1966 Cessna 310k Good plane or not?? Whats it worth?

From Aviation Consumer:
Cessna 310
One of the most distinctive silhouettes there is, the 310 can deliver good service...but be careful of gear rigging and fuel system management.


Out of production but not necessarily outdated,
the 310s are fast-flying haulers that come in
myriad versions. This is a long-nosed ’78 model.

The Cessna 310 is one of the classics of general aviation, enjoying a 27-year production run during which it served as Cessna’s answer to the Beech Baron, Piper Aztec, Commander 500, and Aerostar. More than 5,400 were built, and there are several major variations.

With so much to choose from, any serious buyer should be able to find an airplane that fits the bill.

But there are things to be careful of when considering a 310. First and foremost is the gear, which is relatively delicate and sensitive to proper rigging and maintenance. The airplane can also be a handful to fly, though pilots note that with proper training and due diligence, it can make a good IFR platform. Finally, there’s the 310’s somewhat unusual fuel system, though pilots report that it’s no big deal.

For those readers who are old enough to want to avoid thinking about it, the 310 should look familiar: it was the costar of television’s Sky King adventure series. In fact, the current owner of the third and final 310 used in the show (a 1967 D model), Songbird III, wrote to tell us that it’s being fully restored. Anyone interested in the airplane or the show is invited to call Ed Lachendro at (414) 475-2544.

History
The 310 was introduced in 1954, a year after Piper’s PA-23 Apache. Though the PA-23 would later be a direct competitor to the 310, the original Apache was far down the scale on power. The 310 competed more directly against the Twin Commander 520 (discontinued that same year) and Beech Twin Bonanza, which was dropped a few years later in favor of the Travel Air and 55 Baron.

The 310 was Cessna’s first modern business twin, reflecting the company’s strong growth in the 1950s. It was a time when many of the now-familiar Cessnas were first introduced: the earlier 140s and 170s were giving way to 172s and 182s. Cessna was moving aggressively into the business market, and the 310 was a key part, and first element, of that plan. In 1954, Cessna’s entire model line consisted of the 170, 180 and 195; so, the 310 represented a giant leap forward for the company.

The 310 was the company’s only twin for several years. The nearly identical 320 came out in 1962, followed by the pushme-pullyou Skymaster in 1964. The popular 400 series followed in 1965 with the ill-fated 411.

Unlike many airplanes with long production runs, the 310 went through steady refinement over the years, with a slew of designation letters following the model number. Cessna got up to the 310R (with a few gaps) before ending production in 1981.

The first 310s, built in 1954, were sold as 1955 models. They had 240 HP Continental O-470 engines housed in very tight and aerodynamic (for the time) cowlings. Flaps were of the split type for aerodynamic efficiency (no external flap brackets), and the gear was of electromechanical design. Distinguishing marks of these early models are multiple rear windows, a straight tail, and “tuna tanks,” so-called for their shape. The 310 was built through the 1957 model year. The 310B in 1958 brought a 100-pound boost in gross weight.

1959 saw the first big change in the 310, with the switch to fuel-injected 260 HP Continental IO-470D engines and another rise in gross weight This airplane was dubbed the 310C. In 1960, Cessna put a swept tail on the airplane, calling it the 310D.

The next significant change was in 1962, with the 310G. Cessna introduced their canted “Stabila-Tip” tanks, said to be more aerodynamically efficient than the old tanks. (The tuna tanks also had a fuel-pickup problem and an AD mandated a hefty increase in unusable fuel.) This 310, with canted tanks, swept fin and short nose, is one of the most attractive light twins ever built.

More refinements followed: increases in cabin size, further increases in gross weight, various increases in auxiliary tank size and the availability of three-bladed props. One significant difference was the switch from overwing from underwing exhaust on the 310I, and the accompanying introduction of wing lockers.

In 1969, Cessna consolidated its model line, offering a turbocharged variant of the 310 alongside the normally aspirated 310P instead of the 320. The T-310P had 285 HP Continental TSIO-520-B engines, standard three-bladed props and a 5400-pound gross weight, compared to the 310P’s 260-HP IO-470V Continentals, optional three-bladed props and 5200-pound gross.

