A 310 owner reveals what ownership of a twin Cessna is really like.
The Cessna 310 was the first twin-engine aircraft produced by Cessna after World War II. The 310 prototype, powered by 240 hp Continental O-470-B engines, first flew Jan. 3, 1953. The aircraft was certified March 22, 1954. Production began immediately and continued through 1980.
A September 1954 Flying cover story introduced the 310 to the masses with the headline, “Business Asked for It,” written by Cessna Aircraft Company president Dwane L. Wallace. Wallace cited the popularity of military surplus conversions as an indicator of the strong need for a purpose-built twin for the business flyer. He opined that “[when] properly used, [aircraft] are, without question, REAL BUSINESS TOOLS.”
Cessna’s advertisements of the day claimed the 310 was “at least five years ahead in design and engineering,” and that “it looks and is smart and fast.”
As for the size of the market for a new business-class twin? Wallace’s writing was prescient. “It may seem difficult to predict the future of the twin-engine market. I do know that the need is almost unlimited and, knowing the American way of doing business, I make the assumption that therefore the market is practically unlimited.”
Over the next three decades, his words rang true. A total of 5,449 Cessna 310s were produced from 1954 to 1980. They were not just business airplanes; they were TV stars, too. The Cessna 310 (a B model and D model) had a prominent role in the popular “Sky King” TV series (also a radio show) of the 1950s.
Nowadays, the Cessna 310 isn’t the fastest airplane on the ramp, nor is it the most economical to own and operate. Many of the early 310s are no longer with us, and those that are still around are often “put out to pasture,” tied down in a far corner of the airport, surrounded by cracked asphalt or overgrown grass.
However, some of these classic twins have been saved from a slow melt into the tarmac. Gale Cawley rescued his 1965 Cessna 310J from a miserable fate in the spring of 2002.
Gale isn’t quite the 310 owner that Dwane Wallace had envisioned a half-century prior, as Gale had no desire to operate the airplane for business. Instead, he wanted a personal touring aircraft which would increase his three-hour-flight range. The 310 offered impressive speed and useful load for a low initial acquisition cost. He knew that it wouldn’t be the cheapest to keep in the air, but he believed the cross-country capabilities of the aircraft would offset the ongoing costs.
The 310 lived up to Gale’s expectations. His home base of South Haven Area Regional Airport (KLWA) in southwest Michigan provided a jumping-off point for flights around the United States. He owned the aircraft for 15 years before selling it to a friend.
Gale said he also wanted the 310 because, frankly, it was a cool airplane. He recounted listening to the old “Sky King” radio shows a half-century earlier. Young Gale would have likely been thrilled to know that after an extensive Air Force and airline career, he would acquire a Cessna 310 and fly it, Sky King-style, to his friend’s cattle ranch in rural Oregon!
Cessna Flyer’s Scott Kinney had a chance to talk with Gale about what he learned from owning and flying the 310.
Q: What sort of shape was your 310 in when you acquired it?
It had lived, I’ll say, a bit of a rough life. It was delivered new to the U.S. Air Force in 1965. The civilian logs started in 1975. It had about 4,000 hours on the airframe when I bought it. The guy I got it from was a businessman. He’d used the 310 to scout for new franchise sites around the country.
The airplane had been the subject of some drama in the years before I bought it. It had been held as evidence without flying for three years. There had been some sort of legal dispute over an annual inspection bill… the bill was something like a hundred thousand dollars. Once that finally got cleared up, it was on the market for another year before I bought it.
I made the guy an offer that I thought was pretty low. He accepted, as he was happy to be done with it. I figured I’d gotten the 310 for a good price, so maybe wasn’t as diligent as I should’ve been with the pre-buy.
I wasn’t surprised that it was a project… turns out, though, it was a real fixer-upper!
The left engine was run out. The right engine wasn’t timed out, but I didn’t have much confidence in it. Both props were high-time. As far as the avionics, they weren’t much better. The airplane had a dated panel with old radios.
Q: Where do you begin with a project like that?
