix), you're looking at $30K+ in overhaul at the very bottom end. Or if the hot section needs any work, $30K is just a starting point. Last time I spoke with Brian at Arkansas Turbine, the hots averaged around $80-120K.

The reality is that turbines, although much more reliable and when everything works don't cost more, they can eat your lunch at any given moment. Almost nothing catastrophic on a piston plane needs those kind off reserves (perhaps with the exception of the engine blowing up).

Yes and no. That was what I convinced myself with as well , but the reality is that on a Garrett turbine, if the Woodward fuel controller packs up, or you run out of adjustment to increase FF (even worse if it's a Bendix), you're looking at $30K+ in overhaul at the very bottom end. Or if the hot section needs any work, $30K is just a starting point. Last time I spoke with Brian at Arkansas Turbine, the hots averaged around $80-120K.

The reality is that turbines, although much more reliable and when everything works don't cost more, they can eat your lunch at any given moment. Almost nothing catastrophic on a piston plane needs those kind off reserves (perhaps with the exception of the engine blowing up).