Breaking with its practice of tacking on a different letter each year, Cessna stuck with the 310Q and T-310Q for five years. In 1975 a big change occurred with the 310R II and T-310R II.

Aside from another bump in gross weight and the move to 285 HP Continental IO-520M engines on the normally aspirated model, the 310R got a whacking great nose job. The proboscis grew 32 inches, and housed a sizable baggage compartment. The 310R also boasted an improved landing gear, though it was still not as rugged as many would like.

The 310R was the final development of the airplane, and stayed in production until the line was closed down in 1981.

The almighty dollar
As expected, prices for the 310 vary widely based on age and condition. Average normally aspirated 310s run from $40000 for the earliest models up to $191000 for the newest 310R. The market treats the various 310s pretty evenly: there’s no real marked jump with model changes as often happens. The biggest gap is between the 310Q and 310R—the 1974 310Q averages $117000, while the 1975 310Q averages $139000. The gap for the turbo models is similar.

Owners give good marks to the 310 instrument
panel and controls for human engineering, but
not always to Cessna radios. The fuel system
on later models can be easily mismanaged.


How good an investment is a twin? Twins are popular with some pilots because of the perceived safety advantage of having an extra engine. This, of course, must be balanced against the extra hazard posed by single-engine operations when low and slow. The debate has gone on for many years.

Money talks, though, and the true cost of a twin is doubled engine maintenance and fuel bills. The marketplace’s answer to the single-vs.-twin question seems to be “go for the single...your wallet will thank you.” Hence the following fascinating tidbit: a 1981 Beech A36 Bonanza, average price new $160,000, now goes for about $200,000. A 1981 Cessna 310R II, average price new $234,000, now goes for $220,000.

For comparison purposes, a 1981 Beech Baron 58 (same horsepower) fetches about $270,000. A 1981 Piper Aztec (250 HP engines) about $157,000.

Performance
This is a strong point of the 310. The early models can deliver cruise speeds of 175 KTAS, and the later ones better than 190 if needed. Turbocharged 310s can do 225 at max cruise. Lower power settings (60 to 65 percent) result in 170 to 180 KTAS in the normally aspirated models. Engine-out performance is better than average, with normally aspirated single-engine rate of climb pegged at anywhere from 330 to 380 FPM, depending on model. Turbo single-engine performance is even more impressive: from 390 to 440 FPM—that’s up in turboprop territory, and very impressive for a piston twin. Fuel burn varies with model, but figure about 31 GPH for the later versions.

The normally aspirated models are happiest in the low teens, while the turbos have service ceilings in the mid-20s. Single-engine service ceiling is about 7000 to 7500 feet, or 17,000-18,000 for the turbo.

Short-field performance is quite good on paper. Landing over a 50-foot obstacle in a 310R will consume 1790 feet, compared to a 58 Baron’s 2498. Takeoff over that same obstacle will take 1700 feet in the 310, while the Baron will want 2100 feet. Pilots report that real-world operations aren’t as good as these numbers would have you believe.

Handling
310s have a reputation for Dutch roll in the hands of new pilots, caused in part by high rotational inertia due to the extra weight of fuel at the wingtips. Experienced owners report that it’s easily damped with proper technique, however.

The 310 makes for a good, stable IFR platform, according to owners, with excellent cruise stability.

On approach, some power has to be carried. The 310 doesn’t glide well, with big props blanking out much of the wing and flaps that produce a lot more drag than lift. Approach speeds are relatively high. Crosswind landings are simple due to good aileron and rudder authority.

Because the gear makes the airplane sit up high, new pilots are cautioned to be careful of hard landings. Combined with the relative fragility of the gear, these can be a real problem.

Loading
Up through the 310G, the series is about average for baggage space (about average means frequently having to carry some in the cabin). With the stretched cabin of the 1963 310H, more baggage space was opened up.

Though the 310s are six-seaters with beamy
cabins, great for cross-country cruising, the
rear two seats are too cozy for comfort except
for children. A wide baggage door is a worth-
while option. This is a ’76 model.


Along with that, weight and balance has to be watched more closely. The nose was extended a little starting with the 310K, which helps spread the load. The nacelle lockers introduced on the 310I makes loading options even better. An optional large baggage door was introduced on the 310P. It greatly eases the task of loading and arranging aft baggage.