In the first year, I had both 260 hp Continental IO-470-D engines overhauled. The left engine was overhauled and installed by G&N Aircraft. Poplar Grove did the right engine.
So, why did I use two different shops? Well, I sent the 310’s left engine to G&N as it needed to be done immediately. They’d overhauled my Cessna 210’s IO-520 engine a few years prior. They used chrome cylinders on that one, and I had them do the same with the 310’s left engine.
Not long after I’d had the left engine overhauled, I started having trouble with the chrome cylinders in the 210.
I had the 310’s right engine overhauled several months after the left.
I did a little more research and found that the big Continentals didn’t do well with chrome cylinders. I also read more about other shops and saw that Poplar Grove was one of the best in the country. I decided to give Poplar Grove a try and had them use steel cylinders.
Both shops did good work. I had no trouble with either engine during my 15 years of ownership.
I sent the props off to Tiffin Aire. They called me and asked me if I was sitting down. I knew that the props were high-time, but as Tiffin explained, there had been some “creative” record keeping in the past, and the serial numbers of the blades didn’t match the logs. Without proper records, the props were junk, and went into the dumpster. I bought new three-blade Hartzell props from Tiffin Aire.
Avionics followed shortly afterward. In addition to a much-needed radio update, I replaced the old Loran with a [Bendix King] KLN 89B GPS, and I put in a modern S-Tec 50 autopilot. I also had the instruments rearranged into a basic T configuration. Joliet Avionics (now J.A. Air Center) did the work.
I had a very thorough first annual and made sure everything was checked, including control rigging—pullies, cables and so on.
As all of this was getting done, I went to Flight Safety in Wichita, Kansas, to get some simulator training to make sure I was ready to fly the 310 when the work was complete.
Q: That’s a lot of work!
Yes, and it was not cheap, but it was well worth it. By the time all of that was done, I had a great “Sky King” airplane that flew very well.
Q: How did it perform?
I could go fast, but that cost a lot of fuel. Depending on power settings, I saw fuel burns between 22 and 28 gph.
I babied the engines and didn’t use more than 60–65 percent power for most flights. I liked a combination of 23 inches map and 2,300 rpm. The 23-squared combination “sang in sync,” and gave me a fuel flow of around 25 gph.
I consistently saw cruise speeds of between 165 and 170 ktas.
With a usable fuel capacity of 130 gallons (100 gallons in the mains, 30 gallons in the auxiliary tanks), I had a range of about four hours with a comfortable VFR reserve.
While the three-bladed props probably didn’t increase cruise speed by too much, they certainly helped with takeoff and climb. They also made for smooth and quiet operation.
Normally, I flew with the right rear seat out in order to have more baggage space. The baggage door was located on the right side of the fuselage, which gave me easy access to the right rear seat area.
Q: Did the aircraft have any other modifications?
Yes, it had MicroAero vortex generators (VGs) on the wings and the vertical stabilizer. The VGs provided exceptional stability at the slow end of the envelope. The airplane simply wouldn’t break hard or drop a wing in a stall. It would just go into a very smooth sink.
The VGs allowed for slightly slower approach and landing speeds if you wanted. I always used the printed book speeds and felt those worked well. I felt that the VGs were a superb addition to the airplane.
Q: Any issues with useful load or center of gravity?
My 310J was a six-seater, but it was shorter and a few hundeds pounds lighter than later models of the 310.
The useful load was around 1,700 pounds. I didn’t usually come anywhere close to maximum gross. The majority of my flying was solo.
I took it to Oshkosh one year with all the seats filled and full tanks. That put my takeoff weight close to max gross. It was summer and hot, so the 310 climbed out a little slower, but it handled it well.
Setting elevator trim correctly was very important. Whether taking off with just myself or six people in the airplane, a trim setting close to the “takeoff” mark worked well. The direction (up or down) from the mark depended on the load. When I flew alone, the aircraft was a little nose-heavy, but it wasn’t hard to compensate for that with a slight up trim setting. Q: Were there any operational quirks that you noticed?
