Cessna 340

The 340 is the classic tradeoff airplane; it gives you the ability to carry passengers in pressurized comfort, but forget about filling the seats.

One thing above all else makes an airplane work we’ll as a business transport: High altitude capability. It means that much of the weather can be flown over, which can make all the difference between getting there and staying on the ground. While turbocharging will get the airplane up to altitude, its pressurization that makes the experience attractive to the executives occupying the cabin.

Enter the 340. Its a relatively economical way to go for a company with a need for a pressurized twin. Though not without its shortcomings-most notably certain loading limitations and an overly complex fuel system-the 340 is nevertheless a fine airplane, one that fits its mission well.

The 340 was introduced in 1972 as a lower-cost alternative to the 414, which had arrived in 1970. It was intended to fit into the gap between light twins like the Cessna 310, Piper Aztec, and Beech Baron, and more expensive cabin-class airplanes such as the Beech Duke, Piper P-Navajo and Cessna 421 Golden Eagle.

Though it carries a 300-series number, the 340 and 414 are very similar, sharing the same wing, flaps, ailerons, landing gear and engines. The 340 also has an air-stair door, unlike the 310. Because its lighter and has a smaller cabin, the 340 cruises about seven to 12 knots faster than the 414 on the same fuel. But for the speed, the 340 sacrifices payload (more on that later).

If the prospect of flying above most weather and traffic snarls, free of the constraints of nosebags, appeals to you, the price for admission varies from about $170,000 for an early model to over $330,000 for one of the last off the line. It should be noted that the low figure assumes that the early models engines have been upgraded to the higher-horsepower variant found on later models: While we have no definitive information on this, its a safe bet that there are very few 340s flying which have not been upgraded to the more powerful engines.

Engines installed on 340s from 1972 through 1975 were Continental TSIO-520Ks, which produce 285 horsepower at 33 inches manifold pressure from sea level to 16,000 feet. However, as noted above, most of the K engines in early 340s have been converted to Js or Ns. The TSIO-520J engine, used on early 414s, produces 310 HP at 36 inches manifold pressure. The N engine, installed on later 414s and 340s (the N-engine airplanes are called 340As), produces 310 HP at 38 inches. The major difference between the K engine and the J and N variants is that the latter are equipped with intercoolers (which reduce temperature of induction air as it moves from turbocharger compressors into induction manifolds).

The N engines produce their rated 310 HP up to 20,000 feet and provide higher cruise speeds and better climb and single-engine performance. Three-blade McCauley propellers, formerly an option, also became standard equipment in 1976; earlier 340s came with two-blade McCauleys.

Certification for flight into known icing conditions, when properly equipped, came in 1977. The next year, a maximum ramp weight of 6,025 pounds was approved, and max weight for takeoff and landing was set at 5,990 pounds for the 340A (compared with 5,975 pounds for the 340).

The last notable change occurred in 1979, with the switch to TSIO-520NB engines (the B denotes use of a heavier crankshaft). Subsequent modification of cylinders, valve lifters and piston pins by Continental increased TBO of the NB engines from 1,400 to 1,600 hours in 1983. But Cessna didnt build any 340As (or much of anything else) that year; and after putting together a scant 17 of the airplanes in 1984, production was terminated.

Though service ceiling touches nearly 30,000 feet, most owners operate between 16,000 and 24,000 feet, where they get 190 to 205 knots on about 30 gallons per hour at 65 percent power and 200 to 217 knots on 32 to 34 GPH using 75 percent power.

Rate of climb at sea level is a respectable 1,650 FPM, but climb performance tapers rapidly above 20,000 feet to a dawdling 300 to 400 FPM in the mid-20s. The 340s single-engine ROC is 315 FPM, better than the 414 (290 FPM), Beech P58 Baron (270) and the Piper 601P (240) and 602P (302) Aerostars. In its class, the 340 is outshone only by its much lighter, centerline-thrust stablemate, the pressurized Skymaster, which climbs 375 FPM on one engine. Single-engine minimum control speed is 82 knots. Stall speeds are 79 knots, clean, and 71 knots in landing configuration.