By the 310I, cubic feet available certainly began to exceed the lifting and weight-and-balance capacity of the airplane. C-310s with lots of avionics and other options compound the loading exercise. Even without radar, some 310s with full fuel push the forward CG limit with just a pilot in front, so there are times when seating has to be assigned.

The 310 is a hefty airplane, particularly in its later variants. Gross weights eventually reached approximately 5500 pounds. Basic empty weight started at 2840 pounds for the original. It exceeds 3000 pounds by the 310C, nears 3200 in the 310P and exceeds 3600 in the 310R (turbo models are heavier still).

Payload with full fuel varies depending upon the model, equipment and fuel tank arrangement. Usable fuel capacity can be 100, 132, 142, 182 or 203 gallons—from 600 to 1218 pounds of fuel. Payload in a lightly equipped 310C with auxiliary tanks might exceed 700 pounds, while it could be as low as 400 pounds in a 310R.

Other loading and operating considerations were introduced in the later models. As maximum operating weight increased, limits such as maximum landing weight and zero fuel weight became factors.

Zero fuel weight is a payload limitation that confuses some pilots. A T310R, for example, has a zero fuel weight of 5015 pounds. Anything between that and maximum ramp weight has to be fuel. In one aircraft, maximum payload is 1059 pounds, which can handle six FAA adults (170 pounds) and 39 pounds of baggage. Figuring a maximum ramp weight of 5534 pounds, 519 pounds of fuel can be put in the main tanks.

Calculating climb to cruise altitude of 12000 feet, this allows just under three hours of flight plus reserve at 65% power. The airplane can cover roughly 500 NM in still air with max payload. With all tanks installed and full, on the other hand, it can haul a couple of people and some baggage more than 1200 NM, again at 65% power.

Fuel system
All of those responding to our request for feedback felt the need to point out that the 310’s fuel system has gotten a bad rap, and that it’s not as tough to deal with as people think. The 310’s system on airplanes with all the optional tanks is certainly more complicated than most, and it does have a number of idiosyncrasies not shared by other airplanes. Whether these make it hard to deal with depends on your point of view. We’ll leave it to the reader to decide.

It is true that 310s are not unduly prone to fuel mismanagement accidents, so despite the complexity of the system, pilots seem to have little trouble dealing with it.

It starts with nomenclature. Ask any line person where the main tanks are on a given airplane, and it’s likely they’ll point to the wing. Not so on the 310. For some reason, Cessna decided to designate the tip tanks as the mains, and the wing tanks as the auxiliaries.

This has caused accidents. In 1987 over Delta, Utah a pilot unfamiliar with the fuel system crashed because he thought the mains were in the wings and the auxes at the tips. He ran the mains dry.

Another scenario goes like this...Pilot: “Top off the mains, please.” Lineperson: “Yes, sir,” whereupon the auxiliaries get filled to the brim. The pilot then takes off without checking, and with the fuel selectors on the main (tip) tanks as required in the POH. You can guess the rest.

That’s not the only tricky thing about the 310’s fuel system. A fully equipped 310 with wing locker tanks can have up to ten fuel drain points, eight fuel pumps and a rather complex plumbing system. There’s no separate gauge for each tank, though the gauge does switch automatically to read the tank being used (but not the wing locker tanks, which have no fuel level senders). The pilot can read the tanks not being used by toggling a switch.

Fuel feeds to the engines from either the mains or the aux tanks (but not the wing locker tanks). The mains have to be run for 60 minutes if the airplane has 20-gallon aux tanks (or 90 minutes for 30-gallon aux tanks) because excess fuel is pumped back to the mains, and if there isn’t room for it, it goes overboard.

The mains also are the receptacle for the contents of the wing locker tanks. The same caveat applies—there has to be room enough for the fuel, so the pilot waits until there’s 180 pounds or less in the mains before transferring fuel from the locker tanks. Then the transfer pumps are run until the idiot lights go on. At that point the mains may or may not be full, depending on whether the aux tanks have been used and whether the transfer was done with room to spare in the mains.

But wait, there’s more. The fuel pickup from the mains is at the rear of the tank, which means that it won’t get picked up properly during descent. So, Cessna provided continuous-duty fuel pumps that move fuel from the front to the back of the tank. These pumps are wired to the landing light circuit breaker, so if the landing light shorts the mains can unport.