A few. Preflights were mostly straightforward, but you needed to be careful when you were under the right wing. There’s a speed vane, which runs the Hobbs meter, on the bottom of the wing. It’s a little tab that sticks out. When air flows over it, it compresses and touches an electrical contact, activating the meter. It’s possible to accidentally snag [the tab] and bend the vane. I did, and that prompted me to get my mechanic to fix it. He placed small protective rails on each side of the vane, so it would still get airflow but wouldn’t catch on loose clothing if you brushed against it.
Fuel management was a little different, too. I learned not to fuel the main (wingtip) tanks all the way to the filler caps. If you did, fuel would siphon out the vents as your speed increased on the takeoff roll.
The auxiliary tanks had their own peculiar features. If you select the auxiliary tanks, the engine-driven fuel pump draws from these tanks. However, the pump draws more fuel than the engines burn. The excess is pumped back into the main tanks (not, as you might assume, into the auxiliary tanks). So, even though you were burning, say, 13 to 14 gph with each engine, you could draw down the two 15-gallon auxiliary tanks in about 45 minutes. The main tank quantities would increase slightly.
There’s another thing about the auxiliary tanks which could cause an “uh-oh” moment if you weren’t expecting it. When the airplane was cruising and hit slight turbulence, it had a tendency to yaw. When the auxiliary tanks were low, the yaw would push fuel away from the fuel intake, and the engines would sputter. The answer to this phenomenon was to either ride a rudder to stabilize the swaying or to switch back to the mains when turbulence was expected.
Another surprise was that the Janitrol cabin heater would not work unless the proper air vents to the cabin were opened. I learned this one the hard way, and had a very chilly flight!
Q: Did you operate your engines rich or lean of peak?
I only had single-cylinder EGT gauges on each engine. I ran the engines rich of peak. I figured burning just a tad more fuel was, in the long run, less expensive. I didn’t like the idea of replacing valves or cylinders if I ran them too hot.
Q: Speaking of replacing things, how were your maintenance costs?
I had most of my work done at a Cessna-certified shop—Michigan Aviation in Pontiac, Michigan. My basic annual inspection ran about $3,600 on average. Any extra work cost more, of course. I really tried to keep up on the maintenance. I feel that good maintenance is cheap life insurance. I live in an area where hangars and other fixed costs are low, and that allowed me to spend money on quality work.
There were a few surprises during the 15 years I owned the aircraft. On this particular model of Cessna 310, the rear wing spars are vulnerable to corrosion from exhaust gases. I learned about this firsthand as I had to replace the left rear wing spar. That was a $10,000 bill. I had the work done at TAS Aviation in Defiance, Ohio. They specialize in twin Cessnas and 310s.
Q: Any other thoughts on the 310?
It was a wonderful cross-country airplane. It took me so many places: to visit my son in Connecticut, my friends in Arizona, my daughters in South Carolina and my siblings in Kansas City. I used it exclusively as a personal aircraft. I put around 400 hours on it during my ownership.
It was also not as expensive as you might think. I found the overall cost to run the 310 was about 40 percent more than my Cessna 210.
A friend of mine talked me into selling him the 310 last year. He’s put over a hundred hours on it in the last eight months. He’s taken it around the country as well as to the Caribbean and Mexico. In retrospect, it may have been my loss and his gain!
Gale Cawley earned his private pilot certificate in 1960 at Stockert Flying Service in South Bend, Indiana. Since then, he’s flown for the U.S. Air Force, the Indiana Air National Guard and spent 33 years with American Airlines. He holds ATP, flight engineer and CFII certificates and has logged over 26,000 hours. In addition to the Cessna 310 and 210, Gale owned a farm airstrip of his own for 14 years. Scott Kinney is a self-described aviation geek (#avgeek), private pilot and instructor (CFI-Sport, AGI). He is associate editor for Cessna Flyer. Scott and his partner Julia are based in Eugene, Oregon. They are often found buzzing around the West in their vintage airplane. Send questions or comments to .
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