To its credit, Cessna provided information on accelerate-stop and accelerate-go performance in 340 POHs. The book indicates that, under standard conditions, a 340 that loses an engine at lift-off speed (91 knots) can be brought to a full stop within 3,000 feet of brake release. The book also indicates that should a pilot decide to go after losing one on lift-off, the airplane will clear a 50-foot obstacle after traveling less than 4,000 feet over the ground after brake release.

The performance figures above are for 340s with 310-HP engines. Those that still have 285-HP K engines (if any) are nearly 20 knots slower in cruise, use roughly 200 feet more runway for takeoff and climb 1,500 FPM on both engines, 250 FPM on one.

Handling and comfort
No bad habits is how most owners characterize the handling characteristics of their 340s, and most claim to have had very little difficulty transitioning to the heavier twin from lighter and less complicated aircraft.

The airplane does present a double whammy of sorts, being rather clean and therefore difficult to slow down on one hand, and having relatively low gear and flap operating speeds on the other.

For example, flaps can be extended 15 degrees at 160 knots (the limit is 156 knots in the first 300 airplanes built) to help slow the airplane down to max gear-extension speed, a pitiable 140 knots. But slowing the airplane to 160 knots without shock-cooling the engines can be a problem. Owners say descents and approaches require careful planning.

Once the airplane is slowed down with gear and flaps deployed, however, it tends to sink like a rock, according to owners, and some power must be maintained right into the flare. This is due in part to the flaps, which are of the split variety: great at producing drag, but not so good at increasing lift.

The heavy-iron ambience of the air-stair door wears off quite quickly when occupants must squeeze through a very narrow (seven-inch) aisle to their seats. Once seated, though, the cabin is quite comfortable. The 340s cabin is 46.5 inches wide and 49 inches high, about the same size as an Aerostars and 4.5 inches wider than a P-Barons.

The pressurization system is the same as those found in Cessnas 400-series twins. Maximum differential is 4.2 psi, providing an 8,000-foot cabin up to 20,000 feet; above that, the cabin climbs with the airplane. Most buyers passed on the standard automatic-control set-up, which activates and deactivates while climbing or descending through 8,000 feet, and equipped their 340s with the optional variable-control system, which allows the pilot to program cabin altitude and rate of climb. The variable system maintains a sea level cabin up to 9,000 feet, then maintains the pilot-selected cabin altitude until a 4.2-psi differential is reached.

Managing the pressurization system actually is a piece of cake, requiring only a few seconds each flight. The pilot merely dials in field elevation plus 500 feet before takeoff and landing, and cruise cabin altitude on initial climb. (Of course, saying that you don’t have to fuss much with the system doesnt mean you don’t have to monitor it carefully during flight.)

Fuel system
Its the fuel system that keeps a 340 pilot on his toes. Start with the tip tanks, the mains, which hold 100 usable gallons. Add up to four auxiliary wing tanks, two holding 40 gallons, the other two holding 23 gallons. Throw in locker tanks, which add another 40 gallons. Thats up to 203 gallons in containers strewn throughout the length of the wings. Remember to use the mains, alone, for takeoff and landing. The engines will feed directly from the auxiliary tanks, but fuel in the lockers has to be transferred to the mains. Of course, you have to make room in the mains, first. And if you have only one locker tank (which many 340s do have), remember to use crossfeed; dump all 120 pounds from a locker into one tip tank, and the imbalance will be enough to upset even your autopilot.

Unfortunately, Cessna never got around to simplifying the fuel systems in its 300-series twins (Crusader excepted) as it did in most of the 400s.

For whatever reason, Cessna chose to designate the tip tanks main, just as they did on the 310. This can, and has, caused some problems. Ramp attendants have filled the wrong tanks (Just top off the mains….), and pilots (particularly transitioning pilots) have switched to the aux tanks thinking they were drawing from the tips, and vice versa.

Empty seats
Probably the biggest drawback to the 340 is its load-carrying ability. Most are very we’ll equipped and can accommodate only around 1,600 to 1,700 pounds of fuel and payload. (The useful loads shown in the accompanying specifications table are maximums and valid only for unequipped airplanes.) Load enough gas for a 4.5-hour flight with reserves, and you can take along only two passengers and their bags. Fill the seats with 170-pound FAA clones and pack away their regulation 30 pounds of baggage each, and you can carry enough fuel for a 1.5-hour jaunt.