It’s also possible for the pilot to have as much as 30 gallons of fuel that can’t be used. The aux tanks feed directly to the engines, so the only pump that serves these tanks is the engine-driven one. In the event of a fuel pump or engine failure, the aux tank on that side becomes useless...no crossfeed from the aux tanks, and no transfer is possible.

Those big tip tanks were originally designed as a safety feature. The idea is to get as much of the fuel as far from the cabin as possible. In fact, one of the prototypes was landed gear-up, and the tip tanks separated just as they were designed to do, with no post-crash fire.

All those tanks can carry a great deal of fuel, making for six-hour endurance in later models. Early models can go four hours.

Landing gear
The other 310 system that gets a lot of attention is the landing gear. It is fairly long and spindly, and more delicate than that of some other airplanes. The fact that there’s a lot of fuel hanging out on the wingtips tends to exacerbate the side loads on the gear, as well.

As mentioned above, the long gear legs make the airplane sit much higher than some pilots are used to. This makes hard landings a real possibility, and the gear just can’t take that much abuse.

The gear has a number of critical components that must be attended to and properly rigged during annual inspections. If this is done properly, trouble can be avoided, but failure to treat the gear right increases the odds of failure dramatically.

According to Larry Ball’s The Twin Cessna Flyer, nearly half of all twin Cessna accidents and incidents are directly related to the gear, and a quarter of all accidents and incidents are related to failure of the nose gear idler bellcrank under the pilot’s feet.

AOPA’s Air Safety Foundation further subdivides accidents and incidents into pilot-caused and machine-caused accidents. According to a report prepared for ASF by Aviation Consumer contributor Mike Busch (a 310 owner), two-thirds of the machine-caused accidents in 310s are gear-related.

Later model 310s have heavier main gear torque tubes and side brace support brackets. Cessna has a kit available to retrofit earlier airplanes.

Another aspect of the gear that deserves mention is the brakes. Early models had Goodyears, which caused some problems. Many were retrofitted with the later, and better, Clevelands. Still, the 310 is large and heavy enough that braking performance can be marginal.

Maintenance
A scan of Service Difficulty Reports shows, not surprisingly, that the majority of squawks arise from the landing gear. Aside from the nose gear idler bellcrank, the gear displays a variety of problems associated with torque tubes, support brackets and trunnions. Most of these problems can be traced to a lack of proper maintenance and/or hard usage.

Also high up on the list was the fuel system; not for any particular design issue, but simply because there’s a lot of plumbing involved. Putting the main tanks all the way out on the wing tips means long fuel lines, and the large number of tanks, drains and pumps means a lot of fittings that can leak. Older tuna-tank models had a lot of problems with their fuel bladders, but this was dealt with through an AD.

The engines on many 310s are Continental 520s, which have a well-known propensity for case cracking. The IO-470s used on earlier airplanes are much less likely to develop cracks.

Also worth noting are exhaust-related corrosion problems, particularly on early airplanes with over-the-wing augmentor exhaust systems. Turbo models in particular have failure-prone exhaust systems, and are subject to a 50-hour visual inspection AD, 75-23-8. At the time of our last look at the 310 in 1996, the FAA was considering a stiff update to the AD that thankfully did not come to pass.

The props are subject to a couple of ADs: these include the infamous McCauley prop inspection AD (95-24-05) and 94-17-3, repetitive inspection of the prop hub grease fittings.

Other recent and notable ADs include: 98-1-8, replacement of two-piece carb venturis with one-piece units; 97-26-17, ultrasonic inspection of the crankshafts with possible replacement; 96-12-22, repetitive inspections of the engine oil filter adapters; and 96-20-7, repetitive inspection of the combustion tubes on the Janitrol cabin heater.

The most recent type-specific AD, 90-02-13, covers the main landing gear barrel inner bearings. It applies to the 310, 340 and all piston-powered 400 series Cessnas except those with trailing link main gear. It requires inspections for cracks, including magnetic particle inspection every 1,000 hours or the replacement of the bearings with an improved part.

Other miscellaneous problems: magnesium seat back brackets that fail (this has resulted in some accidents), and periodic inspection requirements on the 100-amp Prestolite alternators on 310s with deice equipment.