Considering the severe payload limitations, the baggage space in the 340 seems a cruel joke. Among the cabin, nose and locker compartments, there’s a cavernous 53 cubic feet of space in which a maximum of 930 pounds can be crammed. That is, however, the maximum. Most 340s have at least one fuel tank occupying a locker, and nose baggage compartment space typically is compromised by avionics gear.

There’s good news, though. The installation of vortex generators brings with it a 300-lb increase in gross weight, and considering an entire VG kit weighs about as much as the air in your tires, its about as close to a free lunch as you can get. One owner called the installation of VGs a real no-brainer. While there’s no way to prove this, we suspect that the efficacy of the vortex generator kits has served to boost the value of 340s at a surprising rate.

Like any other high-performance airplane, a 340 is not one to tolerate skimpy maintenance. If overhaul prices in the $20,000 range (times two), annual inspections at several thousand dollars and operating expenses above $200 an hour are enough to curl your toes (as they do ours), don’t expect to have a good time owning a 340.

Those with the wherewithal to have a good time, though, should be aware of a few items gleaned from typical service difficulty reports that might conspire to ruin their day. First, there are the TSIO-520 crankcases, which have a history of cracking. In mid-1976, Continental switched to heavier cases, which helped a bit but certainly provided no panacea. A couple of knowledgeable sources estimated that about two-thirds of the engines flying in 340s right now probably are cracked in one place or another.

But not all cracks are critical, and the same sources said theyve been seeing far fewer catastrophic engine failures caused by crankcase cracks. The reports also showed cracked cylinders and cylinder heads to be a rather frequent problem. Cracked and blown-out cockpit windows were the subject of several reports, as were cracked Bendix mag housings and distributor blocks, loose horizontal and vertical stabilizer attach bolts and cracked waste gate couplings.

Of course, any prepurchase inspection will include a check for compliance with all ADs, and there have been quite a few. One requires removal of certain oil filters, which were found prone to leak. Another AD (88-03-07) requires inspection of fuel crossfeed lines for chafing and modification of firewall stiffener flanges and fuel lines. AD 87-23-08 calls for ultrasonic inspection of the crankshafts, as does 97-26-17. 75-23-8 mandates repetitive inspections of the exhaust system. 96-20-7 calls for repetitive inspections of the Janitrol cabin heater. 96-12-22 requires repetitive inspections of the oil filter adapters. 95-24-5 deals with repetitive prop inspections. 90-2-13, a type-specific directive, called for replacement of the main landing gear inner barrel bearings.

One very important directive to check for is 82-26-05, which requires visual checks for cracks in the rudder balance weight rib every 100 hours until a new rib is installed. Such cracks have been the subject of numerous service difficulty reports.

Much the 340 fleet has had engine modifications performed by RAM Aircraft Corp. RAM, which enjoys an excellent reputation among owners of 300- and 400-series Cessnas, has offered a variety of mods under different names. There are several different mods, among which are the (now discontinued) Series II new Series IV, and Series VI packages, which feature a variety of improvements including new camshafts manufactured by Crane, brand-new steel cylinders, and Hartzell Q-tip props (Series II only), among other things. The packages include a seventh stud on crankcase cylinder pads, which reduces the stresses in these areas that often cause cracks.

Improved intercooling systems are available from American Aviation, and are highly recommended by owners. The installation includes ram-air inlet ducts below the engine nacelles and more efficient (American says 28 to 70 percent more efficient) heat exchanger cores. The company says its system cuts the temperature of air entering the engine from about 170 degrees to 80 degrees, improving rate of climb by up to 300 FPM and adding up to 15 knots in cruise.

A STOL mod for 340s is offered by Sierra Industries. It includes installation of Robertson-designed Fowler flaps and a trim spring that precludes the need to retrim the elevators when the flaps are raised or lowered. Sierra says the mod decreases accelerate-stop distances by 40 percent and improves short-field performance about 15 percent.

Precise Flight makes speed brakes for the C-340. Theyre of novel design, and project into the airstream from a snug enclosure at the aft end of the engine nacelles.

One of the most intriguing safety-enhancing mods for the C-340 are the aforementioned vortex generators, which for all intents and purposes eliminate Vmc and give great control at low airspeed. A bonus is a 300-pound boost in the gross weight. VGs are available from Micro Aerodynamics, V/G Systems and Robertson.

Owners organization
There is one club that offers extensive support for the 340, in addition to all other twin Cessnas. The Twin Cessna Flyer is headed by Larry A. Ball. (219) 749-2520. Also worth joining is the Cessna Pilots Association (www.cessna.org, (805) 922-2580).

Summing up
If its a light pressurized twin youre looking for, there arent that many choices. Besides the 340, there are the Aerostar 601P and 602P, and the Pressurized Baron. The Aerostars are the pilots airplanes of the group; theyre fast (about 20 knots faster) and demand no less than sharp, heads-up flying. However, payload capacity is even worse than the 340s, and though the cabin is the same size, the Cessna twins feels more roomy and comfortable. The Baron is slightly faster than the 340 and has a greater useful load; but it is a bit more expensive.

More than the Aerostar and even the Baron, the 340 exudes cabin class, thanks to its airstair door and tall stance. And it can outclimb the other airplanes. (If you really want a cabin-class twin, check out a 414. It isn’t that much more expensive, and the 414A has a much simpler fuel system.)

Owner Comments
I moved from an F33A Bonanza to the 340 last year. The Bonanzas quality was much higher. The inside of the 340 is trash. Plastic garbage, peeling and cracking. All of the Cessna interiors are like this.

Mine has STOL mods and VGs, with a weight increase. It can carry my family of three adults, plus one 45 lb. child, 186 gallons of fuel, and more baggage than will fit in my station wagon. Thats its good point-its much more comfortable than the F33A, at gross, for long trips. My wife loves it.

With the mods, it lands like a Bonanza, at 80 knots over the fence, without a flare, and let it settle on. However, no more grass strips. Its easy to fly once trimmed. Fuel burn is 36-44 GPH (!), but its pressurized, and you can really get up into the wind and go. I don’t go above 17,000. Approaches and crosswinds are no problem. Other than takeoff and landing, you basically monitor the systems, of which there are many.

Costs are high. When you land they park you with the big iron, and you pay for it, literally, coming and going. Maintenance is outrageous. Parts are a problem, even if you want to pay top dollar, and believe me you’ll pay that and more! Even Cessna doesnt have parts for its own planes. Of course, every maintenance procedure is a learning experience for the shop as we’ll as for me. The boots have to be inspected and repaired regularly, or you’ll blow your vacuum pumps. The rudder has to be inspected every hundred hours, and if you have the automatic aux fuel pump, get rid of it.

The ideal 340 is one with runout engines, so you know what youve got and can fix it your way. I didnt do this, and paid for it. Regarding the props, if youre not sure about them, get them inspected, not overhauled. Theyll be cleaned and resealed, and, unless real damage is found, theyre okay. If theyre close to service limits, an overhaul will make them scrap and cost big bucks.

With no multiengine time (1,200 TT, 950 retract) getting insurance was difficult. They required a simulator course (SimCom in Florida was great, and worth every penny), and 15 hours with an instructor. I ended up with low coverage for four times what the Bonanza cost. This second year, its gone down a little.

Money is the only requirement for this airplane (though it helps to have a large void in the common sense area of your brain). Once its in shape, if ever, and you can put the costs out of your mind, its a pleasure, but its certainly no Bonanza.

-Name withheld by request

Our company has owned a 78 340A for eight years. The airplanes size, speed, and range fit our companys travel needs very well. The total cost to fly the aircraft over the last 1,450 hours has been $191,745, or $132.24 per hour. This does not include a pilots salary or any financing costs. It also ignores the fact that our aircraft is now worth about $75,000 more than we paid for it. During this time weve had both engines majored, overhauled the props, installed a new interior and had the airplane painted. We also added the American Aviation intercooler kit and upgraded the avionics to King Silver Crown. All of these costs are included in the above figure.