Mods
As with all twins for which they are available, we highly recommend the installation of vortex generators. Micro Aerodynamics makes a kit, and also offers nacelle strakes that reportedly improve stall behavior. VGs are also available from Robertson.

There’s a STOL kit available from Sierra Industries, but the cost is so high that its value is questionable. Vortex generators will give you a much greater return for one-tenth the cost.

One mod that got good reviews from owners are spoilers, which allow pilots to keep the controllers happy with rapid descents without killing the engines in the process.

Also available are engine and prop upgrades from Colemill Enterprises for the 310F through Q, which carry with them gross weight increases. A choice of IO-520 or Voyager IO-550s is offered. Owners of T310s who want engine upgrades can get them from RAM Aircraft.

Owner’s group
Owners of twin Cessnas have their own support organization in the form of The Twin Cessna Flyer, headed by Larry Ball. Membership gets you a newsletter and the right to attend well-worthwhile seminars on operations. Call (219) 749-2520. The general Cessna group of choice is the Cessna Pilot’s Association (www.cessna.org, (805) 922-2580).

 

What about a Cessna 210? Not sure how fast you want to go or how much you want to carry, but the 210 is fast and can haul some stuff along the way. 206 or 182 might work as well... albeit at a slower pace. If this is truly your first "ownership" experience you may want to look at fixed gear, retracts add a lot to upkeep and annuals. The Piper Saratoga line (Lance etc) would be another place to look particularly if you would rather have a low wing aircraft.

Good luck!

 

Upgrade is that GPS or Loran in the bottom of the radio rack in the center of th panel. Is that a KLN 90B or a KLN 88 Loran? they used the same format and outlay before changing to the KLN 89 and the color screen KLN 94.
It looks like a basic 310. It's a very capable airplane with a roomy cabin in it's class. I like them a lot more than a Baron. My buddy has a 310R with a Garmin 530/ 430 stack. His has fresh engines, about 125 SMOH. He did the TBO's when he got it. He got the plane for $75k and dumped another $40K into the engines. He estimates it's a $130K plane with the avionics and low time engines. But then again, the economy is down.
Start doing some comparables in www.tradeaplane.com, www.controller.com, and the others. Maybe find a Vref manual.

 

Looking at that exterior pic, it looks like you don't have de ice equipment on it. That will lower the price more. It sounds like it's out of annual. Maybe you could use that opportunity to do a pre buy on it, offer to have the prebuy costs incorporated into it. If their A&P has a working history on the plane, then maybe he can tell you more on the history of it.

 

How did it work out?

310s are quick and haul well.

 

You do realize that thread is over 8 years old?

 

Well, I have been working up a comment that just before the thread I flew Ernie Gann's 310 in the early seventies . He came over to Paine Field , Everett Wa. to pick me up so that we could spend a day at his place in Friday Harbor to discuss illustrating his book. I think that he was testing my experience as an "old pilot" when he announced that I had the airplane when we were on the apron. He knew damn well that I had no experience in a 310 but I went ahead anyway. We got to Friday Harbor and I set up for a landing on the strip, a short asphalt 50 foot wide affair with the required power lines at the north end. As I was approaching the end of a short final he announced that he had the airplane with the statement that, " I don't think that you want this landing!" Whereupon he dumped the nose and hauled back on the wheel just after crossing the power lines and we made a firm but smooth landing with a roll out humming with the sound of agressive braking. The airplane was very nice to fly and I was given the privilege of making the take off, flight, and landing at PAE. A fun day!

 

Anybody else old enough to remember when Sky King switched from a Cessna T-50 to the 310?

 

Yes, but not going to admit it in public........

 

yeah, I remember my kids watching when he switched to a C310. Does anybody remember spending 15 cents to purchase the latest G8 And His Battle Aces? How about Bill Barnes Air Trails?

 

Yes, sat in the Living Room in Albuquerque watching the 'Song Bird' after his 'Bamboo Bomber'.
We lived under the N/S runway so I could look out the window and watch planes landing while I watched Sky and Penny solve heinous crimes on the tube.

 

Bob- A little too far back even for me. Mine was RAF Flying Review in the late 50s. Even had an article in one on Dad's mid-air in a P-51D right after the war.