Our 340 has the Robertson STOL kit which allow us to use short strips (2,700 ft.). The intercoolers resulted in a speed increase of 7 knots, but this is offset by the STOL kit, which cuts speed by five knots. Speeds at 75% range from 190 knots at 12,000 feet to 205 at 21,000. Flight planning 35 GPH works out about right for three-hour flights.

-Michael A. Wicklund
Doniphan, Mo.

I have a 1981 340A. It is highly modified with American intercoolers, spoilers, O&N wing locker fuel tanks (total fuel capacity 220 gallons), and VGs.

The most pilot-intensive system is fuel management, my airplane particularly so because of its seven tanks. The stock Cessna system returns unburned fuel to the tip tanks when on the aux wing tanks, making it somewhat difficult to use timing as a method of fuel management. Because of the nature of the fuel injection system more fuel is delivered to the pump than is needed by the engines, and therefore, its returned to the main tanks. The POH says not to use the aux tanks during descent. This is impractical because of the large number of tanks, which make it difficult to manage fuel in such a way that all the remaining fuel is in the mains. Ive found that descending on the aux tanks is not a problem as long as the descent angle is moderate and you switch to the mains before entering the pattern. The engines can only draw fuel from the mains and auxes, so the locker and nacelle tanks have transfer pumps to move fuel to the mains.

On a long trip, start the transfer as soon as you have half-tanks in the mains. The reason for this is that if one of the transfer pumps fails (they have for me), you can plan an alternate destination if you really needed the fuel in the lockers or nacelle. Also, its possible to cause fuel to vent overboard if the mains don’t have enough room in them before the transfer. Incidentally, Cessna in their infinite wisdom never put a gauge in the nacelle tank, so you need to monitor the main gauges to see if they are dropping faster than normal, which will indicate if the transfer is working.

-Richard Jaffe
Cheshire, Conn.

Im the President of The Twin Cessna Flyer, an owners organization with about 2,000 members of which about 250 own 340s. We specialize in support of all twin-engine Cessnas.

A lot of shoppers ask if the 340 would cost more for maintenance because of pressurization. The original 340 came with a Janitrol pressurization system. Parts for this system are extremely rare and hard to find. The 1975 and later models came with the Garrett Mini system and this became the standard on all of the 340, 414 and 421 models from then on. Cessna still supports this system. We find the pressurization to be a low maintenance item and operation is as simple as it gets. If you have pressurization problems, we find that this can almost always be corrected by repairing leaks in the pressure vessel. Leaky door seals, emergency exit seals and the small rubber covers on floor drains cause most leaks. Most other problems involve the outflow valves.

The biggest maintenance problem with the 340, as on almost all turbocharged aircraft, is the exhaust system. Weve seen several incidents where holes in the exhaust system adjacent to the right engine rail have led to extreme corrosion. Any 340 owner should expect to replace one major section of the exhaust once each year. Cessna has new parts in stock and Parts Exchange in Fort Mill, SC does a superior job of rebuilding (800-548-2665).

The landing gear on the 340 is the same as on all other twin Cessna aircraft using the electromechanical landing gear. This system, starting with the 310 and going through the 421B has gotten a fair share of press because it causes more incidents and accidents than any other system. We feel this is due to a lack of proper and timely maintenance rather than improper design. Any twin Cessna should have the landing gear completely rigged every 200 hours or annually, whichever comes first. Its cheap insurance.

Many are under the impression that the 340 will cost more to operate because it is cabin class, turbocharged and pressurized. If you replace the cabin door seals every 15 years, the 340 will cost no more than any other turbocharged model.

Even though a 140 gallon fuel system was standard, most if not all have 163. Add air conditioning in the right nacelle and a 20 gallon aux tank in the left and you have superior range and comfort.

The 520 series Continentals have had their share of problems, addressed through ADs and service bulletins. We are finding far fewer cylinder problems now compared to three or four years ago. We would suggest that replacement cylinders be factory new in either steel of Cerminil. We believe that more cylinder failures result from shock heating during takeoff than from shock cooling during descent. Use of proper procedures should avoid both.

Where the really shines is in initial purchase cost. There is nothing on the market to compare, unless you consider the P-Baron, and the 340 offers cabin class, equal useful load and a quieter ride for less money compared year-by-year. The true useful load will be full fuel, three adults and baggage. We suggest that all 340s have vortex generators installed. This gives you an extra 300 lb. for takeoff, and can eliminate Vmc.

Finally, we recommend that prospective purchasers contact Jerry Temple Aviation at (214) 416-3140 and get an information packet. It contains information not readily available elsewhere.

-Larry A. Ball
New Haven, Ind.

No aircraft of any type has gotten more benefit from vortex generators than the 340. For years Ive heard owners say they love their 340, but with 163 gallons of fuel on board its a 2.5 person airplane. With the 300-lb increase in gross weight given by the VGs, you can put four big men on board and still have payload left over. Hence, owners who might have traded up are keeping their 340s, and more buyers are looking for them. This is driving prices to all-time highs.

Speaking of VGs, Ive flown and purchased kits for most every type of Cessna twin. The VGs might look the same, but the products from Micro Aerodynamics are the best in my opinion. The kits come faster, the paperwork is more complete, and after-sale support is much better. I estimate that about half the fleet now has VGs installed. Practically every sale I make involves v/g installation, if the plane doesnt have them already.

Practically all of the early 285-HP 340s today have 310 HP engines. Ive never even seen a 285-HP model. There are also the usual RAM mods upping the horsepower to 326 or 335. Im a big fan of American Aviation Intercoolers. For about $10,000 you get a lot of value. Ive seen the 10-14 KTAS improvement they advertise. They also work to keep the cylinder temps down.

The only 340 that I avoid is the 1984 model. I believe 16 were made. In reality, most were begun in 1982 and just stored in various states until Cessna thought a few could be forced into distribution. These models cost a great deal more than the 1982 models they really were, and owners are into them for about $100,000 more than the identical 1982 model.

Most 340s come some with the 163 gallon fuel system. Some have the single 20-gallon left-side wing locker tank as well. Most have factory or JB air conditioning. The factory unit precludes a second wing locker tank. Today, factory a/c parts can be a problem. The JB system is expensive, and goes in the nose.

Most 340 buyers are stepping up from light twins or high-performance singles. Theyve come to realize that airplanes like this will probably not be built again. And if so, at what price? A new non-pressurized 58 Baron costs over $800,000. A low-time 340A is not bad by comparison at $250,000-$300,000. Theyre an excellent investment.

-Jerry Temple
Carrollton, Texas

For combination business and personal flying I cant find a more versatile or well-suited aircraft than the 340. I have over 800 hours in the past five years in a 1976 model. Its often more airplane than I need, but when I fill 4-6 seats the 340 really shines. don’t believe that you cant fill the seats and the tanks, as those 310 HP Continentals will lift more than I can carry in my station wagon.

Hourly costs, flying 160 hours per year, 65% power run $220 including tax, insurance, hangar, and reserves. The airplane has a reputation as maintenance intensive, but then any airplane with so many systems will require a lot of maintenance. All in all, it is a wonderful machine.

-Charles M. Lineberry
Charlotte, N.C.

Were on our second 340. We had the RAM Series IV conversion done a little over a year ago. Ive been very happy with that and picked up about 10 knots. Weve had a few warranty problems that were handled locally, and RAM always paid for it without any fuss. I recommend them highly.

We already had VGs on the plane, so the RAM conversion didnt give us any useful load. However, we did remove the air conditioner and picked up about 120 lbs. Avionics upgrades netted another 40. Current useful load with the sixth seat removed is 1,920 lbs. We leave the sixth seat out except for the rare occasion when we have six aboard.

One of the things about the airplane you want to be very careful about is icing. The tail seems to be very sensitive to icing and you don’t want to wait too long to cycle the boots. The rest of the deice equipment, as long as you have a heated windshield, does an excellent job. Our old 340 had an alcohol windshield. That did not work nearly as we’ll as the electric plates. Also in icing conditions you have to be careful not to try to climb at too great an angle of attack. I always maintain 130 to 140 knots climbing in icing.

-Gary Stenson
St. Paul, Minn.

Also With This Article
Click here to view the charts for Resale Values, Payload Compared and Prices Compared.
Click here to view the Cessna 340 features guide.